Analysis on Non-acid-resistance Causes and Influencing Factors of Cold-rooling and Black-annealing Carbon Steel Strip

The cause for appearing irregular splotches and etch pits on the surface of Q235 steel cold-rolling and black-annealing steel strip after acid cleaning and before galvanization was analyzed, and factors influencing the corrosion resistance of carbon steel strip were also studied by corrosion test. The results show that the main reason for production irregular splotches and etch pits was the uneven surface microstructure and the pearlite was gathered distribution. Material and microstructure state were the main influence factors of acid resistance of the carbon steel strip. Under the same acid corrosion conditions, the higher the carbon content was and the larger the deformation was, the more easily the steel strip was corroded.