ASTM A420-2019 pdf free download

ASTM A420-2019 pdf free download.Standard Specification for Piping Fittings of Wrought Carbon Steel and Alloy Steel for Low-Temperature Service
1. Scope
1.1 This specification 2 covers wrought carbon steel and alloy steel fittings of seamless and welded construction, cov- ered by the latest revision of ASME B16.9, ASME B16.11, MSS SP-79, MSS SP-83, MSS SP-95, and MSS SP-97. Fittings differing from these ASME and MSS standards shall be furnished in accordance with Supplementary Requirement S58 ofSpecification A960/A960M. These fittings are for use in pressure piping and pressure vessel service at low tempera- tures. 1.2 Optional supplementary requirements are provided for fittings where a greater degree ofexamination is desired. When desired, one or more ofthese supplementary requirements shall be specified in the order. 1.3 This specification is expressed in both inch-pound units and in SI units. However, unless the order specifies the applicable “M” specification designation (SI units), the mate- rial shall be furnished to inch-pound units. 1.4 The 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.
5. Material
5.1 The starting material for fittings shall be fully killed steel, consisting offorgings, bars, plates, sheet, and seamless or fusion welded tubular products with filler metal added and shall conform to the chemical requirements in Table 1. The steels shall be made using recognized melting practices neces- sary to produce steels that shall meet the impact requirements of this specification.
6. Manufacture
6.1 Forging or forming operations shall be performed by hammering, pressing, piercing, extruding, upsetting, working, bending, fusion-welding, or machining, or by a combination of two or more of these operations. The forming procedure shall be so applied that it will not produce injurious defects in the fittings. 6.2 All welds, including welds in tubular products from which fittings are made, shall be (1) made by welders, welding operators and welding procedures qualified under the provi- sions ofASME Section IX, (2) heat treated in accordance with Section 7 of this specification, and (3) nondestructively exam- ined throughout the entire length of each weld in accordance with Section 15 of this specification. The radiography of welds shall be done either prior to or after forming at option of manufacturer. Personnel performing NDE examinations shall be qualified in accordance with SNT-TC-1A. 6.3 The welded joints of the fittings shall be finished in accordance with the requirements of Paragraph UW-35 (a) of Sectio n VIII, Division 1 of ASME Boiler and Pressure Vessel Code. 6.4 All butt-weld tees manufactured by cold-forming meth- ods shall be liquid penetrant or magnetic particle examined by one of the methods specified in Supplementary Requirement S52 or S53 of Specification A960/A960M. This examination shall be performed after final heat treatment by NDE personnel qualified under the provisions of SNT-TC-1A. Only the side- wall areas of the tee need be examined. This area is defined by a circle that covers the area from the weld bevel of the branch outlet to the centerline of the body or run. Internal and external surfaces shall be examined when size permits accessibility. After the removal of any cracks, the tees shall be re-examined by the original method. Acceptable tees shall be marked with the symbol PT or MT, as applicable, to indicate compliance. 6.5 Stubends may be produced with the entire lap added by the welding of a ring, made from plate or bar of the same alloy grade and composition, to the outside of a straight section of pipe, provided the weld is double welded, is a full penetration joint, satisfies the requirements of 6.2 for qualifications and radiography and 7.1 for post weld heat treatment.