Study on Grindability of Cutting Tool Materials (1st Report)

This is a report on grinding action of high speed steels in constant feeding load, that is, free infeed plunge-cut grinding. A grinding wheel is WA46G6V and the used high speed steels are SKH4 (18-4-1-10) and HV5. The latter is said to be improved in the resistance of tool wear behaviour by adding high vanadium and high carbon. The relations between grinding ratio, grinding force and grinding time are obtained. The wheel wear in grinding is observed by a micro-scope also. The conclusions are as follows. 1. Though a small difference in grinding force between SKH4 and HV5 is observed, SKH4 differs remarkably from HV5 in grinding ratio. The grinding ratio of SKH4 is far better than HV5 in both this value and in a tendency of G-t curves. 2. The poor grinding raio of HV5 will make it difficult to apply it to multiple teeth cutter in the grinding accuracy. SKH4 is more preferable than HV5. 3. The wear, fracture and breakdown of a grinding wheel grains progress rapidly in case of high load. 4. The free infeed plunge-cut grinding process is seemed to be severer in view of the poor grinding ratio than the conventional grinding method of high speed steels.