arc lengths of electrode and the feeding of the wire are automatically controlled. The welding operator’s job is reduced to positioning the gun at a correct angle and moving it along the seam at a controlled travel speed. Hence less operator skill is required with this process as compare to TIG and manual metalarc process. Yet basic training is required in the setting up of the equipment and manipulation of the gun must be provided to the operator to ensure quality GMAW welding (Jang et al. 2005, Praveen and Yarlagadda, 2005).
 S. H. Zoalfakar, A. A. Hassan “Analysis and Optimization Of Shielded MetalArc Welding Parameters On Mechanical Properties Of Carbon Steel Joints By Taguchi Method” International Journal Of Advanced Engineering And Global Technology I Vol-05, Issue-01, January 2017,Pp.1431-1444  Gautam Kocher, Om Parkash, Sachit Vardhan“ Hardfacing By Welding To Increase Wear Resistance Properties Of EN31by MR 3LH Electrode International Journal Of Emerging Technology And Advanced Engineering, Volume 2, Issue 2, February 2012, Pp. 102-105
ABSTRACT: Hard facing is one of the most useful and economic way to improve the properties and then performance of a component that depends upon the selected alloys for welding process. Many Industries face the problem of wear on components in service. Due to wear the components need replacement, which may costs money and causes downtime of the equipment. To overcome this problem hardsurfacing is carried out. In this work, the hard facing alloys were deposited on mild steel (Base material) by a shielded metalarc welding (SMAW) method. Two different composition of Fe-Co-Ni Hard facing alloy were employed to investigate the effect of the microstructure. The experiment is conducting by varying welding parameters like voltage, travel speed and current. Specimens of size 265×125×12mm were used for depositing the hardfacing layers.Microstructure characterization analysis were made using Metalargical Microscope, Microhardness test is made using Hardness testing machine.
elements, is one of the most extensively used alloys because it has desirable properties such as weldability, machinability and corrosion resistance. Major applications of this alloy include its use in aircraft and aerospace components and in the transportation industry [2; 3]. The corrosion resistance of aluminum alloy welds is determined in part by the type of alloy, the filler alloy and the welding process. For aluminum alloys, gas metalarc welding (GMAW) and gas tungsten arc welding (GTAW) are frequently used in welding processes [4-8]. The friction stir welding (FSW) process developed in 1991 by The Welding Institute has also been employed successfully. The advantages of FSW over arc welding processes include improved mechanical properties and reduced microstructural change[9-11]. Few studies have been published on the corrosion and welding of aluminum alloy 6061 [12-15]. According to Nikseresht et al., Fe-rich coarse intermetallic particles act as a cathodic region during the corrosion of 6061 alloy weldment in 3.5 wt. % NaCl. In addition, the weld metal (Ecorr=-704 mV vs. SCE) had better corrosion resistance than the base metal (Ecorr=-728 mV vs. SCE). In another study, Fahimpour et al. demonstrated that 6061 joined by FSW had higher corrosion resistance than GTAW in seawater solution. However, they reported that both welded regions were susceptible to corrosion attack . Paglia and Buchheit found that aluminum alloy 6061 welded by FSW was susceptible to localized corrosion correlated with precipitate-free zones and coarse precipitates, such as Mg (Zn 2 , AlCu). As noted, the localized corrosion began with pitting and propagated as intergranular
Welding is a metal joining process widely used in many manufacturing facilities around the world. It involves the process of heating the base and filler metals to a high temperature that leads to the formation of fumes. Welding emissions consist of gaseous pollutants and micron and sub-micron particles consisting of different heavy metals. Health risks associated with exposures to weld fume is well recognized in the literature. This research evaluates emissions and emission factors applicable to gas metalarc welding (GMAW) on AH 36 (mild steel) and 316 L (stainless steel). Emission factors evaluated consisted, total fume, chromium, cobalt, lead, manganese, and nickel. A weld fume chamber is used to capture the welding fumes onto a filter and then further analyzed to quantify the total fume and heavy metal emissions. Critical operating parameters such as current, voltage, shielding gas, welding speed, and contact tube to work distance (CTWD) are considered while evaluating emissions and emission factors. The parameters with greater influence on emissions are selected, and then the heavy metal emissions are quantified by varying those parameters using inductively coupled plasma atomic emission spectrometry (ICP-AES) and portable XRF (X-Ray Fluorescence) analyzer. The heavy metal results from the ICP-AES and XRF are compared to explore the feasibility of using XRF analyzer in quantifying the heavy metals in welding fumes. Using the heavy metal emissions, the lifetime carcinogenic and non- carcinogenic risks are evaluated for the GMAW process. The mild steel (MS) and stainless steel (SS) statistical analysis results indicate current and voltage are most influencing parameters in generating the fumes in GMAW. This research found a significant linear relationship between ICP-AES and XRF heavy metal results. The lifetime carcinogenic and non-carcinogenic risks results indicate high potential health risks if not properly managed.
These electrodes contain over 30 per cent organic material coverings such as alpha flock, wood flour or others cellulose. These electrodes develop a strong plasma jet which gives excellent penetration. These are all position electrode used with only direct current polarity (Radhakrishnan, 2007). Because of the organic material and moisture content, these electrodes have a very strong arc force but at the same time the weld metal freezes very quickly. This method of welding is fast and economical for pipelines which welded with the progression vertically downward. Impact toughness properties which are very good may be met with modern cellulosic electrodes (Lincoln Electric, 1999). Cellulosic coated shielded metalarc welding electrodes E6011, E6010 are traditionally used for deposition of pipeline girth weld and are capable of high deposition rates of welding (Ramirez and Johnson, 2010). E6010 Electrodes
This investigation is to analyze “effect by using oxygen content chemical on mechanical i.e. Penetration & hardness Properties of material. Using the gas metalarc welding process”. Effect of welding current, voltage and gas flow rate weld material having 8mm thickness of material (IS2062). During this two different types of chemical powder is used Tio2 and Sio2. After the welding sample are subjected to the testing such as penetration test and the hardness test. The oxidized chemical Tio2 and Sio2 are effective for gas metalarc welding. Depth Vs. width ratio is highest claimed under oxidized chemical Tio2 and Sio2 as we compare it with normal gas metalarc welding.
2) Finding The Limit Of Process Variables: Balance among the input parameters in gas metalarc welding (GMAW) characterizes the metal transfer modes, microstructure and influences the geometry and mechanical properties of welded joints. The appropriate selection of microstructure is an important factor to futher improve the weldability, strength and toughness behaviour, the time involved in the production is more and also the processing steps are linearly increased. Costly and time consuming experiments are required in order to determine the optimal welding process parameters due to complex nature of the welding process. Problems that do not have algorithmic solutions or algorithmic solutions are too complex to be found.
Ideally, the work should be positioned during welding so that the molten weld metal is held in placed by gravity. It also enables high currents to be used, leading to faster welding. This implies that the work can be turned or manoeuvred . Many fabrications do not lend themselves to this treatment, and much of the welding in industry is done ‘in position’. The welder controls the weld by lowering the heat input to reduce the fluidity and to give a small pool which solidifies before it has time to run out of the joint. At the same time, the direction of the arc, i.e. the angle between the electrode and the weld surface, can be varied to position the weld pool to the best advantage.
As the thermal expansion coefficient changes in a material, its expansion-contraction due to various temperatures is understandably affected. Due to the rapid, non- equilibrium heating/melting of the weld metal, coupled with the constraint imposed by the surrounding plate, the filler material does not have sufficient time to expand. Upon cooling of the weld metal, heat is conducted to the adjacent plate, resulting in contraction of the weld metal and expansion of the surrounding material. Once thermal equilibrium between the weld metal and the adjacent plate occurs, further cooling will take place by convection and approximately uniform contraction will occur. Thus the majority of distortion is introduced to the structure during the cooling phase. This is evident within the welding process where this expansion-contraction effect is highly significant as it has a direct impact upon the residual stresses present within the structure following cooling. It was found that at higher shielding gas flow rates, the thermal expansion coefficients were higher throughout the temperature range. This will therefore lead to a greater volumetric expansion contraction within the weld metal, which will in turn lead to greater residual stress within the structure.
When the drop finally detaches under gravitational force, it falls to the workpiece, leaving an uneven surface and often causing spattering. As a result of the large molten droplet, the process is generally limited to flat and horizontal welding positions. In vertical position, large molten droplet is deflected by gravity. The most widely used shielding gas for globular transfer is carbon dioxide since it is low in cost and allows globular transfer to take place at all usable welding currents . Globular transfer uses higher voltages (25-35 volts) and high amperages (50-170 amps) depending on electrode size. One popular use of globular transfer is a mild steel electrode wire and carbon dioxide shielding gas. Some welders may refer to welding wholly with carbon dioxide or mixed with 75 % argon as being spray transfer, but technically at about 22 volts and higher, it is always a globular transfer. Also, production applications often find success using this mixture of shielding gases at amperages and voltages above short circuit transfer, but below spray arc transfer. An example is fillet welds on 1 / 4 ” mild steel, flat position
The electrodes for flux-cored arc welding consist of a metal shield surrounding a core of fluxing and/or alloying compounds as shown in figure .The cores of carbon steel and low alloy electrodes contain primarily fluxing compounds. Some of the low alloy steel electrode cores contain high amounts of alloying compounds with a low flux content. Most low alloy steel electrodes require gas shielding. The sheath comprises approximately 75 to 90 present of the weight of the electrode. Self-shielded electrodes contain more fluxing compounds than gas shielded electrodes. The compounds contained in the electrode perform basically the same functions as the coating of a covered electrode used in shielded metalarc welding.
power source characteristic is essentially drooping type, which means that power sources designed for and used in manual metalarc welding A (MMAW) can be directly used for TIG welding. For better arc stability and a smooth arc, the OCV of the power source should be between 70 and 80 V (RMS). Argon is monatomic gas (i.e. its molecule consists of one atom instead of two atoms in the case of common gases like oxygen, nitrogen, chlorine, etc.) it is extracted from the atmosphere by liquefaction of air and refined to 99.9% purity. It is supplied as compressed gas in cylinders.
Today's aluminium alloys together with their various tempers, comprise a wide welding procedure development, It is important to understand the differences between the many alloys available and their various performances and weld ability characteristics. When developing arc weld procedures for these alloys, consideration alloy are usually the Gas Tungsten Arc Welding (GTAW) process and the Gas MetalArc Welding (GMAW) process, due to their comparatively easier applicability and better economy. The weld Fusion Zone (FZ) typically exhibits coarse columnar grains because of the prevailing thermal conditions during the weld metal solidification must be given to the specific alloy being welded. It is often said that arc welding of aluminium is not difficult, it is just different It is believed that an important part of understanding in differences is to become familiar with the various alloys, this series incorporates alloys which are considered unsuitable for arc welding. The preferred welding processes for fabricating the AA7075
The present work deals with optimization of welding process variables by using Metal inert gas welding.The aim of my work is to study the hardness that affect the welding joint of dissimilar metals. Stainless Steel 304 was welded to C-25 carbon steel using a metal inert gas welding which also known as gas metalarc is welding with the help of filler wire of stainless steel and 0.8 mm diameter. Argon gas was used as shielding gas in this process. Dissimilar metals welding have great scope in advanced technology now a days owing to their high strenght, hardness, and corrosion resistance properties. The combination of midium carbon steel and austenitic stainless steel has got large number of application in industry such as tublar product, building and costruction, nuclear plant, and heat exchanger assembly etc. Due to the fact that low cost of C-25 carbon steel and corrosion resistance property of stainless steel. All these applications are require welding of the two which can perform the desired service requirement of the industry. In this experiment we got that the hardness depend on the variable parameter and wire feed rate is the main effective parameter.
the buried arc welding technique is capable of achieving higher welding speeds and filler metal deposition rates than a globular arc. Weld speed can reach 2,540 mm/min and clean-up is minimal (Lienert et al. 2011). Stol et al. (2006) studied the use of buried arc GMAW for seam welds. The buried arc approach has great potential for use in the automotive, railroad, and marine industries for welding subassemblies. An example application is welding of edges and sides of aluminium parts as an alternative to GMAW. Controlled globular arc mode can be used for fillet or seam welds in lap or T-joints and square groove butt joints. It is suitable for the mechanized welding of thin section material at high speeds and can be used in fully mechanized or auto- matic gas metalarc welding. It is also used in the welding of pipe cylinders. A buried arc can be used in car applica- tions in butt welding for the body and semi-automatic welding for the frame and body (Kielhorn et al. 2001; Aoki et al. 2003; Kah et al. 2013).
This research work represents a detailed study of experimental and Computational analysis of properties of the Heat Affected Zone in a Corten A588 steel when it is welded in Gas MetalArc Welding (GMAW) without the edge preparation process and the ER70S-6 is used as filler wire. The model is subjected to Tensile and Hardness tests to study the effectiveness of the weld under these circumstances. Further, a Finite Element Method analysis is carried out to study the thermal distribution over the model and the deformation caused by the residual stress due to the thermal loads that are applied on the specimen during the welding process. The model is created in CREO and the analysis is carried out in ANSYS. Keywords: Heat Affected Zone (HAZ); GMAW;Corten steel; thermal distribution; residual stresses; Hardness test.
At this point, when these localized parts of the weldment becomes brittle, and load is applied, it would not have sufficient strength to resist fracturing. In recent times, other welding processes have been introduced into the country, such as the gas metalarc welding (GMAW) process gas tungsten arc welding process and submerged metalarc welding process. These welding processes have been used for welding of both aluminum and steel products. GMAW is a welding process that joins metals by heating the metal with an electric arc between a continuously fed consumable electrode wire and the workpiece. Kim et al., (1991) were of the opinion that GMAW is the most common method for arc welding of steels and aluminum alloys. Screeraj et al., (2013) wrote that GMAW is a multi-objective and multifactor metal fabrication technique.
SMAW has many applications in the field of pipeline work, shipbuilding, maintenance and repair industries, offshore platforms, naval Industries and construction of steel structures . Generally, the fabrication process involves the joining of stainless steel components by means of a suitable fusion welding process such as shielded metalarc welding (SMAW) . This process is widely practiced in most of the industries for fabrication, maintenance and repair of welds . Due to these reasons and their wide applications SMAW process was selected for the welding of AISI304 stainless steel
Chen (2012) state that, gas metalarc welding is a method that melts and joint metal by heating them with an arc. The arc is between continuously fed filler wire (consumable) electrode and the workpiece. This technique most commonly used carbon dioxide (CO2) and argon (Ar) as an inert gas to protect arc and molten weld pool from outside contaminant. Argon (Ar) gas requires a lower arc voltage for ionization and provides excellent arc welding stability, and good weld profile on the base metal. Carbon dioxide (CO2) is used for welding applications requiring high heat. Carbon dioxide (CO2) produces a wider arc column and good conductor of thermal energy with higher thermal conductivity than argon. CO2 can improve depth of fusion, improve wetting action and travel speeds but can't provide arc welding stability