To provide a quenching method of a coated steel material, in which the damage of the coating layer of plated layer, etc., can be restrained and it is profitable to secure the original function of the coating layer of the plated layer, etc.
When the quenching treatment is applied to the coated steel material closely sticking the coating layer having lower m.p. or b.p. than that of the steel material on the steel material, the steel material is heated to the quenching temp. and cooled so that the basic structure of the steel material after quenching becomes the co-existing structure of ferrite and martensite. In this way, the transformation strain with the quenching treatment is restrained, and the damage, such as peeling of the coating layer, is restrained.
ONISHI MASAZUMI
NISHIO MASAHIRO
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