关键词: SA508-3钢, 筒体锻件, 热处理, 数值模拟

Abstract: Heat treatment process of a thick-section cylinder forging made of SA508-3 steel was simulated using Transvalor Simheat software. The quenching process for small-sized specimens was designed according to the cooling curve at the thickness center of the cylinder forging obtained from the simulation, and the specimens were subjected to quenching and tempering to verify the accuracy of heat treatment simulation results. The simulation results show that during quenching process, the cooling rate at the center of the forging wall thickness is approximately 0.44 ℃/s, the microstructure is mainly bainite without ferrite, and the hardness of core is the lowest, about 204 HB. After quenching and tempering, the forging surface is in a compressive stress state, with a local maximum compressive stress of approximately 73 MPa, and the forging diameter increases by about 19 mm. This indicates that in actual production, the outer circle machining allowance should be appropriately reduced or the inner circle machining allowance should be increased before the quenching and tempering of the cylinder forging. The test verification results show that the tensile properties and -20 ℃ impact properties of the small-sized specimens after quenching and tempering meet the technical requirements. The microstructure after quenching is consistent with the microstructure at the thickness center of the cylinder forging obtained from the simulation, but the hardness is slightly higher than the simulated results. This indicates that the Transvalor Simheat simulation software can effectively predict the microstructure and properties of thick-section forgings.

Key words: SA508-3 steel, cylinder forgings, heat treatment, numerical simulation