Investigate the Optimum Parameter and Weldment Performance for Induction Brazing of WC and SS420

• Main Authors: Di-Hsiang Chou, 周荻翔
• Other Authors: Shyankay Jou
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/amppr9

博士 === 國立臺灣科技大學 === 工程技術研究所 === 99 === Tungsten Carbide (WC) is a very hard, brittle and relatively expensive cermet. It is often joined to more economical material, such as martensitic 420 stainless steel (SS420), to form a hybrid cutting tool stock. This paper summarizes a study on the optimization of an induction brazing process joining these two materials using BAg-22 as filler metal. This study uses an integrated approach consisting of finite element analysis (FEA) modeling and experimental verifications. The results show that using the optimum process parameters derived from simulation, average joint strengths of 370 MPa for shear were obtained. The hardness in WC was unaffected by the brazing heat. However, softening in the SS420 next to the fusion interface was constantly observed in the experiments. After analysis it appears that this weakening phenomenon is due to localized carbide precipitation in SS420 arising from heating during the induction brazing process. Experimental results indicate that by reducing the heat input and using the proper copper fixing jig to enhance the cooling can avoid the softening caused during brazing process. The simulation results show that the best clamp position of end milling is on stainless steel 5 mm to the weld joint. The performance test shows that the cutting force for full WC and hybrid WC/SS420 is similar and the cutting force decrease as the rotating speed increases. But in micro observation of cutting force for hybrid WC/SS420, it can absorb the cutting force more than full WC end milling, which shows better resistance to breakage in WC tool.