Properties of High Temperature Oxidation of Heat-resistant Steel with Aluminium and Copper

Abstract

The research is focused on a novel aluminum and copper-containing heat-resistant steel. The steel was designed by the material performance simulation software JmatPro, performed high-temperature oxidation tests at 650 °C and 700 °C atmospheric conditions, and analyzed the high-temperature oxidation processes and its mechanisms.The phase transtions and surface morphology of the oxide films were studied using X-ray diffraction (XRD), electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The results showed that the equilibrium phase of the test steel is composed of γ phase and δ phase at 1050 °C and tranforms to tempered martensite and δ-Fe mixed structure after heat treatment. The preferential oxidation of Fe and Cr and the internal oxidation of Al occurred during the high temperature oxidation of the test steel. The oxide films were formed with various shape and weak bonding properties after high-temperature oxidation at 650℃. To the contrary, the oxide films more regular and evenly distributed, and has a certain protective effect after high-temperature oxidation at 700 ℃. The oxide films were divided into two layers, Fe2O3 is main element in the outer layer, the inner layer is mainly consisting the oxide of Cr. However, the addition of Cu element can promote the diffusion of Al and Si elements, which is beneficial to the formation of Al2O3 and SiO2 protective oxide films and excellent in high temperature oxidation resistance.

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 ]. …”

The Effect of Zr on the High‐Temperature Oxidation Resistance of 12Cr Ferritic/Martensitic Steels

“…Elements, like Cr, Si, Al, and Mn, are usually added to improve the oxidation resistance of steels by forming protective oxide layers, Cr 2 O 3 , SiO 2 , Al 2 O 3 , and Mn oxides, respectively. [16][17][18][19][20][21][22] The addition of rare earth elements also plays a significant role in improving the high-temperature oxidation resistance of steels. [23,24] As another common alloying element in steels, Zr, can not only improve the size and distribution of inclusions but also enhance the impact and creep resistance of steels.…”