For the purposes of determining compliance with the specified limits for requirements of the properties listed in this specification, an observed value or a calculated value shall be rounded as indicated in accordance with the rounding method of Practice E29.

This specification covers four grades of wrought niobium and niobium alloy bar, rod, and wire as R04200-Type 1, reactor grade unalloyed niobium; R04210-Type 2, commercial grade unalloyed niobium; R04251-Type 3, reactor grade niobium alloy containing 1 % zirconium; and R04261-Type 4, commercial grade niobium alloy containing 1 % zirconium. The chemical; and mechanical properties requirements, such as Brinell hardness, tensile strength, yield strength, and elongations; as well as the temper designations are detailed.

1.1 This specification covers four grades of wrought niobium and niobium alloy bar, rod, and wire as follows:

1.1.1 R04200-Type 1—Reactor grade unalloyed niobium,

1.1.2 R04210-Type 2—Commercial grade unalloyed niobium,

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

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

1.2 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.

1.3 The following precautionary caveat pertains only to the test methods portion 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.