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 five grades of wrought niobium and niobium alloy strip, sheet, and plate. These are reactor grade unalloyed niobium (R04200-Type 1), commercial grade unalloyed niobium (R04210-Type 2), reactor grade niobium alloy containing 1% zirconium (R04251-Type 3), commercial grade niobium alloy containing 1% zirconium (R04261-Type 4), and RRR grade pure niobium (R0xxxx-Type 5). The RRR grade pure niobium is used in superconducting applications that require ultra high purity, making it conducive to very large grains that can adversely affect formability. It is therefore not recommended for other applications. The materials shall be made from ingots produced by vacuum or plasma arc welding, vacuum electron-beam melting, or a combination of these three methods. The various niobium mill products covered by this specification are formed with the conventional extrusion, forging, swaging, rolling, and drawing equipment normally available in metal working plants. Samples for chemical and tension testing shall be taken from the finished material after the metallurgical processing to determine conformity to this specification. The samples may be taken prior to final inspection and minor surface conditioning by abrasion and pickling shall be representative of the finished product.