The Microstructure And Performance Research Of Pure Copper Prepared Through The Liquid Die Forging Technology

An advanced quality and high production processing was created by the liquid die forging technology. Under the rational technologic parameter, sample was showed that internal structure was tight, surface was luster and mechanical property was good. The experimental programming was made by controlling other parameters invariant and admitting a parameter variant. At the same time, important technological parameters of experiment were optimized, and operating instructions and requires were studied.T1,T2 electrolyzing copper(≥99.9%Cu) was selected to do the experiment as raw materials. The pure copper was prepared by liquid die forging and the process parameters was obtained as follows: (1) die forging pressure: 10MPa- 20MPa, (2) pouring temperature: 1100℃- 1200℃, (3) forging die preheated temperature : 200℃- 300℃, (4) starting pressurization time: 3s- 10s, (5) keeping pressure time: 20s-50s. The sample was processed and heat treatment. The heat treatment process parameters was selected as follows: (1) heat treatment temperature: 250℃-350℃, (2) heat treatment time: 1.5h-2.5h.By means of large-scale metallographic microscope MeF3 and scanning electron microscopy, the organization and tensile fracture of pure copper sample marking by liquid die forging are analyzed. On the basis of analysis, the result shows that the internal organization is tight, grains are very fine and tensile fracture has feather of dimple fracture. The density of pure copper which was prepared by the liquid die forging technology achieved 9.35g/cm~3, the density was improved about 4%, Comparing with that of pure copper prepared through metal mold casting (8.9g/cm~3). The room temperature tensile strength which is tested by the omnipotent materials testing machinery controlled by computer achieved 287MPa, was improved 80%, Comparing with that of pure copper prepared through metal mold casting(130- 150MPa). the HBRVU-187.5 optical sclerometer was used to test HBS of pure copper which was prepared by the liquid die forging technology, HBS achieved 87.9, was improved 30%, Comparing with that of pure copper prepared through metal mold casting(50- 60HBS). electric conductivity test showed that the electric conductivity of pure copper prepared by the liquid die forging technology achieved 101%IACS, met the demand of IACS. According to the test of friction&wear, the pure copper prepared by liquid die forging technology has better wear-resistance.By means of comparing macroscopical feature, microstructure, mechanical properties and electric conductivity of pure copper sample under different process parameter of liquid die forging technology. we can summarize the best parameter of liquid die forging technology: (1)die forging pressure: 20MPa, (2) pouring temperature: 1150℃, (3) forging die preheated temperature: 250℃. By means of comparing microstructure and performance of pure copper sample with different heat treatment process parameters (temperature and time), we can summarize the best parameter of heat treatment process parameters: (1) heat treatment temperature: 300℃, (2) heat treatment time: 2h.