รายละเอียดเอกสาร

This specification covers the standard requirements for low-carbon age-hardened nickel-copper-chromium-molybdenum-columbium alloy steel forgings for pressure vessel components. Materials shall be manufactured to a killed fine austenitic grain size, by vacuum degas melting process. Heat treatment shall be conducted, according to class, by: normalizing and precipitation hardening (Grade A, Class 1); liquid quenching and precipitation hardening (Grade A, Class 2); or double liquid-quenching, tempering, double austenitizing, and precipitation hardening (Grade B). Heat and product analyses shall be used to evaluate the conformance of forgings to required chemical compositions. Tensile, notch toughness, and Charpy impact requirements shall be examined, for which one of four sampling methods may be employed. One tension test and one impact test (for three samples) shall be made for each forging. Dimensions and finishes of the forgings shall conform to that specified by the purchaser. Repair welding shall also be performed only if permitted by the purchaser.