Casting Production Of The Typical Defects Of The Tp2 Copper Tube And Properties

The TP2 copper tubes are widely applied to the air conditioning and refrigeration industry. With the development of air-conditioning industry towards to environmental protection, lower energy consumption and higher efficiency, the needs of high quality air-conditioning and refrigeration copper tubes increase quickly. The extrusion process is a traditional method for the TP2 copper tubes, in which continuous casting solid billet is extruded to hollow tube billet firstly and then drawn to tube. This method for production of copper tubes has the following disadvantages: long period, complicated process and high production cost. So it is not suitable for demands of the copper tube enterprises which pursue for the higher production efficiency and the lower cost. But the new cast & roll process method firstly cast to the horizontal continuous casting hollow tube billet, then roll by three-roller planetary rolling, and then spin to tubes. The copper tubes produced by cast & roll technology has stable performance, high productivity and low cost,it can satisfy use's requirements. Thus, it has widespread applications in the copper tube.In this paper, the cast-rolling process of the TP2 copper tube was investigated. Study of horizontal continuous casting, three-roll planetary rolling, pulling together the impact of internal thread TP2 copper tube. The main work was carried out in L and N Enterprises. The main contents are as follows:The two Enterprises process of TP2 copper tube was summarized and analyzed, and the various influencing factors of the TP2 copper tube were studied. The rule of the defects during the process and the relationship of the defects and the technological condition had been found, and some effective measures to prevent the defects were proposed. for the process of pulling together "Black Lines" phenomenon which L Enterprises recurring appear had been researched, and use finite element software simulation of the TP2 copper tube union pull technology. Results indicated that:(1) The continuous casting process is the key process. The quality of horizontal continuous casting tube billet affects the final product quality. The grain of casting blank which L Enterprise produced were oversize, affected the quality of the sequence processed products;(2) TP2 copper tube joint pull "Black Lines" is in fact micro-cracks, The reason for the formation of "Black Lines" is three-roll planetary rolling surface "bamboo marks of TP2 copper tube; (3) The simulation results can be seen: The "bamboo marks" is direct cause which caused surface "Black Lines" of copper tube. If we want reduce the copper tube surface "Black Lines", we should reduce the "bamboo marks" depth and increasing the "bamboo marks" width.(4) The continuous casting process is the key process, the grain of casting blank which L Enterprise produced were oversize, affected the quality of the sequence processed products. The copper tubes suffered two contrary processes both work-hardening and dynamic recrystallization softening during the roll process of the three-roll planetary, and obtained the dynamic recrystallization after the roll.