The type of wear on the latest coated cemented carbide inserts for stainless steel machining has been studied with machining tests on SANMAC SAF 2205. The results have been compared with the wear of inserts when machining SAF 2205 standard grade and two different AISI 329 grades.

A test method that emphasises the effect of discontinuous wear such as chipping, flaking and notch wear has been used. The results are presented as the volume of produced chips for one cutting edge. Five different cutting speeds, from 100 to 225 m/minute, have been tested. This method of presenting machinability results has been chosen, instead of the more common Taylor relationship, due to the big difference in types of wear when machining the materials under investigation.

All results are based on general turning tests. However, the results could also be applied to other types of metal cutting operations if the deformation speed in the chip forming process and the temperature are taken into consideration.

Special attention has been paid to the development of wear on the inserts. All types of wear have been noted, but crater wear only for the standard SAF 2205 material. In all tests plastic deformation is an active type of wear. The effect of discontinuous wear types decreases with increased machinability.

The results show that it is possible to improve the machinability of SAF 2205 resulting in delayed and decreased effects of irregular types of wear. This means that it is possible to use more wear resistant insert grades to further increase the benefits of improved machinability SANMAC SAF 2205. This will also result in more consistent tool-life when machining SANMAC SAF 2205.