Research of Microstructure and Property of Laser Alloying on the Surface of P20 Steel Compared with Nitriding

Abstract

The experiment of laser alloying on the surface of P20 steel was made. Tungsten carbide (WC) powder was used as alloying material. The microstructure and property of laser alloying layer and nitriding layer are studied. The research showed that laser alloying layer had better properties such as minute crystals, deeper layer, higher hardness and good metallurgical bonding with base metal. The average hardness of alloying zone was 600HV0.2. The average hardness of phase-change hard zone was 450HV0.2. P20 steel was widely used in the field of plastic mold manufacture, especially mold core and cavity. Abrasion, corrosion and pressure resulted in change of mold size and shape which could greatly affect molding precision. Using laser alloying, the good wear layer would be made on the surface of p20 steel and would greatly increase the mold useful life.

Effect of Refining Slag on the Inclusions of Hard Wire Steel during Melting Process

“…For steels of high strength prestressed wire and stranded wire which diameters are usually larger than 5 mm, method of aluminum deoxidation in steelmaking can be used to lower the oxygen content. In addition, slag of high basicity and low FetO content should be made in the secondary refining, through which small sized spherical non-metallic inclusions of CaO-SiO 2 -Al 2 O 3 system are formed [8,9]. In the current works, the effect of different refining slag composition on the total oxygen content and inclusions in steel was investigated in 100 t UHP Electric Furnace -LF -Billet CC process.…”