【国外标准】 Standard Specification for Pearlitic Malleable Iron

This specification covers pearlitic malleable iron castings for general. The chemical composition of the iron shall be such as to produce the mechanical properties required by this specification. Hardness test and tensile test shall be made to conform to the requirements specified. The microstructure of the pearlitic malleable iron shall consist of temper carbon nodules uniformly distributed in a matrix of ferrite, pearlite, and tempered transformation products of austenite. All castings on visual examination, shall be sound and free from obvious shrinkage and porosity.1.1 This specification covers pearlitic malleable iron castings for general engineering usage at temperatures from normal ambient to approximately 750 °F [400 °C].1.1.1 For continuous service at temperatures up to 1200 °F [650 °C], design factors should be incorporated to compensate for possible property changes, as demonstrated by Marshall and Sommer2 and by Pearson.31.2 Without knowledge of casting geometry and process details, no quantitative relationship can 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 SI units or inch-pound units are to be regarded separately as standard. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in nonconformance with the standard.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.