ASTM A 748/A 748M

This specification covers statically cast dual metal rolls with the outer layer of the roll body being chilled white iron of different chemical composition than the core and journals of the roll which is gray cast iron. The castings are suitable for pressure containing parts such as pressure vessels, the design strength of which is based on the gray iron portion of the cylinder, and for service at the specified temperatures. The melting procedure shall be optional with the foundry and the casting process shall be controlled to produce a metallurgical bond between the chilled white iron exterior and gray iron interior. The chilled white iron exterior shall be made to the specified minimum hardness and the gray iron portion of the roll shall conform to the applicable class as determined by design requirements. The roll shall conform to the tensile strength requirement to be determined by tensile test and shall meet the required thickness. All surfaces shall be machined or ground, or both, prior to the rolls being placed into service.