High-temperature oxidation of four hot-work tool steels

Abstract

Hot-work tool steels have very good mechanical properties, especially strength, hardness and wear resistance at high temperatures. Therefore, hot-work tool steels are used for different applications, such as the high-pressure die casting of light alloys, the extrusion of polymers and forging. Since all these processes are operating at high temperatures, the main focus of this research was to investigate the high-temperature oxidation resistance of tool steels. We investigated the high-temperature oxidation at two different temperatures: 500°C and 700°C. The following tool steels were analyzed: HTCS-130, W600, RavnexHD and Dievar. Tests were made in an air atmosphere, while the heating and cooling were made in a controlled argon atmosphere. Simultaneous thermal analysis (STA 449 C Jupiter), scanning electron microscopy (SEM and EDS) and X-ray diffraction were used as the investigation methods. The results showed that during high-temperature oxidation at 500°C Dievar steel has the best oxidation resistance, followed by RavnexHD, HTCS-130 and W600. However, at 700°C the results were different, HTCS-130 had the best oxidation resistance, followed by Dievar, W600 and RavnexHD.

High-Temperature Oxidation Behavior of Cr-Ni-Mo Hot-Work Die Steels

“…The parabolic rate law was assumed for the sake of simplicity, and the approximate parabolic rate constants k ″ (oxidation constant) of the two test steels were calculated from Figure 2 using the equation: Δ W 2 = k ″ t where Δ W is the weight gain per unit area (mg·cm −2 ), and t is the oxidation time (h) [ 27 ]. The derived k ″ values are shown in Figure 3 with those from previous studies [ 28 , 29 , 30 , 31 ]. As shown in Figure 3 , the oxidation constant k ″ gradually increases as the oxidation temperature rises, indicating a gradual decrease in oxidation resistance with increasing temperature.…”

“… Parabolic rate constants k” of oxidation of two hot-work die steels at 600 °C. The other k” values of hot-work steels were reported by Tilen [ 28 , 29 ], Ziming [ 30 ], and Hong [ 31 ]. …”

Development Trend in Composition Optimization, Microstructure Manipulation, and Strengthening Methods of Die Steels under Lightweight and Integrated Die Casting

“…The new Dievar hot-working die steel from ASSAB Sweden is a premium steel grade developed specifically for the demanding applications of high-pressure die casting [ 36 , 37 ]. The die steel sets the industry benchmark for its superior toughness and ductility and the longest die life with a low risk of cracking.…”

Early Spalling Analysis of Large Particles in High-Cr Steel during Thermal Fatigue: Relevant Mechanisms

“…However, there are differences in the oxidation of chromium hot work tool steels. The choice of a an appropriate heat treatment and the addition of molybdenum slow down the oxidation process [ 2 ]. In addition, molybdenum-rich carbides are resistant to oxidation and remain intact, whereas the surrounding matrix is completely oxidized [ 1 , 3 ].…”