ASTM International

Standard Specification for Premium Quality Alloy Steel Blooms and Billets for Aircraft and Aerospace Forgings
 N A646/A646M

Annotation

This specification covers premium quality alloy steel semifinished rolled or forged blooms and billets for reforging into critical parts such as aircraft landing-gear forgings.

Blooms and billets, hereinafter referred to as blooms, are semifinished steel products, hot rolled or forged to approximate cross-sectional dimensions. Blooms may be square, round, hexagonal, octagonal, or rectangular in section. For the purposes of this specification, minimum bloom section size will be 16 in.2 [103 cm2].

This specification covers two basic classifications of steel:

Class I—Vacuum-induction melted or consumableelectrode vacuum melted, or other suitable processes which will satisfy the quality requirements of this specification.

Class II—Air-melted vacuum degassed.

Class III—Air melted electric furnace ladle refined and vacuum degassed

The values stated in either inch-pound or SI (metric) units are to be regarded separately as standards.Within the text and tables, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.

Unless the order specifies the applicable "M" specification the material shall be furnished to the inch-pound units.

*A Summary of Changes section appears at the end of this standard.