基于铸辗连续成形的42CrMo铸造环坯高温力学性能及临界应变计算  

High Temperature Mechanical Properties and Calculation of Critical Strain for 42CrMo Ring Blank Based on Casting-rolling Forming

作　　者：武永红[1] 李永堂[1] 齐会萍[1] 付建华[1] 

机构地区：[1]太原科技大学金属材料成形理论与技术山西省重点实验室,太原030024

出　　处：《机械工程学报》2017年第6期45-52,共8页Journal of Mechanical Engineering

基　　金：国家自然科学基金重点(51135007);国家自然科学基金(51575371);高等学校博士学科点基金优先发展计划(20111415130001)资助项目

摘　　要：针对铸辗连续成形工艺中高温出模环形铸坯的易裂缺陷,采用Gleeble-3500热力模拟试验机对铸造42CrMo钢环坯进行高温拉伸试验,分析其高温强度、热塑性等力学行为,预测高温易裂敏感温度区。结果表明:铸造42CrMo钢的抗拉强度随温度的升高及应变速率的减小而减小。断面收缩率随应变速率增大而增大。1 100℃时,试样开始发生动态再结晶。试验条件下,材料存在两个脆性温度区,分别为红脆性温度区和高温脆性温度区。高温脆性是导致铸造42CrMo高温出模环坯产生裂纹的内在原因。能谱分析表明:硫化物、氧化物等夹杂物极易诱发裂纹的发生。根据试验结果,建立铸造42CrMo钢的峰值流动应力模型及产生裂纹的临界应变模型,该模型可为优化铸辗连续成形工艺,避免铸造缺陷,提高铸件质量提供指导。Ring blanks removed from the mold under high temperature are easy to emerge crack defect in casting-rolling continuous forming process. According to this, high temperature tensile test of as-cast 42CrMo steel is carded out in a Gleeble-3500 thermal-mechanical simulator. Mechanical behaviors of the steel such as high temperature strength, thermoplastic, etc, are analyzed. The cracking sensitive to temperature zone is predicted. It is shown from the results that the tensile strength decreases with the increase of temperature and the decrease of strain rate, and reduction of area increases with the increase of strain rate. Dynamic recrystallization occur at the temperature of 1 100 ~C. There are two brittleness zones under the experimental conditions, which are red brittleness temperature zone and high temperature brittleness temperature zone respectively. High temperature brittleness is the intrinsic cause that leads to crack for as-cast 42CrMo high temperature ring blank. The energy spectrum analysis indicates that the cracks are easily induced by sulfide and oxide and other inclusions, Based on the experimental results, the peak flow stress model and the critical strain model of the crack are established for as-cast 42CrMo steel. The proposed models are helpful to optimize casting-rolling continuous forming process, avoid casting defects and improve the quality of the castings.

关 键 词：金属材料 高温力学性能 动态再结晶 临界应变 

分 类 号：TG142[一般工业技术—材料科学与工程]