Study on cooling process of copper tube after three-roll planetary rolling

Abstract

Copper tubes are efficient heat exchange parts in refrigeration industry, and their quality has a bearing on the grade of corresponding products. The cooling process of copper tube after three-roll planetary rolling is a key step in the production of copper tube by the casting and rolling method, and its cooling effect matters to the quality of copper tube products. Aiming at the characteristics of motion of a rolled piece in the through water cooling with a cooling water jacket, the method of “stepwise” moving cooling water jacket was used in this paper to achieve equivalence to the motion of the rolled piece, realizing finite element simulation of the whole process of three-roll planetary rolling and cooling of copper tube. The velocity field and pressure field of the fluid in the cooling water model were analyzed, and it was found that there existed a flow “dead zone” with the velocity below 8 m/s, there was a “negative pressure” phenomenon, and there were more eddy currents occurring. Through the study on the temperature field during the cooling process of the rolled piece, it was found that there was a phenomenon of non-uniform temperature distribution in the cooling process of the rolled piece. With the maximum temperature difference at each monitoring point in the cooling process of rolled piece as the evaluation criterion for the uniformity of temperature distribution in the cooling process of rolled piece, the process parameters affecting the rolled piece cooling effect, including the size of water inlet, the size of water outlet, and the pressure of entering water, were studied respectively, and the optimum process parameter values for improving the quality of rolled pieces were finally obtained. The accuracy of the model was verified by comparatively analyzing the metallographic microstructure and microhardness between the factory produced sample and the thermally simulated sample.