Walter’s next-generation Silver Tiger CVD Inserts

First to be introduced will be the universal WKP 35S (S for Silver) insert for milling cast iron and steel workpieces. A customer trial on a 42CrMo4 steel forging with the Silver Tiger insert running at 260 m/min, 0.5 mm/rev feed and 3 mm depth of cut against the incumbent WK35 grade from Walter recorded a 70 per cent improvement in tool life. The high level of toughness and hardness is achieved through a new surface treatment that significantly reduces the in-cycle machining stresses of both wet and dry applications. The result is an insert that will compensate for any brittleness that may develop as a result of the CVD coating process. In addition, the CVD-Al2O3 grade coating counters any influence from thermal shock that can lead to thermal cracking at the cutting edge and minimise tribochemical wear on the flank face. The Silver Tiger designation reflects the insert's two-tone finish of glossy silver on its flank face and black on the rake angle face. Not only is this colour combination highly distinctive, but it also provides a practical indication of wear.