ASTM A748/A748M-87(2022)

ABSTRACT 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. SCOPE 1.1 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, the design strength of which is based on the gray iron portion of the cylinder. The castings are suitable for service at temperatures up to 450 °F [232 °C]. 1.2 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. 1.3 The following safety hazards statement pertains only to the test method portion, Section 9, 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. 1.4 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.