Study On Integral Casting Process For Copper Water Jacket By Embeding Cu-Ni-Nb Copper Pipe Based On ProCAST

Cast copper cooling water jacket is a key cooling element in metallurgical furnaces. It not only realizes intensified metallurgy, but also can protect the metallurgical furnace and extend service life of furnaces. Cast copper cooling water jacket cooling effect is related to the thermal conductivity of Cu and interface between cast copper and pipe. However, the thermal conductivity of interface is determined by interface structure. For Cu / Cu water jacket, Cu pipes are easy to wear. For Cu/Fe water jacket, Cu/Fe have low mutual solubility and Fe has poor heat conduction. For Cu/Ni Cu alloy water jacket, interface can withstand high heat load, but NiCu has low thermal conductivity so that the surface of water jacket have high temperature, which are not conducive to the formation and reconstruction of furnace slag. In this paper,aiming at the difficulty of embedded copper pie, steel pipe and NiCu alloy pipes casting process, using CuNi30Nb3Fe1 alloy as embedded pipes and adopting the integral casting process of cast copper cooling water jacket, combining the process simulation of water jacket casting filling and solidification by using ProCAST software with experimental verification, the integral casting process of embedded cast copper cooling water jacket were optimized and the interface bonding state of cast copper and embedded pipes. The main conclusions are as follows.The size of water jacket test pieces size are 150 mm × 100 mm × 96 mm. The internal diameter of pipe is 36 mm and its wall thickness was 4 mm in the embedded Cu-Ni-Nb copper water jacket test pieces. According to solidification characteristics of copper casting pieces and structure characteristics of embedded water jacket test pieces, the pouring positions of water jacket casting pieces were selected. The risers were designed by proportion method. Three different casting process scheme were designed-openly pouring from the bottom, openly pouring from the middle and rain pouring from the top. Casting process simulation results show that when the pouring temperature is 1250℃ and the inlet velocity is 1.0m/S and the embedded preheating temperature is 250℃, mold filling are stable poured from the bottom and casting is no shrinkage porosity defects.Openly Pouring from the bottom was used in pouring system. Analyzing temperature simulation field in different pouring temperature water jacket test pipes by openly pouring, results show that when pouring temperature ranged from 1250 ℃to 1300 ℃, the highest temperature of five special position node on the outer surface of embedded pipe all reached its melting point 1185.32℃ and lasted for a period of time; the inner surface temperature of each node failed to meet its melting point. It explains that test pieces interface of water set would happen fusion and buried pipes were not melt. When the pouring temperature is 1350 ℃, the highest temperature on the inner surface of the embedded pipes is 1192℃. It exceed the melting point, and lasted about 29 s. The embedded pipes are most possibility fused.Under atmospheric conditions, the water jacket test pieces were molded by sand casting. Analyzing the interface fusion of the test pieces obtained by different pouring temperatures, the results show that when pouring temperature is 1200℃, interface between water jacket pieces is partly mechanically combined. When pouring temperature is 1250 ℃ or 1300 ℃, test interface of water jacket begin diffusion and fusion. Diffusion layers are wider in 1300 ℃. When pouring temperature are 1200℃,1250℃ and 1300 ℃, no clearance rate of water jacket test interface are 50.6%, 98.2%,98.5% correspondingly. When pouring temperature is 1350 ℃, the embedded pipes are worn.The simulation results are in agreement with the experimental results.The size of industrial water jacket casting pieces are 1080 mm × 460 mm ×100mm. The internal diameter is 36 mm and wall thickness is 4 mm for industrial embedded Cu-Ni-Nb copper water jacket test pieces. According to the solidification characteristic and large size structure of the embedded copper cooling water jacket casting pieces, its pouring positions were selected. The risers were designed by proportion method. Three different casting process scheme were designed-flatly pouring from the bottom, vertical pouring from the bottom and inclined pouring from the bottom. Casting process simulation results show that when the preheating temperature of pipes is 250℃, the inclined mold filling process poured from the bottom have no phenomenon of flying, turbulence and other phenomena. The filling process are basically stable. The solidification process realize the sequential solidification. The probability of shrinkage and porosity are very little. Aiming at inclined pouring process scheme, simulation results were optimized by increasing the size of riser and the feeding of riser. When the pouring temperature is 1250℃, the preheating temperature of the embedded pipes is 250℃and the inlet velocity is1.0m/S,simulation results show that casting have no shrinkage porosity defects.The inclined pouring from the bottom was used in pouring system. Thesimulation results of temperature field in different pouring temperature and preheating temperature show that the higher the pouring temperature is, the greater the fusion possibility of buried pipes are. When the pouring temperature is 1250℃ and 1300℃,the highest temperature of the pipes in the 0.6 mm and 2 mm wall thickness reach its melting point, and the melt time is about 35 s and 32 s respectively. The inner surface temperature did not reach melt points. Analyzing pouring temperature and the effect of preheating temperature on fusions, it confirm that when the preheating temperature of embedded pipes is 250℃ and pouring temperature is 1250 ℃~1300℃, it can basically guarantee for industrial embedded Cu-Ni-Nb copper water jacket interface to achieve good metallurgical bonding and the embedded pipes are not melt to wear.