CAN/CSA-G40.21-M92

1.1 This Standard covers structural quality steel plates, shapes, hollow sections, sheet piling, and bars for general construction and engineering purposes. 1.2 A number of strength levels are available under this Standard and are designated by the minimum yield strength in megapascals. The grades, types, and strength levels normally available are shown in Table 1. Charpy V-Notch categories are shown in Tables 10A and 10B. The purchaser must specify the grade and, if applicable, the category. 1.3 The types of steel covered by this Standard are the following: (a) Type G - General Construction Steel. Steels of this type meet specified strength requirements; however, the chemical control is not such that all of these steels may be welded satisfactorily under normal field conditions. These steels are primarily designed for applications involving bolted connections or for welding under carefully controlled shop conditions. (b) Type W - Weldable Steel. Steels of this type meet specified strength requirements and are suitable for general welded construction where notch toughness at low temperatures is not a design requirement. Applications may include buildings, compression members of bridges, etc. (c) Type WT - Weldable Notch-Tough Steel. Steels of this type meet specified strength and Charpy V-Notch impact requirements and are suitable for welded construction where notch toughness at low temperature is a design requirement. The purchaser, in addition to specifying the grade, must specify the required category of steel that establishes the Charpy V-Notch test temperature and energy level. Applications may include primary tension members in bridges and similar elements. (d) Type R - Atmospheric Corrosion-Resistant Steel. Steels of this type meet specified strength requirements. The atmospheric corrosion resistance of these steels in most environments is substantially better than that of carbon structural steels with or without a copper addition*. When properly exposed to the atmosphere, these steels can be used bare (unpainted) for many applications. These steels may be welded readily up to the maximum thickness covered by this Standard. Applications include unpainted siding, unpainted light structural members, etc, where notch toughness at low temperature is not a design requirement. (e) Type A - Atmospheric Corrosion-Resistant Weldable Steel. Steels of this type meet specified strength requirements. The atmospheric corrosion resistance of these steels in most environments is substantially better than that of carbon structural steels with or without a copper addition.* When properly exposed to the atmosphere, these steels can be used bare (unpainted) for many applications. These steels are suitable for welded construction where notch toughness at low temperature is not a design requirement and are often used unpainted. Applications are similar to those for Type W. (f) Type AT - Atmospheric Corrosion-Resistant Weldable Notch-Tough Steel. Steels of this type meet specified strength and Charpy V-Notch impact requirments. The atmospheric corrosion resistance of these steels in most environments is substantially better than that of carbon structural steels with or without a copper addition.* When properly exposed to the atmosphere, these steels can be used bare (unpainted) for many applications. These steels are suitable for welded construction where notch toughness at low temperature is a design requirement. The purchaser, in addition to specifying the grade, must specify the required category of steel that establishes the Charpy V-Notch test temperature and energy level. Applications may include primary tension members in bridges and similar elements. *For methods of estimating the atmospheric corrosion resistance of low-alloy steels, see ASTM G101. (g) Type Q - Quenched and Tempered Low Alloy Steel Plate. Steels of this type meet specified strength requirements. While these steels may be readily welded, the welding and fabrication techniques are of fundamental importance and must not adversely a