工程科学学报，第38卷，第7期：973978,2016年7月 Chinese Journal of Engineering,Vol.38,No.7:973-978,July 2016 DOI:10.13374/j.issn2095-9389.2016.07.012:http://journals.ustb.edu.cn 局部感应加热对高强钢方管二次辊压成形的影响 彭雪锋”，陈强”，王宇”，刘靖”，韩静涛)四，晏培杰》 1)北京科技大学材料科学与工程学院，北京1000832)上海宝钢型钢有限公司，上海201900 ☒通信作者，E-mail:hanit@usth.edu.cn 摘要本文通过对高强钢方管角部进行局部感应加热，提高其弯角区域的成形性能，降低其变形抗力，由此在不影响非变 形区域组织性能的前提下，获得所需方管的截面尺寸和组织性能.在热辊压过程中，坯料在没有模具限制的方管角部外侧邻 近区域发生堆积，且随着加热温度上升，角部外侧金属堆积更明显.同时，在方管内角表层出现显微裂纹恶化，裂纹以树枝状 生长.热辊压成形后的残余温度会产生一个自回火过程，能够明显降低残余应力，且随着温度的升高，残余应力降低的幅度 变大.当加热温度在650℃以上时，自回火对残余应力的影响大于宏观裂纹的扩展能力，起主导作用，且压扁过程中压下量超 过方管对角线长度2/3时也不会产生裂纹. 关键词高强钢：方管：辊压成形：感应加热：显微裂纹 分类号TG142.1:TG335.7 Effect of local induction heating on secondary roll-forming of high strength square tubes PENG Xue-feng,CHEN Qiang,WANG Yu,LIU Jing,HAN Jing-tao,YAN Peijie? 1)School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2)Shanghai Baosteel Section Steel Co.Lid.,Shanghai 201900,China Corresponding author,E-mail:hanjt@ustb.edu.cn ABSTRACT The formability of corners was improved by heating the corner area of high strength square tubes with induction coils. Under the premise of not impacting the undeformed zone,we obtained the ideal sectional dimension,microstructure and properties of products.In the hot roll forming process,the billet accumulated at the outside area of square comners without mold restrictions.With rising temperature,the accumulation became more serious.At the same time,microcracks deteriorated on the surface of the inner tube,while the cracks grew up in a form of arborization.A self-tempering process would be produced by residual temperature after hot roll forming,which could significantly reduce the residual stress.The residual stress sharply decreased as the temperature increased. When the heating temperature was above 650C,the influence of self-tempering on the residual stress was greater than the extended capability of macrocracks and played a leading role;there was no crack when the distance was larger than 2/3 of diagonal length at flattening test. KEY WORDS high strength steel;tubes:roll forming:induction heating:microcracks 随着世界汽车保有量的持续增长，汽车轻量化将 使得车身材料厚度和使用量减小，从而达到降低车身 是汽车行业必须要突破的一大瓶颈，将超高强钢应用 质量的目的”，进而降低车身质量所带来的能耗，最终 于汽车行业能够很好地解决这一难题.一方面，超高 达到节能减排的目的.在车身结构中，超高强钢广泛 强钢的抗拉强度高达900MPa,能够大幅度地改善车身 应用于保险杠、加强板、防撞柱、车盖顶、横梁、边梁等 的安全性能：另一方面，由于超高强钢的高强度特性， 刚度要求较高的部件 收稿日期：20150805工程科学学报，第 38 卷，第 7 期: 973--978，2016 年 7 月 Chinese Journal of Engineering，Vol． 38，No． 7: 973--978，July 2016 DOI: 10． 13374 /j． issn2095--9389． 2016． 07． 012; http: / /journals． ustb． edu． cn 局部感应加热对高强钢方管二次辊压成形的影响 彭雪锋1) ，陈 强1) ，王 宇1) ，刘 靖1) ，韩静涛1) ，晏培杰2) 1) 北京科技大学材料科学与工程学院，北京 100083 2) 上海宝钢型钢有限公司，上海 201900  通信作者，E-mail: hanjt@ ustb． edu． cn 摘 要 本文通过对高强钢方管角部进行局部感应加热，提高其弯角区域的成形性能，降低其变形抗力，由此在不影响非变 形区域组织性能的前提下，获得所需方管的截面尺寸和组织性能． 在热辊压过程中，坯料在没有模具限制的方管角部外侧邻 近区域发生堆积，且随着加热温度上升，角部外侧金属堆积更明显． 同时，在方管内角表层出现显微裂纹恶化，裂纹以树枝状 生长． 热辊压成形后的残余温度会产生一个自回火过程，能够明显降低残余应力，且随着温度的升高，残余应力降低的幅度 变大． 当加热温度在 650 ℃以上时，自回火对残余应力的影响大于宏观裂纹的扩展能力，起主导作用，且压扁过程中压下量超 过方管对角线长度 2 /3 时也不会产生裂纹． 关键词 高强钢; 方管; 辊压成形; 感应加热; 显微裂纹 分类号 TG142. 1; TG335. 7 Effect of local induction heating on secondary roll-forming of high strength square tubes PENG Xue-feng1) ，CHEN Qiang1) ，WANG Yu1) ，LIU Jing1) ，HAN Jing-tao1)  ，YAN Pei-jie2) 1) School of Materials Science and Engineering，University of Science and Technology Beijing，Beijing 100083，China 2) Shanghai Baosteel Section Steel Co． Ltd． ，Shanghai 201900，China  Corresponding author，E-mail: hanjt@ ustb． edu． cn ABSTＲACT The formability of corners was improved by heating the corner area of high strength square tubes with induction coils． Under the premise of not impacting the undeformed zone，we obtained the ideal sectional dimension，microstructure and properties of products． In the hot roll forming process，the billet accumulated at the outside area of square corners without mold restrictions． With rising temperature，the accumulation became more serious． At the same time，microcracks deteriorated on the surface of the inner tube，while the cracks grew up in a form of arborization． A self-tempering process would be produced by residual temperature after hot roll forming，which could significantly reduce the residual stress． The residual stress sharply decreased as the temperature increased． When the heating temperature was above 650 ℃，the influence of self-tempering on the residual stress was greater than the extended capability of macrocracks and played a leading role; there was no crack when the distance was larger than 2 /3 of diagonal length at flattening test． KEY WOＲDS high strength steel; tubes; roll forming; induction heating; microcracks 收稿日期: 2015--08--05 随着世界汽车保有量的持续增长，汽车轻量化将 是汽车行业必须要突破的一大瓶颈，将超高强钢应用 于汽车行业能够很好地解决这一难题． 一方面，超高 强钢的抗拉强度高达900 MPa，能够大幅度地改善车身 的安全性能; 另一方面，由于超高强钢的高强度特性， 使得车身材料厚度和使用量减小，从而达到降低车身 质量的目的［1］，进而降低车身质量所带来的能耗，最终 达到节能减排的目的． 在车身结构中，超高强钢广泛 应用于保险杠、加强板、防撞柱、车盖顶、横梁、边梁等 刚度要求较高的部件．