硫化物形貌对非调质钢力学性能各向异性的影响
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摘要
为了明确硫化物变性处理前后材料力学性能各向异性的变化规律,利用金相显微镜、SEM、拉伸及冲击试验机研究了工业生产的具有不同硫化物形貌特征(硫化物变性与未变性处理)的35MnVS非调质钢锻态力学性能的各向异性。结果表明,经变性处理后硫化物由未经变性处理的细长条状向短棒状或纺锤状转变,硫化物长宽比在1～8范围内的个数比例由未经变性处理的不到40%提高到变性处理后的90%以上,且分布更加均匀,组织有所细化。硫化物变性处理能够明显地降低试验钢塑性和韧性的各向异性,断面收缩率和冲击功的各向异性分别减小了约10%和34%,横向断口形貌由脆性的朽木分层状向韧窝韧性断裂转变。
To investigate the effect of sulfide morphology on anisotropic mechanical properties of as-forged microalloyed forging steel, two heats of commercial ferritic-pearlitic microalloyed forging steel 35 MnVS with different sulfide morphologies(sulfide modified and non-modified) were studied by using optical microscopy, scanning electron microscopy, tensile and impact tests. The results show that after sulfide modification, the sulfide shape changed from highly elongated to rod-like and slightly elongated, and the fraction of sulfides with aspect ratio(the ratio of length to width of sulfide) in the range of 1 to 8 increased from lower than 40%(for sulfide non-modification) to higher than 90%; moreover, the distribution of the modified sulfides was more uniform and the microstructure was refined. The modification of sulfide could significantly alleviate the anisotropy of both ductility and toughness by relative decrease of ～10% and ～34%, respectively. The predominant facture mechanism changed from brittle fracture with many elongated sulfides promoted quasi-cleavage strips to ductile dimple fracture after sulfide modification.
To investigate the effect of sulfide morphology on anisotropic mechanical properties of as-forged microalloyed forging steel, two heats of commercial ferritic-pearlitic microalloyed forging steel 35 MnVS with different sulfide morphologies(sulfide modified and non-modified) were studied by using optical microscopy, scanning electron microscopy, tensile and impact tests. The results show that after sulfide modification, the sulfide shape changed from highly elongated to rod-like and slightly elongated, and the fraction of sulfides with aspect ratio(the ratio of length to width of sulfide) in the range of 1 to 8 increased from lower than 40%(for sulfide non-modification) to higher than 90%; moreover, the distribution of the modified sulfides was more uniform and the microstructure was refined. The modification of sulfide could significantly alleviate the anisotropy of both ductility and toughness by relative decrease of ～10% and ～34%, respectively. The predominant facture mechanism changed from brittle fracture with many elongated sulfides promoted quasi-cleavage strips to ductile dimple fracture after sulfide modification.
引文
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[10] Temmel C,Ingesten N G,Karlsson B.Fatigue anisotropy in cross-rolled,hardened medium carbon steel resulting from MnS inclusions[J].Metallurgical and Materials Transactions,2006,37A(10):2995.
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[13] 李梦龙,王福明,李长荣,等.原位观察MnS对非调质钢拉伸性能各向异性的影响[J].工程科学学报,2016,38(9):1257.(Li M L,Wang F M,Li C R,et al.In-situ observation of MnS effect on the tensile strength anisotropy of non-quenched and tempered steel[J].Chinese Journal of Engineering,2016,38(9):1257.)
[14] Ghosh A,Modak P,Dutta R,et al.Effect of MnS inclusion and crystallographic texture on anisotropy in Charpy impact toughness of low carbon ferritic steel[J].Materials Science and Engineering,2016,654A:298.
[15] 肖国华,董瀚,王毛球,等.镁和镁钙处理对非调质钢中硫化物形态的影响[J].钢铁,2011,46(4):65.(Xiao G H,Dong H,Wang M Q,et al.Effect of Ma/Ca-treatment on morphology of sulfide in non-quenched and tempered steel[J].Iron and Steel,2011,46(4):65.)
[16] 董正强,蒋波,张朝磊,等.曲轴用非调质钢C38N2轧制过程中MnS夹杂演变规律[J].材料热处理学报,2015,36(8):144.(Dong Z Q,Jiang B,Zhang C L,et al.Evolution of MnS in non-quenched and tempered crankshaft steel C38N2 during rolling[J].Transactions of Material and Heat Treatment,2015,36(8):144.)
[17] 夏云进,郭鑫,李杰,等.锆、铝脱氧对钢中硫化物生成行为的影响[J].钢铁,2016,51(2):38.(Xia Y J,Guo X,Li J,et al.Effects of Zr,Al deoxidation on formation behavior of sulfides in steel[J].Iron and Steel,2016,51(2):38.)
[18] 余圣甫,雷毅,谢明立,等.晶内铁素体的形核机理[J].钢铁研究学报,2005,17(1):47.(Yu S F,Lei Y,Xie M L,et al.Nucleation mechanisms of intragranular ferrite (IGF)[J].Journal of Iron and Steel Research,2005,17(1):47.)
[19] Kaynak C,Ankara A,Baker T J.Inclusion induced anisotropy of short fatigue crack growth in steel[J].Materials science and technology,1996,12(7):557.
[20] Hosseini S B,Temmel C,Karlsson B,et al.An in-situ scanning electron microscopy study of the bonding between MnS inclusions and the matrix during tensile deformation of hot-rolled steels[J].Metallurgical and Materials Transactions,2007,38A(5):982.
[2] 陈思联,惠卫军,王连海,等.节能低成本高品质非调质钢的研发[J].钢铁,2014,49(6):1.(Chen S L,Hui W J,Wang L H,et al.Research and development of energy-saving high performance microalloyed forging steels[J].Iron and Steel,2014,49(6):1.)
[3] Tsunekage N,Tsubakino H.Effects of sulfur content and sulfide-forming elements addition on impact properties of ferrite-pearlitic microalloyed steels[J].ISIJ International,2001,41(5):498.
[4] 李梦龙,王福明,李茂旺,等.S含量对中碳非调质钢拉伸性能的影响[J].金属热处理,2015,40(5):1.(Li M L,Wang F M,Li M W,et al.Effect of sulfur content on tensile property of medium carbon non-quenched and tempered steel[J].Heat Treatment of Metals,2015,40(5):1.)
[5] 姚登元,吴华杰,陆鹏雁,等.钙处理对含硫非调质钢中硫化物形态的影响[J].中国冶金,2017,27(4):11.(Yao Y D,Wu H J,Lu P Y,et al.Effect of Ca treatment on sulfides morphology in S-bearing non-quenched and tempered steel[J].China Metallurgy,2017,27(4):11.)
[6] 王毓男,包燕平.BN型易切削钢中夹杂物的控制及对切削性能的影响[J].钢铁研究学报,2017,29(5):382.(Wang Y N,Bao Y P.Contral of inclusion in BN free cutting steel and its effect on machinability[J].Journal of Iron and Steel Research,2017,29(5):382.)
[7] 程慧静,王福明,李长荣,等.易切削非调质38MnVS钢中硫化物析出规律热力学分析[J].材料热处理学报,2010,31(11):161.(Cheng H J,Wang F M,Li C R,et al.Thermodynamic analysis of sulfide precipitation behavior in a free-cutting microalloyed 38MnVS[J].Transactions of Materials and Heat Treatment,2010,31(11):161.)
[8] Ishikawa F,Takahashi T.The formation of intragranular ferrite plates in medium-carbon steels for hot-forging and its effect on the toughness[J].ISIJ International,1995,35(9):1128.
[9] 许中波,Gammal E L.钢中夹杂物含量及其形态对钢力学性能的影响[J].钢铁研究学报,1994,6(4):18.(Xu Z B,Gammal E L.Infulence of inclusion content and morphology on mechanical properties of steel[J].Journal of Iron and Steel Research,1994,6(4):18.)
[10] Temmel C,Ingesten N G,Karlsson B.Fatigue anisotropy in cross-rolled,hardened medium carbon steel resulting from MnS inclusions[J].Metallurgical and Materials Transactions,2006,37A(10):2995.
[11] Cyril N S,Fatemi A.Experimental evaluation and modeling of sulfur content and anisotropy of sulfide inclusions on fatigue behavior of steels[J].International Journal of Fatigue,2009,31(3):526.
[12] Pessard E,Morel F,Morel A,et al.Modelling the role of non-metallic inclusions on the anisotropic fatigue behaviour of forged steel[J].International Journal of Fatigue,2011,33(4):568.
[13] 李梦龙,王福明,李长荣,等.原位观察MnS对非调质钢拉伸性能各向异性的影响[J].工程科学学报,2016,38(9):1257.(Li M L,Wang F M,Li C R,et al.In-situ observation of MnS effect on the tensile strength anisotropy of non-quenched and tempered steel[J].Chinese Journal of Engineering,2016,38(9):1257.)
[14] Ghosh A,Modak P,Dutta R,et al.Effect of MnS inclusion and crystallographic texture on anisotropy in Charpy impact toughness of low carbon ferritic steel[J].Materials Science and Engineering,2016,654A:298.
[15] 肖国华,董瀚,王毛球,等.镁和镁钙处理对非调质钢中硫化物形态的影响[J].钢铁,2011,46(4):65.(Xiao G H,Dong H,Wang M Q,et al.Effect of Ma/Ca-treatment on morphology of sulfide in non-quenched and tempered steel[J].Iron and Steel,2011,46(4):65.)
[16] 董正强,蒋波,张朝磊,等.曲轴用非调质钢C38N2轧制过程中MnS夹杂演变规律[J].材料热处理学报,2015,36(8):144.(Dong Z Q,Jiang B,Zhang C L,et al.Evolution of MnS in non-quenched and tempered crankshaft steel C38N2 during rolling[J].Transactions of Material and Heat Treatment,2015,36(8):144.)
[17] 夏云进,郭鑫,李杰,等.锆、铝脱氧对钢中硫化物生成行为的影响[J].钢铁,2016,51(2):38.(Xia Y J,Guo X,Li J,et al.Effects of Zr,Al deoxidation on formation behavior of sulfides in steel[J].Iron and Steel,2016,51(2):38.)
[18] 余圣甫,雷毅,谢明立,等.晶内铁素体的形核机理[J].钢铁研究学报,2005,17(1):47.(Yu S F,Lei Y,Xie M L,et al.Nucleation mechanisms of intragranular ferrite (IGF)[J].Journal of Iron and Steel Research,2005,17(1):47.)
[19] Kaynak C,Ankara A,Baker T J.Inclusion induced anisotropy of short fatigue crack growth in steel[J].Materials science and technology,1996,12(7):557.
[20] Hosseini S B,Temmel C,Karlsson B,et al.An in-situ scanning electron microscopy study of the bonding between MnS inclusions and the matrix during tensile deformation of hot-rolled steels[J].Metallurgical and Materials Transactions,2007,38A(5):982.