Abstract: When the H-beam is hot-rolled, there are cracks on the surface.And the causes of the cracks were analyzed by chemical composition inspection, metallographic observation, scanning electron microscope and energy spectrometer.The results show that the cracks are enriched with low-melting impurity elements such as copper, and copper causes hot brittle cracks on the surface of the billet.The high residual copper content in the steel is the main reason of the surface cracks.In order to reduce or avoid the influence of residual copper on the hot workability of the steel, the content of residual copper must be strictly controlled during production, and scrap steel should be used rationally.