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

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. The materials covered by this specification are R04200-Type 1 which is a reactor grade unalloyed niobium, R04210-Type 2 which is a commercial grade unalloyed niobium, R04251-Type 3 which is a reactor grade niobium alloy, and R04261-Type 4 which is a commercial grade niobium alloy. The ingot metal for all four types shall be vacuum or plasma arc melted, vacuum electron-beam melted, or any combination of these three methods. The materials shall conform to the required chemical composition for carbon, nitrogen, oxygen, hydrogen, zirconium, tantalum, iron, silicon, tungsten, nickel, molybdenum, hafnium, titanium, boron, aluminum, beryllium, chromium, and cobalt. The ingots shall also conform to the required maximum Brinell hardness.

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, for example, force for hardness testing in kN, 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 and health practices and determine the applicability of regulatory limitations prior to use.