Galvanized steel sheet having excellent fatigue strength in resistance spot welding portion, and method for manufacturing same

Abstract

The present invention relates to a galvanized steel sheet having excellent fatigue strength in a resistance spot welding portion, and a method for manufacturing the same. A galvanized steel sheet according to one aspect of the present invention may include a base steel sheet and a zinc-based plating layer formed on a surface of the base steel sheet, in which a concentration distribution of oxygen and one or both of silicon and manganese measured in a depth direction from the surface of the base steel sheet may have a form showing a maximum point in the depth direction from the surface, the absolute value of the difference between the depth at which the maximum of the concentration distribution of oxygen is formed and the depth at which the maximum of the concentration distribution of one of silicon and manganese is formed may be 0.5 [mu] m or less.

Description

technical field [0001] The present invention relates to a galvanized steel sheet excellent in fatigue strength of a resistance spot welded portion and a method for producing the same. Background technique [0002] Due to problems such as environmental pollution, the control of vehicle exhaust and fuel efficiency is increasingly strengthened. Therefore, the demand for reducing fuel consumption by reducing the weight of automobile steel sheets is increasing, and thus various high-strength steel sheets with high strength per unit thickness have been developed and launched. [0003] High-strength steel generally refers to steel with a strength of 490 MPa or more, but it is not necessarily limited to this, transformation-induced plasticity (TRIP) steel, twin-induced plasticity (TWIP) steel, dual-phase (Dual Phase, DP) steel, complex phase (Complex Phase, CP) steel, etc. may belong to high-strength steel. [0004] In addition, automotive steel is supplied in the form of a plated...

AI Technical Summary

Problems solved by technology

[0005] However, when galvanizing the surface of a high-strength steel sheet, there is a problem that spot weldability deteriorates

That is, in the case of high-strength steel, the tensile strength is high and the yield strength is also high, so it is difficult to eliminate the tensile stress generated during welding by plastic deformation, so there is a high possibility of microcr

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