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.
This abstract is a brief summary of the referenced standard. It is informational only and not an official part of the standard; the full text of the standard itself must be referred to for its use and application. ASTM does not give any warranty express or implied or make any representation that the contents of this abstract are accurate, complete or up to date.
1.1 This specification covers requirements for low-carbon age-hardening nickel-copper-chromium-molybdenum-columbium alloy steel forgings for pressure vessel components.
1.2 Forgings under this specification are available as Grades A or B. Grade A may be ordered in one or two classes as follows:
1.2.1 Grade A Class 1—Normalized-and-precipitation-heat-treated, providing a minimum yield strength of 55 ksi [380 MPa] and a minimum tensile strength of 65 ksi [450 MPa].
1.2.2 Grade A Class 2—Quenched-and-precipitation-heat-treated, providing a minimum yield strength of 65 ksi [450 MPa] and a minimum tensile strength of 75 ksi [MPa].
1.2.3 Grade A was the original steel composition in this specification.
1.3 Although the material is readily weldable, welding procedures are of fundamental importance and must be such as not to affect adversely the properties of the material, especially in the heat-affected zone. It is presupposed that welding procedures will be suitable for the material being welded.
1.4 Supplementary requirements, including those applicable in Specification A 788/A 788M, are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.
1.5 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 non-conformance with the standard.
1.6 This specification is expressed in both inch-pound and SI units. However, unless the order specifies the applicable “M” specification designation [SI units], the material shall be furnished to inch-pound units.
2. Referenced Documents (purchase separately) The documents listed below are referenced within the subject standard but are not provided as part of the standard.
A275/A275M Practice for Magnetic Particle Examination of Steel Forgings
A370 Test Methods and Definitions for Mechanical Testing of Steel Products
A388/A388M Practice for Ultrasonic Examination of Steel Forgings
A788/A788M Specification for Steel Forgings, General Requirements
E208 Test Method for Conducting Drop-Weight Test to Determine Nil-Ductility Transition Temperature of Ferritic Steels
E604 Test Method for Dynamic Tear Testing of Metallic Materials
ASME Boiler and Pressure Vessel Code--Section IX, Welding Qualifications
precipitation hardening steel; pressure containing parts; pressure vessel service; steel forgings—alloy; Age-hardening alloys--specifications; Alloy steel forgings--specifications; Nickel alloy forgings--specifications; Nickel-copper alloy steel--specifications; Precipitation-hardening metals/alloys--specifications; Pressure-containing parts; Pressure vessel steel forgings--specifications;
ICS Number Code 77.140.30 (Steels for pressure purposes)
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Citing ASTM Standards
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