Research On The Liquid Forging Process Of 45 Steel Supports And Its Microstructure And Properties

45 steel materials have a series of excellent features such as good plasticity and toughness and high strength and recovery,which will get good mechanical properties,physical properties and corrosion resistance through specific treatments.It is widely used in processing and manufacturing of weapons and equipment parts.In this paper,the components of a certain weapon and equipment are taken as the starting point,based on the 2000 k N general hydraulic press,theliquid forging die was designed and manufactured.The numerical simulation of the casing process was carried out based on the software Pro CAST,which optimized the processing parameters of the quantitative feeding device.The possible defects of the parts under different filling speeds were studied.The influence of the technological parameters such as pouring temperature of metal liquidwas simulated and analyzed.The influence of the technological parameters such as the pouring temperature of metal solution,the preheating temperature of mold and the holding time of pressure on the microstructure and mechanical properties of the formed metal was studied.The optimal pouring temperature of the molten metal is 1540?~1560?.The best mold preheating temperature is 300?~350?.The optimal amount of pressure holding time is 35s~40s.The quality problems of the forming parts are summarized,such as cold separation,surface defects and internal shrinkage,which can be s olved by increasing the packing time,controlling the temperature of the molten metal and the temperature of the mold and changing the mold lubrication.The structure and mechanical properties of the cover were analyzed.The structure of the flanges is relatively dense,the grain distribution is uniform.The bottoms of the covers are prone to shrinkage,and the mechanical properties are relatively low.The fractured morphology of the tensile specimen is analyzed.There are a lot of dimples and certain microvoids in the fracture.Some parts are distributed along the crystal fault.The fracture mechanism is mainly ductile fracture with a certain degree of cleavage fracture.To sum up,the structure of 45 steel formed by liquid forging is dense,and the strength index,hardness index and friction coefficient are higher than that of the raw material,but the plastic index is lower than that of the raw material due to the dendrite segregation,the deterioration of the quality of steel liquid and the existence of non-metallic inclusions during the solidification process.