ASTM B391-03

1.1 This specification covers unalloyed and alloyed niobium ingots prepared by vacuum- or plasma-arc melting or electron-beam melting to produce consolidated metal for processing to various mill shapes.

Note 1—Committee B10 has adopted "niobium" as the designation for Element No. 41, formerly named "columbium."

1.2 The materials covered by this specification are:

1.2.1 R04200-Type 1—Reactor grade unalloyed niobium,

1.2.2 R04210-Type 2—Commercial grade unalloyed niobium,

1.2.3 R04251-Type 3—Reactor grade niobium alloy containing 1 % zirconium, and

1.2.4 R04261-Type 4—Commercial grade niobium alloy containing 1 % zirconium.

1.3 Unless a single unit is used, for example force for hardness testing in kN, the values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are for information only.

1.4 The following precautionary caveat pertains only to the test method portions of this specification: This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.