ASTM B 391:2018

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. 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, 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. 1.4 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.