ASTM A400 - 69(2012)

    Standard Practice for Steel Bars, Selection Guide, Composition, and Mechanical Properties

    Active Standard ASTM A400 | Developed by Subcommittee: A01.15

    Book of Standards Volume: 01.05


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    Significance and Use

    If the desired mechanical properties are as described in 4.1.1 for material identified as Classes P-1 through P-7, or in 4.1.2 for material identified as Classes Q-1 through Q-7, the strength level desired can be based on hardness or the equivalent tensile or yield strength as shown in Tables 1-4. If the desired mechanical properties are as set forth in 4.1.3 for material identified as Classes R-1 through R-6, the strength level is based on yield strength as shown in Tables 5 and 6.

    The user, after determining the mechanical property requirements of the critical section (that carrying the greatest stress) of the part, should select the composition or compositions from Tables 1-6 that fulfills these requirements and is most suitable for processing.

    1. Scope

    1.1 This practice covers the selection of steel bars according to section and to the mechanical properties desired in the part to be produced. This is not a specification for the procurement of steel. Applicable procurement specifications are listed in Section 5.

    1.2 Several steel compositions intended for various sections and mechanical property requirements are presented in Tables 1-6. The criteria for placing a steel composition in one of the three general class designations, Classes P, Q, and R (described in Section 4) are as follows:

    1.2.1 Classes P and Q should be capable of developing the mechanical properties shown in Tables 1-4 by liquid quenching from a suitable austenitizing temperature, and tempering at 800°F (427°C) or higher. A hardness indicated by tests made at a location shown in Fig. 1, A, B, or C, is taken as evidence that a composition is capable of meeting other equivalent mechanical properties shown in the tables. Normal good shop practices are assumed, with control of austenitizing and tempering temperatures, and mild agitation of the part in the quenching bath.

    1.2.2 Class R should be capable of developing the mechanical properties shown in Tables 5 and 6 as hot rolled, by cold drawing, or by cold drawing with additional thermal treatment. The locations for obtaining tension tests are described in 6.2.

    1.3 It is not implied that the compositions listed in the tables are the only ones satisfactory for a certain class and mechanical property requirement. Steels with lower alloy contents are often satisfactory through the use of special processing techniques.

    1.4 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.

    TABLE 1 Steels for Moderately Quenched PartsClasses P-1 Through P-7
    (Applicable to oil-quenching or equivalent rate of heat-removal.)

    Note 1—Steels listed as approved for a certain section or strength may be used for lighter sections and lower strengths.

    Note 2—Steel composition numbers correspond to SAE, AISI, or ASTM designations. Those in italics are no longer considered standard grades due to decreased usage.

    Note 3—An H-steel with the same grade designation as a standard SAE-AISI steel is capable of meeting the same section and strength requirements as the standard steel (see Specification A304), and is the preferred method of specification.

    Note 4—Steels having a maximum carbon content of 0.40 % or over, or a hardness of HB 293 or over after heat-treating, are not recommended for applications involving welding.




    Desired Minimum
    Hardness
    Equivalent
    Tensile
    Strength, psiA
    Equivalent
    Yield
    Strength, psiA
    MinimumB
    As-Quenched
    Hardness
    Class
    P-1
    P-2
    P-3
    P-4
    P-5
    P-6
    P-7
    Diameter of Round (or Distance Between Faces of Square
    or Hexagonal) Sections, in.C
    To ½, incl Over ½ to 1, incl Over 1 to 11/2, incl Over 1½ to 2, inclOver 2 to 21/2, incl Over 2½ to 3, incl Over 3 to 31/2, incl
    Thickness of Flat Sections, in.C
    HBHRC
    HB
    HRC
    To 0.3, incl
    Over 0.3 to 0.6, incl
    Over 0.6
    to 1,
    incl
    Over 1
    to 1.3,
    incl
    Over 1.3
    to 1.6,
    incl
    Over 1.6
    to 2.0,
    incl
    Over 2.0
    to 2.3,
    incl
    229 to 293,
    incl
    20 to 33,
    incl
    110 000 to
    145 000,
    incl
    90 000 to
    125 000,
    incl
    388 421330
    4130 50B30
    5132
    8630
    Over 293
    to 341,
    incl
    Over 33
    to 38,
    incl
    Over 145 000
    to 170 000,
    incl
    Over 125 000
    to 150 000,
    incl
    409 441335 94B30 314041374142 9840 4337
    31354135
    4042 4640
    5135 8640
    8740
    Over 341
    to 388,
    incl
    Over 38
    to 42,
    incl
    Over 170 000
    to 190 000,
    incl
    Over 150 000
    to 170 000,
    incl
    455 48134041374140 4145 41474340
    31406145TS4140 98404337
    4047 8642 86B45
    4135 864594B40
    5140 8742
    8637
    TS14B50
    50B40
    Over 388 to
    429, incl
    Over 42
    to 45,
    incl
    Over 190 000
    to 205 000,
    incl
    Over 170 000
    to 185 000,
    incl
    496 511345 86455147 41428660 4147 4150E4340
    40638740 5155 414598404161 41619850
    40688742 516043374340TS4150
    41409260 6150 8650 86B45
    46409261 9262 8655
    5145TS414050B60
    515050B46 94B40 51B60
    864050B4481B45
    864250B50

    A 1 psi = 0.006895 MPa.

    B Minimum as-quenched hardness for obtaining desired hardness after tempering at 800°F (427°C) or higher.

    C 1 in. = 25.4 mm.

    TABLE 2 Steels for Drastically Quenched PartsClasses P-1 Through P-7
    (Applicable to water-quenching or equivalent rate of heat-removal See Note 5)

    Note 1—Steels listed as approved for heavier sections or higher strengths may be used in the same conditions for lighter sections and lower strengths.

    Note 2—Steel composition numbers correspond to ASE, AISI, or ASTM designations. Those in italics are no longer considered standard grades due to decreased usage.

    Note 3—An H-steel with the same grade designation as a standard SAE-AISI steel is capable of meeting the same section and strength requirements as the standard steel (see Specification A304), and is the preferred method of specification.

    Note 4—Steels having a maximum carbon content of 0.40 % or over, or a hardness of HB 293 or over after heat-treating, are not recommended for applications involving welding.

    Note 5—Parts made of steel with a carbon content of 0.33 % or higher, where the section is under 1 1/2 in. (38.1 mm) should not be quenched in water without careful exploration for quench-cracking.


    Desired Minimum
    Hardness
    Equivalent
    Tensile
    Strength, psiA
    Equivalent
    Yield
    Strength, psiA
    MinimumB
    As-Quenched
    Hardness
    Class
    P-1P-2 P-3P-4P-5P-6P-7
    Diameter of Round (or Distance Between Faces of Square
    or Hexagonal) Sections, in.C
    To ½ , incl
    Over ½ to 1, incl
    Over 1 to 11/2, incl
    Over 1½ to 2, incl
    Over 2 to 21/2, incl
    Over 2½ to 3, incl
    Over 3 to 31/2, incl
    Thickness of Flat Sections, in.C
    HB
    HRC
    HB
    HRC
    To 0.3, incl
    Over 0.3 to 0.6, incl
    Over 0.6
    to 1.0,
    incl
    Over 1.0
    to 1.3,
    incl
    Over 1.3
    to 1.6,
    incl
    Over 1.6
    to 2.0,
    incl
    Over 2.0
    to 2.3,
    incl
    229 to 293,
    incl
    20 to 33,
    incl
    110 000 to
    145 000,
    incl
    90 000 to
    125 000,
    incl
    388 428625413094B30
    8627 5130
    8630
    50B30
    Over 293
    to 341,
    incl
    Over 33
    to 38,
    incl
    Over 145 000
    to 170 000,
    incl
    Over 125 000
    to 150 000,
    incl
    409 4440321330 1335 1340D 3140 4137
    40375132 5135 3135D4135 4337
    413094B305140 4640 9840
    5130 50B40 8637D
    8630 8640
    TS14B35 8740
    508B30

    A 1 psi = 0.006895 MPa.

    B Minimum as-quenched hardness for obtaining desired hardness after tempering at 800°F (427°C) or higher.

    C 1 in. = 25.4 mm.

    D These steels have insufficient hardenability for Class P-4, because of difference in test locations, but are satisfactory for other smaller sizes.

    TABLE 3 Steels for Moderately Quenched PartsClasses Q-1 Through Q-7
    (Applicable to oil-quenching or equivalent rate of heat-removal.)

    Note 1—Steels listed as approved for heavier sections or higher strengths may be used in the same conditions for lighter sections and lower strengths.

    Note 2—Steel composition numbers correspond to ASE, AISI, or ASTM designations. Those in italics are no longer considered standard grades due to decreased usage.

    Note 3—An H-steel with the same grade designation as a standard SAE-AISI steel is capable of meeting the same section and strength requirements as the standard steel (see Specification A304), and is the preferred method of specification.

    Note 4—Steels having a maximum carbon content of 0.40 % or over, or a hardness of HB 293 or over after heat-treating, are not recommended for applications involving welding.

    Desired Minimum
    Hardness
    Equivalent
    Tensile
    Strength,
    psiA
    Equivalent
    Yield
    Strength,
    psiA
    MinimumB
    As-
    Quenched
    Hardness
    Class
    Q-1Q-2Q-3Q-4Q-5Q-6Q-7
    Diameter of Round (or Distance Between Faces of Square
    or Hexagonal) Sections, in.C
    To 1/2, incl
    Over ½
    to 1,
    incl
    Over 1
    to 11/2,
    incl
    Over
    11/2
    to 2,
    incl
    Over 2
    to 21/2,
    incl
    Over 2½
    to 3,
    incl
    Over 3
    to 31/2,
    incl
    Thickness of Flat Sections, in.C
    HBHRCHBHRC To 0.3, incl
    Over 0.3 to 0.6,
    incl
    Over 0.6
    to 1.0,
    incl
    Over 1.0
    to 1.3,
    incl
    Over 1.3
    to 1.6,
    incl
    Over 1.6
    to 2.0,
    incl
    Over 2.0
    to 2.3,
    incl
    187 to 293,91 (Rb)95 000 to75 000 to388421330 86308637314041404142
    incl to 33, 145 000, 125 000,4130 50B308740TS4140
    incl incl incl513294B40
    Over 293Over 33OverOver4094413353140 87404137 TS414081B45414241454147
    to 341, to 38,145 000125 0004042 50B30413541404337
    incl incl to to5135464086429840
    170 000,150 000, 94B308640864586B45
    incl incl8742
    Over 341Over 38OverOver455481340 86371345 87424142 94B4051B60


    2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.

    ASTM Standards

    A108 Specification for Steel Bar, Carbon and Alloy, Cold-Finished

    A304 Specification for Carbon and Alloy Steel Bars Subject to End-Quench Hardenability Requirements

    A311/A311M Specification for Cold-Drawn, Stress-Relieved Carbon Steel Bars Subject to Mechanical Property Requirements

    A322 Specification for Steel Bars, Alloy, Standard Grades

    A633/A633M Specification for Normalized High-Strength Low-Alloy Structural Steel Plates

    A675/A675M Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality, Mechanical Properties


    ICS Code

    ICS Number Code 77.140.60 (Steel bars and rods)

    UNSPSC Code

    UNSPSC Code


    DOI: 10.1520/A0400-69R12

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