Researching Of Processing Microstructure And Mechanical Property Of Electro-slag Casting GH132High-temperature Alloy

In this paper, GH132alloy hearth rolls have been successfully produced by the ESC (Electro-slag Casting) and heat treatment process. The mechanical properties meet the design requirements and the process is simple and economic as compared to the casting+forging+heat treatment process.In order to suppress the burning of titanium, the titanium power with high resistance was designed. The composition ratio (mass,%) was13.5CaF2-45Al2O3-27CaO-7MgO-7.5TiO2. Based on the theory of co-existence, the element activity the titanium power with high resistance was calculated. The activity for each element was CaF2,0.1; Al2O3,0.042; CaO,0.177; MgO,0.052; TiO2,0.02.The best casting process parameters were obtained:casting current4000A, casting voltage57V and the thickness of casting slag layer200mm. The microstructure of GH132alloy consists of the austenite matrix, and the average grain size of austenite is about100p.m. In addition, there exists obvious cellular crystal, dendrite and grain boundary precipates.The axial tensile strength of GH132alloy is about750MPa; the radial tensile strength is about730MPa; the flexural strength is about1135MPa; the impact toughness is about80J/cm2. From the surface of the ingot to the center, the tensile strength, flexural strength and impact toughness gradually reduce, but the change of mechanical properties with the direction is no obvious.The results of mechanical properties show that the mechanical properties of the ESC GH132high-temperature alloy achieve the requirements of users, and the casting process instead of forging can be realized.