Coated inserts for rough milling

Abstract

Coated milling insert has a WC-Co cemented carbide with a low content of cubic carbides and a highly W-alloyed binder phase and a coating including an inner layer of TiCxNy with columnar grains followed by a layer of κ-Al2O3 and a top layer of TiN. The coated milling insert is particularly useful for milling of grey cast iron with or without cast skin under wet conditions at low and moderate cutting speeds and milling of nodular cast iron and compacted graphite iron with or without cast skin under wet conditions at moderate cutting speeds.

Description

CROSS-REFERENCES TO RELATED APPLICATIONS

[0001] The present application is a reissue of U.S. Pat. No. 6,638,609 B2, which claims the benefit of priority to Swedish Application No. 0004079-0 filed Nov. 8, 2000.FIELD OF THE INVENTION

[0002] The present invention relates to coated cemented carbide cutting tool inserts, particularly useful for milling of grey cast under wet conditions, preferably at low and moderate cutting speeds but also for milling of nodular cast iron and compacted graphite iron under wet conditions at moderate cutting speeds.BACKGROUND OF THE INVENTION

[0003] It is well known that for cemented carbide cutting tool inserts used in the machining of cast irons, the cutting edge is worn by different wear mechanisms such as chemical and abrasive wear but the cutting edge is generally also subjected to crack formation due to the intermittent cutting load, resulting in so called chippings and edge fractures caused by different types of cracks in the inserts.

[0004] Different type...