ASTM A995/A995M-20

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Designation: A995/A995M − 19 A995/A995M − 20
Standard Specification for
Castings, Austenitic-Ferritic (Duplex) Stainless Steel, for
Pressure-Containing Parts
This standard is issued under the fixed designation A995/A995M; the number immediately following the designation indicates the year
of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval.
A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope*
1.1 This specification covers austenitic-ferritic (duplex) stainless steel castings for valves, flanges, fittings, and other
pressure-containing parts.
1.2 The duplex stainless steels offer a combination of enhanced mechanical properties and corrosion resistance when properly
balanced in composition and properly heat treated. Ferrite levels are not specified, but these grades will develop a range of
approximately 30 to 60 % ferrite with the balance austenite. It is the responsibility of the purchaser to determine which grade shall
be furnished depending on design and service conditions, mechanical properties, and corrosion-resistant characteristics.
NOTE 1—Because of the possibility of precipitation of embrittling phases, the grades included in this specification are not recommended for service
at temperatures above 600 °F [315 °C].
1.3 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each
system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the
two systems may result in nonconformance with the standard.
1.4 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
2. Referenced Documents
2.1 ASTM Standards:
A488/A488M Practice for Steel Castings, Welding, Qualifications of Procedures and Personnel
A703/A703M Specification for Steel Castings, General Requirements, for Pressure-Containing Parts
E125 Reference Photographs for Magnetic Particle Indications on Ferrous Castings
E165/E165M Practice for Liquid Penetrant Testing for General Industry
E562 Test Method for Determining Volume Fraction by Systematic Manual Point Count
G48 Test Methods for Pitting and Crevice Corrosion Resistance of Stainless Steels and Related Alloys by Use of Ferric Chloride
Solution
3. Terminology
3.1 Definitions of Terms Specific to This Standard:
3.1.1 duplex stainless steel—an iron-chromium-nickel-molybdenum alloy that, when properly heat treated, consists of
approximately 30 to 60 % ferrite with the balance austenite.
4. General Conditions for Delivery
4.1 Material furnished to this specification shall conform to the applicable requirements of Specification A703/A703M,
including the supplementary requirements that are indicated on the purchaser order. Failure to comply with the general
requirements of Specification A703/A703M constitutes nonconformance with this specification. In case of conflict between the
requirements of this specification and Specification A703/A703M, this specification shall prevail.
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee A01.18
on Castings.
Current edition approved March 1, 2019May 1, 2020. Published March 2019May 2020. Originally approved in 1998. Last previous edition approved in 20182019 as
A995/A995M – 18a.A995/A995M – 19. DOI: 10.1520/A0995_A0995M-19.10.1520/A0995_A0995M-20.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
A995/A995M − 20
TABLE 1 Heat Treatment Requirements
Grade Heat Treatment
1B Heat to 1900 °F [1040 °C] minimum, hold for sufficient time to heat
casting uniformly to temperature, quench in water or rapid cool by
other means.
2A Heat to 2050 °F [1120 °C] minimum, hold for sufficient time to heat
casting uniformly to temperature, quench in water or rapid cool by
other means.
3A Heat to 1950 °F [1070 °C] minimum, hold for sufficient time to heat
casting uniformly to temperature, quench in water or rapid cool by
other means.
4A Heat to 2050 °F [1120 °C] minimum for sufficient time to heat casting
uniformly to temperature and water quench, or the casting may be
furnace cooled to 1850 °F [1010 °C] minimum, hold for 15 min
minimum and then water quench. A rapid cool by other means may
be employed in lieu of water quench.
4A Heat to 2050 °F [1120 °C] minimum, hold for sufficient time to heat
casting uniformly to temperature, and water quench; or the casting
may be furnace cooled to a temperature no lower than 1850 °F
[1010 °C], hold for 15 min minimum and then water quench. A rapid
cool by other means may be employed in lieu of water quench.
5A Heat to 2050 °F [1120 °C] minimum, hold for sufficient time to heat
casting to temperature, furnace cool to 1910 °F [1045 °C] minimum,
quench in water or rapid cool by other means.
5A Heat to 2050 °F [1120 °C] minimum, hold for sufficient time to heat
casting to temperature, furnace cool to a temperature no lower than
1910 °F [1045 °C], then quench in water or rapid cool by other
means.
6A Heat to 2010 °F [1100 °C] minimum, hold for sufficient time to heat
casting uniformly to temperature, quench in water or rapid cool by
other means, or the casting may be furnace cooled to a temperature
no lower than 1925 °F [1050 °C], hold for 15 min minimum, and then
quench in water or rapid cool by other means.
7A Heat to 2065 °F [1130 °C] minimum, hold for sufficient time to heat
casting to temperature, furnace cool to 1940 °F [1060 °C] minimum,
quench in water or rapid cool by other means.
7A Heat to 2065 °F [1130 °C] minimum, hold for sufficient time to heat
casting to temperature, furnace cool to a temperature no lower than
1940 °F [1060 °C], then quench in water or rapid cool by other
means.
5. Ordering Information
5.1 It is the responsibility of the purchaser to specify all requirements that are necessary for material ordered under this
specification. Such requirements may include, but are not limited to, the following:
5.1.1 A description of the casting by pattern number or drawing (dimensional tolerances shall be included on the casting
drawing),
5.1.2 Quantity (weight and number of castings),
5.1.3 Specification designation and date of issue,
5.1.4 Grade of steel,
5.1.5 Supplementary requirements including acceptance criteria, and
5.1.6 Additional requirements.
6. Process
6.1 The steel shall be made by the electric furnace process with or without separate refining.
7. Heat Treatment
7.1 All castings shall be heat treated in accordance with Table 1.
8. Chemical Composition
8.1 The steel shall conform to the requirements as to chemical composition prescribed in Table 2.
9. Tensile Properties
9.1 One tension test shall be made from each heat and shall conform to the requirements as to tensile properties prescribed in
Table 3.
10. Quality
10.1 When additional inspection is desired, Supplementary Requirements S5, S6, and S10 may be ordered.
A995/A995M − 20
A,B
TABLE 2 Chemical Requirements
Material Grade Element, %
Type
Carbon Manganese Phosphorus Sulfur Silicon Chromium Nickel Molybdenum Nitrogen Copper Tungsten Other
UNS
CD4MCuN (1B) 0.040 1.00 0.040 0.040 1.00 24.5–26.5 4.7–6.0 1.70–2.30 0.10–0.25 2.7–3.3 . . . . . .
25Cr-5Ni-Mo-
Cu-N
J93372
CE8MN (2A) 0.080 1.00 0.040 0.040 1.50 22.5–25.5 8.0–11.0 3.0–4.5 0.10–0.30 . . . . . . . . .
24Cr-10Ni-Mo-N
J93345
CD6MN (3A) 0.060 1.00 0.040 0.040 1.00 24.0–27.0 4.0–6.0 1.75–2.50 0.15–0.25 . . . . . . . . .
25Cr-5Ni-Mo-N
J93371
CD3MN (4A) 0.030 1.50 0.040 0.040 1.00 21.0–23.5 4.5–6.5 2.5–3.5 0.10–0.30 1.00 . . . . . .
22Cr-5Ni-Mo-N
J92205
C
CE3MN (5A) 0.030 1.50 0.040 0.040 1.00 24.0–26.0 6.0–8.0 4.0–5.0 0.10–0.30 . . . . . . . . .
25Cr-7Ni-Mo-N
J93404
CD3MWCuN 0.030 1.00 0.030 0.025 1.00 24.0–26.0 6.5–8.5 3.0–4.0 0.20–0.30 0.50–1.00 0.50–1.00 . . .
D
(6A)
25Cr-7Ni-Mo-N
J93380
E
CD3MWN (7A) 0.030 1.00–3.00 0.030 0.020 1.00 26.0–28.0 6.0–8.0 2.0–3.5 0.30–0.40 1.00 3.0–4.0 B:
27Cr-7Ni-Mo-
0.0010–0.0100
W-N
Ba:
J93379
0.0002–0.0100
Ce + La:
0.005–0.030
A
All values are maximums, except where a range is provided.
B
Where ellipses (.) appear in this table, there is no requirement, and the element need not be analyzed for or reported.
C
% Cr + 3.3 % Mo + 16 % N $ 40.
D
% Cr + 3.3 (% Mo + 0.5 % W) + 16 % N $ 40.
E
% Cr + 3.3 (% Mo + 0.5 % W) + 16 % N $ 45.
TABLE 3 Tensile Requirements
Grade 1B 2A 3A 4A 5A 6A 7A
25Cr-5Ni-Mo- 24Cr-10Ni- 25Cr-5Ni- 22Cr-5Ni- 25Cr-7Ni- 25Cr-7Ni- 27Cr-7Ni-
Type
Cu-N Mo-N Mo-N Mo-N Mo-N Mo-N Mo-W-N
Tensile strength, 100 [690] 95 [655] 95 [655] 90 [620] 100 [690] 100 [690] 100 [690]
ksi [MPa], min
Yield strength 70 [485] 65 [450] 65 [450] 60 [415] 75 [515] 65 [450] 75 [515]
(0.2 % offset),
ksi [MPa], min
Elongation in 2 in. 16 25 25 25 18 25 20
[50 mm],
A
%, min
A
When ICI test bars are used in tensile testing as provided for in this specification, the gage length to reduced section diameter ratio shall be 4:1.
11. Repair by Welding
11.1 Repairs shall be made using procedures and welders qualified under Practice A488/A488M.
11.2 The composition of the deposited weld metal may be similar to that of the casting or may be suitably alloyed to achieve
the desired corrosion resistance and mechanical properties.
11.3 Weld repairs shall be subject to the same quality standards as used to inspect the castings.
12. Post-Weld Heat Treatment After Major Weld Repair
12.1 Weld repairs shall be considered major in the case of a casting that has leaked on hydrostatic testing or when the depth
of the cavity after preparation for repair exceeds 20 % of the actual wall thickness, or 1 in. [25 mm], whichever is smaller, or when
2 2
the extent of the cavity exceeds approximately 10 in. [65 cm ]. All other weld repairs shall be considered minor.
12.2 Castings shall be heat treated after major weld repairs. Heat treatment after minor weld repairs is not required unless
Supplementary Requirement S11 is included in the purchase order.
A995/A995M − 20
12.3 Post-weld heat treatment shall be in accordance with Table 1.
13. Keywords
13.1 austenitic-ferritic; duplex stainless steel; pressure-containing; steel castings
SUPPLEMENTARY REQUIREMENTS
The following supplementary requirements shall not apply unless specified in the purcha
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