钛微合金中锰钢强韧化机制研究
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摘要
低碳中锰钢因为其优异的力学性能及低成本的成分设计逐渐被应用到海洋平台用厚板生产制备中,通过对钛微合金化低碳中锰钢进行控轧控冷工业试验,观察不同厚度位置的显微组织及析出物形貌,测定了室温拉伸及低温冲击韧性,并对其强韧化机制进行了分析。结果表明,试验钢基体为板条宽度200～400 nm的回火马氏体和宽度为50～100 nm的逆转变奥氏体复合层状组织,且全厚度方向组织性能均匀性较好,屈服强度均大于760 MPa、屈强比均小于等于0.88、伸长率均大于20%、-60℃冲击功均大于200 J。试验钢的主要强韧化机制有亚微米尺度的复合层状组织、大角度晶界韧化机制、亚稳态逆转变奥氏体TRIP效应、Ti(C,N)粒子的细晶强化及析出强化效应,多种强化机制叠加作用,最终获得高强韧的中锰钢厚板。
Low-C medium-Mn steel has been gradually applied to the production and preparation of heavy plate for offshore platform usage due to its excellent mechanical properties and low-cost composition design. The industrial thermo-mechanical control process test was conducted on Ti microallyed low-C medium-Mn steel. The morphologies of microstructure and precipitates at different positions along thickness direction were studied,and tensile strength and impact toughness were measured. Moreover,the strength-toughness mechanism was investigated. The results show that the matrix of experimental steel is laminated structure composed of tempered martensite with strip width of 200-400 nm and reversed austenite with strip width of 50-100 nm. Moreover, excellent homogeneity of microstructures and properties are obtained. Results indicate that for all experimental steels, the yield strength exceeds 760 MPa, yield ratio is no more than 0.88, elongation rate are more than 20%, and the impact energy measured at-60 ℃ exceeds 200 J. Sub-micron laminated of matrix structure, toughening mechanism of large angle grain boundary, transformation-induced plasticity effect of metastable austenite, as well as fine-grained strengthening and precipitation strengthening of Ti(C,N)are the major strengthening and toughening mechanisms, which work together and finally obtain the medium manganese thick plate with high strength and toughness.
Low-C medium-Mn steel has been gradually applied to the production and preparation of heavy plate for offshore platform usage due to its excellent mechanical properties and low-cost composition design. The industrial thermo-mechanical control process test was conducted on Ti microallyed low-C medium-Mn steel. The morphologies of microstructure and precipitates at different positions along thickness direction were studied,and tensile strength and impact toughness were measured. Moreover,the strength-toughness mechanism was investigated. The results show that the matrix of experimental steel is laminated structure composed of tempered martensite with strip width of 200-400 nm and reversed austenite with strip width of 50-100 nm. Moreover, excellent homogeneity of microstructures and properties are obtained. Results indicate that for all experimental steels, the yield strength exceeds 760 MPa, yield ratio is no more than 0.88, elongation rate are more than 20%, and the impact energy measured at-60 ℃ exceeds 200 J. Sub-micron laminated of matrix structure, toughening mechanism of large angle grain boundary, transformation-induced plasticity effect of metastable austenite, as well as fine-grained strengthening and precipitation strengthening of Ti(C,N)are the major strengthening and toughening mechanisms, which work together and finally obtain the medium manganese thick plate with high strength and toughness.
引文
[1] Uemori R,Fujioka M,Inoue T,et al.Steels for marine transportation and construction[J].Nippon Steel Technical Report,2012,101:37.
[2] 郝文魁,刘智勇,王显宗,等.海洋平台用高强钢强度及其耐蚀性现状及发展趋势[J].装备环境工程,2014,11(2):50.(Hao W K,Liu Z Y,Wang X Z,et al.Current situation and prospect of studies on strength and corrosion resistance of high strength steel for ocean platform[J].Equipment Environmental Engineering,2014,11(2):50.)
[3] Liu D S,Cheng B G,Chen Y Y.Strengthening and toughening of a heavy plate steel for shipbuilding with yield strength of approximately 690 MPa[J].Metallurgical and Materials Transactions,2014,44A(1):440.
[4] Bouaziz O,Allain S,Scott C P,et al.High manganese austenitic twinning induced plasticity steels:A review of the microstructure properties relationships[J].Current Opinion in Solid State and Materials Science,2011,15(4):141.
[5] Li Y,Li W,Min N,et al.Effects of hot/cold deformation on the microstructures and mechanical properties of ultra-low carbon medium manganese quenching-partitioning-tempering steels[J].Acta Materialia,2017,139:96.
[6] 宋丽娜,兰鹏,刘春秀,等.第3代汽车用中锰钢的研究现状[J].钢铁研究学报,2015,27(7):1.(Song L N,Lan P,Liu C X,et al.Research situation of medium manganese steel for 3rd generation automobile sheet[J].Journal of Iron and Steel Research,2015,27(7):1.)
[7] Han J,Silva A K,Ponge D,et al.The effects of prior austenite grain boundaries and microstructural morphology on the impact toughness of intercritically annealed medium Mn steel[J].Acta Materialia,2017,122:199.
[8] Niikura M,Morris J W.Thermal processing of ferritic 5Mn steel for toughness at cryogenic temperatures[J].Metallurgical Transactions,1980,11A(9):1531.
[9] Zou Y,Xu Y B,Hu Z P,et al.Austenite stability and its effect on the toughness of a high strength ultra-low carbon medium manganese steel plate[J].Materials Science and Engineering,2016,675A:153.
[10] Lan L L,Qiu C L,Zhao D W,et al.Effect of single pass welding heat input on microstructure and hardness of submerged arc welded high strength low carbon bainitic steel[J].Science and Technology of Welding and Joining,2013,17(7):564.
[11] Hu J,Du L X,Wang J J,et al.Effect of welding heat input on microstructures and toughness in simulated CGHAZ of V-N high strength steel[J].Materials Science and Engineering,2013,577A:161.
[12] Haidemenopoulos G N,Kermanidis A T,Malliaros C,et al.On the effect of austenite stability on high cycle fatigue of TRIP 700 steel[J].Materials Science and Engineering,2013,573A(20):7.
[13] 李岩,杜敬超,定巍,等.临界退火温度对中锰TRIP钢组织和性能的影响[J].钢铁研究学报,2018,30(3):185.(Li Y,DU J C,Ding W,et al.Influence of intercritical annealing temperature on microstructure and mechanical properties of medium Mn TRIP steel[J].Journal of Iron and Steel Research,2018,30(3):185.)
[14] Sun B H,Fazeli F,Scott C,et al.Critical role of strain partitioning and deformation twining on cracking phenomenon occurring during cold rolling of two duplex medium manganese steels[J].Scripa Materialia,2017,130:49.
[15] 刘彦明,石凯,周勇,等.9Ni钢的热处理及低温韧度[J].热加工工艺,2007,36(16):77.(Liu Y M,Shi K,Zhou Y,et al.Heat treatment and low temperature toughness of 9Ni steel[J].Hot Working Technology,2007,36(16):77.)
[2] 郝文魁,刘智勇,王显宗,等.海洋平台用高强钢强度及其耐蚀性现状及发展趋势[J].装备环境工程,2014,11(2):50.(Hao W K,Liu Z Y,Wang X Z,et al.Current situation and prospect of studies on strength and corrosion resistance of high strength steel for ocean platform[J].Equipment Environmental Engineering,2014,11(2):50.)
[3] Liu D S,Cheng B G,Chen Y Y.Strengthening and toughening of a heavy plate steel for shipbuilding with yield strength of approximately 690 MPa[J].Metallurgical and Materials Transactions,2014,44A(1):440.
[4] Bouaziz O,Allain S,Scott C P,et al.High manganese austenitic twinning induced plasticity steels:A review of the microstructure properties relationships[J].Current Opinion in Solid State and Materials Science,2011,15(4):141.
[5] Li Y,Li W,Min N,et al.Effects of hot/cold deformation on the microstructures and mechanical properties of ultra-low carbon medium manganese quenching-partitioning-tempering steels[J].Acta Materialia,2017,139:96.
[6] 宋丽娜,兰鹏,刘春秀,等.第3代汽车用中锰钢的研究现状[J].钢铁研究学报,2015,27(7):1.(Song L N,Lan P,Liu C X,et al.Research situation of medium manganese steel for 3rd generation automobile sheet[J].Journal of Iron and Steel Research,2015,27(7):1.)
[7] Han J,Silva A K,Ponge D,et al.The effects of prior austenite grain boundaries and microstructural morphology on the impact toughness of intercritically annealed medium Mn steel[J].Acta Materialia,2017,122:199.
[8] Niikura M,Morris J W.Thermal processing of ferritic 5Mn steel for toughness at cryogenic temperatures[J].Metallurgical Transactions,1980,11A(9):1531.
[9] Zou Y,Xu Y B,Hu Z P,et al.Austenite stability and its effect on the toughness of a high strength ultra-low carbon medium manganese steel plate[J].Materials Science and Engineering,2016,675A:153.
[10] Lan L L,Qiu C L,Zhao D W,et al.Effect of single pass welding heat input on microstructure and hardness of submerged arc welded high strength low carbon bainitic steel[J].Science and Technology of Welding and Joining,2013,17(7):564.
[11] Hu J,Du L X,Wang J J,et al.Effect of welding heat input on microstructures and toughness in simulated CGHAZ of V-N high strength steel[J].Materials Science and Engineering,2013,577A:161.
[12] Haidemenopoulos G N,Kermanidis A T,Malliaros C,et al.On the effect of austenite stability on high cycle fatigue of TRIP 700 steel[J].Materials Science and Engineering,2013,573A(20):7.
[13] 李岩,杜敬超,定巍,等.临界退火温度对中锰TRIP钢组织和性能的影响[J].钢铁研究学报,2018,30(3):185.(Li Y,DU J C,Ding W,et al.Influence of intercritical annealing temperature on microstructure and mechanical properties of medium Mn TRIP steel[J].Journal of Iron and Steel Research,2018,30(3):185.)
[14] Sun B H,Fazeli F,Scott C,et al.Critical role of strain partitioning and deformation twining on cracking phenomenon occurring during cold rolling of two duplex medium manganese steels[J].Scripa Materialia,2017,130:49.
[15] 刘彦明,石凯,周勇,等.9Ni钢的热处理及低温韧度[J].热加工工艺,2007,36(16):77.(Liu Y M,Shi K,Zhou Y,et al.Heat treatment and low temperature toughness of 9Ni steel[J].Hot Working Technology,2007,36(16):77.)