700 MPa级高塑低碳低合金钢的多相组织调控及性能
周文浩, 男, 1987年生, 博士生
修回日期: 2014-10-23
网络出版日期: 2015-05-01
基金资助
*国家重点基础研究发展计划资助项目 2010CB630801
REGULATION OF MULTI-PHASE MICROSTRUCTURE AND MECHANICAL PROPERTIES IN A 700 MPa GRADE LOW CARBON LOW ALLOY STEEL WITH GOOD DUCTILITY
Revised date: 2014-10-23
Online published: 2015-05-01
通过临界退火、临界回火以及回火的多步热处理方式, 研究了低碳低合金钢的组织演变与力学性能. 结果表明, 临界退火后的组织为板条状的临界铁素体及贝氏体/马氏体的双相组织. 经临界回火后, 为临界铁素体、回火贝氏体/马氏体以及残余奥氏体的多相组织. 残余奥氏体呈粒状和条状, 分布在铁素体/贝氏体(马氏体)相界面及贝氏体/马氏体板条之间, 含量高达29%, 并在回火后保持稳定, 主要通过C, Mn, Ni和Cu在逆转奥氏体中的富集来稳定. 临界退火及回火过程中, NbC在铁素体及贝氏体/马氏体中析出, 呈球状、椭圆形或不规则形状, 平均尺寸为10 nm; 富Cu的析出相在临界回火及回火过程中形成, 呈球状分布于铁素体及残余奥氏体中, 尺寸在10~30 nm 之间. 通过残余奥氏体的应变诱导塑性(TRIP)效应及纳米析出相的析出强化作用, 实验钢具有优异的力学性能: 屈服强度高于700 MPa, 抗拉强度高于900 MPa, 均匀延伸率高于20%, 总延伸率高于30%.
周文浩 , 谢振家 , 郭晖 , 尚成嘉 . 700 MPa级高塑低碳低合金钢的多相组织调控及性能[J]. 金属学报, 2015 , 51(4) : 407 -416 . DOI: 10.11900/0412.1961.2014.00576
Low carbon and low alloy steels require good combination of strength and ductility to ensure safety and stability of structures. Heat treatment in intercritical area can not only produce multi-phase microstructure, but also lead to the redistribution of alloying elements in different phases. Multi-step intercritical heat treatment is favorable to obtain retained austenite that is stabilized by repeated enrichment of alloying elements in reversed austenite and nanometer-sized precipitate that are primarily formed during tempering. Excellent mechanical properties are contributed by transformation-induced-plasticity effect of retained austenite and precipitation hardening effect of nanometer-size precipitates. In this work, the microstructural evolution and relative mechanical properties were investigated in a low carbon low alloy steel processed by a three-step heat treatment, namely, intercritical annealing, intercritical tempering and tempering. The microstructure was a typical dual-phase microstructure consisting of intercritical ferrite and bainite/martensite after intercritical annealing, and primarily comprised of intercritical ferrite, tempered bainite/martensite and retained austenite after intercritical tempering. Retained austenite with volume fraction of 29% distributed at the ferrite/bainite (martensite) boundaries and betweent bainitic/martensitic laths. Retained austenite was stabilized by enrichment of C, Mn, Ni and Cu in reversed austenite during the reversion transformation process. NbC precipitates with average size of 10 nm was formed in ferrite matrix and bainite/martensite, while Cu-containing particles in size range of 10~30 nm precipitated in ferrite and retained austenite during intercritical tempering and tempering process. The morphology of NbC precipitates was spherical, elliptical and irregular, and copper precipitates were spherical. With the combination of transformation-induced-plasticity (TRIP) effect of retained austenite and precipitation hardening, the steel possessed outstanding mechanical properties: yield strength > 700 MPa, tensile strength > 900 MPa, uniform elongation > 20%, and total elongation > 30%.
| [1] | Dong H, Wang M Q, Weng Y Q. Iron Steel, 2010; 45(7): 3 |
| [1] | (董 瀚, 王毛球, 翁宇庆. 钢铁, 2010; 45(7): 3) |
| [2] | Liu L, Yang Z G, Zhang C, Liu W B. Mater Sci Eng, 2010; A527: 7205 |
| [3] | Yoo J D, Hwang S W, Park K T. Mater Sci Eng, 2009; A508: 234 |
| [4] | Misra R D K, Challa V S A, Venkatsurya P K C, Shen Y F, Somani M C, Karjalainen L P. Acta Mater, 2015; 84: 339 |
| [5] | Lee T, Koyama M, Tsuzaki K, Lee Y H, Lee C S. Mater Lett, 2012; 75: 169 |
| [6] | Sugimoto K I, Mobayashi M, Hashimoto S I. Metall Mater Trans, 1992; 23A: 3085 |
| [7] | Sugimoto K I, Tsunezawa M, Hojo T, Ikeda S. ISIJ Int, 2004; 44: 1608 |
| [8] | Speer J G, Matlock D K, De Cooman B C, Schroth J G. Acta Mater, 2003; 51: 2611 |
| [9] | Misra R D K, Zheng H, Wu K M, Karjalainen L P. Mater Sci Eng, 2013; A579: 188 |
| [10] | Kang J, Zhou X G, Wang G D. Steel Rolling, 2009; 26(3): 34 |
| [10] | (康 健, 周晓光, 王国栋. 轧钢, 2009; 26(3): 34) |
| [11] | Miller R L. Metall Trans, 1972; 3: 905 |
| [12] | Niikura M, Morris J W. Metall Trans, 1980; 11: 1531 |
| [13] | Luo H W, Shi J, Wang C, Cao W Q, Sun X J, Dong H. Acta Mater, 2011; 59: 4002 |
| [14] | Shi J, Sun X J, Wang M Q, Hui W J, Dong H, Cao W Q. Scr Mater, 2010; 63: 815 |
| [15] | Zhou W H, Guo H, Xie Z J, Wang X M, Shang C J. Mater Sci Eng, 2013; A587: 366 |
| [16] | Zhou W H, Wang X L, Venkatsurya P K C, Guo H, Shang C J, Misra R D K. Mater Sci Eng, 2014; A607: 569 |
| [17] | Xie Z J, Yuan S F, Zhou W H, Yang J R, Guo H, Shang C J. Mater Des, 2014; 59: 195 |
| [18] | Takaki S, Fukunaga K, Syarif J, Tsuchiyama T. Metall Trans, 2004; 45: 2251 |
| [19] | Sakuma Y, Matsumura O, Takechi H. Metall Trans, 1991; 22A: 489 |
| [20] | Thomas G. Metall Trans, 1978; 9A: 447 |
| [21] | Chi C Y, Dong J X, Liu W Q, Xie X S. Acta Metall Sin, 2010; 46: 1145 |
| [21] | (迟成宇, 董建新, 刘文庆, 谢锡善. 金属学报, 2010; 46: 1145) |
| [22] | Ray A, Dhua S K. Mater Charact, 1996; 37: 1 |
| [23] | Zhang Y H, Zhao H J, Kang Y L. Hot Working Tech, 2006; 35(6): 62 |
| [23] | (张迎晖, 赵鸿金, 康永林. 热加工工艺, 2006; 35(6): 62) |
| [24] | Funakawa Y, Shiozaki T, Tomita K, Yamamoto T, Maeda E. ISIJ Int, 2004; 44: 1945 |
| [25] | Yen H Y, Chen P Y, Huang C Y, Yang J R. Acta Mater, 2011; 59: 6264 |
| [26] | He B B, Huang M X, Liang Z Y, Ngan A H W, Luo H W, Shi J, Cao W Q, Dong H. Scr Mater, 2013; 69: 216 |
| [27] | Zhang K, Zhang M H, Guo Z H, Chen N L, Rong Y H. Mater Sci Eng, 2011; 528A: 8486 |
| [28] | Zhou W H, Guo H, Xie Z J, Shang C J. Mater Des, 2014; 59: 195 |
/
| 〈 |
|
〉 |
