ASTM International Standard Specification for Niobium and Niobium Alloy Ingots ASTM B391-09

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.