This part of ISO 630 specifies qualities for high-yield-strength quenched and tempered structural steels. This part of ISO 630 applies to steel plates rolled on a reversing mill which are used in the quenched and tempered condition and normally intended for welded or bolted structures. This part of ISO 630 does not include the following structural steels, some of which are covered by other International Standards: — Sheet and strip — refer to ISO TC 17/SC 12, Continuous mill flat rolled products; — Tubular products — refer to ISO TC 5/SC 1, Steel tubes. NOTE Lists of standards covered by ISO/TC 17/SC 12 and ISO/TC 5/SC 1 are available on the ISO Web site. This part of ISO 630 covers 10 grades. Grades S460Q, S500Q, S550Q, S620Q, S690Q, S890Q and S960Q are covered in Annex A. Grades SG460Q, SG500Q, and SG700Q are covered in Annex B.