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Nb对C Si Mn Cr双相钢相变规律、组织和性能的影响 总被引:4,自引:0,他引:4
根据C Si Mn Cr和C Si Mn Cr Nb实验钢的相变规律,在实验室进行了控轧控冷实验研究,分析了微合金元素Nb对高强度热轧双相钢相变规律、组织和性能的影响。实验结果表明,Nb可显著推迟铁素体和珠光体转变,并显著降低铁素体开始转变温度,但对铁素体终止转变温度和贝氏体转变温度区间基本没有影响。经Nb微合金化后,实验钢的屈服强度和抗拉强度增幅均在100 MPa以上,屈服强度的增幅高于抗拉强度,且在强度大幅度升高的同时,伸长率下降并不明显,表明Nb的细晶强化作用对提高中温卷取热轧双相钢强度级别的效果明显。 相似文献
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C Si Mn Cr Nb钢双相组织性能的柔性控制 总被引:1,自引:0,他引:1
根据C Si Mn Cr Nb试验钢的双道次变形和分段冷却热模拟试验结果,进行了试验钢控轧控冷试验,分析了工艺参数对试验钢组织和性能的影响,获得了具有不同力学性能的铁素体+马氏体或铁素体+贝氏体双相组织。结果表明,试验钢两段轧制分段冷却后550 ℃卷取获得铁素体+马氏体双相组织,屈服强度415 MPa,抗拉强度710 MPa,伸长率23.0%,屈强比0.59。500 ℃卷取得到铁素体加粒状贝氏体双相组织,与550 ℃卷取相比,屈服强度升高35 MPa,抗拉强度降低45 MPa,伸长率略微降低。 相似文献
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在Gleeble-3500热模拟试验机上进行冷轧超高强度双相钢的连续退火工艺研究,利用光学显微镜、扫描电镜、透射电镜和拉伸试验研究了连续退火过程中各个参数对1000MPa级冷轧双相钢组织性能的影响.结果表明:试验用钢在退火温度800℃下保温80s,可以得到抗拉强度为1030MPa、延伸率为14%超高强双相钢;随着退火温度的升高,屈服强度和抗拉强度降低.当退火温度为830℃时,显微组织中粒状的非马氏体组织明显增多.过时效温度低于300℃时,屈服强度和抗拉强度变化不大;当过时效温度超过300℃时,抗拉强度急剧下降,屈服强度先降低后升高,在过时效温度为360℃时开始出现屈服平台. 相似文献
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研究了低碳铝镇静钢08Al中单独添加硼、钛和同时添加硼、钛对其组织和力学性能的影响,结果显示,在相同控轧控冷工艺条件下,单独添加微量硼对盘条的屈服强度和抗拉强度影响不大,单独添加质量分数0.057%的钛可使盘条屈服强度和抗拉强度升高约20 MPa,同时添加质量分数为0.004 8%的硼和质量分数为0.07%的钛可使盘条屈服强度和抗拉强度显著提高,试验中,屈服强度由260升高到316 MPa,提高了56 MPa,抗拉强度由363升高到463 MPa,提高了100 MPa。同时添加硼和钛使强度提高的原因主要是由于获得了具有高位错密度的不规则的准多边形铁素体,同时细片层珠光体相变强化对该钢强度的升高也有一定贡献。 相似文献
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为了进一步提升双相钢性能、探究Nb-V元素复合添加对双相钢组织性能的影响,在实验室研发了Nb-V微合金化的冷轧双相钢。利用连退模拟试验机、扫描电镜等设备,系统地研究了退火温度和过时效温度对双相钢组织性能的影响。结果表明,抗拉强度和伸长率随着退火温度的升高变化不大,屈服强度在组织中铁素体含量明显减少后有显著提升;Nb、V元素的添加细化了组织,可以提高综合性能。随着过时效温度的升高,试验钢主要组织由起初低温时的淬火马氏体+回火马氏体变为高温时的粒状贝氏体,残余奥氏体比例也逐渐增大。高温过时效时,试验钢强度的降低主要由回火马氏体的软化造成;低温过时效时,V析出量的增加也对试验钢的强化起到了重要作用。 相似文献
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利用热膨胀仪研究了合金元素硅和铬对C-Si-Mn-Nb系与C-Cr-Mn-Nb系超高强双相钢连续冷却相变规律的影响;采用单向拉伸试验,以及OM、SEM和TEM等方法对比研究了2种DP钢的组织性能与断口形貌。结果表明:硅元素能够提高[Ac1]和[Ac3]点温度,扩大两相区,促进铁素体相变,并能提高马氏体的回火稳定性,改善其形貌和分布;铬元素的添加导致了奥氏体中碳的分布不均匀,使得马氏体内部同时出现了孪晶与板条状精细结构,而且快冷过程中出现了残余奥氏体和马奥岛组织,部分马氏体会在时效过程中发生分解;两钢的抗拉强度均超过1 000 MPa,伸长率超过15%,且含硅的双相钢各项力学性能均要优于含铬的双相钢。 相似文献
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基于C Si Mn Cr Mo系600 MPa级热轧双相钢的组分,设计了不同硅质量分数(0.55%和1.17%)的两种试验钢。采用Gleeble 3500热模拟试验机测定了两种试验钢的连续冷却转变曲线,分析了硅质量分数对试验钢连续冷却过程中组织转变的影响,并研究了硅质量分数对短流程生产中温卷取型热轧双相钢生产工艺的影响。结果表明,相对于w(Si)=1.17%,w(Si)=0.55%使铁素体开始转变温度降低40~50 ℃,明显缩短了铁素体转变的孕育期,并增加了铁素体的体积分数。在CSP线上生产时,低硅钢的终轧温度可控制为820~830 ℃,低的终轧温度使铁素体相变时间增加2.2 s左右,铁素体转变量增加,且后续相变过程中可避免非马氏体组织的出现。因此,低硅钢适合在CSP短流程线上生产中温卷取型热轧双相钢。 相似文献
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The effects of Mn and Cr contents on bainitic transformation kinetics,microstructures and mechanical properties of high-carbon low alloy steels after austempered at 230,300 and 350 ℃ were determined by dilatometry,optical microscopy,scanning electron microscopy,X-ray diffraction and tensile tests. The results showed that Mn and Cr can extend bainitic incubation period and completion time,and with the increase of Mn and Cr content,the bainitic ferrite plate thickness decreased and the volume fraction of retained austenite increased. TRIP( transformation induced plasticity) effect was observed during tensile testing which improved the overall mechanical property. The increase of Mn concentration can improve the strength to a certain extent,but reduce the ductility. The increase of Cr concentration can improve the ductility of bainitic steels which transformed at a low temperature. The low temperature bainitic steel austempered at 230 ℃ exhibited excellent mechanical properties with ultimate tensile strength of( 2146 ± 11) MPa and total elongation of( 12. 95 ± 0. 15) %. 相似文献
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780MPa级冷轧双相钢是低碳低合金钢,主要的金属元素为锰,另外根据强度要求的不同,还加入了适量的Mo、Cr等元素。试验结果表明:690℃卷取可以获得更好的性能;随着退火温度的升高,试验钢的马氏体体积分数增加,强度增加,在820℃获得的综合性能最好;在820℃退火,当退火时间为80~100s时强度变化剧烈;当退火时间超过100s后,变化趋势相对平缓,综合比较,退火时间为100s时,获得的综合性能最好。 相似文献
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CSP流程生产经济型热轧双相钢的工艺与组织性能 总被引:1,自引:0,他引:1
为了在CSP产线上开发新一代经济型热轧双相钢,并确定生产的最佳成分和工艺,介绍了在武钢CSP生产线进行580MPa级热轧双相钢的工业化生产试制情况。分别采用C-Mn-Si系和C-Mn-Si-Cr系钢为原料,通过控制轧制和基于超强冷却设备的控制冷却工艺,成功开发出抗拉强度580MPa级热轧双相钢。通过比较分析2种成分钢的力学性能和微观组织,结果表明:经济型的C-Mn-Si系钢相对于C-Mn-Si-Cr系钢具有屈服强度低、屈强比小、伸长率大的特点,虽然马氏体量相对较少,但具有马氏体呈岛状更加均匀分布在铁素体晶界上等典型双相钢的特征,同时提出了生产过程中控制铁素体析出量和促进马氏体形成的具体措施。 相似文献
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Formable high‐strength low‐alloy TRIP‐aided sheet steels with annealed martensite matrix or TRIP‐aided annealed martensitic steel were developed for automotive applications. The steels possessed a large amount of plate‐like retained austenite along annealed martensite lath boundary, the stability of which against the strain‐induced transformation was higher than that of the conventional TRIP‐aided dual‐phase steel with polygonal ferrite matrix. In a tensile strength range between 600 and 1000 MPa, the TRIP‐aided annealed martensitic steels exhibited superior large elongation and reduction of area. In addition, the steels possessed the same excellent stretch‐flangeability and bendability as TRIP‐aided bainitic steel with bainitic ferrite matrix. These properties were discussed by matrix structure, a strength ratio of second phase to matrix, retained austenite stability, internal stress in matrix and so on. 相似文献
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By using a static and high-speed material testing machine,tensile deformation behaviors of two kinds of SiMn TRIP(transformation induced plasticity)steels and DP(dual phase)steel were studied in a large range of strain rates(0.001-2 000s-1).Temperature variation during adiabatic heating and the amount of retained austenite at fracture were measured by an infrared thermometer and an X-ray stress analyser,respectively.The microstructure of steels was observed by optical microscopy(OM)and scanning electron microscopy(SEM)before and after tensile test.It was found from the experimental results that the tensile strength of these steels increased,and the fracture elongation firstly decreased and subsequently increased,as the strain rate increased in the range of 0.1-2 000s-1.The temperature raised during adiabatic heating of TRIP steel was in the range of 100-300℃,while that of the DP steel was in the range of 100-220 ℃.The temperature rise of these steels increased with increasing the strain rate,as well as the amount of the transformed retained austenite in TRIP steels.It was confirmed that austenite to martensite transformation is not suppressed by adiabatic heating. 相似文献