ISO 630-4:2021

This document specifies qualities for high-yield-strength quenched and tempered structural steels. It applies to steel plates and wide flats rolled on a reversing mill which are used in the quenched and tempered condition and normally intended for welded or bolted structures.

This document covers 10 grades and 5 qualities. GradesS460Q, S500Q, S550Q, S620Q, S690Q, S890Q and S960Q are covered in AnnexA. GradesSG460Q, SG500Q, and SG700Q are covered in AnnexB. Not all grades are available in all qualities, and some qualities have Charpy V-notch requirements.

The steels specified in this document are applicable to hot-rolled flat products with a minimum nominal thickness of 3mm and a maximum nominal thickness of 200mm for grades S460Q, S500Q, S550Q, S620Q and S690Q, a maximum nominal thickness of 125mm for grades S890Q and S960Q, a maximum nominal thickness of 100mm for grades SG460Q and SG500Q and a maximum nominal thickness of 150mm for grade SG700Q.

This document does not include the following structural steels, some of which are covered by other International Standards:

— Sheet and strip— refer to ISOTC17/SC12, Continuous mill flat rolled products;

— Tubular products— refer to ISOTC5/SC1, Steel tubes.

NOTE1 Lists of standards covered by ISO/TC17/SC12 and ISO/TC5/SC1 are available on the ISO website.

NOTE2 In all parts of ISO 630, the term of "thickness" is considered as "nominal thickness", unless otherwise stated.