ASTM A447/A447M-93(2003)
(Specification)Standard Specification for Steel Castings, Chromium-Nickel-Iron Alloy (25-12 Class), for High-Temperature Service
Standard Specification for Steel Castings, Chromium-Nickel-Iron Alloy (25-12 Class), for High-Temperature Service
SCOPE
1.1 This specification covers iron-base, heat-resisting alloy castings of the 25% chromium, 12% nickel class, intended for structural elements, containers, and supports in electric furnaces, petroleum still tube supports, and for similar applications up to 2000°F [1095°C]. The purchaser should inform the manufacturer when the service temperatures are to exceed 1800°F [980°C].
1.2 In the absence of significant proportions of elements other than those prescribed in Section 4, the two types of alloys covered by this specification may in general be distinguished as follows:
1.2.1 Type I- Alloys characterized by relatively low limiting creep stress at temperatures between 1500 and 2000°F [815 and 1095°C], and relatively high ductility at ordinary temperatures after aging for short periods at temperatures between 1300 and 1500°F [705 and 815°C].
1.2.2 Type II- Alloys having relatively high limiting creep stress but which may develop low ductility at ordinary temperatures when aged for short periods at temperatures between 1350 and 1500°F [730 and 815°C].
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 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.
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Designation: A 447/A447M – 93 (Reapproved 2003)
Standard Specification for
Steel Castings, Chromium-Nickel-Iron Alloy (25-12 Class),
for High-Temperature Service
This standard is issued under the fixed designationA447/A447M; 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 800/A800M Practice for Steel Castings,AusteniticAlloy,
Estimating Ferrite Content Thereof
1.1 This specification covers iron-base, heat-resisting alloy
E 8 Test Methods forTensionTesting of Metallic Materials
castings of the 25 % chromium, 12 % nickel class, intended for
E 21 Test Methods for Elevated Temperature Tension Tests
structural elements, containers, and supports in electric fur-
of Metallic Materials
naces, petroleum still tube supports, and for similar applica-
tions up to 2000°F [1095°C]. The purchaser should inform the
3. General Conditions for Delivery
manufacturer when the service temperatures are to exceed
3.1 Material furnished to this specification shall conform to
1800°F [980°C].
the requirements of Specification A 781/A 781M, including
1.2 In the absence of significant proportions of elements
any supplementary requirements that are indicated in the
otherthanthoseprescribedinSection4,thetwotypesofalloys
purchase order. Failure to comply with the general require-
coveredbythisspecificationmayingeneralbedistinguishedas
ments of Specification A 781/A 781M constitutes nonconfor-
follows:
mance with this specification. In case of conflict between the
1.2.1 Type I—Alloys characterized by relatively low limit-
requirements of this specification and Specification A 781/
ingcreepstressattemperaturesbetween1500and2000°F[815
A 781M, this specification shall prevail.
and 1095°C], and relatively high ductility at ordinary tempera-
tures after aging for short periods at temperatures between
4. Process
1300 and 1500°F [705 and 815°C].
4.1 The alloy for the castings shall be made by the electric-
1.2.2 Type II—Alloys having relatively high limiting creep
furnace process or by any other process approved by the
stress but which may develop low ductility at ordinary tem-
purchaser.
peratures when aged for short periods at temperatures between
1350 and 1500°F [730 and 815°C].
5. Heat Treatment
1.3 The values stated in either inch-pound units or SI units
5.1 Except as otherwise agreed upon between the manufac-
are to be regarded separately as standard. Within the text, the
turer and the purchaser, the manufacturer shall not be required
SI units are shown in brackets. The values stated in each
to heat treat the castings.
system are not exact equivalents; therefore, each system must
be used independently of the other. Combining values from the
6. Chemical Composition
two systems may result in nonconformance with the specifi-
6.1 The castings shall conform to the requirements of Table
cation.
1 as to chemical composition.
2. Referenced Documents
7. Sampling
2.1 ASTM Standards:
7.1 MaterialforthetestsspecifiedinSections10,12,and13
A 781/A781M Specification for Castings, Steel and Alloy,
may be taken from separately cast test blocks of a form such as
Common Requirements, for General Industrial Use
that shown in Fig. 1, from another type of test block, from the
castings, or from coupons attached to the castings, as may be
agreed upon between the manufacturer and the purchaser.
This specification is under the jurisdiction of ASTM Committee A01 on Steel, 7.2 Material for the magnetic permeability test specimen
Stainless Steel and Related Alloys and is the direct responsibility of Subcommittee
(Section 11) may be taken, prior to heat treatment, from the
A01.18 on Castings.
same coupon as the specimen for the tension test after aging;
Current edition approved Oct. 1, 2003. Published October 2003. Originally
approved in 1944. Redesignated as A 447 in 1961. Last previous edition approved
in 1998 as A 447/A 447M – 93 (1998).
2 3
Annual Book of ASTM Standards, Vol 01.02. Annual Book of ASTM Standards, Vol 03.01.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
A 447/A447M – 93 (2003)
TABLE 1 Chemical Requirements
7.3 In the case of castings for unusual or severe service, the
test coupons shall be attached to the castings at convenient
Element Composition, %
locationsasmaybeagreeduponbetweenthemanufacturerand
A
Ni 10.00–14.00
the purchaser.
Cr 23.00–28.00
7.4 In all cases, it shall be the manufacturer’s duty to
C 0.20–0.45
N, max 0.20
provide a sufficient number of samples for the specified tests.
Mn, max 2.50
Si, max 1.75
8. Number of Tests
P, max 0.05
S, max 0.05
8.1 The purchaser shall specify not more than two tests.The
Fe and other elements as may be agreed upon between the
tests shall be selected from the following list, with the
manufacturer and the purchaser
restriction that not more than one of the tension tests at high
A
Commercial nickel usually carries a small amount of cobalt, and within the
temperature (that is, 8.1.3 or 8.1.4) may be required:
usual limits cobalt shall be counted as nickel.
8.1.1 Tension test after aging,
8.1.2 Magnetic permeability test,
8.1.3 Stress-rupture test, and
8.1.4 Short-time high-temperature tension test.
9. Retests
9.1 Mechanical Tests—If any of the specimens first chosen
for any of the mechanical tests agreed upon fail to conform to
the specified requirements, an additional specimen from the
same melt may be tested. This additional specimen shall
conform to the requirements prescribed for the test in question.
9.2 Magnetic Test—If the magnetic permeability of the
specimen first tested does not conform to the requirement
prescribed in 11.1, three additional specimens from the same
melt may be tested. At least two of these shall conform to the
prescribed requirement.
10. Tensile Properties After Aging
10.1 The tensile properties of the material after aging shall
conform to the following requirements:
Type I Type II
Tensile strength, min, ksi [MPa] 80 [550] 80 [550]
Elongation in 2 in. [50 mm], min, % 9 4
10.2 Samples from which the tension specimens are to be
taken shall be heated for 24 h at 1400 6 25°F [760 6 14°C]
and allowed to cool at least down to 400°F [205°C] at rates not
exceeding 200°F [110°C]/h. The tension test specimens shall
be machined from the heat-treated sample, and shall conform
to the dimensions shown in Fig. 1 of Test Methods E 8.
10.3 The tension test shall be made in accordance with Test
TABLE Continued
Methods E 8.The speed of head of the testing machine shall be
Metric Equivalents
so adjusted that the rate of separation of the gage marks on the
in. [mm] in. [mm]
test specimen shall not exceed 0.1 in. [3 mm]/min.
1 1
⁄8 [3.2] 3 ⁄2 [88.9]
⁄2 [12.7] 4 [101.6]
11. Magnetic Permeability
1 1
1 ⁄16 [27.0] 4 ⁄16 [103.2]
1 ⁄2 [38.1] 5 [127.0] 11.1 The magnetic permeability of the material shall con-
3 [76.2] 11 [279.4]
form to the following requirements:
Magnetic Permeability,
NOTE—Pour through head; cover molten head with powdered charcoal,
max
coke dust, etc., immediately after pouring, in order to keep head fluid as
Type I 1.70
long as possible. Type II 1.05
FIG. 1 Test Block for Tension Test Specimen
NOTE 1—The magnetic permeability test gives a qualitative indication
of the ferrite content for alloys falling within the range of chemical
from suitable specimens cast as part
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