【摘要】 为了探索低温加热水韧处理的可行性,采用金相分析方法观察了ZGMn13高锰钢经不同温度的水韧处理,以及分别经950℃和1050℃加热及随后末端冷却处理后距末端不同距离处的组织。并根据末端冷却处理时所得到的相关数据,通过有关理论分析分别计算出从加热温度950℃和1050℃冷却时获得全部奥氏体组织的临界冷却速度。结果表明,对于1.2 mass%含碳量的ZGMn13高锰钢,水韧处理加热温度达到950℃时即可完全获得单相奥氏体组织。但与1050℃加热保温及末端冷却时不在奥氏体基体上出现沿晶碳化物的端距超过100 mm的相比,950℃加热保温末端冷却的端距却小得多,为65 mm。通过相关的传热学理论计算出,950℃加热处理时获得奥氏体的临界冷却速度为0.78℃/s,高于1050℃常规水韧加热处理不足0.63℃/s的临界冷却速度。相应地,950℃加热处理时零件的临界冷却直径约为170 mm。因此,对于含碳量较低的ZGMn13型高锰钢,在零件直径不超过170 mm时,采用950℃的水韧处理完全可以获得单相奥氏体组织。更多还原

【Abstract】 In order to investigate the feasibility of water toughening treatment of ZGMn13( Hadfield) steel at lower temperature,microstructure of the steel water cooled from different heating temperatures was studied. The microstructure of the steel jominy end-quenched from 950 ℃ and 1050 ℃ by end water cooling at different distances from the quenched end was observed by metallographic analysis method. The critical cooling rates of the Hadfield steel heated at 950 ℃ and 1050 ℃ for acquiring wholly austenite were obtained by theoretical analysis based on the experimental result. The results show that for Hadfield steel with 1. 2 mass% C,the microstructure with full austenite can be got when the temperature reaches 950 ℃. The maximum distance from the quenched end for disappearance of the intergranular carbide in austenite matrix is 65 mm for the Hadfield steel heated at 950 ℃ in jominy end quench test,which is less than the value of 100 mm at 1050 ℃. Calculated by the heat transfer theory,the critical cooling rate for full austenite at 950 ℃ is 0. 78 ℃ / s,higher than the value of 0. 63 ℃ / s at 1050 ℃. Accordingly,the critical cooling diameter of the part heated at 950 ℃ is about 170 mm for water toughening treatment of Hadfield steel. Therefore,when the diameter of Hadfield steel part with lower carbon content does not exceed 170 mm,the single-phase austenite can be obtained when the part is heated at 950 ℃ and water cooled.更多还原