Many manufacturers of mold copper tubes are working hard to improve their service life. First, the single cone on the inner wall of the copper tube is designed as a multi-cone, which is developed to a parabolic surface. From the perspective of copper tube raw materials, from pure copper, phosphor bronze to silver copper and chromium zirconium copper. Advance thermal conductivity, improve deformation resistance and longevity. However, the traditional process of using hard chrome plating is still used in the coating of the inner wall of the copper pipe. The chrome plating layer has high hardness and good wear resistance, but the plating layer is thin and has fine cracks.
In addition, the thermal expansion coefficients of chromium and copper are very different. More transverse cracks appear when used at elevated temperatures. During continuous casting, molten steel penetrates the copper surface through cracks, producing more cracks. Therefore, in the long-term corrosion of molten steel, the chrome-plated layer will powder and fall off, and its wear resistance will be greatly reduced.