Tool life and wear mechanism of uncoated and coated milling inserts

Abstract
A systematic study was conducted for face milling inserts cutting 4140 preheat treated steel. The flank wear of uncoated C5 carbide insert, as well as TiN, TiAlN, and ZrN coated inserts was evaluated and ranked. Tool life was expressed as the function of cutting speed and feed. This information is useful for production optimization. Wear mechanisms of attrition, abrasion, mechanical fatigue, and thermal fracture were identified and were represented by wear maps. The TiN and TiAlN coatings provided significant improvement in tool life. The ZrN coated inserts performed about as well as the uncoated C5 carbide inserts.