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.
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:
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.
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.
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.
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.
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