第36卷第4期 北京科技大学学报 Vol.36 No.4 2014年4月 Journal of University of Science and Technology Beijing Apr.2014 高强度含铜钢奥氏体连续冷却转变产物的强韧性 杨才福，刘翊之，柴锋四，苏航，罗小兵 钢铁研究总院工程用钢所，北京100081 ☒通信作者，E-mail:chai_fenge@sina.comm.cn 摘要研究了高强度含铜钢HSLA80和HSLA100奥氏体连续冷却转变产物的强度和韧性随冷却速率的变化规律，探讨了 连续冷却过程中形成的Cu沉淀的特征和熟化规律.在Gleeble3800热模拟试验机上进行0.1℃·s1至20℃·s的连续冷却 实验，利用扫描电镜和透射电镜分析了显微组织和Cu沉淀.结果表明，随冷却速率提高，HSLA80的连续冷却转变组织由多边 形铁素体向块状铁素体和贝氏体转变，在冷速0.1~1℃·g范围内C如发生沉淀，两者综合作用造成随冷却速率提高钢的硬 度分阶段变化，而韧性逐渐提高：HSLA1O0的连续冷却转变组织以贝氏体为主，且不发生Cu的沉淀，随冷却速率提高钢的硬 度基本保持不变，但韧性发生剧烈变化.连续冷却过程中形成的Cu沉淀在等温过程中的熟化符合Ostwald熟化规律，半径随 时效时间变化. 关键词高强度钢：铜：连续冷却：沉淀：Ostwald熟化 分类号TG142.4 Strength and toughness of austenite decomposition products in high strength Cu-bearing steel during continuous cooling YANG Cai-fu,LIU Yi-zhi,CHAI Feng,SU Hang,LUO Xiao-bing Institute of Engineering Steel,Central Iron and Steel Research Institute,Beijing 100081,China Corresponding author,E-mail:chai_feng@sina.com.cn ABSTRACT The effects of cooling rate on the strength and toughness of austenite decomposition products in high strength Cu-bearing steels HSLA80 and HSLA100 were investigated during continuous cooling.Characterization and ripening of Cu precipitates formed dur- ing continuous cooling were discussed.Continuous cooling experiments from 0.1 to 20Cswere carried out by Gleeble thermo-simu- lation.Microstructures and Cu precipitates were observed by scanning electron microscopy and transmission electron microscopy.It is found that the microstructure of austenite decomposition products in HSLA80 steel changes from polygonal ferrite to granular ferrite and bainite with increasing cooling rate.Cu precipitation occurs during continuous cooling within the cooling rate of 0.1 to ICs.Due to the microstructure and Cu precipitates,the hardness changes by stages and the toughness increases gradually as the cooling rate in- creases.The microstructure of austenite decomposition products in HSLA100 steel is mainly bainite and Cu precipitation does not oc- cur,so that the hardness does not change on the whole,but the toughness varies dramatically with increasing cooling rate.Ripening of Cu precipitates formed during continuous cooling obeys the Ostwald law.The radius of Cu precipitates increases with aging time KEY WORDS high strength steel:copper:cooling:precipitates:Ostwald ripening 在超低碳和C山沉淀强化思路下开发出的高强 系列钢的奥氏体在一定冷速范围内连续冷却，转变 度含铜钢具有良好的强韧性匹配和焊接性能习， 产物中可能产生细小分散的Cu析出.根据这 目前主要应用于船体建造、海洋工程、大型工程机械 一现象，对于厚度规格不大的钢，可结合热机械控制 等领域，具有很大发展潜力.高强度含铜钢的典型 工艺(TCP)制定适当的加工工艺，从而省去再加 生产工艺为热轧+再加热固溶处理+等温时效.该 热固溶处理工序，在保证钢的强度的前提下，降低能 收稿日期：201302-一1 DOI:10.13374/j.issn1001-053x.2014.04.004:http:/journals.ustb.edu.cn第 36 卷 第 4 期 2014 年 4 月 北京科技大学学报 Journal of University of Science and Technology Beijing Vol． 36 No． 4 Apr． 2014 高强度含铜钢奥氏体连续冷却转变产物的强韧性 杨才福，刘翊之，柴 锋，苏 航，罗小兵 钢铁研究总院工程用钢所，北京 100081  通信作者，E-mail: chai_feng@ sina． com． cn 摘 要 研究了高强度含铜钢 HSLA80 和 HSLA100 奥氏体连续冷却转变产物的强度和韧性随冷却速率的变化规律，探讨了 连续冷却过程中形成的 Cu 沉淀的特征和熟化规律． 在 Gleeble3800 热模拟试验机上进行 0. 1 ℃·s － 1 至 20 ℃·s － 1 的连续冷却 实验，利用扫描电镜和透射电镜分析了显微组织和 Cu 沉淀． 结果表明，随冷却速率提高，HSLA80 的连续冷却转变组织由多边 形铁素体向块状铁素体和贝氏体转变，在冷速 0. 1 ～ 1 ℃·s － 1 范围内 Cu 发生沉淀，两者综合作用造成随冷却速率提高钢的硬 度分阶段变化，而韧性逐渐提高; HSLA100 的连续冷却转变组织以贝氏体为主，且不发生 Cu 的沉淀，随冷却速率提高钢的硬 度基本保持不变，但韧性发生剧烈变化． 连续冷却过程中形成的 Cu 沉淀在等温过程中的熟化符合 Ostwald 熟化规律，半径随 时效时间 t 1 /3 变化． 关键词 高强度钢; 铜; 连续冷却; 沉淀; Ostwald 熟化 分类号 TG142. 4 Strength and toughness of austenite decomposition products in high strength Cu-bearing steel during continuous cooling YANG Cai-fu，LIU Yi-zhi，CHAI Feng ，SU Hang，LUO Xiao-bing Institute of Engineering Steel，Central Iron and Steel Ｒesearch Institute，Beijing 100081，China  Corresponding author，E-mail: chai_feng@ sina． com． cn ABSTＲACT The effects of cooling rate on the strength and toughness of austenite decomposition products in high strength Cu-bearing steels HSLA80 and HSLA100 were investigated during continuous cooling． Characterization and ripening of Cu precipitates formed dur￾ing continuous cooling were discussed． Continuous cooling experiments from 0. 1 to 20 ℃·s － 1 were carried out by Gleeble thermo-simu￾lation． Microstructures and Cu precipitates were observed by scanning electron microscopy and transmission electron microscopy． It is found that the microstructure of austenite decomposition products in HSLA80 steel changes from polygonal ferrite to granular ferrite and bainite with increasing cooling rate． Cu precipitation occurs during continuous cooling within the cooling rate of 0. 1 to 1 ℃·s － 1 ． Due to the microstructure and Cu precipitates，the hardness changes by stages and the toughness increases gradually as the cooling rate in￾creases． The microstructure of austenite decomposition products in HSLA100 steel is mainly bainite and Cu precipitation does not oc￾cur，so that the hardness does not change on the whole，but the toughness varies dramatically with increasing cooling rate． Ｒipening of Cu precipitates formed during continuous cooling obeys the Ostwald law． The radius of Cu precipitates increases with aging time t 1 /3 ． KEY WOＲDS high strength steel; copper; cooling; precipitates; Ostwald ripening 收稿日期: 2013--02--11 DOI: 10． 13374 /j． issn1001--053x． 2014． 04． 004; http: / /journals． ustb． edu． cn 在超低碳和 Cu 沉淀强化思路下开发出的高强 度含铜钢具有良好的强韧性匹配和焊接性能［1--3］， 目前主要应用于船体建造、海洋工程、大型工程机械 等领域，具有很大发展潜力． 高强度含铜钢的典型 生产工艺为热轧 + 再加热固溶处理 + 等温时效． 该 系列钢的奥氏体在一定冷速范围内连续冷却，转变 产物中可能产生细小分散的 Cu 析出［4--6］． 根据这 一现象，对于厚度规格不大的钢，可结合热机械控制 工艺( TMCP) 制定适当的加工工艺，从而省去再加 热固溶处理工序，在保证钢的强度的前提下，降低能