Active Standard ASTM A921 / A921M | Developed by Subcommittee: A01.15
Book of Standards Volume: 01.05
Historical (view previous versions of standard)
This specification covers hot-wrought, special quality microalloyed carbon steel bars intended for use as hot forging stock. The bars shall be hot-wrought, as-wrought, unless thermal treatment is necessary to ensure cold shearability. The steel specimens shall be killed and shall conform to the fine grain size requirement. Heat analysis and product analysis shall be performed wherein the specimens shall conform to the required chemical compositions of vanadium, columbium, and molybdenum.
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1.1 This specification covers hot-wrought, special quality microalloyed carbon steel bars intended for use as hot forging stock. The bars shall be hot-wrought, as-wrought, unless thermal treatment is necessary to ensure cold shearability.
1.2 The bars shall be furnished to chemical composition only. Chemical composition is based on standard carbon steel grades modified to include microalloying elements such as columbium (niobium), vanadium, or molybdenum. Desired mechanical properties are developed in the subsequent hot forging and controlled cooling operations.
1.3 Sections and sizes of bar steel available are covered in Specification A29/A29M.
1.4 Supplementary requirements S1 to S6 are provided for use when additional controls or requirements are desired. These shall apply only when specified on the purchase order.
1.5 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text and tables, 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.
1.6 Unless the order specifies the applicable “M” specification designation, the material shall be furnished to the inch-pound units.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A29/A29M Specification for Steel Bars, Carbon and Alloy, Hot-Wrought, General Requirements for
A576 Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality
A788/A788M Specification for Steel Forgings, General Requirements
E45 Test Methods for Determining the Inclusion Content of Steel
ICS Number Code 77.140.20 (Steels of high quality)
UNSPSC Code 31132100(Steel forgings); 30263600(Carbon steel bars)