Ground Surface Integrity Research Articles

Surface Integrity of Grinding of Bearing Steel GCr15 with CBN Wheels

This paper gives the investigation on surface integrity of grinding of hardened bearing steel GCr15 with resin bonded cubic boron-nitride (CBN) wheels. CBN wheels, when well dressed, offer significant advantages compared with aluminium oxide wheels, especially at high metal-removal rates. The compressive residual stresses are only produced when CBN wheels are used, the harmful tensile residual stresses are formed very easily with aluminium oxide wheels. However, CBN wheels after dressing with SiC stick cannot get a good result, serious thermal damage and big surface roughness are induced on the ground surface. Two new dressing techniques— elastic dressing and ultrasonic vibration dressing have been advanced, they are successful in well dressing CBN wheels and make the wheels have a strong cutting capacity to obtain higher ground surface integrity. Our experiments show that in dry grinding of bearing steel GCr15 with CBN wheels boronization takes place, it can increase wear-resistance of the ground surface about 30%.

研削表面特性から解明したＢＯＲＡＺＯＮ ＣＢＮホイールの最適研削条件

An optimum grinding condition was found by making clear the relation among the grinding performance of CBN grinding wheel, the grinding mechanism and the ground surface integrity. Following results are obtained : (1) The ground surface integrity observed through grinding chips, ground surface state, residual stress, crystallinity, structure and hardness distribution take a turn for the worse in slipping area. (2) The degree of worse depends on the load rate put on cutting edges. (3) The condition which wheel life is the longest, i.e., (g/a)-2.29 l1.76 = 1.98 × 109 is an optimum grinding condition including the ground surface integrity.