【国外标准】 Standard Specification for Tantalum and Tantalum Alloy Ingots

8.1 For the purpose of determining compliance with the specified limit for requirements of the properties listed in the tables, an observed value or a calculated value shall be rounded as indicated in accordance with the rounding method of Practice E29.AbstractThis specification covers unalloyed and alloyed tantalum ingots prepared by vacuum-arc melting, electron-beam melting, or powder-metallurgy consolidation to produce consolidated metal for processing to various mill shapes. The materials covered by this specification are classified according to types: R05200; R05400; R05255; R05252; and R05240. The ingot metal for types R05200, R05255, R05252, and R05240 may be prepared by vacuum-arc melting, electron beam furnace melting, or a combination of these two methods. The metal for type R05400 is defined as powder-metallurgy consolidation unalloyed tantalum. The material shall conform to the chemical composition requirements for carbon, oxygen, nitrogen, hydrogen, niobium, iron, titanium, tungsten, molybdenum, silicon, nickel, and tantalum.1.1 This specification covers unalloyed and alloyed tantalum ingots prepared by vacuum-arc melting, electron-beam melting, or powder-metallurgy consolidation to produce consolidated metal for processing to various mill shapes.1.2 The materials covered by this specification are:1.2.1 R05200, unalloyed tantalum, electron-beam furnace or vacuum-arc melt, or both,1.2.2 R05400, unalloyed tantalum, powder-metallurgy consolidation,1.2.3 R05255, tantalum alloy, 90 % tantalum 10 % tungsten, electron-beam furnace or vacuum-arc melt, or both,1.2.4 R05252, tantalum alloy, 97.5 % tantalum 2.5 % tungsten, electron-beam furnace or vacuum-arc melt, or both, and,1.2.5 R05240 tantalum alloy, 60 % tantalum 40 % columbium, electron-beam furnace or vacuum-arc melt, or both.1.3 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.