图(a)为热轧态Q690NHH扫描组织,可以看出,由于水冷冷速较快,钢板组织为板条贝氏体+少量粒状贝氏体,700℃临界回火后,钢板组织转变为粒状贝氏体+M-A,进一步提高钢板的强韧性。
Figure (a) is the scanning structure of the hot rolled Q690NHH. It can be seen that due to the fast water cooling rate, the steel plate structure is lath bainite + a small amount of granular bainite. After the critical tempering at 700 ℃, the steel plate structure transforms into granular. Bainite + MA further improves the strength and toughness of the steel plate.