Development Of Single-layer Brazed Super-hard Abrasive Forming Wheel Manufactured With Ultra-high Frequency Induction Brazing

Single-layer brazed superhard abrasive wheels have several advantages, such as high bonding strength, long tool life and high chip storage space, which also have excellent grinding performance in high efficiency grinding. However, due to high temperature during brazing, the thermal deformation of the wheel is beyond control. At present, the thermal deformation of the wheel could be minimized with the method of local induction heating, nevertheless this method have just been applied in manufacturing parallel grinding wheel with simple profile. There are no reports about the solution to the uneven temperature distribution of forming wheel with complex profile during induction brazing, which significantly limits the quality improvement of brazed superhard abrasive forming wheels.It is proposed that simplifying the complex profile of forming wheel to characteristic forming blade, in order to solve the problem of the uneven temperature distribution of the forming wheel with ultra-high frequency induction heating. The influences of different inductor structures on the temperature distribution of characteristic forming blade has been analyzed. Then the inductor structure used for induciton brazing of dovetail furrow forming wheel has been optimized to realize the uniform temperature distribution of the forming blade. The main contents in this paper are as follows:1)The research on forming wheel could be simplified to the analysis of concave and convex characteristic forming blade. The influences of coil and magnetizer structure on the temperature distribution of concave and convex characteristic forming blade have been analyzed. In order to improve the heating efficiency of concave profile, and reduce the convex heating efficiency at the same time, software, FLUX has been used to simulate the process of induction heating. The above research results provide the data base for optimization of the inductor structure used to ultra-high frequency induction brazing of forming wheel.2) Based on the research results of the characteristic forming blade temperature field, the influence of magnetizer length on the temperature field of forming blade has been analyzed. Brazed single-layer CBN forming wheel has been fabricated with structure optimized inductor by ultra-high frequency continous induction brazing. Moreover, the surface morphology and thermal deformation of the grinding wheel have also been evaluated. The results reveal that grits on the surface of the grinding wheel are orderly arranged, and the filler metal with no accumulation and oxidation phenomena is evenly distributed on the wheel surface. Meanwhile, it has been observed that the deformation of the wheel is less than 13μm after brazing, which is the same as the accuracy of the electroplated single layer CBN wheel.3)Experimental investigations have been carried out for high-efficiency profile grinding of the Ti-6Al-4V alloy. The performance of the grinding wheel has been evaluated in terms of grinding force, grinding temperature, ground surface dimension, contour precision, ground surface integrity and grinding wheel wear. It turns out that both the grinding force ratio and temperature are low under different grinding parameters conditions, which means that the CBN wheel has good sharpness. Moreover, the ground surface dimensional and contour precision can meet the design requirements, and abrasion wear is primary during the grinding process, which verified the strong retention strength to grains and satisfied grinding performance of the brazed wheel.