Effect of AlTiN-coating oblique guillotine tools on their performance when shearing electrical steel sheets

Abstract

An AlTiN coating was deposited onto a cemented carbide oblique guillotine tool using arc ion plating technology to improve its shearing performance and wear resistance. Shearing experiments were subsequently conducted using sheets of electrical steel to study the performance of the coated and uncoated tools. Other important aspects, such as the quality of the shearing fracture surface, edge radius, shear force, and degree of tool wear, were also investigated as a function of shearing time. The results show that the performance of the AlTiN-coated tool is greatly superior to that of the uncoated tool. During the normal shear stage, the shear force of the coated tool was 14.7% less than that of the uncoated tool. The coated tool also suffered smaller amounts of tool wear and change in edge radius compared to the uncoated tool. Moreover, the electrical steel sheet sheared using the coated tool was found to have fracture surfaces of significantly higher quality than that sheared using the uncoated tool. Evidence of this can be seen in the larger sheared zones, lower fracture zones, shorter burrs, and much-reduced degree of work hardening obtained using the coated tool. The uncoated cemented carbide tool was mainly subjected to cobalt-loss induced wear, abrasive wear, and oxidative wear. The results indicate that the AlTiN coating is able to significantly improve the shear performance and service life of shearing tools.