Home>ASTM Standards>ASTM A748-87(R2018) pdf free download

ASTM A748-87(R2018) pdf free download

ASTM A748-87(R2018) pdf free download.Standard Speci fication for Statically Cast Chilled White Iron-Gray Iron Dual Metal Rolls for Pressure Vessel Use
1. 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 accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
3. Ordering Information
3.1 Orders for material under this specification shall include the following information: 3.1.1 ASTM designation and year of issue, 3.1.2 Dimensions of dual rolls, 3.1.3 Class of gray iron in the roll core (see 4.2), 3.1.4 Inspection requirements, if different (see 10.1), 3.1.5 Certification, if required (see 11.1), and 3.1.6 Special position of marking information, if required (see 12.1). 3.2 Any additional requirements not covered in this speci- fication are subject to agreement between the manufacturer and purchaser.
4. Materials and Manufacture
4.1 The melting procedure shall be optional with the foundry. 4.2 The chilled white iron exterior of the roll body shall be made to a minimum hardness of 60 Scleroscope “C.” The gray iron portion of the roll shall conform to the applicable class of Specification A278/A278M, as determined by design require- ments. The scope of this specification shall include Nos. 20, 25, 30, 35, 150, 175, 200, and 250 of Specification A278/A278M. 4.3 The casting process shall be controlled to produce a metallurgical bond between the chilled white iron exterior and gray iron interior of the roll body.
5. Test Requirements
5.1 Tensile Requirements—Tensile bars removed from a prolongation at one end of the roll journal, in accordance with Specification A278/A278M, shall have a tensile strength not less than 80 % of that specified by the applicable class of Specification A278/A278M. 5.2 Thickness of Chilled White Iron: 5.2.1 The thickness of the clear chilled white iron plus the mottled iron at the roll face shall not be more than 30 % of the total finished wall thickness.
10. Inspection
10.1 The inspector representing the purchaser shall have free entry at all times, while work on the contract of the purchaser is being performed, to all parts of the manufacturer’s works that concern the manufacture of the material ordered. The manufacturer shall afford the inspector all reasonable facilities to satisfy him that the material is being furnished in accordance with this specification. Unless otherwise specified, all tests and inspections shall be made at the place of manufacture prior to the shipment, and shall be so conducted as not to interfere unnecessarily with the operation of the works.

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