Material Specification Guide

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Material Guide

for API

6A (New)

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Ordering API 19th

Edition Products

Four Criteria for Individual Parts (i.e. valves,

hangers, etc.)

1. Temperature Class -- API holds the user responsible for choosing

temperature class

2. Material Class -- API holds the user responsible for choosing material

class

3. PSL (Product Specification Level) -- API recommends PSL's to the user 4. PR (Performance Requirement) -- API minimum or added optional cycle

testing of designs

Note: When ordering, please specify at least the first two of the four criteria.

Examples of what these designations mean in the

description of a part

U-AA-1-1

U 0 to 250? F (-18 to 121? C)

AA General service with H2S partial Pressure <0.05 psi and

non-corrosive with CO2 partial pressure <7 psi

1 PSL 1 per API recommendations or customer order

1 PR1 (minimum level) API cycle testing has been completed

PU-EE-0,5-3-2

PU -20 to 250? F (-29 to 121? C) combines P (-20 to 180? F or -29 to 82? C) and U (0 to 250? F or -18 to 121? C)

EE-0,5 NACE sour service with maximum 0.5 psi H2S partial

pressure and mildly corrosive with CO2 partial pressure

From 7 psi to 30 psi

non-corrosive with CO2 partial pressure <7 psi 3 PSL 3 per API recommendations or customer order 2 PR2 (2nd level) API cycle testing has been completed on the design

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Temperature Class

"Choosing temperature ratings is the ultimate responsibility of the user" … API 6A 19th Edition

Considerations for ordering

• Equipment is rated for service in a specific temperature range or ranges

• Maximum production flowing temperature

• Mud circulating temperature?

• Minimum seasonal temperature

• Temperature Classes • K -75 to 180?F (-60 to 82?C) • L -50 to 180?F (-46 to 82?C) • N -50 to 140?F (-46 to 60?C) • P -20 to 180?F (-29 to 82?C) • R Room Temperature • S 0 to 140?F (-18 to 60?C) • T 0 to 180?F (-18 to 82?C)

*S or T apply for most standard duty slip casing hangers • U 0 to 250?F (-18 to 121?C)

*U is common for generally available wellheads and valves • V 35 to 250?F (2 to 121?C)

• X 0 to 350?F (-18 to 180?C) -- ref. Annex G

• Y 0 to 650?F (-18 to 345?C) -- ref. Annex G

• Combinations of Classes are available:

Examples PU = -20 to 250?F (-29 to 121?C)

High Temperature Service

High temperature service [Temp Ratings X( 0-350?F or -18 to 180?C) and Y (0-650?F or -18 to 345?C)] is addressed in API 6A Annex G. Customers ordering equipment for high temperature service may choose between the following two options.

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Temperature Class

… cont'd

1. Equipment rated for full pressure at high temperature (Temp X only)

• Tensile strength testing is performed at the high end of the temperature range

• Yield strength at high temperature must equal the minimum yield strength at room temperature

• Special alloys are often required

2. Equipment derated for lower pressure at high temperature

VWUSA does not "derate" Temp X equipment nor does it recommend that customers do so

Formulas for Calculating Derated Pressures

Full Pressure @ room temperature x derating factor = Lowered pressure rating @ high temperature

With this method, a piece of carbon/low alloy equipment rated for 5,000 psi Temp U (0-250?F or -18 to 121?C) service would be derated by a factor of 0.85 to 4,250 psi for Temp X (0 to 350?F or -18 to 180?C)

Example: 5,000 psi x .085 = 4,250 psi

API 6B Flange "Derating" Chart

Pressure Rating Psi (MPa)

Derated Temp X Pressure Psi (MPa)

Derated Temp Y Pressure Psi (MPa)

2,000 (13,8) 1,905 (13,1) 1,430 (9,9)

3,000 (20,7) 2,860 (19,7) 2,145 (14,8)

5,000 (34,5) 4,765 (32,8) 3,575 (24,7)

API 6BX Flange "Derating" Factors

Derating Factor Material

Temp X Temp Y

Carbon & low alloy steels 0.85 0.75

Martensitic stainless steels 0.85 0.75

Austenitic & duplex stainless steels 0.80 0.73

Corrosion-resistant alloys 0.95 0.85

Material Guide (API 6A 19th Edition) 3

Material Class

Some NACE MR0175/ISO15156 changes will affect material selection and equipment cost.

Partial Pressure of H

2

S determines if NACE applies

• 0.05 psia and up requires NACE (unchanged from previous

editions)

• Above 0.5 psia 17-4 Stainless Steels may not be used for mandrel

hangers and stems (new requirement) • Above 1.5 psia

• 410 Stainless Steels may not be used for mandrel hangers and stems (new requirement)

Manufacturers have commonly used 17-4 SS materials for hangers and stems up to 3-4 psia partial pressure of H2S

(depending on the manufacturer's design allowables). • Allowable materials for hangers & stems above 1.5 psia

• Inconels

• Duplex Steels

• Chlorides in sour service above 140?F or 60?C (new requirement)

316 Stainless may not be used

Manufacturers have commonly used 316 SS for grease fittings in H2S service.

• Have you been successfully using materials and trims that would no longer comply with NACE?

API 6a Annex O states….

"NACE MR0175 / ISO 15156 includes provisions for the qualification of materials for a specific sour service application which is outside the parameters defined in that standard, by means of testing or

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Material Class

… Cont'd

"Choosing material class and specific materials for specific conditions is the ultimate responsibility of the user."

… API 6A 19th Edition

documented field history.1 This can include the use of materials in fluid

conditions exceeding the limits defined MR0175 / ISO 15156, or the use of materials not addressed in MR0175 / ISO 15156. For such sour service applications, equipment may be described and marked as Material Class ZZ."

API Material Class ZZ may be used when materials and trims that have

previously been used for sour service will not comply with current NACE MR0175/ISO15156 standards.

"The manufacturer shall meet material specifications supplied or approved by the purchaser…"

ZZ class parts marking and descriptions will be determined between the customer and manufacturer.

Suffixes for Material Classes DD, EE, FF and HH

"will include … the maximum allowable partial pressure of H2S"

• 0,5 = 0.5 psia maximum partial pressure of H2S

(example: EE-0,5)

• 1,5 = 1.5 psia maximum partial pressure of H2S

(example: FF-1,5)

• NL = No limit to H2S

(example: DD-NL)

• Other material class suffixes may be applicable, depending on materials of construction

1

NACE MR0175/ISO 15156 specification states in section 8.2 duration of the documented field experience shall be at least two years.

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Material Class

… Cont'd

Trim Selection Chart

For combinations of H2S and CO2 partial pressures

Note: Partial pressures of H2S and CO2 should be determined separately.

Partial Pressure Formulas

H2S psia = H2S PPM

1,000,000 x working pressure Or

H2S psia = H2S % x working pressure And

CO2 psia = CO2 % x flowing pressure

H2S Partial Pressure

0 to <0.05 psia 0.05 to 0.5 psia >0.5 and <1.5

psia1 >1.5 psia1 0 to <7 psia AA Non-Sour Non-Corrosive EE-0,5 or DD-0,5 Sour Non-Corrosive DD-1,5 or EE1,52 Sour Non-Corrosive DD- NL or EE-NL3 Sour Non-Corrosive 7 psia to 30 psia BB Non-Sour Slightly Corrosive EE-0,5 Sour Slightly Corrosive EE-1,52 Sour Slightly Corrosive EE-NL3 Sour Slightly Corrosive >30 psia to <200 psia CC Non-Sour Moderately to Highly Corrosive FF-0,5 Sour Moderately to Highly Corrosive FF-1,52 Sour Moderately to Highly Corrosive FF-NL3 Sour Moderately to Highly Corrosive CC or HH Non-Sour Highly Corrosive FF-0,5 or HH-0,5 Sour Highly Corrosive FF-1,5 or HH-1,5 Sour Highly Corrosive FF-NL or HH-NL Sour Highly Corrosive 200 psia and up Corrosion resistant alloys may be needed.

VWUSA recommends that Corrosion Resistant Alloys be considered beginning at CO2 partial pressures of 200 psia.

Consult with engineering for material selection. Additional factors should be considered.

1_{Material Class ZZ may be used when materials and trims previously used for sour service will}

not comply with current NACE MR0175/ISO15156 standards

2_{17-4 stainless steel is not allowed for stems or tubing hangers ab ove 0.5 psia H} 2S. 3

410 stainless steel is not allowed for stems or tubing hangers above 1.5 psia H2S.

CO

2

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Material Class

… Cont'd

Additional factors which influence the effect of H

2

S

• pH

• Temperature

• Chloride concentration

• Elemental sulfur

Additional factors which influence the effect of CO

2

• pH

• Temperature

• Chloride ion concentration

• Sand Production

• H2S Level

• Water production and composition

• Types and relative amounts of produced hydrocarbons