Characterization of Tool Wear in High-Speed Milling of Hardened Powder Metallurgical Steels

Abstract

In this experimental study, the cutting performance of ball-end mills in high-speed dry-hard milling of powder metallurgical steels was investigated. The cutting performance of the milling tools was mainly evaluated in terms of cutting length, tool wear, and cutting forces. Two different types of hardened steels were machined, the cold working steel HS 4-2-4 PM (K490 Microclean/66 HRC) and the high speed steel HS 6-5-3 PM (S790 Microclean/64 HRC). The milling tests were performed at effective cutting speeds of 225, 300, and 400 m/min with a four fluted solid carbide ball-end mill ( = 6, TiAlN coating). It was observed that by means of analytically optimised chipping parameters and increased cutting speed, the tool life can be drastically enhanced. Further, in machining the harder material HS 4-2-4 PM, the tool life is up to three times in regard to the less harder material HS 6-5-3 PM. Thus, it can be assumed that not only the hardness of the material to be machined plays a vital role for the high-speed dry-hard cutting performance, but also the microstructure and thermal characteristics of the investigated powder metallurgical steels in their hardened state.

Correlating surface roughness, tool wear and tool vibration in the milling process of hardened steel using long slender tools

“…Using these Equations, and in order to obtain Rth¼0.20 mm in both directions, the values of a p and f z used here were 0.077 and 0.079 mm, respectively, for the tools with D ¼8 mm, and 0.095 and 0.096 mm for the tools with D ¼12 mm. These values are close to those recommended by the tool supplier, which suggests depth of cut values of around 0.01D for finishing operations [37] and also close to the value used by Klocke et al [38].…”

Optimization and wear characteristics of TiAlN coated carbide when machining hardened high thermal conductivity (HTCS-150) die steel.

“…Overall, tool wear was slightly decreased as the cutting speed increased from 120 m min −1 to 130 m min −1 . Klocke et al [19] demonstrated the same trend of cutting speed on tool wear, with increasing cutting speed resulting in a significant decrease in tool wear. The authors proposed that increasing the cutting speed would result in an increase in the cutting temperature at the contact zone.…”

Thermomechanical Treatment Influence on the Cutting Behaviour of the HSS Tools

“…By the applying a laser treatment for the tool surface is obtained a good layer hardness, thus as, the tool do not lose its working stability and to make the tool surface more resistant to action in external conditions. For the tool wear not only the hardness of the processed material has a vital role, but also the microstructure and thermal characteristics of the tool material (metallurgical powder) Klocke [3]. Under the action of the vibrations applied during welding, the material behavior is better: the density of the material deposited increases, tensions and friction of the basic material go down Luca [4].…”