【国外标准】 Standard Specification for Cupola Malleable Iron

This specification covers malleable irons for castings made by the cupola process. The chemical composition of the iron shall be such as to produce materials that meet the mechanical property requirements. The tensile test methods for malleable iron are presented in details. At least three tensile test specimens shall be cast from a representative ladle of iron from each 4-h pour period during the purchaser's castings were poured. Only one test specimen need be tested to qualify each pour period and heat treatment batch provided the requirements of this specification are met by the test specimen. The microstructure of the malleable iron shall consist of temper carbon nodules uniformly distributed in a ferritic matrix and shall be free from excessive pearlite, massive carbides, and primary graphite. All castings, on visual examination shall be sound and free from obvious shrinkage and porosity.1.1 This specification covers malleable irons for castings made by the cupola process.1.2 Without knowledge of casting geometry and process details, quantitative relationships cannot be stated between the properties of the iron in the various locations of a casting and those of a test bar cast from the same iron.1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.1.4 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.