ASTM A588 / A588M

This specification covers high-strength low-alloy structural steel shapes, plates, and bars for welded, riveted, or bolted construction but intended primarily for use in welded bridges and buildings where savings in weight or added durability are important. The atmospheric corrosion resistance of this steel in most environments is substantially better than that of carbon structural steels with or without copper addition. When properly exposed to the atmosphere, this steel is suitable for many applications in the bare (unpainted) condition. This specification is limited to material up to 8 in. [200 mm] inclusive in thickness.

Chemical Properties

Grade CarbonA ManganeseA Phosphorus Sulfur Silicon Nickel Chromium Molybdenum Copper Vanadium Columbium
Grade A 0.19 max 0.80–1.25 0.04 max 0.05 max 0.30–0.65 0.40 max 0.40–0.65 ... 0.25–0.40 0.02–0.10 ...
Grade B 0.20 max 0.75–1.35 0.04 max 0.05 max 0.15–0.50 0.50 max 0.40–0.70 ... 0.20–0.40 0.01–0.10 ...
Grade K 0.17 max 0.50–1.20 0.04 max 0.05 max 0.25–0.50 0.40 max 0.40–0.70 0.10 max 0.30–0.50 ... 0.005–0.05B

Note:

A For each reduction of 0.01 percentage point below the specified maximum for carbon, an increase of 0.06 percentage point above the specified maximum for manganese is permitted, up to a maximum of 1.50 %.

B For plates under 1⁄2 in. [13 mm] in thickness, the minimum columbium is waived.

Mechanical Properties

Products Tensile Strength,
min, ksi [MPa]		 Yield point, min,
ksi [MPa]		 Elongation in 8
in. [200 mm],
min, %		 Elongation in 2
in. [50 mm],
min, %
Plates and Bars For Thicknesses
4 in. [100
mm] and
Under		 70 [485] 50 [345] 18B,C 21B,C
For Thicknesses
Over 4 in. [100
mm]
to 5 in. [125
mm] incl		 67 [460] 46 [315] ... 21B,C
For Thicknesses
Over 5 in. [125
mm]
to 8 in.[200
mm] incl		 63 [435] 42 [290] ... 21B,C
Structural
Shapes		 All 70 [485] 50 [345] 18C 21D

Note :

A See specimen orientation under the Tension Tests section of Specification A6/A6M.
B Elongation not required to be determined for floor plate.
C For plates wider than 24 in. [600 mm], the elongation requirement is reduced two percentage points. See elongation requirement adjustments in the Tension Tests section of Specification A6/A6M.
D For wide flange shapes with flange thickness over 3 in. [75 mm], elongation in 2 in. [50 mm] of 18 % minimum applies.

Products