ASTM A602 - 94 (2022)

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Designation: A602 −94 (Reapproved 2022)

Standard Speciﬁcation for

Automotive Malleable Iron Castings

This standard is issued under the ﬁxed designation A602; 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 castings of ferritic, pearlitic,

tempered pearlitic, and tempered martensitic grades of mal-

leable iron used in the products of the automotive and allied

industries. Castings shall be heat treated to meet this speciﬁ-

cation.

1.2 The values stated in inch-pound units are to be regarded

as standard. The values given in parentheses are mathematical

conversions to SI units that are provided for information only

and are not considered standard.

1.3 This international standard was developed in accor-

dance with internationally recognized principles on standard-

ization established in the Decision on Principles for the

Development of International Standards, Guides and Recom-

mendations issued by the World Trade Organization Technical

Barriers to Trade (TBT) Committee.

2. Referenced Documents

2.1 ASTM Standards:

E10 Test Method for Brinell Hardness of Metallic Materials

3. Grades

3.1 The speciﬁed grades with required hardness range and

ﬁnal heat treatment are shown in Table 1.

3.2 The foundry may also produce Grades M4504 and

M5003 by liquid quenching and tempering or alloying, or both.

4. Hardness

4.1 The foundry shall exercise the necessary controls and

inspection procedures to ensure compliance with the speciﬁed

hardness range. Hardness readings shall be taken in accordance

with Test Method E10 after sufficient material has been

removed from the casting surface to ensure representative

hardness readings. The area or areas on the casting where

hardness is to be checked shall be established by agreement

between supplier and purchaser and shown on the drawing.

5. Microstructure Requirements

5.1 Grade M3210 Ferritic Malleable Iron:

5.1.1 The microstructure of Grade M3210 malleable iron

shall consist of temper-carbon nodules distributed in a matrix

of ferrite.

5.1.2 Because of reaction with the annealing furnace

atmosphere, some depletion of carbon and silicon occurs at the

surface of the castings. This usually results in a rim which can

consist of coarse lamellar pearlite underlying a graphite-free

ferritic surface layer. If the pearlite layer is excessive, it can

result in poor machinability. The rim, therefore, shall not

exceed a depth greater than 0.050 in. (1.27 mm) as measured

from the casting surface.

5.1.3 The area below the rim can contain some pearlite;

however, it shall not exceed the amount shown in Fig. 1.

5.2 Grades M4504, M5003, M7002, and M8501:

5.2.1 The microstructure of these other grades of malleable

iron shall consist of temper-carbon nodules distributed in a

matrix of ferrite and lamellar pearlite or tempered pearlite in

air-quenched castings or a matrix of tempered martensite in the

case of liquid-quenched castings.

5.2.2 Because of reaction with the annealing furnace

atmosphere, some depletion of carbon and silicon occurs at the

surface of the castings. This usually results in a rim which can

consist of a graphite-free layer sometimes containing more or

less combined carbon than the underlying material.

5.3 All grades shall be free of primary graphite.

5.4 All grades shall not exceed 2 % spheroidal primary

carbides in the microstructure.

5.5 The maximum surface ferrite layer and denodularized

zone shall be measured after polishing, etching in nital, and

viewing at 100×.

6. Quality Assurance

6.1 Sampling plans are a matter of agreement between

supplier and purchaser. The supplier shall employ adequate

equipment and controls to ensure that parts conform to the

agreed-upon requirements.

This speciﬁcation is under the jurisdiction of ASTM Committee A04 on Iron

Castings and is the direct responsibility of Subcommittee A04.02 on Malleable and

Ductile Iron Castings.

Current edition approved Oct. 1, 2022. Published October 2022. Originally

approved in 1970. Last previous edition approved in 2018 as A602 – 94 (2018).

DOI: 10.1520/A0602-94R22.

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.

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.

7. General

7.1 Castings furnished to this speciﬁcation shall be repre-

sentative of good foundry practice and shall conform to

dimensions and tolerances speciﬁed on the casting drawing.

7.2 Minor imperfections usually not associated with the

structural function may occur in castings. These imperfections

often are repairable; however, repairs shall be made only in

areas allowed by the purchaser and only by approved methods.

7.3 Additional casting requirements may be agreed upon

between the purchaser and supplier. These should appear as

additional product requirements on the casting drawing.

8. Keywords

8.1 casting; ferrite; malleable iron; mechanical properties;

pearlite; temper carbon nodules; tensile strength; yield strength

APPENDIX

(Nonmandatory Information)

X1. MATERIAL DESCRIPTION OF MALLEABLE IRON

X1.1 Deﬁnition and Classiﬁcation

X1.1.1 malleable iron—a cast iron in which the graphite is

present as temper-carbon nodules instead of ﬂakes, as in gray

iron, or small spherulites, as in ductile iron.

X1.1.2 The term “malleable iron” includes all grades of

malleable iron, including those with a ferritic, pearlitic, tem-

pered pearlite, or tempered martensite matrix.

X1.2 Chemical Composition

X1.2.1 The chemical composition of malleable iron gener-

ally conforms to the following range:

Element Composition, %

Total carbon 2.20–2.90

Silicon 0.90–1.90

Manganese 0.15–1.25

Sulfur 0.02–0.20

Phosphorus 0.02–0.15

X1.2.2 Individual foundries will produce to narrower ranges

than those shown above. The composition is controlled such

that the molten iron solidiﬁes with all the carbon in the

combined form producing a “white iron” structure free of

graphite, which is heat treated to speciﬁcations.

X1.3 Microstructure

X1.3.1 The microstructure of malleable iron consists of a

matrix of ferrite, pearlite, tempered pearlite, or tempered

martensite or combinations of these containing temper carbon

nodules (see Figs. X1.1-X1.6). The structure of the matrix is

controlled by heat treatment or composition, or both.

X1.3.2 The matrix of the M3210 grade of malleable iron is

essentially free of combined carbon, but a small amount of

pearlite is permitted.

X1.3.3 The matrices of the other grades of malleable iron

contain combined carbon as pearlite, tempered pearlite, or

tempered martensite.

X1.3.4 Because of reaction with the annealing furnace

atmosphere, some depletion of carbon and silicon occurs at the

surface of the castings. This usually results in a rim which, if

excessive, can result in poor machinability. The rim on M3210

malleable iron can consist of coarse pearlite underlying a

graphite-free ferritic surface layer. The rim on the other grades

can consist of a graphite-free layer sometimes containing more

or less combined carbon than the underlying material.

TABLE 1 Grades of Malleable Iron

Grade Casting Hardness

Range Heat Treatment

M3210 156 HB max

4.8 BID

min

annealed

M4504 163–217 HB

4.7–4.1 BID

air quenched and tempered

M5003 187–241 HB

4.4–3.9 BID

air quenched and tempered

M5503 187–241 HB

4.4–3.9 BID

liquid quenched and tempered

M7002 229–269 HB

4.0–3.7 BID

liquid quenched and tempered

M8501 269–302 HB

3.7–3.5 BID

liquid quenched and tempered

Brinell impression diameter (BID) is the diameter in millimetres of the impression

of a 10 mm ball at 3000 kg load.

FIG. 1 Reference Photomicrograph Showing Allowable Pearlite

in Grade M3210 Iron (100×; 2 % Nital Etch)

A602 − 94 (2022)

FIG. X1.1 Grade M3210, Approximately HB 143 (100×)

FIG. X1.2 Grade M4504, Approximately HB 207 (100×)

FIG. X1.3 Grade M5003, Approximately HB 229 (100×)

FIG. X1.4 Grade M5503, Approximately HB 229 (100×)

FIG. X1.5 Grade M7002, Approximately HB 262 (100×)

FIG. X1.6 Grade M8501, Approximately HB 285 (100×)

A602 − 94 (2022)

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摘要：

ASTM A602 - 94 (2022) 是美国材料与试验协会发布的一项关于汽车用铁素体和珠光体可淬火碳钢及合金钢铸件的标准规范。该标准最初于1994年批准，2022年进行了最新复审和重新确认，涵盖了适用于汽车工业及其他工程领域的高强度、可热处理钢铸件的化学成分、力学性能、热处理要求及验收条件。标准中规定了多个牌号（如Grade A、Grade B、Grade C等），分别对应不同的抗拉强度、屈服强度和延伸率要求，以满足不同承载和韧性需求。ASTM A602 - 94 (2022) 特别适用于

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