ASTM A420 / A420M

This specification covers wrought carbon steel and alloy steel fittings of seamless and welded construction, covered 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 of Specification A960/A960M. These fittings are for use in pressure piping and pressure vessel service at low temperatures.

Chemical Properties

Grade	Carbon	Manganese	Phosphorus	Sulfur	Silicon	Nickel	Chromium	Molybdenum	Copper	Columbium	Vanadium

Note B: By agreement, the limit for Columbium may be increased up to 0.05 % on heat analysis and 0.06 % on product analysis. Note C: Fittings made from plate or forgings may have 0.90 % max manganese. Note D: Fittings made from plate may have 0.98 % max manganese.

Mechanical Properties

Grade	Tensile strength, min ksi [MPa]	Yield strength, min, ksi [MPa] (0.2 % offset)

Note C: Fittings made from plate or forgings may have 0.90 % max manganese. Note D: Fittings made from plate may have 0.98 % max manganese.

Grade	Elongation
	Standard round specimen, min % in 4 D		Rectangular specimen for wall thickness 5/16		Rectangular specimen for wall thickness less than 5/16
	Longitudinal	Transverse	Longitudinal	Transverse	Longitudinal	Transverse

Note A: For each 1/₃₂ in. [0.79 mm] decrease in wall thickness below 5/₁₆ in. [7.94 mm], a deduction of 1.5 % (grades WPL6, WPL9, and WPL3) or 1.25 % (WPL8) for longitudinal and 1.0 % (grades WPL6, WPL9 and WPL3) for transverse from the values shown above is permitted. The following table gives the minimum value for various wall thicknesses: Note C: Fittings made from plate or forgings may have 0.90 % max manganese. Note D: Fittings made from plate may have 0.98 % max manganese.