The invention relates to manufacturing of high-strength steel coated and plated plate
welding parts, in particular to a
welding flux, a high-strength steel workpiece, a
laser welding joint and a manufacturing method of the
laser welding joint. The solder comprises the following components in percentage by weight: more than or equal to 0.5% of C, 0-0.36% of trace
alloy elements, less than or equal to 2% of Mn, less than or equal to 2% of Si, more than or equal to 6% of 5C + Mn and more than or equal to 2.5% of Fe and other inevitable elements, the trace
alloy element is at least one of Nb, V and Ti elements, and the content of the Nb, V and Ti elements is not more than 0.12%. According to the method, an
aluminum coating does not need to be removed, and the
volume fraction of
lath martensite in the quenched final weld joint is larger than or equal to 90% by means of the
solid solution strengthening effect of C. According to the scheme,
alloy element addition is reduced, cost and
process control difficulty are lowered, thick
carbide is prevented from being formed, the
mechanical property and stability of a joint are improved, and the high
breaking strength and
ductility are achieved; the obdurability and the economical efficiency of the joint are improved.