ASTM A455 / A455M

This specification covers high-tensile strength carbonmanganese steel plates intended for welded pressure vessels.This steel is usually made to a semi-killed or capped deoxidation practice; however, at the purchaser’s or the steel producer’s option, the steel may be made silicon-killed or aluminum-killed.The maximum thickness of plates furnished under this specification shall be 3⁄4 in. [20 mm].For plates produced from coil and furnished without heat treatment or with stress relieving only, the additional requirements, including additional testing requirements and the reporting of additional test results, of Specification A20/A20M apply.

Chemical Properties

Carbon,	Manganese,C	Phosphorus	Sulfur	Silicon,D
0.33 maxA,B	0.79 - 1.30	0.025 maxA	0.025 maxA	0.13

Note: A Applies to both heat and product analyses.

B When the silicon is higher than 0.10 %, the carbon maximum shall be 0.28 %.

C For each reduction of 0.01 percentage point below the specified maximum for carbon, and increase of 0.06 percentage point above the specified maximum for manganese is permitted, up to a maximum of 1.50 % by heat analysis and 1.60 % by product analysis.

D At the purchaser’s or the producer’s option, silicon may be 0.40 % max on heat analysis, 0.45 % max on product analysis.

Mechanical Properties

Thickness	Tensile strength,min: ksi [MPa]	Yield strength,min: ksi [MPa]	Elongation in 8 in. [200 mm] min, %A	Elongation in 2 in. [50 mm] min, %A
Up to 0.375 in. [9.5 mm]	75–95 [515–655]	38 [260]	15	22
Over 0.375 to 0.580 in. [15 mm]	73–93 [505–640]	37 [255]	15	22
Over 0.580 to 0.750 in. [20 mm]	70–90 [485–620]	35 [240]	15	22

Products