This specification covers cold-formed welded and seamless high-strength, low-alloy round, square, rectangular, or special shaped structural tubing for welded, riveted, or bolted construction of bridges and buildings and for general structural purposes where high strength and enhanced atmospheric corrosion resistance are required (Note 1). The atmospheric corrosion resistance of this steel in most environments is substantially better than carbon steel with or without copper addition (Note 2). When properly exposed to the atmosphere, this steel can be used bare (unpainted) for many applications. When this steel is used in welded construction, the welding procedure shall be suitable for the steel and the intended service.
| Elements | Heat Analysis | Product Analysis |
|---|---|---|
| Carbon, max | 0.20 | 0.24 |
| Manganese, max | 1.35 | 1.40 |
| Phosphorus, max | 0.15 | A |
| Sulfur, max | 0.05 | 0.06 |
| Copper, min | 0.20B | 0.18B |
A Because of the degree to which phosphorus segregates, product analysis for
this element is not technologically appropriate for rephosphorized steels unless
misapplication is clearly indicated.
B If chromium and silicon contents are each 0.50 minimum, then the copper
minimums do not apply.
| Tensile strength, min, ksi [MPa] | Yield point, min, ksi [MPa] | Elongation in 2 in. (50.8 mm) min, % |
|---|---|---|
| 70 000 (483) | 50 000 (345) | 19A |