一种连杆用非调质钢的连续冷却转变

Continuous Cooling Transition of Non-quenched and Tempered Steel for Connecting Rods

通过Gleeble-3800热模拟机研究了一种连杆用中碳非调质钢的连续冷却转变组织变化规律,分析了冷却速度对转变组织和显微硬度的影响。结果表明,当冷却速度小于0.1℃/s时,组织为铁素体-珠光体;当冷却速度大于0.5℃/s时,开始发生贝氏体转变,在0.5～0.8℃/s冷速范围内,组织为铁素体-珠光体+贝氏体;当冷却速度大于1℃/s时开始发生马氏体转变,随着冷却速度的增加,贝氏体、马氏体含量逐渐增加,当冷却速度大于8℃/s时,组织全部为马氏体。实验钢的显微硬度随着冷却速度的提高而增加。

Microstructure evolution of medium-carbon non-quenched and tempered steel after continuous cooling transition for connecting rod was studied by Gleeble-3800 thermal simulation machine,and the effect of cooling rate on its microstructure and micro-hardness was analyzed.The result shows that its microstructure is ferrite-pearlite when the cooling rate is less than 0.1℃/s.Bainite transformation occurs when the cooling rate is greater than 0.5℃/s and has ferrite-pearlite+bainite with decreacing the cooling rate to 0.1℃/s^0.8℃/s.The martensitic transformation is occurred when the cooling rate is higher than 1℃/s,and more bainite and martensite can be observed with increasing the cooling rate.The microstructure of steel is all martensite when the cooling rate is higher than 8℃/s.Furthermore,the micro-hardness of the experimental steel increases with increasing the cooling rate.