Defect Formation Mechanism and Influence of Processing Parameters on Surface Quality of Copper Clad Steel Composite Wires Prepared by Core-Cladding Continuous Casting
Copper clad steel (CCS) composite wires with the carbon steel core diameter of 8 mm and copper cladding thickness of 1 mm were prepared by core-cladding continuous casting method under argon protection. The effects of melt temperature, molten metal height and drawing velocity on the surface quality were investigated. The formation mechanisms of the surface defects were discussed. The results showed that CCS wires with good surface quality could be continuously fabricated at a melt temperature of 1120 to 1200°C, a molten metal height of 2 to 4 cm and a drawing velocity of 10 to 30 mm/min. Raising the melt temperature, increasing the molten metal height or decreasing the drawing velocity is in favor of improvements in the surface quality. Insufficient supplement of liquid copper during solidification shrinkage resulted in surface dimple. Transverse hot cracking and exposed steel defect appeared because the frictional force between cladding metal and mold was larger than the tensile strength of cladding metal under high temperature.