JMatPro在45钢热轧棒材工艺设计中的应用

Application of JMatPro in the Process Design of 45 Steel Hot Rolled Rod

摘要

利用金属材料相图与性能计算软件JMatPro对45号钢进行分析。通过软件计算得到了45号钢不同温度下的平衡相组成、过冷奥氏体等温转变曲线(TTT)、过冷奥氏体连续转变曲线(CCT)以及奥氏体化加热过程中描述时间、温度和奥氏体化程度的TTA图。铁碳合金相图结合计算结果亚共析钢45号钢的液相线温度为1493℃，高温铁素体开始析出的温度是在低于1493℃，温度降至1480℃时第一滴液相转变为奥氏体温度在（1480℃-1415℃）液相不断向奥氏体转变，液相成分不断减少，奥氏体成分增多达到1415℃固相线时所用液相合金全部转变为奥氏体温度降低奥氏体不发生相变。奥氏体中碳的溶解度降低在774时奥氏体开始向铁素体转变，温度在（774℃-727℃）碳在奥氏体中溶解度逐渐下降将从奥氏体中析出先共析铁素体，降到温度727℃时剩余奥氏体发生共析转变为铁素体、珠光体和少许渗碳体，在727到常温时将从铁素体中析出铁素体最终室温组织委铁素体和渗碳体。依据模拟结果，制定了棒材45号钢轧制工艺，经检测基体组织为铁素体+珠光体，晶粒度8.5级，屈服强度≥375 MPa，抗拉强度≥620 MPa，断后伸长率≥15 %。

Abstract

Analyze 45# steel using the metal material phase diagram and performance calculation software JMatPro. The equilibrium phase composition, undercooled austenite isothermal transformation curve (TTT), undercooled austenite continuous transformation curve (CCT), and TTA diagram describing time, temperature, and degree of austenitization during the austenitization heating process of 45 steel were calculated through software. The liquid phase temperature of hypoeutectoid steel 45 is 1493℃, and the temperature at which high-temperature ferrite begins to precipitate is below 1493℃. When the temperature drops to 1480℃, the first drop of liquid phase transforms into austenite at a temperature between 1480℃ and 1415℃. The liquid phase continuously transforms into austenite, and the liquid phase composition decreases continuously. When the austenite content increases to the solid phase line at 1415℃, all the liquid phase alloys used transform into austenite without undergoing phase transformation. The solubility of carbon in austenite decreases at 774℃, and the austenite begins to transform into ferrite. At temperatures between 774℃ and 727℃, the solubility of carbon in austenite gradually decreases, and ferrite will first eutectoid from austenite. When the temperature drops to 727℃, the remaining austenite undergoes eutectoid transformation into ferrite, pearlite, and a small amount of cementite. At 727℃ to room temperature, ferrite will precipitate from ferrite, and the final room temperature structure will be composed of ferrite and cementite. Based on the simulation results, a rolling process for bar 45 steel was developed. After testing, the matrix structure was found to be ferrite+pearlite, with a grain size of 8.5, a yield strength of ≥ 375 MPa, a tensile strength of ≥ 620 MPa, and an elongation at break of ≥ 15%.

关键词

45钢 / 棒材 / 热力学 / 相变 / JMatPro

Key words

45 steel / Bar / Thermodynamics / Phase transition / JMatPro

参考文献

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