This specification covers a precipitation hardening bolting material (UNS N07718) for high temperature service. The alloy shall be multiple melted using consumable electrode practice in the remelt cycle or shall be induction melted under vacuum. Requirements for solution treatment, precipitation heat treatment, straightening, and thread forming by rolling are detailed. Remelt ingots shall conform to the chemical composition requirements (as to chemical and product analyses) prescribed for the following elements: carbon, manganese, silicon, phosphorus, sulfur, chromium, cobalt, molybdenum, columbium, titanium, aluminum, boron, iron, copper, and nickel. Tensile, hardness, and stress rupture tests shall be performed and test specimen shall meet the requirements specified for tensile strength, yield strength, elongation, Brinell hardness, and stress rupture. The method of determining the minimum full size breaking strength for headed fastener is given. Metallography shall be taken for microstructure and macrostructure properties including grain size and flow lines.

1.1 This specification covers a precipitation hardening bolting material (UNS N07718) for high temperature service.

1.2 This specification is expressed in both inch-pound and in SI units. However, unless the order specifies the applicable "M" designation (SI units), the material shall be furnished to inch-pound units.

1.3 The values stated in either inch-pounds or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification.