Experimental Study on High-frequency Induction Brazing of PCD Compact
Post Date: 12 Oct 2010 Viewed: 528
The polycrystalline diamond (PCD) compact is composed of polycrystalline diamond layer and hard alloy layer. Due to PCD"s high hardness, high wear-resistance and high intension of hard alloy, the PCD compact has an outstanding cutting performance. The PCD cutting tool is composed of PCD compact and base material. It can be obtained by means of brazing with proper brazing filler alloy, soldering flux, a certain PCD compact and base material, then grinded with some methods. Nowadays, the high-frequency induction brazing is commonly used in the brazing of PCD compact. However, the PCD cutting tool sometimes can break off when it is used in practice because of PCD compact"s poor brazing technics. Thus, looking for proper brazing filler alloy and soldering flux and improving cutting tools" brazing performance become an urgent affair in the development of PCD cutting tools.Firstly, high-frequency induction brazing experiments were carried out in air atmosphere with three different brazing filler alloys, three different soldering fluxes and three different base materials, using high-frequency induction brazing machine GP15-CW6. The shearing experiments were carried out using cutting tools obtained in brazing experiment and the cutting tools" shearing strength was measured. The results of shearing experiment indicate that 1# filler alloy can contact hard alloy YD201 better than other filler alloys and 3# filer alloy contact 45# steel best in three filler alloys. Optimized arrangements of base material with brazing filler and soldering flux are 3# filler alloy-QJ102-45# steel and 1# filler alloy -F500A-YD201.Secondly, we found that there are three main breakage forms of cutting tools through looking into the pictures got in the shearing experiments: the break-off of tool head caused by air holes and inclusion disfigurements in the joints, fracture of PCD compact for its non-enough intensity, fracture of base material for its low intensity. There"re few situation that the tool head was broken off because of air holes and inclusion disfigurements in the joint, which indicates that the cutting tools" performance is good enough to be used in practice.Finally, the cutting tools" joints were observed by means of metalloscope and the scanning electron microscope (SEM) and the elements" distributions were investigated using the electron probe (EPMA). It can be found that most of the joints were combined excellently, with no obvious brazing disfigurement, and a transitional zone of solid solution between the filler alloy and hard alloy was created. But there"re also some disfigurements in some joints.