Renewable Carbide Performance Improvement And Process Optimization Studies

Since the birth of cemented carbide, the issue of recycling has been focused by in-group sources. Recycling of waste is in line with the national policy of recycling economy. It could reduce the consumption of resources and keep sustainable development of the cemented carbide industry. Meantime, it could prevent further deterioration of ecological environment. From this point, there are of great significance. In this paper, the core objective of study was the efficient use of second-source.First of all, combing of the actual situation of enterprises, zinc-process was optimized through adjusting the alloy size, the amount of zinc and zinc melting time. This way, recovery rate was improved and the impurity content of reclaimed material was reduced, too. Result shows that:the recovery rate and quality of reclaimed material could be insured under alloy size of below 5mm, melting time of more than 10 hours and the amount of zinc of about 1:1.Secondly, the chemical and physical properties of reclaimed material were tested by a series of detection methods. So, theoretical foundation was provided for the preparation of regenerated cemented carbide. Result shows that:reclaimed WC had regular shape, high degree of crystallinity, more adequate combined carbon and uneven distribution of size. Reclaimed Co powder had a dendritic shape, wider distribution of size and more rough Co grains. Meantime, reclaimed material often contained higher content of oxygen and Chemical impurities. All of these factors had a negative significant impact on the microstructure and properties of regenerated cemented carbide.Then, as a research object, WC-Co cemented carbide was produced with reclaimed WC powder and Co powder. One production technology of regenerated cemented carbide was worked out through adjusting parameter of carbon balance, milling time and sintering temperature. Result shows that:regenerated cemented carbide which possessed good comprehensive performance was prepared under carbon content of WC of 5.90%, sintering temperature of 1410℃and wet milling time of 48 hours; As defect affecting the property of regenerated cemented carbide, pore and inclusion become the fracture origin most possibly. Moreover, this defect was more obvious than traditional cemented carbide.Finally, the influence of rare earth oxide on the structure and properties of regenerated cemented carbide was studied with adding trace rare earth oxide Y2O3. To broaden the applied range of reclaimed material, the mechanism of action was discussed preliminarily. Result shows that: through adding trace rare earth oxide Y2O3, grain homogeneity and porosity of alloy got improved, the stability of a-Co in binding phase was enhanced also. Thus, the strength of alloy was improved to some extent and the feasibility of adding rare earth oxide to regenerated cemented carbide to enhance performance was proved.