This specification covers high-strength low-alloy structural steel shapes, plates, and bars for welded, riveted, or bolted construction intended primarily for use as structural members where savings in weight [mass] or added durability are important. The atmospheric corrosion resistance of the 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 can be used bare (unpainted) for many applications (see Note 1). This specification is limited to material up to 4 in. [100 mm], inclusive, in thickness.
| Element | Composition, % |
|---|---|
| Type 1 | |
| Carbon, max | 0.15 |
| Manganese, max | 1.00 |
| Phosphorus, max | 0.15 |
| Sulfur, max | 0.05 |
| Copper, min | 0.20 |
| Plates and BarsA | Structural Shapes | |||||
|---|---|---|---|---|---|---|
| For thicknesses 3⁄4 in.[20 mm], and under | For thicknesses over3⁄4 to 11⁄2 in. [20 to 40 mm], incl | For thicknesses over11⁄2 to 4 in. [40 to 100 mm], incl | For flange or leg thicknesses 1.5 in. [40 mm] and under | For flange thicknesses over 1.5 in. [40 mm] to 2 in. [50 mm], incl | For flange thicknesses over 2 in. [50 mm] | |
| Tensile strength, min, ksi [MPa] | 70 [480] | 67 [460] | 63 [435] | 70 [485] | 67 [460] | 63 [435] |
| Yield point, min, ksi [MPa] | 50 [345] | 46 [315] | 42 [290] | 50 [345] | 46 [315] | 42 [290] |
| Elongation in 8 in. [200 mm], min, % | 18B,C | 18B,C | 18B,C | 18C | 18 | 18 |
| Elongation in 2 in. [50 mm], min, % | 21C | 21C | 21C | 21 | 21 | 21D |
A. See the Orientation subsection in 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
the Elongation Requirement Adjustments subsection in the
Tension Tests section of Specification A6/A6M.
D. For wide flange shapes over 426 lb/ft [634 kg/m], elongation in 2 in. [50 mm] of 18 % minimum applies.