ST52-3G钢等温热处理组织性能研究
发布时间：2018-07-31 05:04
【摘要】：随着工业的发展,特别是汽车制造业的发展,冷轧钢板的需求量得到迅速地增长,因为冷轧钢板具备功能性高、生产原材料丰富、生产成本相对较低和可批量生产等特点,决定了其短时间内的难以替代性。随着用户对钢材性能的要求越来越高,使得改善钢材的力学性能和性能预测成为了研究热点,而热处理作为改善钢材组织和性能最常用的一种方法,为了能获得更适合于各个用途性能的钢铁材料,对其深入研究是必要的。本文以ST52-3G钢冷轧板为研究对象,以Gleeble-1500D为研究手段,根据用户对冷轧钢板的力学性能要求,研究不同等温热处理温度和保温时间下其组织演变规律,特别是铁素体的再结晶规律,以及预测不同等温热处理温度和保温时间下的力学性能,为实际生产制定热处理工艺提供参考。本论文的主要内容包括如下:ST52-3G钢过冷奥氏体连续冷却相转变曲线的测定(Continuous Cooling Transformation—CCT)。用Gleeble-1500D热模拟试验机的膨胀仪测得膨胀曲线,用切线法测得Ac1、Ac3及相转变点,并结合金相-硬度法,得到ST52-3G钢的CCT曲线,同时还做了50℃/s快速加热下的Ac1、Ac3,快速加热的临界转变点比标准条件的提高显著。等温热处理试验。等温热处理工艺主要研究不同加热温度和保温时间下的组织演变规律,结果表明:ST52-3G钢在等温热处理过程中,加热温度在500℃~550℃区间,其微观组织仅发生了回复,在650℃~850℃区间,发生铁素体的再结晶,而950℃时,冷却过程中依次发生铁素体转变、珠光体转变和贝氏体相变。同时建立了再结晶铁素体晶粒尺寸经验模型,拟合相关系数为0.9830。等温热处理力学性能模型的建立。通过等温热处理的ST52-3G钢力学性能数据分析,并依据JMAK模型及再结晶和未再结晶部分加权平均的思想建立了ST52-3G钢的力学性能模型,结果表明:屈服强度、抗拉强度和伸长率的拟合相关系数分别达到0.9761、0.9175和0.9429,平均绝对误差分别为14.54 MPa、23.44 MPa和1.07%,平均相对误差分别为2.47%、2.67%、6.72%,可见模型具有较高的精度,为实际生产提供理论参考。
[Abstract]:With the development of industry, especially the development of automobile manufacturing industry, the demand for cold-rolled steel plate has been increasing rapidly, because cold-rolled steel plate has the characteristics of high function, abundant raw materials, relatively low production cost and batch production. Determine its short period of time difficult to replace. With the increasing demands of customers on steel properties, improving the mechanical properties and performance prediction of steel has become a research hotspot, and heat treatment is the most commonly used method to improve the microstructure and properties of steel. In order to obtain more suitable steel materials for various purposes, it is necessary to study them in depth. In this paper, the microstructure evolution law, especially the recrystallization law of ferrite, is studied under different isothermal heat treatment temperature and holding time according to the mechanical properties of cold rolled ST52-3G steel sheet and Gleeble-1500D. The mechanical properties of different isothermal heat treatment temperature and holding time are predicted. The main contents of this thesis are as follows: determination of the continuous cooling phase transformation curve of supercooled austenite in the steel of 1: ST52-3G (Continuous Cooling Transformation-CCT). The expansion curve of ST52-3G steel was obtained by using the expansion instrument of Gleeble-1500D thermal simulator, and the phase transition point by means of tangent method. The CCT curve of ST52-3G steel was obtained by means of metallographic hardness method. At the same time, the critical transition point of the rapid heating is improved significantly than that of the standard condition at 50 鈩，
本文编号：2154492
[Abstract]:With the development of industry, especially the development of automobile manufacturing industry, the demand for cold-rolled steel plate has been increasing rapidly, because cold-rolled steel plate has the characteristics of high function, abundant raw materials, relatively low production cost and batch production. Determine its short period of time difficult to replace. With the increasing demands of customers on steel properties, improving the mechanical properties and performance prediction of steel has become a research hotspot, and heat treatment is the most commonly used method to improve the microstructure and properties of steel. In order to obtain more suitable steel materials for various purposes, it is necessary to study them in depth. In this paper, the microstructure evolution law, especially the recrystallization law of ferrite, is studied under different isothermal heat treatment temperature and holding time according to the mechanical properties of cold rolled ST52-3G steel sheet and Gleeble-1500D. The mechanical properties of different isothermal heat treatment temperature and holding time are predicted. The main contents of this thesis are as follows: determination of the continuous cooling phase transformation curve of supercooled austenite in the steel of 1: ST52-3G (Continuous Cooling Transformation-CCT). The expansion curve of ST52-3G steel was obtained by using the expansion instrument of Gleeble-1500D thermal simulator, and the phase transition point by means of tangent method. The CCT curve of ST52-3G steel was obtained by means of metallographic hardness method. At the same time, the critical transition point of the rapid heating is improved significantly than that of the standard condition at 50 鈩，
本文编号：2154492
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