Structure And Property Study Of The Wear-resistant And Heat-resistant Steel

For the wear-resistant and heat-resistant parts working at high temperature and abrasive wear, their material not only requires high-temperature strength and certain wear resistance, but also requires good oxidation resistance to meet the demand for their performance. According to the working condition of the wear-resistant and heat-resistant parts, this paper designs 10 groups composition of the wear-resistant and heat-resistant steel by the orthogonal experimental method reasonably. Their C, Cr, Ni, Si, Mn, N, Re, S and P content are almost same, but Ti and W content are different. The microstructure of the wear-resistant and heat-resistant steel at as-cast and at annealing is analyzed through the metallographical observing and X-ray diffraction. The oxidation resistance is studied on the wear-resistant and heat-resistant steel and 1Cr18Ni9 at 900℃ and 1100℃ respectively and the oxidation film of the wear-resistant and heat-resistant steel is analyzed through X-ray diffraction. Meanwhile, Brinell hardness test is carried on the wear-resistant and heat-resistant steel. The wear resistance of the wear-resistant and heat-resistant steel before and after oxidation is tested by ML-100 abrasive wear testing machine. The influence of Ti and W on the microstructure, hardness and wear resistance of the wear-resistant and heat-resistant steel is researched and analyzed.The experimental results are below. The microstructure of the wear-resistant and heat-resistant steel at as-cast is austenite + a small amount of ferrite + carbide. The ferrite in the matrix has disappeared and Cr₇C₃ carbide has transformed into Cr₂3C₆ carbide after annealing. And the microstructure is obviously thinning and uniform. Cr₂3C₆ and Cr₇C3 carbide exist along grain boundary and can hinder the grain boundary slipping effectively. The MC carbide exists dispersedly along the grain boundary and in the grain and can improve the strength of the steel. The wear-resistant and heat-resistant steels are totally oxidation resistant at 900℃ and oxidation resistant at 1100℃. Their surfaces have formed protective oxidation film and the oxidation film improves the service life of material under high-temperature.lCrl8Ni9 is both weak oxidation resistant at 900°C and 1100°C and it's surface hasn't formed protective oxidation film. So the wear-resistant and heat-resistant steels' oxidation resistance is obviously superior to lCrl8Ni9's. After oxidation at 900°C, the oxidation film of the wear-resistant and heat-resistant steel consists of C^Ch, spinel structure (FeCr2O4, NiCr2O4) and a small amount of Fe2(>3 and Fe3O4. After oxidation at 1100°C, the oxidation film consists of C^Ch, spinel structure (FeCr2O4, NiCr2O4) and Fe3C>4. With the content of Ti and W element increasing, the hardness and wear resistance of the wear-resistant and heat-resistant steel increase. It is because Ti and W combine with C to form a quantity of hard particle of TiC and WC. especially TiC, can raise the hardness and wear resistance of the wear-resistant and heat-resistant steel. It is significant to add proper content Ti element in wear-resistant and heat-resistant steel. The prototype castings of alumina thermal technic equipments with the wear-resistant and heat-resistant steel acquire good application in alumina factory of Shandong aluminium industry stock limited company.