D0L:10.13374/.issn1001-053x.2012.s1.012 第34卷增刊1 北京科技大学学报 Vol.34 Suppl.1 2012年6月 Journal of University of Science and Technology Beijing Jun.2012 连轧钢管限动芯棒温度场及热疲劳有限元分析 李永超”赵志毅)四 占中杰逢宁”徐昆2) 1)北京科技大学材料科学与工程学院，北京1000832)宝钢集团常州轧辊制造公司，常州213019 ☒通信作者，E-mail:zhaozhiyi@ustb.cdu.cm 摘要针对34OMPM机组(Multi--Stand Pipe Mill限动芯棒连轧管机组)芯棒服役过程建立三维有限元模型，研究芯棒在服役 过程中温度场变化规律.同时，通过对热应力的研究，分析了芯棒热疲劳裂纹萌生机理及裂纹在芯棒内部的扩展规律.对比 实测数据与模拟结果，认为所建立的有限元模型能够反映芯棒温度变化趋势.芯棒首次脱管后表面最高温度为630℃，此后 经历三次反复的水冷降温和空冷返温过程，冷却结束后表面最高温度为98℃.脱管后，芯棒表面轴向和环向压缩热应力均达 到900MPa,第三次水冷结束时刻，轴向拉伸热应力达到186MPa,环向拉伸热应力达到221MPa.芯棒的拉压交变热应力使其 表面出现热疲劳裂纹并逐渐扩展，环向裂纹扩展至距表面17.5mm深、轴向裂纹扩展至距表面20mm深时会显著受阻，热应力 对轴向裂纹的促进作用强于环向裂纹. 关键词钢管：芯棒：温度场：热应力：疲劳裂纹 分类号TG333.8 Finite element analysis on the temperature field and thermal fatigue of the retained mandrel in a multi-stand pipe mill LI Yong-chao”,ZHA0 Zhi-yi),ZHAN Zhong jie2》,PANG Ning'',XU Kun》 1)School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2)Baosteel Group Changzhou Roll Manufacture Company,Changzhou 213019,China Corresponding author,E-mail:zhaozhiyi@ustb.edu.cn ABSTRACT A finite element model of retained mandrel service process in 340MPM (Multi-Stand Pipe Mill)was built to research the temperature field change of the mandrel.The thermal stress of the mandrel was also studied to analyze the initiation mechanism and propagation law of fatigue cracks in the mandrel.A comparison between the measured data and the simulation results indicates that the model can reflect the temperature change of the mandrel.After the mandrel was detached from the tube,the highest temperature of the mandrel surface went up to 630C.Then the mandrel went through three times of temperature-falling in water-cooling stages and three times of temperature-rising in air-cooling stages.At the end of the whole cooling process,the highest temperature of the mandrel surface was 98 C.Both the axial compressive stress and circumferential compressive stress reached to 900 MPa after the mandrel was detached from the tube.At the end of the 3rd water-cooling stage,the axial stress reached to 186 MPa,while the circumferential stress reached to 221 MPa.Cyclic thermal stress could lead to crack initiation and propagation in the mandrel,yet circumferential cracks would be significantly blocked at the place of 17.5mm away from the surface,while axial cracks would be significantly blocked at the place of 20 mm away from the surface.The impetus for axial cracks which came from thermal stress was stronger than that for circumfer- ential cracks. KEY WORDS steel pipe:mandrels:temperature field;thermal stress:fatigue cracks 芯棒是钢管生产中一种重要的变形工具，其服疲劳裂纹等形式的缺陷.为了达到提高芯棒使用寿 役条件非常恶劣，温度场变化情况较为复杂，并且承 命、降低生产成本的目的，必须对芯棒在服役过程中 受急冷急热的热应力.长期服役之后，芯棒会出现 的温度场及热应力进行研究.但是，对芯棒温度的 收稿日期：201202-16第 34 卷 增刊 1 2012 年 6 月 北京科技大学学报 Journal of University of Science and Technology Beijing Vol． 34 Suppl． 1 Jun． 2012 连轧钢管限动芯棒温度场及热疲劳有限元分析 李永超1) 赵志毅1) 占中杰2) 逄 宁1) 徐 昆2) 1) 北京科技大学材料科学与工程学院，北京 100083 2) 宝钢集团常州轧辊制造公司，常州 213019 通信作者，E-mail: zhaozhiyi@ ustb． edu． cn 摘 要 针对 340MPM 机组( Multi-Stand Pipe Mill 限动芯棒连轧管机组) 芯棒服役过程建立三维有限元模型，研究芯棒在服役 过程中温度场变化规律． 同时，通过对热应力的研究，分析了芯棒热疲劳裂纹萌生机理及裂纹在芯棒内部的扩展规律． 对比 实测数据与模拟结果，认为所建立的有限元模型能够反映芯棒温度变化趋势． 芯棒首次脱管后表面最高温度为 630 ℃，此后 经历三次反复的水冷降温和空冷返温过程，冷却结束后表面最高温度为 98 ℃ ． 脱管后，芯棒表面轴向和环向压缩热应力均达 到 900 MPa，第三次水冷结束时刻，轴向拉伸热应力达到 186 MPa，环向拉伸热应力达到 221 MPa． 芯棒的拉压交变热应力使其 表面出现热疲劳裂纹并逐渐扩展，环向裂纹扩展至距表面 17. 5 mm 深、轴向裂纹扩展至距表面 20 mm 深时会显著受阻，热应力 对轴向裂纹的促进作用强于环向裂纹． 关键词 钢管; 芯棒; 温度场; 热应力; 疲劳裂纹 分类号 TG333. 8 Finite element analysis on the temperature field and thermal fatigue of the retained mandrel in a multi-stand pipe mill LI Yong-chao 1) ，ZHAO Zhi-yi 1) ，ZHAN Zhong-jie 2) ，PANG Ning1) ，XU Kun2) 1) School of Materials Science and Engineering，University of Science and Technology Beijing，Beijing 100083，China 2) Baosteel Group Changzhou Roll Manufacture Company，Changzhou 213019，China Corresponding author，E-mail: zhaozhiyi@ ustb． edu． cn ABSTRACT A finite element model of retained mandrel service process in 340MPM ( Multi-Stand Pipe Mill) was built to research the temperature field change of the mandrel． The thermal stress of the mandrel was also studied to analyze the initiation mechanism and propagation law of fatigue cracks in the mandrel． A comparison between the measured data and the simulation results indicates that the model can reflect the temperature change of the mandrel． After the mandrel was detached from the tube，the highest temperature of the mandrel surface went up to 630 ℃ ． Then the mandrel went through three times of temperature-falling in water-cooling stages and three times of temperature-rising in air-cooling stages． At the end of the whole cooling process，the highest temperature of the mandrel surface was 98 ℃ ． Both the axial compressive stress and circumferential compressive stress reached to 900 MPa after the mandrel was detached from the tube． At the end of the 3rd water-cooling stage，the axial stress reached to 186 MPa，while the circumferential stress reached to 221 MPa． Cyclic thermal stress could lead to crack initiation and propagation in the mandrel，yet circumferential cracks would be significantly blocked at the place of 17. 5 mm away from the surface，while axial cracks would be significantly blocked at the place of 20 mm away from the surface． The impetus for axial cracks which came from thermal stress was stronger than that for circumfer￾ential cracks． KEY WORDS steel pipe; mandrels; temperature field; thermal stress; fatigue cracks 收稿日期: 2012--02--16 芯棒是钢管生产中一种重要的变形工具，其服 役条件非常恶劣，温度场变化情况较为复杂，并且承 受急冷急热的热应力． 长期服役之后，芯棒会出现 疲劳裂纹等形式的缺陷． 为了达到提高芯棒使用寿 命、降低生产成本的目的，必须对芯棒在服役过程中 的温度场及热应力进行研究． 但是，对芯棒温度的 DOI:10.13374/j.issn1001-053x.2012.s1.012