ASTM A988-98(2002)

Standard Specification for Hot Isostatically-Pressed Stainless Steel Flanges, Fittings, Valves, and Parts for High Temperature Service

SCOPE
1.1 This specification covers hot isostatically-pressed, powder metal, stainless steel piping components for use in pressure systems. Included are flanges, fittings, valves, and similar parts made to specified dimensions or to dimensional standards, such as in ASME specification B16.5.
1.2 Several grades of martensitic, austenitic, and austenitic-ferritic stainless steels are included in this specification.
1.3 Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.
1.4 This specification is expressed in both inch-pound units and in SI units. Unless the order specifies the applicable "M" specification designation (SI units), however, the material shall be furnished to inch-pound units.
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as the standard. Within the text, the SI units are shown in parentheses. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.
1.6 The following safety hazards caveat pertains only to test methods portions 8.1, 8.2, 9.5-9.7, and Section 10 of this specification:  This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 09-Mar-1998
• ICS: 49.025.10 - Steels
• Technical Committee: A01 - Steel, Stainless Steel and Related Alloys
• Drafting Committee: A01.22 - Steel Forgings and Wrought Fittings for Piping Applications and Bolting Materials for Piping and Special Purpose Applications

Relations

• Replaces: ASTM A988-98 - Standard Specification for Hot Isostatically-Pressed Stainless Steel Flanges, Fittings, Valves, and Parts for High Temperature Service
• Effective Date: 10-Mar-1998
• Replaced By: ASTM A988/A988M-98(2002)e1 - Standard Specification for Hot Isostatically-Pressed Stainless Steel Flanges, Fittings, Valves, and Parts for High Temperature Service
• Effective Date: 10-Mar-1998

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
Designation: A 988 – 98 (Reapproved 2002)
Standard Specification for
Hot Isostatically-Pressed Stainless Steel Flanges, Fittings,
Valves, and Parts for High Temperature Service
This standard is issued under the fixed designation A 988; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope A 370 Test Methods and Definitions for MechanicalTesting
of Steel Products
1.1 This specification covers hot isostatically-pressed, pow-
A 751 Test Methods, Practices, and Terminology for
der metal, stainless steel piping components for use in pressure
Chemical Analysis of Steel Products
systems. Included are flanges, fittings, valves, and similar parts
A 923 TestMethodsforDetectingDetrimentalIntermetallic
madetospecifieddimensionsortodimensionalstandards,such
Phase in Wrought Duplex Austenitic/Ferritic Stainless
as in ASME specification B16.5.
Steels
1.2 Several grades of martensitic, austenitic, and austenitic-
E 112 Test Methods for Determining the Average Grain
ferritic stainless steels are included in this specification.
Size
1.3 Supplementary requirements are provided for use when
E 165 Test Method for Liquid Penetrant Examination
additional testing or inspection is desired. These shall apply
E 340 Test Method for Macroetching Metals and Alloys
only when specified individually by the purchaser in the order.
E 606 Practice for Strain-Controlled Fatigue Testing
1.4 This specification is expressed in both inch-pound units
G 48 Test Method for Pitting and Crevice Corrosion Resis-
and in SI units. Unless the order specifies the applicable “M”
tance of Stainless Steels and Related Alloys by Use of
specification designation (SI units), however, the material shall
Ferric Chloride Solution
be furnished to inch-pound units.
2.2 MSS Standard:
1.5 The values stated in either inch-pound units or SI units
SP 25 Standard Marking System for Valves, Fittings,
are to be regarded separately as the standard. Within the text,
Flanges, and Unions
theSIunitsareshowninparentheses.Thevaluesstatedineach
2.3 ASME Specifications and Boiler and Pressure Vessel
system are not exact equivalents; therefore, each system must
Codes:
be used independently of the other. Combining values from the
B16.5 Dimensional Standards for Steel Pipe Flanges and
two systems may result in nonconformance with the specifi-
Flanged Fittings
cation.
2.4 ASME Specification IX Welding Qualifications:
1.6 The following safety hazards caveat pertains only to test
SFA-5.4 Specification for Corrosion-Resisting Chromium
methods portions 8.1, 8.2, 9.5-9.7, and Section 10 of this
and Chromium-Nickel Steel CoveredWelding Electrodes
specification: This standard does not purport to address all of
SFA-5.9 Specification for Corrosion-Resisting Chromium
the safety concerns, if any, associated with its use. It is the
and Chromium-Nickel Steel Welding Rods and Bare
responsibility of the user of this standard to establish appro-
Electrodes
priate safety and health practices and to determine the
SFA-5.11 Specification for Nickel and Nickel-Alloy Cov-
applicability of regulatory limitations prior to use.
ered Welding Electrodes
2. Referenced Documents
3. Terminology
2.1 ASTM Standards:
3.1 Definitions of Terms Specific to This Standard:
A 262 Practices for Detecting Susceptibility to Intergranu-
3.1.1 can, n—the container used to encapsulate the powder
lar Attack in Austenitic Stainless Steels
duringthepressureconsolidationprocess;itispartiallyorfully
A 275/A 275M Test Method for Magnetic Particle Exami-
removed from the final part.
nation of Steel Forgings
1 4
This specification is under the jurisdiction of ASTM Committee A01 on Steel, Annual Book of ASTM Standards, Vol 03.01.
Stainless Steel, and RelatedAlloys and is the direct responsibility of Subcommittee Annual Book of ASTM Standards, Vol 03.03.
A01.22 on Steel Forgings and Wrought Fittings for PipingApplications and Bolting Annual Book of ASTM Standards, Vol 03.02.
Materials for Piping and Special Purpose Applications. AvailablefromManufacturersStandardizationSocietyoftheValveandFittings
Current edition approved Mar. 10, 1998. Published September 1998. Industry (MSS), 127 Park St., NE, Vienna, VA 22180-4602.
2 8
Annual Book of ASTM Standards, Vol 01.03. Available from American Society of Mechanical Engineers (ASME), ASME
Annual Book of ASTM Standards, Vol 01.05. International Headquarters, Three Park Ave., New York, NY 10016-5990.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
A 988 – 98 (2002)
3.1.2 compact, n—the consolidated powder from one can. It 4. Ordering Information
may be used to make one or more parts.
4.1 It is the responsibility of the purchaser to specify in the
3.1.3 consolidation, n—the bonding of adjacent powder
purchase order all requirements that are necessary for material
particles in a compact under pressure by heating to a tempera-
ordered under this specification. Such requirements may in-
ture below the melting point of the powder.
clude, but are not limited to, the following:
3.1.4 fill stem, n—the part of the compact used to fill the
4.1.1 Quantity (weight or number of parts),
can. It is not integral usually to the part produced.
4.1.2 Name of material or UNS number,
3.1.5 hot isostatic-pressing, n—a process for simulta-
4.1.3 ASTM designation and year of issue,
neously heating and forming a compact in which the powder is
4.1.4 Dimensions (tolerances and surface finishes should be
contained in a sealed formable enclosure usually made from
included),
metal and the so-contained powder is subjected to equal
4.1.5 Microstructure examination if required (5.1.4),
pressure from all directions at a temperature high enough to
4.1.6 Inspection (15.1),
permit plastic deformation and consolidation of the powder
4.1.7 Whether rough part or finished machined (8.2.2),
particles to take place.
4.1.8 Supplementary requirements, if any,
3.1.6 lot, n—a number of parts made from a single powder
4.1.9 Additional requirements (see 7.2 and 17.1), and
blend following the same manufacturing practice.
4.1.10 Requirement, if any, that the manufacturer shall
3.1.7 part, n—a single item coming from a compact, either
prior to or after machining. submit drawings for approval showing the shape of the rough
part before machining and the exact location of test specimen
3.1.8 powder blend, n—a homogeneous mixture of powder
from one or more heats of the same grade. material (see 9.3).
3.1.9 rough part, n—the part prior to final machining.
TABLE 1 Chemical Requirements
Composition, %
UNS Phosphorus, Sulfur, Columbium Tantalum,
Grade Carbon Manganese Silicon Nickel Chromium Molybdenum Titanium
Designation max max plus Tantalum max
Martensitic Stainless Steels
S41000 13 chromium 0.15 max 1.00 max 0.040 0.030 1.00 max 11.5–13.5 . . . . . . . . . . . .
S41026 13 chromium 0.15 max 1.00 max 0.02 0.02 1.0 max 1.00–2.00 11.5–13.5 0.40–0.60 Other Elements
0.5 molybdenum Cu 0.50 max
S41500 13 chromium, 4 0.05 max 0.50–1.00 0.030 0.030 0.60 max 3.5–5.5 11.5–14.0 0.50–1.00 . . . . . . . . .
nickel
S42390 12 chromium, 1.0 0.18–0.25 1.00 max 0.030 0.030 1.00 max 0.30–0.80 11.5–12.5 0.80–1.20 Other Elements
molybdenum, N 0.03–0.08
modified V 0.25–0.35
with vanadium Cb 0.08–0.15
Austenitic Stainless Steels
A
S30400 18 chromium, 8 0.08 max 2.00 max 0.045 0.030 1.00 max 8.0–11.0 18.0–20.0 . . . . . . . . . . . .
nickel
A
S30403 18 chromium, 8 0.035 max 2.00 max 0.045 0.030 1.00 max 8.0–13.0 18.0–20.0 . . . . . . . . . . . .
nickel,
low carbon
B
S30451 18 chromium, 8 0.08 max 2.00 max 0.045 0.030 1.00 max 18.0–11.0 18.0–20.0 . . . . . . . . . . . .
nickel,
modified with
nitrogen
S30453 18 chromium, 8 0.030 max 2.00 max 0.045 0.030 1.00 max 8.0–11.0 18.0–20.0 . . . . . . . . . . . .
nickel,
modified with
nitrogen
A
S31600 18 chromium, 8 0.08 max 2.00 max 0.045 0.030 1.00 max 10.0–14.0 16.0–18.0 2.00–3.00 . . . . . . . . .
nickel,
modified with
molybdenum
A
S31603 18 chromium, 8 0.030 max 2.00 max 0.045 0.030 1.00 max 10.0–14.0 16.0–18.0 2.00–3.00 . . . . . . . . .
nickel,
modified with
molybdenum, low
carbon
B
S31651 18 chromium, 8 0.08 max 2.00 max 0.045 0.030 1.00 max 10.0–13.0 16.0–18.0 2.00–3.00 . . . . . . . . .
nickel,
modified with
molybdenum and
nitrogen
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
A 988 – 98 (2002)
TABLE 1 Continued
Composition, %
UNS Phosphorus, Sulfur, Columbium Tantalum,
Grade Carbon Manganese Silicon Nickel Chromium Molybdenum Titanium
Designation max max plus Tantalum max
B
S31653 18 chromium, 8 0.030 max 2.00 max 0.045 0.030 1.00 max 10.0–13.0 16.0–18.0 2.00–3.00 . . . . . . . . .
nickel,
modified with
molybdenum and
nitrogen
S31700 19 chromium, 13 0.08 max 2.00 max 0.045 0.030 1.00 max 11.0–15.0 18.0-20.0 3.0–4.0 . . . . . . . . .
nickel
3.5 molybdenum
S31703 19 chromium, 13 0.030 max 2.00 max 0.045 0.030 1.00 max 11.0–15.0 18.0–20.0 3.0–4.0 . . . . . . . . .
nickel,
3.5 molybdenum
S21904 20 chromium, 6 0.04 max 8.0–10.0 0.045 0.030 1.00 max 5.5–7.5 19.0–21.5 . . . . . . Other Elements
nickel, 9 N 0.15–0.40
manganese
S31254 20 chromium, 18 0.020 max 1.00 max 0.030 0.010 0.80 max 17.5–18.5 19.5–20.5 6.0–6.5 . . . Other Elements
nickel, 6 Cu 0.50-1.00
molybdenum, low N 0.18-0.22
carbon
S31725 19 chromium, 15 0.030 max 2.00 max 0.045 0.030 1.00 max 13.5–17.5 18.0–20.0 4.0–5.0 . . . Other elements
nickel, 4 N0.20max
molybdenum
S31726 19 chromium, 15 0.030 max 2.00 max 0.045 0.030 1.00 max 14.5–17.5 17.0–20.0 4.0–5.0 . . . Other Elements
nickel, 4 N 0.10–0.20
molybdenum
N08367 22 chromium, 25 0.030 max 2.00 max 0.040 0.030 1.00 max 23.50– 20.0–22.0 6.0–7.0 Other Elements
nickel, 25.50 N 0.18–0.25
6.5 molybdenum, Cu 0.75 max
low
carbon
S32654 25 chromium, 22 0.020 max 2.0–4.0 0.030 0.005 0.50 max 21.0–23.0 24.0–25.0 7.0–8.0 Other Elements
nickel, N 0.45–0.55
7 molybdenum, low Cu 0.30–0.60
carbon
Austenitic-Ferritic Stainless Steels
S31803 22 chromium, 5.5 0.030 max 2.00 max 0.030 0.020 1.00 max 4.5–6.5 21.0–23.0 2.5–3.5 . . . Other Elements
nickel, N 0.08–0.20
modified with
nitrogen
S32205 22 chromium, 5.5 0.030 max 2.00 max 0.030 0.020 1.00 max 4.5–6.5 22.0–23.0 3.0–3.5 Other Elements
nickel, modified Cu 0.75 max
with high nitrogen N 0.14-0.20
S32950 26 chromium, 3.5 0.030 max 2.00 max 0.035 0.010 0.60 max 3.5–5.2 26.0–29.0 1.00–2.50 . . . Other Elements
nickel, N 0.15-0.35
1.0 molybdenum
S32750 25 chromium, 7 0.030 max 1.20 max 0.035 0.020 0.80 max 6.0-8.0 24.0–26.0 3.0-5.0 . . . Other Elements
nickel, 4 max N 0.24–0.32
molybdenum, Cu 0.50 max
modified with
nitrogen
S39274 25 chromium, 7 0.030 max 1.0 max 0.030 0.020 0.80 max 6.0–8.0 24.0–26.0 2.50–3.50 . . . Other Elements
nickel, max max N 0.24–0.32
modified with Cu 0.20–0.80
nitrogen W 1.50–2.50
and tungsten
C
S32760 25 chromium, 7 0.030 max 1.00 max 0.030 0.010 1.00 max 6.0–8.0 24.0–26.0 3.0–4.0 . . . Other Elements
nickel, 3.5 N 0.20–0.30
molybdenum, Cu 0.50–1.00
modified with W 0.50–1.00
nitrogen and
tungsten
S39277 25 chromium, 7 0.025 max 0.80 max 0.025 0.002 0.80 max 6.5–8.0 24.0–26.0 3.0–4.0 . . . Other Elements
nickel, Cu 1.20–2.00
3.7 molybdenum W 0.80–1.20
N 0.23–0.33
A
S30400, S30403, S31600, and S31603 shall have a maximum nitrogen content of 0.10 %.
B
S30451, S31651, S30453, S31653 shall have a nitrogen content of 0.10 to 0.16 %.
C
%Cr+3.3 3 %Mo+16 3 %N>40min.
NOTICE: This standard has either been superseded and replaced by a new version or withdrawn. Contact ASTM
International (www.astm.org) for the latest information.
A 988 – 98 (2002)
5. Materials and Manufacture 7. Heat Treatment
7.1 Except as provided in 7.2, the final heat treatment of all
5.1 Manufacturing Practice:
parts shall be in compliance with the requirements of Table 2.
5.1.1 Compacts shall be manufactured by placing a single
Afterhotisostatic-pressingandpriortofinalheattreatment,the
powderblendintoacan,evacuatingthecan,andsealingit.The
compactsmaybeannealed,attheoptionoftheproducer,either
can material shall be selected to ensure that it has no deleteri-
asapartoftheconsolidationprocessorasaseparateoperation.
ous effect on the final product. The entire assembly shall be
7.2 When agreed upon by the purchaser, liquid quenching
heated at a temperature and placed under sufficient pressure for
maybeappliedtothemartensiticstainlesssteelsinplaceofthe
a sufficient period of time to ensure that the final consolidated
furnace cool or air cool specified inTable 2, provided that such
part meets the density requirements of 8.1.1.1. One or more
quenching is followed by tempering in the temperature ranges
parts shall be machined from a single compact.
as required in Table 2. Martensitic parts that are liquid
5.1.2 Thepowdershallbeprealloyedandmadebyamelting
quenched and tempered shall be marked “QT.”
method capable of producing the specified chemical composi-
7.3 The final heat treatment shall be performed before or
tion, such as but not limited to, air or vacuum induction
after machining at the option of the producer.
melting, followed by gas atomization.
7.4 See Section S15 if a particular heat treatment method is
5.1.3 When powder from more than one heat of the same
specified by the purchaser in the order.
grade is used to make a blend, the heats shall be mixed
thoroughly to ensure homogeneity.
8. Structural Integrity Requirements
5.1.4 The compact shall be sectioned and the microstructure
8.1 Microporosity—The parts shall be free of microporosity
examined to check for porosity and other internal imperfec-
as demonstrated by measurement of density as provided in
tions. It shall meet the requirements of 8.1.2. The sample shall
8.1.1 or by microstructural examination as provided in 8.1.2.
betakenfromthefillstemorfromalocationinapartasagreed
8.1.1 Density Measurement:
upon by the manufacturer and purchaser.
8.1.1.1 The density measurement shall be used for accep-
5.1.5 Unless otherwise specified in the purchase order, the
tance of material but not for rejection of material. The
manufacturer shall remove the can material from the surfaces
measured density for each material shall exceed 99 % of the
of the consolidated compacts by chemical or mechanical
density typical of that grade when wrought and
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