1.1 This specification covers carbon steel castings for general applications that require up to 70 ksi [485 MPa] minimum tensile strength. Note 1 - The grades covered by this specification represent materials that are suitable for assembly with other steel castings or wrought steel parts by fusion welding. It is not intended to imply that all these grades possess the same degree of weldability or that the same welding techniques can be used on all castings. It is the responsibility of the purchaser to establish for himself a suitable welding technique. 1.2 Several grades and two classes of steel castings are covered, as indicated below. The grade and class desired shall be specified by the purchaser. 1.2.1 Grade N-1 - Chemical analysis only. 1.2.2 Grade N-2 - Heat-treated but not mechanically tested. 1.2.3 Grade U-60-30 [415-205] - Mechanically tested but not heat-treated. 1.2.4 Grades 60-30 [415-205], 65-35 [450-240], 70-36[485-250], and 70-40 [485-275] - Heat-treated and mechanically tested. 1.2.5 Class 1 and Class 2 steel castings shall be specified in accordance with 9.2. 1.3 The values stated in either inch-pound units or SI units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system are not exact equivalents; therefore, each system must be used independently of the other. Combining values from the two systems may result in nonconformance with the specification. Inch-pound units are applicable for material ordered to Specification A 27 and SI units for material ordered to Specification A 27M.