In view of the stamping cracking phenomenon of 440 MPa cold rolled steel strip,the failure causes were comprehensively analyzed by means of spectral composition analysis,microstructure observation under metallographic microscope and microscopic fracture inspection under scanning electron microscope.The results show that the composition and properties of the steel strip meet the requirements of the technical agreement.There are sulfide inclusions in some parts of the steel strip.During the stamping process,the stress concentration of the inclusions as the source induces cracks.By adding rare earth elements and calcium treatment to the liquid steel,inducing the inclusion denaturing treatment,or extending the refining stirring time to promote the inclusion floating in the liquid steel,the effect of purifying the liquid steel and optimizing the stamping performance can be achieved.
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