ASTM A 437/A437M : 2015 : R2021

1.1This specification2 covers stainless and alloy-steel bolting material and bolting components specially heat treated for high-temperature service, such as steam turbine, gas turbine, and similar uses. See Specification A962/A962M for the definition of bolting. This material requires special processing and should not be used in general-purpose applications. Bolting furnished as bars shall be hot wrought and may be further processed by centerless grinding or by cold drawing.

1.2The high-temperature properties of the bolting materials and components covered by this specification are dependent upon special heat treatment, which is required. Although the high-temperature properties are not specified, they are implied by control of the chemistry, heat treatment, and room-temperature properties of the bolting material.

1.3Three levels of bolting strength are covered, designated Grades B4B, B4C, and B4D.

1.4The following referenced general requirements are indispensable for application of this specification: Specification A962/A962M.

1.5Supplementary requirements are provided for use at the option of the purchaser. The supplementary requirements shall apply only when specified individually by the purchaser in the purchase order or contract.

1.6This specification is expressed in both inch-pound units and in SI units; however, unless the purchase order or contract specifies the applicable M specification designation (SI units), the inch-pound units shall apply.

1.7The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. 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 non-conformance with the standard.

1.8This 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.