第36卷第8期 北京科技大学学报 Vol.36 No.8 2014年8月 Journal of University of Science and Technology Beijing Aug.2014 曲轴用非调质钢C38N2的静态再结晶行为 蒋 波”，杨忠”，文成”，张建宇”，王海龙”，刘雅政四 1)北京科技大学材料科学与工程学院，北京1000832)西宁特殊钢集团有限责任公司，西宁810005 ☒通信作者，E-mail:lyzh@usth.edu.cn 摘要通过热模拟实验、光学金相及透射电镜分析观察，研究了奥氏体化条件、变形温度、变形速率、变形量以及道次间隔 时间对曲轴用非调质钢C38N2轧制道次间的静态再结晶体积分数和残余应变率的影响规律.实验结果表明：随着变形温度 的升高、变形速率的增大、变形量的增大或道次间间隔时间的增长，静态再结晶的体积分数逐渐升高，道次的残余应变率逐渐 降低：原始奥氏体晶粒尺寸增大，静态再结晶体积分数降低，但变化不大：在1250℃以下，随着奥氏体化温度的升高，静态再结 晶体积分数降低不明显，但在1250℃以上，奥氏体化温度的升高明显降低了静态再结晶体积分数.通过线性拟合以及最小二 乘法，得到静态再结晶体积分数与不同变形工艺参数之间关系的数学模型：对已有残余应变率数学模型进行修正，得到含有 应变速率项的残余应变率数学模型，拟合度较好. 关键词非调质钢：再结晶：残余应变：软化：曲轴 分类号TG142.1 Static recrystallization behaviors of non-quenched steel C38N2 for crankshafts JIANG Bo,YANG Zhong?,WEN Cheng",ZHANG Jian-yu,WANG Hai-long?,LIU Ya-heng 1)School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083,China 2)Xining Special Steel Co.Ld.,Xining 810005,China Corresponding author,E-mail:lyzh@ustb.edu.cn ABSTRACT The effects of austenitizing procedures,deformation temperature,deformation rate,deformation amount and inter-pass time between deformations on the volume fraction of static recrystallization and the residual strain ratio of non-quenched steel C38N2 for crankshafts were carefully investigated by hot simulation tests,quantitative metallography and transmission electron microscopy.Experi- mental observations show that,the volume fraction of static recrystallization increases and the residual strain ratio decreases when the deformation temperature,deformation rate,deformation amount and inter-pass time between deformations rise.The situation is opposite when the austenite grain size increases,but they change inconspicuously.In addition,the volume fraction of static recrystallization de- creases gently when the austenitizing temperature rises below 1250 C.However,it sharply decreases when the austenitizing tempera- ture rises above 1250 C.A mathematical model of the relationship between the volume fraction of static recrystallization and deforma- tion parameters was derived by linear fitting and least square method.Besides,a mathematical model of residual strain ratio concerning the deformation rate term was obtained by modifying the existent mathematical model,and it fits the experimental results better. KEY WORDS non-quenched steel;recrystallization:residual strain:softening:crankshafts 曲轴钢C38N2是一种新型的微合金非调质钢， 心部流动到表面而形成的缺陷同.改善曲轴用材的 代替调质钢制造雷诺发动机曲轴·习.表面发纹缺 心部质量成为轧制过程中的重要目标，通过减少轧 陷是曲轴寿命的常见缺陷，主要是由原始铸锭中气 制过程中的道次软化，促进心部的变形是焊合铸态 孔、疏松等治金缺陷在模锻成形过程中受到挤压由 组织心部疏松、缩孔的有利手段四. 收稿日期：20130808 DOI:10.13374/j.issn1001-053x.2014.08.008:http:/journals.ustb.edu.cn第 36 卷 第 8 期 2014 年 8 月 北京科技大学学报 Journal of University of Science and Technology Beijing Vol． 36 No． 8 Aug． 2014 曲轴用非调质钢 C38N2 的静态再结晶行为 蒋 波1) ，杨 忠2) ，文 成1) ，张建宇1) ，王海龙2) ，刘雅政1)  1) 北京科技大学材料科学与工程学院，北京 100083 2) 西宁特殊钢集团有限责任公司，西宁 810005  通信作者，E-mail: lyzh@ ustb． edu． cn 摘 要 通过热模拟实验、光学金相及透射电镜分析观察，研究了奥氏体化条件、变形温度、变形速率、变形量以及道次间隔 时间对曲轴用非调质钢 C38N2 轧制道次间的静态再结晶体积分数和残余应变率的影响规律． 实验结果表明: 随着变形温度 的升高、变形速率的增大、变形量的增大或道次间间隔时间的增长，静态再结晶的体积分数逐渐升高，道次的残余应变率逐渐 降低; 原始奥氏体晶粒尺寸增大，静态再结晶体积分数降低，但变化不大; 在 1250 ℃以下，随着奥氏体化温度的升高，静态再结 晶体积分数降低不明显，但在 1250 ℃以上，奥氏体化温度的升高明显降低了静态再结晶体积分数． 通过线性拟合以及最小二 乘法，得到静态再结晶体积分数与不同变形工艺参数之间关系的数学模型; 对已有残余应变率数学模型进行修正，得到含有 应变速率项的残余应变率数学模型，拟合度较好． 关键词 非调质钢; 再结晶; 残余应变; 软化; 曲轴 分类号 TG 142. 1 Static recrystallization behaviors of non-quenched steel C38N2 for crankshafts JIANG Bo1) ，YANG Zhong2) ，WEN Cheng1) ，ZHANG Jian-yu1) ，WANG Hai-long2) ，LIU Ya-zheng1)  1) School of Materials Science and Engineering，University of Science and Technology Beijing，Beijing 100083，China 2) Xining Special Steel Co． Ltd． ，Xining 810005，China  Corresponding author，E-mail: lyzh@ ustb． edu． cn ABSTＲACT The effects of austenitizing procedures，deformation temperature，deformation rate，deformation amount and inter-pass time between deformations on the volume fraction of static recrystallization and the residual strain ratio of non-quenched steel C38N2 for crankshafts were carefully investigated by hot simulation tests，quantitative metallography and transmission electron microscopy． Experi￾mental observations show that，the volume fraction of static recrystallization increases and the residual strain ratio decreases when the deformation temperature，deformation rate，deformation amount and inter-pass time between deformations rise． The situation is opposite when the austenite grain size increases，but they change inconspicuously． In addition，the volume fraction of static recrystallization de￾creases gently when the austenitizing temperature rises below 1250 ℃ ． However，it sharply decreases when the austenitizing tempera￾ture rises above 1250 ℃ ． A mathematical model of the relationship between the volume fraction of static recrystallization and deforma￾tion parameters was derived by linear fitting and least square method． Besides，a mathematical model of residual strain ratio concerning the deformation rate term was obtained by modifying the existent mathematical model，and it fits the experimental results better． KEY WOＲDS non-quenched steel; recrystallization; residual strain; softening; crankshafts 收稿日期: 2013--08--08 DOI: 10． 13374 /j． issn1001--053x． 2014． 08． 008; http: / /journals． ustb． edu． cn 曲轴钢 C38N2 是一种新型的微合金非调质钢， 代替调质钢制造雷诺发动机曲轴［1--2］． 表面发纹缺 陷是曲轴寿命的常见缺陷，主要是由原始铸锭中气 孔、疏松等冶金缺陷在模锻成形过程中受到挤压由 心部流动到表面而形成的缺陷［3］． 改善曲轴用材的 心部质量成为轧制过程中的重要目标，通过减少轧 制过程中的道次软化，促进心部的变形是焊合铸态 组织心部疏松、缩孔的有利手段［4］．