ASTM A995/A995M-98(2007)

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Designation: A 995/A 995M – 98 (Reapproved 2007)
Standard Specification for
Castings, Austenitic-Ferritic (Duplex) Stainless Steel, for
Pressure-Containing Parts
This standard is issued under the fixed designationA 995/A 995M; 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.
TABLE 1 Heat Treatment Requirements
1. Scope
Grade Heat Treatment
1.1 This specification covers austenitic-ferritic (duplex)
1B Heat to 1900°F [1040°C] minimum, hold for sufficient time to heat
stainless steel castings for valves, flanges, fittings, and other
casting uniformly to temperature, quench in water or rapid cool by
pressure-containing parts.
other means.
1.2 The duplex stainless steels offer a combination of
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
enhanced mechanical properties and corrosion resistance when
other means.
properly balanced in composition and properly heat treated.
3A Heat to 1950°F [1070°C] minimum, hold for sufficient time to heat
Ferrite levels are not specified, but these grades will develop a
casting uniformly to temperature, quench in water or rapid cool by
other means.
range of approximately 30 to 60 % ferrite with the balance
4A Heat to 2050°F [1120°C] minimum for sufficient time to heat casting
austenite. It is the responsibility of the purchaser to determine
uniformly to temperature and water quench, or the casting may be
which grade shall be furnished depending on design and furnace cooled to 1850°F [1010°C] minimum, hold for 15 min
minimum and then water quench. A rapid cool by other means may
service conditions, mechanical properties, and corrosion-
be employed in lieu of water quench.
resistant characteristics.
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,
NOTE 1—Because of the possibility of precipitation of embrittling
quench in water or rapid cool by other means.
phases, the grades included in this specification are not recommended for
6A Heat to 2010°F [1100°C] minimum, hold for sufficient time to heat
service at temperatures above 600°F [315°C].
casting uniformly to temperature, quench in water or cool rapidly by
other means.
1.3 The values stated in either inch-pound units or SI units
are to be regarded separately as standard. Within the text, the
SI units are shown in brackets. The values stated in each
E 562 Test Method for Determining Volume Fraction by
system are not exact equivalents; therefore, each system must
Systematic Manual Point Count
be used independently of the other. Combining values from the
3. Terminology
two systems may result in nonconformance with the specifi-
cation.
3.1 Definitions of Terms Specific to This Standard:
3.1.1 duplex stainless steel—an iron-chromium-nickel-
2. Referenced Documents
molybdenum alloy which when properly heat treated consists
2.1 ASTM Standards:
of approximately 30 to 60 % ferrite with the balance austenite.
A 488/A 488M Practice for Steel Castings, Welding, Quali-
4. General Conditions for Delivery
fications of Procedures and Personnel
A 703/A 703M Specification for Steel Castings, General
4.1 Material furnished to this specification shall conform to
Requirements, for Pressure-Containing Parts
the applicable requirements of Specification A 703/A 703M,
E 125 Reference Photographs for Magnetic Particle Indica-
including the supplementary requirements that are indicated on
tions on Ferrous Castings
the purchaser order. Failure to comply with the general
E 165 Test Method for Liquid Penetrant Examination
requirements of Specification A 703/A 703M constitutes non-
conformance with this specification. In case of conflict be-
tween the requirements of the specification and Specification
This specification is under the jurisdiction of ASTM Committee A01 on Steel,
A 703/A 703M, this specification shall prevail.
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
A01.18 on Castings.
5. Ordering Information
Current edition approved Nov. 1, 2007. Published December 2007. Originally
approved in 1998. Last previous edition approved in 2003 as A 995 – 98 (2003).
5.1 It is the responsibility of the purchaser to specify all
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
requirements that are necessary for material ordered under this
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
specification. Such requirements may included, but are not
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. limited to, the following:
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A 995/A 995M – 98 (2007)
TABLE 2 Chemical Requirements
A A
Grade 1B 2A 3A 4A 5A 6A
Type 25Cr-5Ni-M0-Cu-N 24Cr-10Ni-Mo-N 25Cr-5Ni-Mo-N 22Cr-5Ni-Mo-N 25Cr-7Ni-Mo-N 25Cr-7Ni-Mo-N
UNS J93372 J93345 J93371 J92205 J93404 J93380
ACI CD4MCuN CE8MN CD6MN CD3MN CE3MN CD3MWCuN
Composition:
Carbon, max 0.040 0.080 0.060 0.030 0.030 0.030
Manganese, max 1.00 1.00 1.00 1.50 1.50 1.00
Silicon, max 1.00 1.50 1.00 1.00 1.00 1.00
Phosphorus, max 0.040 0.040 0.040 0.040 0.040 0.030
Sulfur, max 0.040 0.040 0.040 0.020 0.040 0.025
Chromium 24.5-26.5 22.5-25.5 24.0-27.0 21.0-23.5 24.0-26.0 24.0-26.0
Nickel 4.7-6.0 8.0-11.0 4.0-6.0 4.5-6.5 6.0-8.0 6.5-8.5
Molybdenum 1.70-2.30 3.0-4.5 1.75-2.50 2.5-3.5 4.0-5.0 3.0-4.0
Copper 2.7-3.3 . . . . . . 1.00, max . . . 0.50-1.00
Tungsten . . . . . . . . . . . . . . . 0.50-1.00
Nitrogen 0.10-0.25 0.10-0.30 0.15-0.25 0.10-0.30 0.10-0.30 0.20-0.30
A
%Cr+3.3% Mo+16% N$ 40.
TABLE 3 Tensile Requirements
Grade 1B 2A 3A 4A 5A 6A
Type 25Cr-5Ni-Mo-Cu-N 24Cr-10Ni-Mo-N 25Cr-5Ni-Mo-N 2
...