共查询到19条相似文献,搜索用时 218 毫秒
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对中温卷取工艺下的热轧双相钢组织性能进行了研究。结果表明,Cr、Mo成分体系的热轧双相钢采用3段式冷却后屈强比为0.6,显微组织为准多边形铁素体、岛状马氏体以及细小粒状贝氏体,具有较高的伸长率和扩孔性能。由于贝氏体的存在,缩小了双相钢多相组织之间的强度差,有利于提高其塑性变形过程中的协调变形能力及扩孔性能。通过对应力幅值为430 MPa时双相钢的疲劳断口进行分析,断口具有显著的韧窝、二相粒子、疲劳辉纹、二次裂纹等特征,有利于提高其疲劳强度。 相似文献
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以C-Si-Mn系热轧双相钢为研究对象,通过单道次热模拟实验,研究了不同变形温度下热轧双相钢热变形行为.研究发现,变形温度越高,再结晶越容易;变形温度降低,铁素体晶粒小,热变形流变应力随之下降,并且双相钢中板条马氏体和孪晶马氏体形貌均有退化趋势.通过对不同变形温度下双相钢热变形行为的研究,可以为进一步热轧实验提供理论依据. 相似文献
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通过热轧和模拟超快冷试验,试制出780 MPa级热轧双相钢,研究了马氏体的含量、形貌、分布对热轧双相钢力学性能和n值的影响。结果表明,试验钢经850℃终轧后,组织为铁素体+马氏体,抗拉强度853 MPa,屈服强度464 MPa,屈强比0.54,伸长率19.5%,n值0.14,达到热轧DP780性能要求。在高马氏体含量下(28.2%),随着马氏体含量的增加,组织中的马氏体由弥散分布的片状马氏体逐渐转变为连续的板条状马氏体,马氏体的尺寸逐渐增加;而多边形铁素体部分转变为准多边形铁素体,铁素体尺寸逐渐减小。热轧双相钢的强度和屈强比逐渐提高,而伸长率和n值逐渐降低。 相似文献
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利用奥钢联热模拟试验机模拟980 MPa级双相钢连续退火镀锌过程,利用拉伸试验机、光学显微镜和扫描电镜研究连续镀锌工艺中均热温度和快冷出口温度对双相钢组织及力学性能的影响。结果表明,经热镀锌退火后,980 MPa级双相钢的微观组织为铁素体+马氏体,组织中有Nb,Ti碳氮化物析出。随着均热温度的升高,马氏体体积分数呈逐渐增加的趋势,屈服强度和屈强比不断升高。快冷出口温度从340 ℃升高到430 ℃,马氏体发生回火分解,降低了试验钢的屈服强度,同时改善了伸长率。快冷出口温度为400 ℃时,强塑积达到最大值13.9 GPa·%。当均热温度为840 ℃,快冷出口温度为460~480 ℃时,可以获得抗拉强度在980 MPa级以上的双相钢。 相似文献
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文章研究了在采用低温区大变形和轧后连续冷却工艺时,终轧温度对传统Si-Mn系热轧双相钢组织和性能的影响。结果表明,在试验工艺条件下,试验钢的最终组织均为铁素体+马氏体的双相组织。随着终轧温度(770℃~850℃)的升高,试验钢的屈服强度由415MPa急剧降低到335MPa,而抗拉强度变化不大,约为690MPa;随着终轧温度的升高,铁素体晶粒尺寸逐渐均匀,平均晶粒尺寸先增大,后减小,铁素体含量约为88%;试验钢的n值和延伸率,则随着终轧温度的升高而升高,在温度850℃时,n值达到0.23,延伸率达到28.7%。 相似文献
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A steel containing 0.088 wt% C, 1.2 wt% Mn, and 0.78 wt% Cr was rolled at intercritical temperature (790 °C) and quenched
to produce dual-phase microstructure. Rolling caused anisotropic increase in tensile strength and little change in ductility.
The results suggest that rolling increased strength by a combination of strengthening of the ferrite and an increase in the
stress transferred to the martensite. Up to 20% rolling reduction strengthened the ferrite by work hardening, larger reductions
then reduced the strength of ferrite, anisotropically, due to increased recovery. Subgrains in ferrite were observed after
rolling in the intercritical region which can contribute to the ultimate strength of the rolled material. 相似文献
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采用双相区(α+γ)轧制及双相区短时保温处理相结合的方式,制备了一种高强高韧性低碳低合金铁素体/马氏体双相钢,并采用SEM、室温拉伸试验和维氏硬度检测等手段研究了不同轧制工艺对铁素体/马氏体双相钢组织和性能的影响。结果表明:相对于普通的连续轧制工艺,等温轧制和道次之间短时保温处理相结合的工艺对铁素体/马氏体双相钢的相比例、形貌和尺寸有重要影响。等温轧制及短时保温处理的双相钢的组织明显细化,马氏体相比例增加,组织均匀性显著改善,屈服强度提升了34%,达到1229 MPa,屈强比高达0.78,断口为韧性断口特征,呈细小韧窝状,具有良好的综合力学性能。 相似文献
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E. Ahmad 《Journal of Materials Engineering and Performance》2013,22(8):2161-2167
Low alloy steel containing 0.09 wt.% C was thermomechanically processed with various rolling reductions at intercritical temperature of 790 °C, followed by quenching in the iced brine solution. The flow of the material due to this plastic deformation increased the aspect ratio of the microstructure (α + γ) in the rolling than in the transverse directions. The strengths, both in the longitudinal and transverse directions of rolling were increased because of the development of substructure in ferrite, observed previously. The fibrous microstructure formed after rolling increased the surface area of contact of ferrite and martensite. During tensile deformation the fibrous dual-phase composite had positioned itself for better stress transfer from soft ferrite to hard martensite particles. These microstructural changes associated with hot deformation of the material were accommodated in current modifications in the law of mixture applied to dual-phase steel. A computer simulation was developed to present the deformation behavior of ferrite, martensite, and composite from the experimental tensile data (loads and strain). Different variables were introduced in the simulation for allowing the composite curves to pass through the experimental data points to demonstrate the tensile deformation behavior of ferrite and martensite. The systematic changes in these variables with degree of hot rolling in the intercritical region clearly described the deformation behaviour of ferrite and martensite individually. 相似文献
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通常采用优化孔型的方法使型钢产品变形更加均匀,从而获得理想的显微组织,提升产品性能。但是孔型优化对于变形量分配的调整幅度有限,无法满足多数高品质钢的控轧要求。根据轧制规程设计,H型钢翼缘变形全部集中在万能轧制阶段,为此,研究了在万能轧制段控轧温度对含Nb热轧H型钢组织和性能的影响。结果表明,随着控轧温度的升高,显微组织中铁素体形状由扁平状逐渐变为等轴状,铁素体晶粒平均尺寸先减小后增大且在900 ℃时晶粒尺寸最小。当控轧温度控制在850~900 ℃区段,不仅有效提高生产效率,而且其显微组织为细小均匀的等轴状铁素体+少量珠光体,该温度下试验钢的强度指标优于其他轧制温度,低温冲击韧性也明显提高。 相似文献