18CrNiMo7-6齿轮钢带状组织控制及其对力学性能的影响
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摘要
采用金相显微镜研究了正火冷却工艺对18CrNiMo7-6齿轮钢带状组织的影响。采用显微硬度计、SEM、拉伸试验机、冲击试验机以及金相显微镜研究了不同程度带状组织对淬回火后试验钢显微硬度的均匀性、成分偏析程度和力学性能的影响。试验结果表明:在930℃奥氏体化保温后,采用强风冷却方式快速冷却到610℃,再炉冷到400℃,最后空冷至室温,可以将带状组织降低到1.5级。但若采用连续快速冷却的方式,则会导致大量贝氏体组织的生成;不同带状组织试验钢经850℃淬火、180℃回火热处理后,显微硬度极差值在30~35HB之间,硬度分布均匀性及力学性能各向异性程度相当。
Effect of normalized cooling treatment on banded structure of gear steel 18CrNiMo7-6was analyzed by metallographic microscope.Effects of banded structures with different degree on micro hardness uniformity,composition segregation,mechanical properties of test steels after quenching and tempering were analyzed by microhardness tester,scanning electron microscope,tensile testing machine,impact testing machine and metallographic microscope.The results show that banded structure can be reduced to 1.5degree after austenizing heat preservation at 930℃,strong wind cooling to 610℃,furnace cooling to 400℃ and then air cooling.But continuous rapid cooling can result to a large amount of bainite formation;Micro hardness range of test steels with different banded structure degree is between 30-35 HB after quenching at 850℃ and tempering at 180℃.Hardness uniformity and anisotropy of mechanical properties are comparable.
Effect of normalized cooling treatment on banded structure of gear steel 18CrNiMo7-6was analyzed by metallographic microscope.Effects of banded structures with different degree on micro hardness uniformity,composition segregation,mechanical properties of test steels after quenching and tempering were analyzed by microhardness tester,scanning electron microscope,tensile testing machine,impact testing machine and metallographic microscope.The results show that banded structure can be reduced to 1.5degree after austenizing heat preservation at 930℃,strong wind cooling to 610℃,furnace cooling to 400℃ and then air cooling.But continuous rapid cooling can result to a large amount of bainite formation;Micro hardness range of test steels with different banded structure degree is between 30-35 HB after quenching at 850℃ and tempering at 180℃.Hardness uniformity and anisotropy of mechanical properties are comparable.
引文
[1]Verhoeven J D.A review of microsegregation induced banding phenomena in steels[J].Journal of Materials Engineering and Performance,2000,9(3):286.
[2]Pokorny A,Pokorny J.Solidification and Deformation of Steels[M].Pairs:Berger-Levrault,1967.
[3]Chae D,Koss D A,Wilson A L,et al.The effect of microstructural banding on failure initiation of hy-100steel[J].Metallurgical and Materials Transactions,2000,31A:995.
[4]刘云旭.低碳合金钢中带状组织的成因、危害和消除[J].金属热处理,2000,12:1.
[5]王彦彬.20CrMoH齿轮钢的淬透性及带状组织研究[D].昆明:昆明理工大学,2010.
[6]师江伟,杨涤心,倪峰.电渣重熔的发展及其趋势[J].特钢技术,2004,(3):58.
[7]蔡珍,黄运华,张跃,等.等温温度对低碳齿轮钢带状组织的影响[J].特殊钢,2012,33(4):57.
[8]蔡珍,黄运华,张跃等.冷却速度对铁素体珠光体带状组织的影响机制[J].钢铁研究学报,2012,24(6):25.
[9]Offerman S E,Vandijk N H,Rekveklt M T.Ferrite/pearlite band formation in hot rolled medium carbon steel[J].Materials Science and Technology,2002(18):297.
[10]Grossterlinden R,Kawalla R,Lotter U.Formation of pearlitic banded structures in ferritic-pearlitic steels[J].Steel Research,1992,63(8):331.
[11]Thompson W S,Howell R P.Factors influencing ferrite/pearlite banding and origin of large pearlite nodules in a hypoeutectoid plate steel[J].Materials Science and Technology,1992(8):777.
[12]Kirkaldy J S,Destinonforstmann J V,Brigham R J.Simulation of banding in steels[J].Canadian Metallurgical Quariterly,1962(1):59.
[13]Standard practice for assessing the degree of orieniation of microstructures.ASTM E1268-2001[S].United States:ASTM,2005.
[14]苗国民,吕新科.解决中碳合金钢带状组织缺陷的热处理方法:中国,200410012385[P/OL].2005-03-16[2016-01-02].http://211.152.9.47/sipoasp/zljs/.
[15]George K.Solidification,segregation,and banding in carbon and alloy steels[J].Metallurgical and Materials Transactions,2003,11B(34):781.
[16]Eric D I,Jagle A.Modelling of Microstructural Banding During Transformations in Steel[M].London:University of Cambridge,2007.
[17]冯光宏,李岩,戴蓓蓉,等.在未再结晶区大压下后加速冷却工艺对钢板带状组织的影响[J].钢铁研究学报,1999,11(6):14.
[18]Bastien G P.The mechanism of formation of banded structures[J].Journal of Iron Steel Institute,1957(187):281.
[19]刘源,许磊磊,赵庆权,等.冷却速率和冷却温度对SA-210Gr.C钢中带状组织形成的影响[J].钢铁研究学报,2014,26(6):57.
[2]Pokorny A,Pokorny J.Solidification and Deformation of Steels[M].Pairs:Berger-Levrault,1967.
[3]Chae D,Koss D A,Wilson A L,et al.The effect of microstructural banding on failure initiation of hy-100steel[J].Metallurgical and Materials Transactions,2000,31A:995.
[4]刘云旭.低碳合金钢中带状组织的成因、危害和消除[J].金属热处理,2000,12:1.
[5]王彦彬.20CrMoH齿轮钢的淬透性及带状组织研究[D].昆明:昆明理工大学,2010.
[6]师江伟,杨涤心,倪峰.电渣重熔的发展及其趋势[J].特钢技术,2004,(3):58.
[7]蔡珍,黄运华,张跃,等.等温温度对低碳齿轮钢带状组织的影响[J].特殊钢,2012,33(4):57.
[8]蔡珍,黄运华,张跃等.冷却速度对铁素体珠光体带状组织的影响机制[J].钢铁研究学报,2012,24(6):25.
[9]Offerman S E,Vandijk N H,Rekveklt M T.Ferrite/pearlite band formation in hot rolled medium carbon steel[J].Materials Science and Technology,2002(18):297.
[10]Grossterlinden R,Kawalla R,Lotter U.Formation of pearlitic banded structures in ferritic-pearlitic steels[J].Steel Research,1992,63(8):331.
[11]Thompson W S,Howell R P.Factors influencing ferrite/pearlite banding and origin of large pearlite nodules in a hypoeutectoid plate steel[J].Materials Science and Technology,1992(8):777.
[12]Kirkaldy J S,Destinonforstmann J V,Brigham R J.Simulation of banding in steels[J].Canadian Metallurgical Quariterly,1962(1):59.
[13]Standard practice for assessing the degree of orieniation of microstructures.ASTM E1268-2001[S].United States:ASTM,2005.
[14]苗国民,吕新科.解决中碳合金钢带状组织缺陷的热处理方法:中国,200410012385[P/OL].2005-03-16[2016-01-02].http://211.152.9.47/sipoasp/zljs/.
[15]George K.Solidification,segregation,and banding in carbon and alloy steels[J].Metallurgical and Materials Transactions,2003,11B(34):781.
[16]Eric D I,Jagle A.Modelling of Microstructural Banding During Transformations in Steel[M].London:University of Cambridge,2007.
[17]冯光宏,李岩,戴蓓蓉,等.在未再结晶区大压下后加速冷却工艺对钢板带状组织的影响[J].钢铁研究学报,1999,11(6):14.
[18]Bastien G P.The mechanism of formation of banded structures[J].Journal of Iron Steel Institute,1957(187):281.
[19]刘源,许磊磊,赵庆权,等.冷却速率和冷却温度对SA-210Gr.C钢中带状组织形成的影响[J].钢铁研究学报,2014,26(6):57.