2014-02-04

A clear-cut combination

Machining is only cost-efficient with the right cutting tool material. With Tiger·tec Silver® WMP20S, Walter offers a new, thin CVD coating, which combines the best of both worlds: It is both sharp and wear-resistant.Walter AG has not exaggerated with regard to the new cutting tool material: Thanks to a thin coating of Tiger·tec Silver®, WMP20S combines two characteristics, which until now have often been contradictory: Sharp-cutting geometries and a wear-resistant CVD layer.

As tough materials, stainless steels in the ISO M material group require indexable inserts with sharper cutting edges. However, when machining commercial steels such as ISO P, the wear resistance of the tool is paramount, generated in part by the precise cutting edge shape. Walter already offers solutions for both areas of application, with the cutting tool material grades Tiger·tec® WSM (PVD coating) and Tiger·tec Silver® WPP..S (CVD coating). The new member of the Tiger·tec Silver® product family, WMP20S, is right in the middle.

What makes this new cutting tool material so special? Johannes Seifer, from Turning Product Marketing at Walter AG, Tübingen, small batch specialist gives three answers to this question:

We will not replace our tried and tested WSM- and WPP.S grades. They have their rightful place in mass production. The strengths of WMP20S lie in small batch and prototype production. Here, manufacturers are not always willing to stock the necessary grade range of indexable inserts which are required for machining both ISO M and ISO P materials. With WMP20S, significant cost savings can be achieved in this regard by reducing insert inventory.

Thin and strong. WMP20S is only half as thick as conventional CVD coatings. Nevertheless, we achieve the required stability and wear resistance by using our Tiger·tec Silver® technology, which has been established since 2011. An additional mechanical post-treatment transforms the tensile stresses, which result from cooling the indexable insert after applying the CVD coating, into compressive stresses. This in turn provides a special residual stress state, which has a positive effect on the performance of the indexable insert.

Combines all-rounder: Some customers do not want to do without a sharp edge, but at the same time, need longer tool life. In the food and medical industries, stainless steel is used above all for reasons of hygiene. Here, WMPS20S provides an alternative to our long-established WSM grades. In some respects, the cutting tool material may be a compromise, but it combines the best from the worlds of ISO P and ISO M machining: You could say, a real universal cutting tool material.

An overview of Tiger·tec Silver® WMP20S:

  • Primary application of ISO M: Machining stainless materials, such as X5CrNi18-10, AISI 304 (1.4301) and X6CrNiMoTi17-12-2, 316Ti (1.4571)
  • Primary application of ISO P: Machining steels, such as 42CrMo4, 100Cr6 and C45
  • Secondary application of ISO S: Materials such as Inconel 718