共查询到20条相似文献,搜索用时 21 毫秒
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为了满足各行业对钢铁材料提出的更高强度、更好韧性的要求,在钢中加入适量的微合金化元素并结合合理的控扎控冷工艺,有利于在高温轧制阶段获得细小均匀的奥氏体再结晶晶粒,这是提高钢材强度及韧性的有效途径之一。通过Gleeble-3800型热模拟试验机,对两种不同锆含量的低碳微合金Ti-Zr钢进行多道次压缩变形试验,模拟实际轧制情况,研究试验钢在不同锆含量和不同变形方式(等温变形和变温变形)下的热变形行为,并结合组织观察分析讨论了锆含量和变形条件对试验钢奥氏体组织细化行为和析出行为的影响。结果表明,变形温度的升高可以降低高锆钢各道次的流变应力。变温变形条件下,锆含量的升高会提高试验钢各道次的流变应力;奥氏体再结晶晶粒会随着锆含量的升高和变形温度的降低而发生细化,采用变温变形方式比等温变形方式更有利于得到细小的奥氏体晶粒,高锆钢在1 050℃→1 25℃→1 000℃变温变形后得到了最小的奥氏体平均晶粒尺寸(为8.2μm);锆含量升高会提高试验钢中析出相的数量,变形方式对析出相数量的影响不大,变形温度的升高会使析出相发生粗化。锆含量增加所导致的形变诱导析出相的增多,以及变温变形过程中温度的降低,起... 相似文献
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为了研究Ti-Zr微合金钢轧制变形过程中变形温度和Zr含量对内部应力应变的分布及奥氏体组织演变的影响,通过热模拟实验和金相分析获得3种不同Zr含量的Ti微合金钢应力应变曲线及奥氏体的晶粒尺寸及分布情况。研究结果表明:变形温度的升高会降低3种实验钢的内部应力,促进应力均匀分布,其中0.12Ti-0.02Zr钢应力下降的最明显,Zr的加入会促进Ti微合金钢再结晶奥氏体的形核和形变诱导析出相的析出,形变储能消耗量增大,不容易在变形过程中积累应力和应变;但过多的Zr会因为大量析出相而使实验钢的变形抗力增大,导致应力和应变累积。综合考虑,使用Ti-Zr复合微合金化技术实现奥氏体组织的超细化均匀时,Zr元素的添加量应控制在0.02%左右。 相似文献
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用Gleeble-1500D热模拟试验机和电子显微镜研究了在950~750℃不同温度下变形50%后0.05C- 0.13Nb钢的组织和析出相。结果表明,随变形温度由950℃下降至750℃,0.05C-0.13Nb钢中多边形铁索体含量(体积分数)由20%增至80%,多边形铁素体晶粒尺寸由9μm降至4μm;变形后的组织由多边形铁索体、粒状贝氏体和1~3μm马氏体/奥氏体岛组成;钢中的析出物为1~10 nm的Nb(C,N),随变形温度降低析出物数量增加。 相似文献
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研究了添加高速钢粉对烧结钢组织与性能的影响。实验结果表明,含20%高速钢的烧结钢综合力学性能最好;添加高速钢粉能导致烧结钢密度减小的冲击韧性降低,当高速钢含量增中时,硬度随之增加,烧结钢中残余奥氏体和马氏体的含量与高速钢的含量呈线性关系。烧结钢中的马氏体显微硬度很高,它主要原高速钢粒子和原铁粒子的连接区域形成。 相似文献
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铸钢车轮的显微组织研究 总被引:2,自引:0,他引:2
在分析美国Abex公司和Griffin公司铸钢车轮的性能、化学成分的基础上,对这两家铸钢一轮的显微组织进行了研究,结果表明,铸钢车轮显示高强度、高强硬度与低塑性、低韧性的特点,其原因是由于碳含量较高和少量合金元素Cr,Ni、Mo和Cu的存在,以及原始铸造组织的粗大,使得铸钢车轮热处理后踏面形成素氏体(或与上贝氏体的混合)组织,辐板部位为粗大珠光体。 相似文献
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Ming-Chun Zhao Bei Tang Yi-Yin Shan Ke Yang 《Metallurgical and Materials Transactions A》2003,34(5):1089-1096
Sulfide stress cracking (SSC) behavior of three microstructures, i.e., ferritic-pearlitic microstructure, ultrafine ferrite microstructure, and acicular ferrite dominated microstructure, was
investigated using the bent-beam test in aqueous hydrogen sulfide (H2S) environments. The critical stress (Sc) values of these three microstructures were determined experimentally to be 1008, 1190, and more than 1260 MPa, respectively.
As a result, the acicular ferrite-dominated microstructure possessed the best SSC resistance, the ultrafine ferrite microstructure
was in a second position, and the ferritic-pearlitic microstructure was relatively the worst. It was analyzed that hydrogen
embrittlement (HE) was the main failure mechanism in SSC cracking for high-strength pipeline steels, and preferential hydrogen
accumulation within the plastic zone of the main crack tip accounted for the exhibited embrittlement. It was remarkable that
the strength values of pipeline steels were not the only factor to determine their SSC susceptibilities. Microstructure played
an important role in the SSC initiation and propagation of pipeline steels. In particular, both the fine dispersed precipitations
of carbonitrides and the high-density tangled dislocations in acicular ferrite, which behaved as the hydrogen traps, should
be attributed to the optimal SSC resistance of pipeline steels. 相似文献
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结构用钢组织控制强化技术的进展 总被引:2,自引:0,他引:2
概述了近10余年来先进工业国家在结构用钢组织控制强化技术方面的研究与应用状况,讨论了未来超高强度结构用钢组织结构设计思路,控制模式与方法。 相似文献
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Ilana Timokhina Elena Pereloma Peter Hodgson 《Metallurgical and Materials Transactions A》2014,45(10):4247-4256
The microstructure of transformation induced plasticity (TRIP) and dual phase (DP) multiphase steels after stamping of an industrial component at different strain levels was investigated using transmission electron microscopy. The TRIP steel microstructure showed a more complex dislocation substructure of ferrite at different strain levels than DP steel. The deformation microstructure of the stamped parts was compared to the deformation microstructure in these complex steels for different “equivalent” tensile strains. It was found that the microstructures are similar only at high levels of strain (>10 pct) for both steels. 相似文献
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Controlled Rolling and Controlled Cooling Technology of Ultra-High Strength Steel with 700 Mpa Grade 总被引:1,自引:0,他引:1
With Gleeble-1500 system, the influences of rolling temperature, finishing tempera ture and cooling rate on the mechanical properties of two ultra-high strength steels were analyzed. The microstructure of the hot rolled specimens was observed by optical microscope, TEM and SEM. The TRIP of HSLA steels was studied. The results show that the yield stress of 700 MPa can be reached for two steels. The controlled rolling and controlled cooling technology has different effects on two sleds, but it is rational to adopt finishing temperature 800℃ for both of them. The microstructure of the steels is mainly bainite, and the influence factors ofmechanical properties are the size of bainite, and the size, distribution, composition and morphology of secondary phases. The deformation of high molybdenum steels at a high temperature with a high cooling rate would promote TRIP. 相似文献