Effect of Coating Thickness on the Characteristics and Dry Machining Performance of TiN Film Deposited on Cemented Carbide Inserts Using CFUBMS

Abstract

This study deals with the effect of coating thickness on the characteristics and dry machining performance of TiN film deposited on cemented carbide inserts using closed-field unbalanced magnetron sputtering (CFUBMS). The turning inserts were coated with TiN film of varying thickness ranging from 1.8 µm to 6.7 µm. The deposited coatings were characterized using grazing incidence X-ray diffraction (GIXRD), Vickers and Knoop microhardness tester, and scratch tester. The machining performance of uncoated and coated carbide inserts was evaluated in dry turning of C40 steel.

The in-house developed TiN-coated carbide insert exhibited around 16 times higher tool life compared to that of the uncoated insert. Performance test clearly showed the weakness of the uncoated K-type carbide relative to its TiN coated counterpart in machining of long chipping material like C40 steel. The present investigation clearly reveals that the developed TiN-coated tool has a potential for augmenting the cutting capability of uncoated K-type carbide, normally recommended for machining of short-chipping material like cast iron, for machining of even long-chipping material like steel.

Keywords:

• Adhesion
• CFUBMS
• Coating thickness
• Microhardness
• TiN
• Tturning

ACKNOWLEDGMENT

The authors gratefully acknowledge the funding support received from the Department of Science and Technology, Government of India, under DST-FIST program (sanction No. SR/FST/ET-11-003/2000 dated 20.5.2002).