PUBLISHED BY THE AMERICAN WELDING SOCIETY TO ADVANCE THE SCIENCE, TECHNOLOGY, AND APPLICATION OF WELDING
AND ALLIED JOINING AND CUTTING PROCESSES WORLDWIDE, INCLUDING BRAZING, SOLDERING, AND THERMAL SPRAYING
3 WELDING JOURNAL
CONTENTS
28 Inverters Improve Control for AC Gas Tungsten Arc Welding Advances in switching devices, microchips, and tungsten technology are making the inverter the power source of choice
R. L. Bitzky and J. Garraux
32 A New Development in Aluminum Welding Wire: Alloy 4943 A new filler metal is designed to give a higher-strength alternative to 4043
T. Anderson
38 How to Improve GTAW Performance
Some pros offer advice on gas tungsten arc welding of thin steel, aluminum, and stainless steel
M. Franklin
44 Induction Heating for Stress Relieving Shortens Lead Times An oil and gas equipment manufacturer finds production help with induction heating
J. Ryan
48 Automated Welding Applied in Deep-Water Pipelines Pipeline laying in the South China Sea is aided by dual-carriage automated gas metal arc welding
J. Xiang-Dong et al.
Welding Journal (ISSN 0043-2296) is published monthly by the American Welding Society for $120.00 per year in the United States and posses-sions, $160 per year in foreign countries: $7.50 per single issue for domestic AWS members and $10.00 per single issue for nonmembers and $14.00 single issue for international. American Welding Society is located at 8669 Doral Blvd., Ste. 130, Doral, FL 33166; telephone (305) 443-9353. Periodicals postage paid in Miami, Fla., and addi-tional mailing offices. POSTMASTER: Send address changes to Welding Journal, 8669 Doral Blvd., Suite 130, Doral, FL 33166. Canada Post: Publi-cations Mail Agreement #40612608 Canada Re-turns to be sent to Bleuchip International, P.O. Box 25542,London, ON N6C 6B2
Readers of Welding Journal may make copies of articles for personal, archival, educational or research purposes, and which are not for sale or resale. Permission is granted to quote from arti-cles, provided customary acknowledgment of authors and sources is made. Starred (*) items excluded from copyright.
Departments
Editorial ...4
Press Time News ...6
News of the Industry ...8
International Update ...14
RWMA Q&A ...16
Book Review ...18
Stainless Q&A ...20
Product & Print Spotlight ...22
Coming Events...52 Certification Schedule ...56 Conferences ...58 Welding Workbook ...60 Society News ...63 Tech Topics ...65 Interpretation AWS 3.0 ...65
Guide to AWS Services ...83
Personnel ...84
Classifieds ...97
Advertiser Index...98
197-s Vacuum-Assisted Laser Welding of Zinc-Coated Steels in a Gap-Free Lap Joint Configuration
A stabilized keyhole allowed zinc vapors to escape in laser welding of zinc-coated steels
S. Yang et al.
205-s Active Droplet Oscillation Excited by Optimized Waveform
Active droplet oscillation is studied as a means of droplet detachment at peak currents lower than the transitional current J. Xiao et al.
218-s High-Temperature Corrosion Behavior of Alloy 600 and 622 Weld Claddings and Coextruded Coatings
Thermogravimetric and solid-state testing demonstrated better corrosion resistance with Alloy 622 under simulated gaseous conditions
J. N. DuPont et al.
Features
Welding Research Supplement
28
32
38
July 2013 • Volume 92 • Number 7
AWS Web site www.aws.org
On the cover: The preferred technique for adding filler metal during gas tung-sten arc welding is to touch the end of the filler rod to the leading edge of the molten pool. (Photo courtesy of Victor Technologies.)
EDITORIAL
How can we best effect change? I’ve given that question a lot of thought over the past couple of years as I have become more involved with the leadership of the American Welding Society. And while our tendency as business people in a competitive world is to go it alone, I’ve come to the conclusion that on many issues, Author Simon Mainwaring was right when he said, “Effectively, change is almost impossible without industry-wide collaboration, cooperation, and consensus.”
The current welding industry workforce development situation poses opportunities and challenges of unprecedented complexity. No single society, organization, person, agency, or government can single-handedly solve the issues at hand. These groups must work together to effectively and efficiently solve these tough problems.
The AWS Foundation is heavily invested in workforce development for the welding industry. Working with other organizations, with a collaborative spirit, has made a sig-nificant impact on these workforce development efforts.
Recently, the American Welding Society and the Manufacturing Institute of the National Association of Manufacturing (NAM) met at AWS World Headquarters in Doral, Fla., to not only establish workforce development objectives, but develop action plans both organizations could work toward jointly. This meeting confirmed and identi-fied the following:
• 82% of manufacturers report a moderate or serious shortage in skilled production workers.
• 75% of manufacturers say the skills shortage has negatively impacted their ability to expand.
• 600,000 jobs in manufacturing are unfilled today because employers can’t find work-ers with the right skills.
• More than 200,000 welding-related jobs will be left unfilled by 2019 because compa-nies won’t be able to find workers with the correct skill sets.
It’s obvious that to close the skills gap, we need to take action now. To that end, the Manufacturing Institute, in partnership with the AWS Foundation, has launched the NAM-endorsed Manufacturing Skills Certification System. This system of nationally portable, industry-recognized credentials validates both the “book” and the “street” smarts needed to be productive and successful on the job.
I won’t list specific projects being considered. After all, some ideas won’t pan out and will be dropped; other not-yet-imagined projects will prove highly successful. However, I will tell you that those who participated in the recent joint meeting in Doral identified nine objectives to support this certification system, and badge (welding process) creden-tialing, master welder certification, women in welding, and weld career data collection are some of the key areas the two organizations will be working on together.
This push by AWS and NAM to solve the workforce development issue is but one of many collaborative efforts in which AWS participates. Your Society is actively involved with trade unions, professional societies, educational institutions, and government agen-cies to advance the science, technology and application of welding, and allied joining and cutting processes. These efforts occur at the local, national, and international levels.
Collaboration isn’t easy. Cooperation takes a lot of hard work. It requires us to set aside our natural inclination to compete with others and instead find satisfaction in how our actions will benefit our industry. When done well, collaborative efforts can produce amazing results. We see that all the time at AWS. As you know, all of the AWS codes, standards, and specifications are consen-sus standards produced by disparate groups within the welding industry who set aside their differences to work together. We have a proven track record of suc-cess through collaboration.
◆
Officers
President Nancy C. ColeNCC Engineering
Vice PresidentDean R. Wilson Well-Dean Enterprises
Vice PresidentDavid J. Landon Vermeer Mfg. Co.
Vice President David L. McQuaid D. L. McQuaid and Associates, Inc.
Treasurer Robert G. Pali J. P. Nissen Co.
Executive DirectorRay W. Shook American Welding Society
Directors
T. Anderson (At Large), ITW Global Welding Tech. Center U. Aschemeier (Dist. 7), Miami Diver J. R. Bray (Dist. 18), Affiliated Machinery, Inc. R. E. Brenner (Dist. 10), CnD Industries, Inc. G. Fairbanks (Dist. 9), Fairbanks Inspection & Testing Services
T. A. Ferri (Dist. 1), Victor Technologies D. A. Flood (At Large), Tri Tool, Inc. S. A. Harris (Dist. 4), Altec Industries K. L. Johnson (Dist. 19), Vigor Shipyards J. Jones (Dist. 17), The Harris Products Group
W. A. Komlos (Dist. 20), ArcTech, LLC T. J. Lienert (At Large), Los Alamos National Laboratory
J. Livesay (Dist. 8), Tennessee Technology Center M. J. Lucas Jr. (At Large), Belcan Engineering D. E. Lynnes (Dist. 15), Lynnes Welding Training
C. Matricardi (Dist. 5), Welding Solutions, Inc. J. L. Mendoza (Past President), Lone Star Welding
S. P. Moran (At Large), Weir American Hydro K. A. Phy (Dist. 6), KA Phy Services, Inc.
W. A. Rice (Past President), OKI Bering R. L. Richwine (Dist. 14), Ivy Tech State College D. J. Roland (Dist. 12), Marinette Marine Corp. N. Saminich (Dist. 21), Desert Rose H.S. and Career Center
K. E. Shatell (Dist. 22), Pacific Gas & Electric Co. T. A. Siewert (At Large), NIST (ret.) H. W. Thompson (Dist. 2), Underwriters Laboratories, Inc.
R. P. Wilcox (Dist. 11), ACH Co. J. A. Willard (Dist. 13), Kankakee Community College M. R. Wiswesser (Dist. 3), Welder Training & Testing Institute
D. Wright (Dist. 16), Zephyr Products, Inc.
Founded in 1919 to Advance the Science, Technology and Application of Welding
Working Together to Build a
Better Tomorrow
Dean R. Wilson AWS Vice President
PRESS TIME
NEWS
Competition Launched for Three Manufacturing Institutes
The Obama Administration is launching competitions to create three new manufac-turing innovation institutes with a federal commitment of $200 million across these five agencies: Defense, Energy, Commerce, NASA, and the National Science Foundation.
The president’s manufacturing agenda starts with his vision for a National Network for Manufacturing Innovation. His fiscal year 2014 budget includes a $1 billion invest-ment at the Departinvest-ment of Commerce to create this network, a model based on ap-proaches that other countries have successfully deployed. Each would serve as a regional hub designed to bridge gaps between basic research and product development, bringing together companies, universities and community colleges, and federal agencies to invest in technology areas encouraging investment and production in the United States.
The Department of Defense will lead two of the new institutes on Digital Manufac-turing and Design Innovation and Lightweight and Modern Metals ManufacManufac-turing, while the Department of Energy will be leading one new institute on Next Generation Power Electronics Manufacturing. Winning teams will be selected and announced later this year. Federal funds will be matched by industry investment, support from state and local governments, and other sources.
Victor
®
Celebrates 100 Years, Launches Two Contests
Victor Technologies™, St. Louis, Μο., has announced the 100th an-niversary of its Victor®brand. The lineup consists of oxyfuel cutting and gas control equipment; Thermal Dy-namics®,encompassing manual and automated plasma cutting systems; TurboTorch®,including air-fuel prod-ucts for brazing and soldering; and Ar-cair®,representing manual and auto-mated gouging systems.
Company founder, L. W. Stettner, who lost an eye in a welding accident, set out to design and build safer cut-ting and welding products. Stettner’s designs resulted in numerous indus-try firsts. For example, Victor cutting and welding torches were assembled with screws, not soldered, to provide a stronger connection in the event of overheating.
Also, the company has launched two contests. A Cut Above is open to students in cutting, welding, and related programs at secondary and postsecondary schools, and will award more than $30,000 in equipment and cash prizes. Beginner students will write a 500-word essay supporting the contest theme, while advanced students will submit a team metal fabrication project incorporating an oxyfuel, airfuel, or plasma cutting process.
The Show Us Your Innovations 2014 calendar contest will award 12 Victor® Medal-ist 250 cutting outfits, and a Victor®Thermal Dynamics®Cutmaster®42 plasma cut-ting system as the grand prize, for the best photos and associated captions of the en-trant using any Victor or Victor Thermal Dynamics cutting equipment.
Both contests run through September, with winners announced at the Victor Tech-nologies booth at FABTECH 2013 in Chicago, Ill. Contests are open to individuals who are residents of the United States or Canada (excluding Quebec). Visit
www.victortechnologies.com/victor100.
Hobart Brothers Co. Consolidates Filler Metal Brands
Hobart Brothers Co., Troy, Ohio, has unveiled a new logo for its Hobart® brand of filler metals. The redesign decision coincides with consolidating the company’s five brands of filler metals — Hobart, McKay®, Tri-Mark®, Corex®, and Maxal® — under the single Hobart brand. The company’s brand of filler metals includes a product line of tubular wires (metal and flux cored), solid wires and covered electrodes for welding car-bon and low-alloy steels, stainless steels and aluminum, as well as hardfacing options.
◆
Publisher Andrew Cullison
Publisher EmeritusJeff Weber Editorial
Editorial DirectorAndrew Cullison
EditorMary Ruth Johnsen
Associate EditorHoward M. Woodward
Associate EditorKristin Campbell
Editorial Asst./Peer Review Coordinator Melissa Gomez
Design and Production Production Manager Zaida Chavez
Senior Production Coordinator Brenda Flores
Manager of International Periodicals and Electronic Media Carlos Guzman
Advertising
National Sales Director Rob Saltzstein
Advertising Sales Representative Lea Paneca
Advertising Sales Representative Sandra Jorgensen
Senior Advertising Production ManagerFrank Wilson
Subscriptions
Subscriptions Representative Tabetha Moore [email protected]
American Welding Society
8669 Doral Blvd., Ste. 130, Doral, FL 33166 (305) 443-9353 or (800) 443-9353
Publications, Expositions, Marketing Committee D. L. Doench, Chair
Hobart Brothers Co. S. Bartholomew, Vice Chair ESAB Welding & Cutting Prod.
J. D. Weber, Secretary American Welding Society
D. Brown, Weiler Brush T. Coco, Victor Technologies International
L. Davis, ORS Nasco D. DeCorte, RoMan Mfg. J. R. Franklin, Sellstrom Mfg. Co.
F. H. Kasnick, Praxair D. Levin, Airgas E. C. Lipphardt, Consultant
R. Madden, Hypertherm D. Marquard, IBEDA Superflash
J. F. Saenger Jr., Consultant S. Smith, Weld-Aid Products D. Wilson, Well-Dean Enterprises N. C. Cole, Ex Off., NCC Engineering J. N. DuPont, Ex Off., Lehigh University L. G. Kvidahl, Ex Off., Northrup Grumman Ship Systems
D. J. Landon, Ex Off., Vermeer Mfg. S. P. Moran, Ex Off., Weir American Hydro E. Norman, Ex Off., Southwest Area Career Center
R. G. Pali, Ex Off., J. P. Nissen Co. N. Scotchmer, Ex Off., Huys Industries R. W. Shook, Ex Off., American Welding Society
Copyright © 2013 by American Welding Society in both printed and elec-tronic formats. The Society is not responsible for any statement made or opinion expressed herein. Data and information developed by the authors of specific articles are for informational purposes only and are not in-tended for use without independent, substantiating investigation on the part of potential users.
Victor Technologies honors the 100th anniversary of its Victor brand by launching a contest for stu-dents and schools, plus a photo/caption challenge. As shown, a student and instructor train with oxy-fuel cutting using a Journeyman system.
To be the preferred supplier of welding
positioning equipment to Liebherr USA, you
have to do a lot of things right. And Koike
Aronson does.
The Virginia facility of Liebherr, one of
the world’s leading manufacturers of mining
equipment, has been buying welding
positioners from Koike for years. “Some of the
original machines are still in operation,” reports
Jim Farley, project manager. “And the service support
is terrific. When it comes to responsiveness we can
get directly to a person who can help.”
The guys on the floor are sold on Koike, too.
“I love the Head and Tailstock,” says Fabrication
Lead Man Charles Moler. “Koike worked with us
so it was designed to fit our needs and reduce
set-up time for each rotation.”
Koike Aronson, Inc./Ransome Arcade, NY USA 800-252-5232
www.koike.com
“
We’ve had such outstanding success
with Koike that we haven’t spoken to
anyone else.”
Left to Right:
Jim Farley
Project Manager
Charles Moler
Fabrication Lead Man
Jim Pfizenmayer
Fabrication Supervisor
Robert Egloff
Fabrication Manager
Koike Aronson Ransome Head and Tailstock positioning a Liebherr mining truck frame.
“
We’ve had such outstanding success
with Koike that we haven’t spoken to
anyone else.”
Jim Farley,Project ManagerScan here for more information.
Follow us on
NEWS OF THE
INDUSTRY
Hypertherm presented the Building America Conference May 7 and 8 at its new manufacturing facility in Lebanon, N.H. About 80 invited guests attended to hear numerous speakers and tour the property.
Evan Smith, president of Hypertherm, introduced “Built in America: Strategies for Success.” He asked what is driving dy-namics by showing a 2004 Business Week cover titled “The three scariest words in U.S. industry: ‘The China Price’” and a recent
TIME magazine cover featuring “Made in the USA.” In the U.S.
“manufacturing renaissance” part of his talk, Smith quoted The Boston Consulting Group: “By 2015...Manufacturing in China will be only 10 to 15% cheaper than in the U.S. — even before inventory and shipping costs are considered.” He stated a bright spot is manufacturing employment has grown faster in the U.S. since the recession than in any other developed economy. For success strategies, as a North American manufacturer, vital fac-tors are creating collaborative workforce development and build-ing strong supply/distribution infrastructures and partnerships.
Kevin Duggan, president of Duggan Associates, discussed “Design for Operational Excellence.” His questions focused on the best way to produce continuous improvement, and asked how do you know where to improve next, why do you strive to create flow and what causes its death, what would your shop floor/ office/supply chain look like if you applied every continuous im-provement tool, and where will your imim-provement journey take you. The steps Duggan listed to achieve operational excellence concerned designing a lean flow, implementing a lean flow and making it visual, creating standard work for the lean flow, mak-ing abnormal flow visual and creatmak-ing standard work for it, teach-ing employees to maintain and improve the flow to the customer, and free management to work on offense.
The guests toured the 160,000-sq-ft facility led by Leadership in Energy and Environmental Design principals.
The extra space is expected to facilitate creating up to 500 new jobs for New Hampshire. The plant includes a reliability lab to test products and manual system assembly lines to make plasma machines with parts close to associates. Ergonomic additions consist of height-adjustable benches. Other featured areas in-clude a piece-by-the-hour
board that monitors per-formance; a cutting tech-nology center offers demonstrations on small/ large machines and nest-ing software; trainnest-ing classrooms; and room for nozzle and electrode expansion.
“We’ve had rapid global growth and needed the space,” Smith said. Since the new location opened, he thinks it has been going remarkably well and added the biggest ongoing need there is to train CNC operators
through the company’s Technical Training Institute, plus printed circuit board assemblers and technicians. Future goals include making the facility a key place for listening to customers and making continued improvements for them.
Event sessions centered on strategic planning, branding, LEAN manufacturing, continuous improvement programs, cus-tomer experience management, motivating and engaging your team, a new measure of cutting efficiency, and the future of air plasma.
In addition, Sydney Finkelstein, Steven Roth professor of management and faculty director of the Tuck Executive Program at the Tuck School of Business at Dartmouth College, reviewed lessons on research he conducted during “Why Smart Executives Fail.” Four red flags in decision making include are your personal experiences misleading you, is your personal self interest cloud-ing your thinkcloud-ing, have you made a dangerous prejudgment that you are locked into, and are inappropriate attachments pushing you in the wrong direction. Finkelstein gave examples of relying on intuition, experience, and training; the surprise of how com-mon it is to act in a self-interested matter and not realize it; in-tellectual honesty with adaptability and open mindedness; and reinforcing values you care about. He listed executive mindset failures, organizational breakdowns, delusions of a dream com-pany, and leadership pathologies as reasons why smart execu-tives fail.
Hypertherm Founder and CEO Dick Couch concluded the event. He recalled the company’s start in 1968 with Bob Dean and tough early years facing hardships in obtaining funding, but said this was a good learning opportunity for designing equip-ment. “We’ve had this no layoff policy for 45 years,” Couch men-tioned as a milestone. Presently, more than 1300 associates de-liver products and services worldwide.
Videos from the conference can be found on the company’s YouTube channel.
— Kristin Campbell, associate editor
Hypertherm’s eco-friendly building in Lebanon, N.H., built long and narrow, leaves the property’s wetlands untouched.
Associates work inside the new location on manual system assembly lines making plasma machines for cutting and gouging metal.
Hypertherm Hosts Building America Conference
9 WELDING JOURNAL
One World Trade Center Receives Its
Stainless Steel Spire
On May 10, the spire for the One World Trade Center build-ing in New York City was permanently installed.
Kammetal – Kusack Architectural Metal Inc., Brooklyn, N.Y.,
an architectural/ornamental metal fabricator, fabricated the top 40 ft of the spire and pinnacle for the building. At 1776 ft, the height pays tribute to the year the United States declared its in-dependence and establishes the center as the tallest building in the Western Hemisphere.
The spire’s glass and stainless steel structure, featuring a ro-tating beacon to illuminate the Manhattan skyline at night, was laser cut on a TRUMPF TruLaser 1030 machine.
KUKA Systems Acquires Utica’s
Plant Engineering Business
KUKA Systems Group, Sterling Heights, Mich., has acquired the plant engineering business of privately owned Utica Compa-nies, Shelby Township, Mich. The purchase price was not dis-closed but is in the low double-digit million euro range. It will absorb Utica’s body structure business that builds car body as-sembly lines and subsystems as well as products like laser weld-ing heads, net forms, and pierce systems; standard press room automation for metal stamping; and hang-on technologies. About 300 Utica employees have joined the more than 1300-member KUKA Systems team in southeastern Michigan.
Hobart Institute Breaks Ground for
Additional Welding Training Area
Driven by demand for welding training and increasing enroll-ment, Hobart Institute of Welding Technology, Troy, Ohio, is ex-panding. The 6360-sq-ft structure will house between 50 and 60
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Kammetal fabricated the top 40 ft of the spire and pinnacle for the new One World Trade Center. The spire’s glass and stainless steel structure was laser cut on a TRUMPF 2D system. (Photo courtesy of DMC Erectors, Inc.)
arc welding booths equipped for all processes and an extensive fume-exhaust system. With a goal to match the original building architectural and aesthetic integrity, construction is set to begin soon. The first classes are expected to utilize the building in late fall 2013. The contract went to Ferguson Construction Co., Sidney, Ohio.
Wall Colmonoy Celebrates
75th Anniversary
Wall Colmonoy, Madison Heights, Mich., an American Weld-ing Society SupportWeld-ing Company Member, is celebratWeld-ing its 75th anniversary. Albert F. Wall founded the materials engineering company in 1938 in Detroit, Mich. Today, it is a global organiza-tion with offices and manufacturing facilities in the United States,
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A rendering by Ferguson Construction Co. shows the Hobart Insti-tute of Welding Technology’s new building addition in Troy, Ohio.
Wall Colmonoy has been owned and operated by the same family for 75 years. Shown is a step for the manufacturing of nickel- and cobalt-based alloys for powder and casting products.
United Kingdom, and France with close to 400 employees. De-veloping new products and technologies with customers, univer-sities, and local government is the driving innovation force. It has been owned and operated by the same family for 75 years.
Manitowoc Welders Improve Technical
Skills Using New Training Program
When Manitowoc’s Grove brand recently looked for a cost-effective way to teach, train, and evaluate welding skills of the
nearly 500 welders who build its cranes, the RealWeld Trainer™ provided an answer. Using patent-pending technology by EWI, it digitally records motions and objectively measures/scores criti-cal welding technique while performing real arc-on welds, plus allows practicing arc-off welds with feedback.
According to Jake Sensinger, manager of weld process engi-neering at Manitowoc’s Shady Grove factory, the system was in-corporated into operations in July 2012. Since then, two machines at the company’s Pennsylvania facility have provided customiza-tion advantages, material cost savings, and faster individualized training. “It’s going to have a tremendous impact on how we put our curriculum together going forward,” he added.
Cee Kay Executives ‘Slowly’ Create a
Snail Sculpture during Cleanup Event
Cee Kay Supply, St. Louis, Mo., sponsored the 11th annual Mission: Clean Stream and Stream Trash Art™ program with the General Motors (GM) Earth Day Festival on April 6 at GM’s plant in Wentzville, Mo. Approximately 1088 tons of trash have been removed from streams and rivers to date.
This is the fifth year in a row the company has participated. Each year, Regional Vice President of Sales Heath Wells and Western Regional Manager Dave Teson create a metal art sculp-ture from cleanup pieces. This time, they fabricated a snail from an old piece of cast iron, which was also converted into a flower pot. It took about 8 h to complete. Company CEO and Owner Tom Dunn also made chocolate ice cream with liquid nitrogen.
Additionally, the American Welding Society’s St. Louis Sec-tion held its 11th annual Mini Weld Show on March 28 at Cee
11 WELDING JOURNAL Paul Boulware, an EWI welding engineer, uses the RealWeld
Trainer™ to explain welding technique fundamentals to a trainee.
Kay’s headquarters. Representatives from more than 20 compa-nies provided hands-on demos and expertise. More than 250 stu-dents, instructors, and industry professionals attended.
Industry Notes
•
CertainTeed Corp.has selected Jonesburg, Mo., as the home for a new asphalt roofing shingle manufacturing/distribution facility and plans to invest $100 million there. It is anticipated an estimated 400 ancillary local jobs in welding, trucking, and maintenance services will support operations when completed.•
SGL Group – The Carbon Co.recognized an investment in its Ozark, Ark., facility to construct new graphitization for manu-facturing graphite electrodes, used in producing steel in elec-tric arc furnaces, with a volume of approximately $26 million.•
Koike Aronson, Inc./Ransome, Arcade, N.Y., is sponsoring “Steaming Toward a Cure for Diabetes” benefitting the Amer-ican Diabetes Association’s Step Out: Walk to Stop Diabetes® campaign of Western New York. The event is set for July 13.•
CRC-Evans Pipeline International, Inc., has opened its new pipeline supply store and warehouse in Tulsa, Okla. The 9000-sq-ft storefront houses a large inventory with standard pipeline construction items. Also, the warehouse carries accessories.•
Optrelis offering prizes at www.facebook.com/OptrelUSA. Welders who like its page and send their best welding photos will be eligible for a monthly drawing to win a new welding hel-met plus an iPod Touch through August. At the contest’s end, all entries will be redrawn for a grand prize of a free trip to Wattwil, Switzerland, where the company is headquartered.SERIOUS COOLING!
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Heath Wells and Dave Teson recently fabricated a snail from an old piece of cast iron, which was converted into a flower pot.
— continued on page 91
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INTERNATIONAL
UPDATE
Qualification Center to Support
Automotive Welding Certification
I-Car Canada, a training and recognition program, is establish-ing a national weldestablish-ing qualification center to serve as a hub for Canadian automotive welding certification. The center will operate in conjunction with a Canada-wide network of welding qualifica-tion instructors that is being established this year.
The new qualification center will be located at CARSTAR’s Vision Park in Hamilton, Ontario. It will serve an immediate audi-ence of repair facilities and insurance staff in the Greater Toronto/Southern Ontario region, but its impact will eventually extend coast to coast. CARSTAR Automotive Canada, Inc., NAPA Auto Parts, and 3M Canada are each contributing to the operation of the center.
Marc Brazeau, president and CEO of the Automotive Industries Association, which operates I-CAR Canada, noted the new center will meet a critical need in the industry. He said, “Most technicians learned how to weld in their apprenticeship program ten, twenty, or even thirty years ago. Given how much vehicle technology has changed in that time with the introduction of aluminum, high-strength steels, and new bonding technologies, it is imperative to offer opportunities for continued learning. Welding is one of the most important skills in the collision repair industry, and it must be done right.”
Sciaky Announces Strategic Partnership
Sciaky, Inc., a subsidiary of Phillips Service Industries and provider of additive manufacturing products, has entered into a business partnership with EVOBEAM GmbH of Mainz, Germany, to further expand its electron beam (EB) welding product portfolio.
Sciaky specializes in large vacuum chamber EB welding systems with internal moving guns. These systems utilize low voltage and high power useful for large-scale parts. EVOBEAM specializes in high throughput, small vacuum chamber EB welding systems with external guns. These systems utilize low voltage and low power use-ful for rapid production of small-scale parts. Under terms of the new agreement, Sciaky and EVOBEAM will market and sell each other’s EB welding technology.
New Dust Collection Facility to Serve the
UK and European Industrial Markets
Camfil Air Pollution Control (APC), a global manufacturer of dust and fume collection equipment, celebrated the grand opening of its new 40,000-sq-ft facility in the United Kingdom to serve industrial customers throughout the UK and Europe. Camfil APC worked closely with the Rochdale Development Agency to find the optimal site for the plant, which is located in the Birch Business
Park in Heywood, Great Manchester, UK. The facility has been operational since April, with a current staff of 40 employees. When fully staffed, it is expected to employ more than 100 people in engi-neering, manufacturing, and support positions.
Lee Morgan, company president, said, “Camfil APC has devel-oped into a global dust collection company over the past five years, with our biggest growth in the UK and European industrial mar-kets. This strategically located facility allows us to expand our man-ufacturing capacity and service our European customer base more effectively.”
The plant includes a four-bay welding area, fabrication capacity, powder paint line, assembly room, and storage space.
Center Promotes Development of
Pipeline Technologies
Subsea 7, a seabed-to-surface engineering, construction, and services contractor, has opened the new Global Pipeline Welding Development Center that will develop subsea pipeline technolo-gies for the oil and gas markets. It is the culmination of a $15.5 million investment by Subsea 7 in the company’s operations base in Clydebank, Scotland. The development was supported with a grant of $1.2 million from Scottish Enterprise.
The center has brought 30 new skilled jobs to the area, as Subsea 7 creates pipeline technologies to satisfy market needs associated with oil and gas discoveries increasingly made in deep-er watdeep-er and toughdeep-er conditions. The new centdeep-er comprises two main operational buildings — Pipeline Development Center 1, a welding inspection center, and Center 2, which houses the R&D and screened radiographic and ultrasound nondestructive exam-ination facilities.
The entire Subsea 7 facility in Clydebank employs 150 people, including more than 65 engineering and project management staff, and has more than 30 skilled welding technicians working on site. The technology developed in Scotland will be deployed by the subsea oil and gas industry across the globe, including the UK, Norway, United States, Brazil, and West Africa.
◆
Pictured is the inaugural session held at I-Car Canada’s nation-al welding qunation-alification center.
The new Heywood facility’s laser cutting unit.
The Global Pipeline Welding Development Center employs more than 30 skilled welding technicians on site.
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Q: We are considering changing our steel
source for several of the parts we produce; however, one of the new materials is not approved by the automotive original equipment manufacturer (OEM). What approval process are they talking about? The proposed replacement appears to be the same as our existing one.A
: The process of joining two materials together is something that never really crosses your mind when you purchase a motor vehicle. In fact, it is almost some-thing that is assumed since your driving of the final product is proof that it can be done. However, as with many things, a lit-tle digging reveals there can be much more to this process than meets the eye. In fact, the idea behind trying to determine how weldable a material is begins to make real good sense once you understand what it entails and its potential impact on the as-sembly of the final product. In actuality, the determination of a material’s weld-ability is really a subset of a much broader characterization process the automotive OEM employs to ensure the material in question is suitable for the intended ap-plication. In other words, material char-acterization is really a methodology used to classify or describe a material that is based on an objective analysis of measur-able characteristics.While this discussion focuses on weld-ability, with the engagement of the right personnel, it could just as easily be a con-versation about determining corrosion re-sistance, formability, or any of a dozen or more other manufacturing traits that need to be accounted for and addressed in order to successfully assemble the final product.
An analogy for the process of material characterization is that of a building in-spector. Building inspectors work behind the scenes and their existence never re-ally crosses your mind. But once you un-derstand they are looking at the structure before the drywall goes up to ensure that all of the other supporting elements of the building (electrical, plumbing, ventilation, etc.) are in place and functional, you begin to understand why their role is so impor-tant from the point of view of protecting the eventual final customer. The welding characterization process works in much the same way as it affords the automotive OEM an opportunity to verify if the ma-terial is truly capable of being processed
in its manufacturing environment, thus protecting you, their customer, and help-ing to ensure that they have made, and you are purchasing, a quality product.
Characterization Methodology
The predominate method utilized by all of the automotive OEMs for welding characterization is resistance spot weld-ing (RSW). For completeness, gas metal arc welding (GMAW) and laser beam welding (LBW) are now also being con-sidered or utilized for OEM characteriza-tion. Additionally, and as one would ex-pect, each OEM typically wants the weld-ability characterization performed in a manner that is consistent with its processes and standards. As a result, the weldability characterization process is often performed on specific types of equipment so as to replicate the unique manufacturing environment in which the material will be used. A partial list of these unique manufacturing elements could in-clude the following:
• Electrode Caps. The list of require-ments in this area alone can be quite ex-tensive and runs the gambit from taper types (male, female), taper standards (RWMA, ISO), body diameters, contact face geometry (RWMA A-nose, ISO-5821 Type-B, etc.), and last, but not least, the actual material (RWMA Class-1 or RWMA Class-2, in all their variations).
• Weld Control. The requirements in this area can cover the make of the con-trol (manufacturer), the type of current [alternating current vs. midfrequency di-rect current (AC vs. MFDC)], and/or the methodology of using the control (auto-matic voltage compensation or constant current). As an aside, our experience has
shown there can be some slight variation in weldability when utilizing different AC controls, but not so with the MFDC units. • Transformer. Once the weld control has been determined, the selection of the transformer is really driven by the weld-ing machine. However, care must be ex-ercised in the selection as the lack of weld-ability variation seen in MFDC weld con-trols can reappear by the selection of the wrong MFDC power supply. This is espe-cially true when performing aluminum characterizations.
• Electrode Cooling. Both the water temperature and flow rate may be speci-fied for a particular characterization. While both are critical elements to be monitored and controlled, our experience has shown the actual physical condition and arrangement of the cooling system (water tube placement, size, integrity, etc.) are far more important than the ac-tual temperature or flow rate.
An important point to keep in mind is that no one characterization evaluation can cover all possibilities. In fact, despite the performance of a thorough weldabil-ity characterization, it may be difficult to predict the necessary weld setup parame-ters for production operations. The rea-son for this is that each test is a singular condition among many possibilities and cannot account for the potential litany of material combinations, root opening or fitup concerns, general condition of the tooling, or other production variables. However, if the weldability characteriza-tion is conducted in a consistent manner, the process will allow for the determina-tion of significant material traits that, when compared to other similar materi-als, can reveal where deviation from the norm has occurred and permit the OEM
RWMA
Q&A
BY DONALD F. MAATZ JR.17 WELDING JOURNAL
to screen for potential issues. An excel-lent source for more detailed information about RSW material weldability charac-terization testing of sheet metal is AWS D8.9 (Ref. 1).
Characterization Elements
Once it has been determined how the material will be welded, the next step is to select the necessary characterization ele-ments that are to be evaluated. The de-sired elements to be evaluated may vary based on the material gauge, coating, and substrate strength. A partial list of these unique characterization elements could include the following:
• Weld Range/Lobe. A weld lobe is a means of graphically expressing the nu-merous combinations of weld current and weld time that produce satisfactory welds for a specific set of conditions (weld force, electrode cap configuration, metal stack-up, etc.) (see Fig. 1 and the March 2012 RWMA Q&A for more details on weld lobes).
• Fracture Mode. This is the appear-ance of the weld after a destructive sepa-ration or peel test. (See the May 2010 RWMA Q&A for more details on frac-ture modes.)
• Weld Strength. This may be deter-mined by either a quasi-static or dynamic test, with the latter being either a fatigue or impact test. The mechanical samples constructed for these evaluations typically test the weld in two directions, either full shear (0 deg) or normal to the weld (90 deg).
• Hold Time Sensitivity. This charac-terization element is related to a change in the weld’s cooling rate and is really a man-made phenomenon related to pro-cessing. The changeover from multifix-ture, cascade-fire gun stations to almost complete robot welding has reduced the likelihood for this to occur. Consequently, some OEM tests no longer evaluate hold time sensitivity performance.
• Electrode Endurance. This element really focuses on the coating of the mate-rial and its wear effect on the electrode. As weld processing has changed, so has this evaluation. Almost entirely gone are the days of open-ended characterization tests that might go for 10,000 (or more) welds, replaced instead by more manage-able, but still meaningful, sprints of just 500–1000 welds.
• Current Sensitivity. The advent of MFDC has brought to the fore the fact that some materials weld better with one current type than the other. While the vast majority of materials do not exhibit a pref-erence, this is still an important evalua-tion element as the selecevalua-tion of current type is one area where the large OEMs and the smaller Tier 2 and 3 suppliers are
most likely to approach welding from di-vergent points of view.
An important point to consider is that the descriptions of the above-mentioned elements do not contain one word regard-ing acceptability criteria. This was done on purpose as each OEM evaluates the ma-terial’s performance of each element against its particular needs, and it would be impossible to try and provide more than the most generic of guidance in this area.
Final Thoughts
It is hoped these descriptions have served to illustrate the challenges facing both the steel and automotive OEM or-ganizations as they strive to produce a quality product in a very competitive en-vironment. At the least it should help il-lustrate there is a great deal that does occur behind the scenes as a product moves from concept to design and that one of the biggest challenges is the selec-tion of the right material for the applica-tion. Just as consumers have a choice with regard as to what they consider important in a vehicle (passenger and/or cargo room vs. performance), the product designer must decide which of the above elements has more credence for their application.
◆
Acknowledgment
The author would like to thank Eric Pakalnins for his invaluable perspective on resistance weldability material charac-terization.
References
1. AWS D8.9:2012, Test Methods for
Evaluating the Resistance Spot Welding Be-havior of Automotive Sheet Steel Materials.
Doral, Fla.: American Welding Society.
DONALD F. MAATZ JR. is a laboratory manager, RoMan Engineering Services. He is past chair of the AWS Detroit Section, serves on the D8.9 and D8D Automotive Welding committees, is vice chairman of the Certified Resistance Welding Techni-cian working group, and is an advisor to the C1 Resistance Welding Committee. He is a graduate of The Ohio State University with a BS in Welding Engineering. This ar-ticle would not have been possible were it not for the assistance from members of the RoMan team. Send your comments/ques-tions to Don at [email protected], or to Don Maatz, c/o Welding Journal, 8669 Doral Blvd., Ste. 130, Doral, FL 33166.
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BY ALEXANDER E. SHAPIRO
Brazing Book Opens
New Technology Horizons,
Gives Practical Information
Advances in brazing: Science, technology and applications, edited by Dušan P.
Sekulić, published in March 2013 by Wood-head Publishing Ltd. (www.woodWood-headpub-
(www.woodheadpub-lishing.com), Cambridge, UK. ISBN-13:
978 0 85709 423 0. 628 pages. Price $305. Advances in brazing: Science, technol-ogy and applications presents three
origi-nal chapters on the fundamentals of braz-ing and sixteen chapters that consist both of new studies done by their respective au-thors as well as state-of-the-art overviews featuring brazing processes used in today’s industry.
What Else Does the
Publication Offer?
This book covers the basics and specifics of brazing technologies related to joining traditional structural materials such as aluminum alloys, nickel superal-loys, oxide ceramics, cemented carbides, diamonds, cubic boron nitride, and new materials that offer challenges to engi-neers such as titanium and nickel inter-metallic alloys, ceramic composites, car-bon-carbon composites, brazing coatings, special glasses, and glass-ceramics.
All chapters present an analysis of con-venient industrial processes and new, ef-fective approaches to join similar and dis-similar combinations of base materials. A broad range of applications regarding
modern brazing technology is described. This is illustrated by examples from auto-motive and cutting tool industries to ap-plications in aerospace, nuclear power, and fuel cells.
In addition, all chapters include sub-stantial numbers of reference of data re-garding wetting, microstructure, strength, and corrosion properties of brazed joints, which means that this volume can easily be used as a reference book appropriate both in academic research laboratories and everyday engineering practices.
Improving Brazing in
Practical Applications
Publication of this book is apparently an important event in the present brazing engineering community, as well as in the welding industry, because many new non-weldable but brazeable structural materi-als appear in the industrial market every year. Most of these materials are required to be joined by brazing.
The authors represent different coun-tries and universities but all of them demonstrate one approach to writing: They apply fundamental knowledge to ex-plain methods of improving brazing in practical applications. The effectiveness of this approach to conveying knowledge is important, especially today, precisely because so many new materials that are challenging to join have entered the in-dustry. If this approach becomes accepted convention, it can be a strong impulse to improving depth of knowledge in brazing, not only as a technology, but as a science.
The Value Theoretical Conceptions Bring
In the last several years, numerous journal publications have analyzed gen-eral practical case studies (procedures of brazing individual materials and proper-ties of their brazed joints), but discussion of new theoretical conceptions is rare. The first three chapters of this book fill in this gap. They overview the following: funda-mental questions of wetting and reactiv-ity at the interface of base materials (chap-ter 1), cri(chap-teria of strength and reliability of brazed structures (chapter 2), and sys-tematic modeling of general procedures in the field of brazing on macro- and micro-scale levels (chapter 3).
The importance of these theoretical conceptions cannot be overestimated. They shall certainly enter into future text-books and university courses on brazing. At the same time, theoretical methods dis-cussed in the first three chapters may
al-ready be used in the field while construct-ing new systems, assessconstruct-ing their reliabil-ity, and testing the appropriateness or suitability of new base materials and filler metals.
Additional Chapter Breakdowns, Including New Approaches to Brazing Superhard Tooling Materials and Processes for Joining Aluminum Alloys
Brazing nickel-based superalloys and stainless steels is discussed in three chap-ters. Chapter 4 demonstrates successful application of boron-free Ni-Cr-Zr filler metals, while chapter 5 is focused on the application of amorphous foils in tradi-tional Ni-Cr-Si-B systems and metallurgi-cal paths in joint formation. Also, two chapters are designated to joining new prospective intermetallic alloys — tita-nium and nickel aluminides.
The authors of chapter 4 introduce new creep-resistant braze alloys of the Ti-Zr-Cr, Ti-Zr-Fe, Ti-Hf-Fe, and Ti-Zr-Mn sys-tems, while chapter 8 discusses the prop-erty effects of base materials on the braz-ing procedure and microstructure of brazed joints made with traditional filler metals such as BAg-8, Ticuni®, Cusil-ABA®, BNi-2, and others. Specifics for applying nickel-based filler metals in man-ufacturing steel pipes and brass or bronze components contacting drinking water are described in chapter 18.
Chapter 6 describes industrial processes and new approaches to brazing superhard tooling materials — diamond and cubic boron nitride. The physics of formation of carbide film on diamond is an essential aspect of the corresponding brazing process, and it is discussed in de-tail. The technology of brazing cemented carbides and superhard materials for cut-ting tool applications is also considered in chapter 14. Both chapters are sup-ported by the analysis of wetting and met-allurgical interactions of filler metals with tool materials.
Several chapters are designated to dif-ferent aspects of joining ceramics and high-temperature composite materials; these summarize practical experience and scientific knowledge accumulated in the world to date. At the same time, all au-thors include results of their original in-vestigations that make these publications especially interesting, because a general review is illustrated by case studies.
Chapters 7, 12, and 16 discuss design, metallization, microstructure, and prop-erties of brazed ceramics both in ceramic-to-ceramic and ceramic-to-metal joints for the needs of the electronic and aerospace
BOOK
19 WELDING JOURNAL
industries. Chapters 11 and 13 are focused on brazing approaches and joint proper-ties of high-temperature ceramic matrix composites, including carbon-carbon composites applied now in aerospace and nuclear industries. Despite sometimes similar base materials mentioned there, a reader will not find any overlapping sci-entific and technical information in these chapters; this reflects an original research and engineering vision by the authors on obtained results.
The original technology and applica-tion of brazed hard coatings by infiltra-tion in cemented carbide particles with silver- and copper-based filler metal is discussed in chapter 15. Applications of glass and glass-ceramic sealants for solid oxide fuel cells and joining SiC-based ce-ramics described in chapter 17 is open-ing a new prospective in manufacturopen-ing energy sources.
Three chapters are designated to new materials and processes of joining alu-minum alloys widely used in the world. Chapter 9 covers the popular topic of brazing aluminum to steel, as well as sol-dering aluminum. Both subjects are com-bined together due to a similar approach of application with reactive fluxes. The chemistry of fluxes is discussed in details that are unique in brazing publications. High-productive technology in controlled atmosphere brazing (CAB) of aluminum is described in chapter 10 featuring the focus of interaction oxides with a flux and furnace atmosphere. This chapter can be used in the next edition of the Brazing
Handbook as is. Finally, the original
tech-nology of fluxless brazing aluminum al-loys and features of this promising process are discussed in chapter 19.
Conclusion
For those just starting to work in the brazing industry, this book is a great pri-mary source of scientific and practical in-formation regarding important proce-dures and tendencies in our technology. A great team of scientists and engineers is collected under the cover of this book.
It’s no doubt this publication shall be-come “a work-table reference book” for many professionals of the brazing indus-try because it is not only a source of use-ful technical information but also opens new horizons in our technology.
◆
ALEXANDER E. SHAPIRO (ashapiro@
titanium-brazing.com) is brazing products
manager at Titanium Brazing, Inc., Colum-bus, Ohio. He is a member of the C3 Com-mittee on Brazing and Soldering, has con-tributed to the 5th edition of the AWS Brazing
Handbook, and the Brazing Q & A column.
STAINLESS
Q&A
BY DAMIAN J. KOTECKIQ:
We did weld cladding (two layers) with E309LT0-4 flux-cored electrodes on a low-alloy steel pressure vessel, then stress relieved it for 8 h at 1150°F. When we removed the vessel from the furnace and allowed it to cool, we found that the weld had separated from the base metal over a large area. It appeared that the weld metal had not adhered to the base metal. When we examined the separated weld, we found that the underside of the cladding was only slightly attracted to a magnet, while the surface of the vessel un-derneath was strongly attracted to a mag-net, which makes us wonder if the weld cladding actually fused to the base metal in the first place. What happened, and what can we do about it?A:
This phenomenon is known as dis-bonding. While its history indicates that it is most common with strip cladding, weld cladding by use of weave beads with other welding processes have also been known to be affected by disbonding. Disbonding is most common when the weld is made with a method that produces wide, flat de-posits with low dilution.Nelson et al. (Refs. 1–3) have studied disbonding to a considerable extent. The mechanism seems not to be entirely clear, but carbide precipitation, impurity segre-gation, a long continuous grain boundary perpendicular to the principal stress, a considerable difference in thermal expan-sion coefficient between the low-alloy steel and the weld cladding, and hydro-gen-induced cracking may all be involved in the disbonding. The characteristic of disbonding is cracking in the fusion zone very close to the fusion boundary along a particular grain boundary termed a “Type II boundary.” Figure 1, taken from Ref. 3, shows the special nature of the Type II boundary that extends parallel to the fu-sion boundary, only a few microns from the fusion boundary, and several grain di-ameters in length.
Figure 2, taken from Ref. 3, shows the disbonded cladding side of the fracture. The crack path is exactly along the Type II boundary. When this cracking occurs along the Type II boundary, only a very thin layer of the weld (perhaps 10 microns or so in thickness) remains attached to the base metal, and no base metal remains at-tached to the cladding. This accounts for your observation that the weld metal side shows very little attraction to a magnet
(only the ferrite in the weld metal is romagnetic, and there is much more fer-rite in the second layer than in the first layer), while the base metal side is strongly attracted to a magnet.
There are several approaches you can use to reduce the tendency for disbond-ing. Since diffusible hydrogen is often in-volved, it is helpful to reduce available diffusible hydrogen. The flux-cored
stain-Fig. 1 — Type 309 cladding over ASTM A508 low-alloy steel. Note that the Type II grain boundary extends continuously along the fusion boundary a few microns into the weld deposit from the fusion boundary.
less steel electrodes of E309LT0-4 type are not always manufactured to low-hy-drogen practice, and exposure to humid air can cause even a low-hydrogen elec-trode to absorb enough moisture to result in a problem. It is not possible to consis-tently measure diffusible hydrogen with austenitic filler metals like 309L because hydrogen does not diffuse appreciably in austenite. However, the transition from the ferritic base metal to the austenitic weld metal will invariably include a martensitic layer adjacent to the fusion boundary, which sometimes extends from the base metal to the Type II boundary. In this zone, hydrogen is mobile enough to cause cracking. The zone between the Type II boundary and the fusion bound-ary consists in part of melted filler metal, and if this filler metal contains enough hydrogen, the potential for cracking is there. So, it is important to maintain low-hydrogen conditions for the filler metal. This includes sourcing filler metal that was baked at the end of manufacture and protecting that filler metal from exposure to moist air. I would also note that the E309LT0-4 electrodes are intended to operate in 75% argon – 25% CO2 shield-ing which tends to produce higher dif-fusible hydrogen than 100% CO2 shield-ing. You might consider switching to CO2 shielding to reduce diffusible hydrogen.
A second approach to the prevention of disbonding is to manipulate the weld-ing procedure to avoid a nearly planar in-terface between weld metal and base metal. A nearly planar interface occurs when the individual weld runs are wide and shallow, as tends to occur in strip cladding and in weld cladding with a weave pattern. It is better to accept a lit-tle higher dilution, with flux-cored arc welding using your E390LT1-4 electrodes or other welding methods by depositing the weld metal in stringer beads instead of weave beads because the stringer beads produce a scalloped fusion bound-ary rather than a planar fusion boundbound-ary, and the scalloped fusion boundary is more resistant to disbonding. Only the first layer of weld cladding needs to be deposited by stringer beads. A second and any subsequent layers can be de-posited with any welding pattern because the geometry of the fusion boundary with the base metal is already established be-fore subsequent layers are deposited.
A third approach is to replace stain-less steel filler metal with nickel-based alloy filler metal. This is a more expensive approach due to the cost of the nickel-based alloys as compared to that of stain-less steel filler metal. Once a layer of
nickel-based alloy, such as NiCr-3 type filler metal has been deposited, it is nec-essary to continue the cladding with the nickel-based alloy because transitions of nickel-based alloy to stainless steel are quite susceptible to solidification crack-ing. The main functions of the nickel-based alloy are to reduce the thickness of any martensitic layer in the transition zone as compared to the thickness of the martensitic layer in the transition zone when stainless steel is deposited, and to reduce the mismatch in coefficient of thermal expansion between the ferritic steel base metal and the weld metal. This latter in turn reduces the stresses at the Type II boundary. If you choose this ap-proach, it is still important to treat the filler metal with good low-hydrogen practice.
None of these approaches will guar-antee freedom from disbonding, but chances are that you can be successful because many other fabricators have been.
◆
References
1. Nelson, T. W., Lippold, J. C., and Mills, M. J. 1999. Nature and evolution of
the fusion boundary in ferritic-austenitic dissimilar metal welds — Part 1: Nucle-ation and growth. Welding Journal 78(10): 329-s to 337-s.
2. Rowe, M. D., Nelson, T. W., and Lippold, J. C. 1999. Hydrogen-induced cracking along the fusion boundary of dissimilar metal welds. Welding Journal 78(2): 31-s to 37-s.
3. Nelson, T. W., Lippold, J. C., and Mills, M. J. 2000. Nature and evolution of the fusion boundary in ferritic-austenitic dissimilar metal welds — Part 2: On-cool-ing transformations. WeldOn-cool-ing Journal 79(10): 267-s to 277-s.
21 WELDING JOURNAL DAMIAN J. KOTECKI is president, Damian Kotecki Welding Consultants, Inc. He is treasurer of the IIW and a member of the A5D Subcommittee on Stainless Steel Filler Metals, D1K Subcommittee on Stain-less Steel Structural Welding; and WRC Subcommittee on Welding Stainless Steels and Nickel-Base Alloys. He is a past chair of the A5 Committee on Filler Metals and Al-lied Materials, and served as AWS president (2005–2006). Send questions to damian@
damiankotecki.com, or Damian Kotecki,
c/o Welding Journal Dept., 8669 Doral Blvd., Ste. 130, Doral, FL 33166.
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