【国外标准】 Standard Specification for Wrought Zirconium and Zirconium Alloy Seamless and Welded Tubes for Nuclear Service (Except Nuclear Fuel Cladding)

16.1 For the purpose of determining compliance with the specified limits of property requirements, an observed value or a calculated value shall be rounded in accordance with the rounding method of Practice E29.Test Rounded Units for Observedor Calculated Value Chemical composition, tolerance (when expressed in decimals) nearest unit in the last right hand place   of figures of the specified limitTensile strength and yield strength nearest 1000 psi (10 MPa)Elongation nearest 1 %AbstractThis specification covers the standard requirements for wrought zirconium and zirconium alloy seamless and welded tubes for nuclear applications except for nuclear fuel cladding. Five grades of reactor grade zirconium and zirconium alloys with R60001, R60802, R60804, R60901, and R60904 UNS number designations are described. Material shall be made from ingots produced by vacuum arc melting, electron beam melting, or other melting process to be carried out in furnaces conventionally used for reactive metals. Seamless tubes may be made by billet extrusion with subsequent cold working, by drawing, swaging, or rocking, with intermediate annealing. Welded tubing shall be made from flat-rolled products by an automatic or semiautomatic welding process with no addition of filler metal and shall be cold reduced by drawing, swaging, or rocking. The products shall be in the recrystallized or cold-worked and stress-relieved conditions and shall be furnished by as-cold reducing, pickling, grounding, polishing, or end-saw cutting, machining, or shearing. Chemical and product analysis shall be performed on the materials which shall meet the chemical composition requirements for tin, iron, chromium, nickel, niobium, oxygen, and other impurity elements. The tensile properties shall be determined by a tensile test method and shall conform to the tensile strength, yield strength, and elongation limits. Steam and water corrosion tests and hydrostatic test shall be conducted to determine the acceptance criteria for corrosion and internal hydrostatic pressure, respectively. Burst properties, contractile strain ratio, grain size, and hydride orientation of the finished tubing shall also be determined.1.1 This specification covers seamless and welded wrought zirconium and zirconium-alloy tubes for nuclear application. Nuclear fuel cladding is covered in Specification B811.1.2 Five grades of reactor grade zirconium and zirconium alloys suitable for nuclear application are described.1.2.1 The present UNS numbers designated for the five grades are given in Table 1.1.3 Unless a single unit is used, for example corrosion mass gain in mg/dm2, the values stated in either inch-pound or SI units are to be regarded separately as standard. The values stated in each system are not exact equivalents; therefore each system must be used independently of the other. SI values cannot be mixed with inch-pound values.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.