Thermal cracking of carbide tools during intermittent cutting

Wear progression of carbide tool in low-speed end milling of stainless steel

“…Comb cracks are more likely to form at high speeds since the amplitude of the temperature variation increases with increasing speed [9,10]. Several researchers had reported the formation of comb cracks at speeds of higher than 100 m/min [4,8,10,11]. Below this speed, no comb crack was formed, but attrition and chipping, due to mechanical loading and the unstable nature of the built-up edge, occurred.…”

Fatigue of Cemented Carbides

“…Relevance of thermal fatigue as the failure mechanism in hardmetal application (Bathia, Pandey, & Shan, 1978;Beste, Hartzell, Engqvist, & Axén, 2001;Chandrasekaran & Venkatesh, 1985;Engqvist et al, 2000; Figure 7 Temperature dependence of the mechanical behavior under cyclic loads for a hardmetal (a) and a cermet (b) between 25 and 900 C in air. Adapted from Kindermann et al (1999).…”

Application of Exponential Smoothing to Machining Precision of Nickel-based Superalloy Waspaloy

“…This superalloy is a hard-to-cut material in machining for the following reasons. (1)(2)(3)(4)(5)(6) (1) Work hardenability: boundary chipping and edge wear of the cutting clearance increase over time, the cuttings are tough and difficult to break off, and case hardening occurs. (7,8) (2) Low thermal conductivity: although general steel can generate cutting heat when being cut, most of the heat is carried away by the cuttings; however, as Waspaloy has low thermal conductivity, it readily accumulates the cutting heat of the tool and machined part; moreover, it has high yielding point, tensile strength, and cutting resistance, making it easy for the cutting edge to induce high pressure and temperature, and plastic deformation of the tool.…”