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ASTM A400 : 69(2012)

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

Standard Details

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, inclOver 1 to 11/2, incl Over 1½ to 2, inclOver 2 to 21/2, inclOver 2½ to 3, inclOver 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
31406145TS414098404337
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
40688742516043374340TS4150
41409260 6150 8650 86B45
46409261 9262 8655
5145TS414050B60
515050B46 94B4051B60
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 1340D31404137
40375132 5135 3135D4135 4337
413094B3051404640 9840
5130 50B408637D
86308640
TS14B358740
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.

General Information

Status : Historical
Standard Type: Main
Document No: ASTM A400 : 69(2012)
Document Year: 1969
Pages: 8
  • Section Volume:
  • 01.05 Volume 01.05 Steel--Bars, Forgings, Bearing, Chain, Tool

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ASTM A400 : 69(2012)

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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
HBHRCHBHRCTo 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 50B3041354140