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采用直接热轧法成功获得了Cu-P-Cr-Ni-Mo双相耐候钢,研究了热轧双相耐候钢的组织、力学性能、腐蚀性能及焊接性能。结果表明:Cu-P-Cr-Ni-Mo热轧双相耐候钢组织均由多边形铁素体及其上分布的不规则的马氏体岛组成;相对于Cu-P-Cr-Ni-Mo耐候钢的常规热轧态,Cu-P-Cr-Ni-Mo热轧双相耐候钢的抗拉强度和屈服强度分别提高了21.6%~37.2%,6%~13.8%,屈强比降低了12.7%~19.7%;Cu-P-Cr-Ni-Mo热轧双相耐候钢的耐腐蚀性能优于09CuPCrNi耐候钢;Cu-P-Cr-Ni-Mo热轧双相耐候钢焊件的抗拉强度比其母材的抗拉强度降低了大约7%,但比常规热轧的Cu-P-Cr-Ni-Mo耐候钢板强度提高了16%。 相似文献
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热轧无缝钢管通过中频感应加热进行循环加热+淬火工艺处理后,基体内的组织将发生多次相变,从而使铁素体以及奥氏体淬火后得到的马氏体晶粒均得以细化。通过循环热处理工艺得到基体为铁素体+马氏体组织的超细晶双相钢,且多次循环后双相钢内的铁素体晶粒可细化到1μm左右。 相似文献
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利用Gleeble3500热模拟试验机研究了冷却工艺对热轧双相钢显微组织的影响,利用扫描电镜和拉伸试验对实验室轧制的双相钢进行了显微组织和力学性能分析。研究结果表明:试验用钢经830 ℃终轧后,空冷6~10 s后快冷至卷取温度(≤200 ℃),可得到室温组织为铁素体(90.7%)+马氏体的热轧双相钢,其屈服强度为335 MPa,抗拉强度为630 MPa,加工硬化率高达0.22,伸长率达26.6%,完全满足热轧DP590钢的要求,试样的马氏体细小弥散分布,平均铁素体晶粒尺寸较小,约为6.4 μm,具有良好的冲压性能。 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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以初始组织为铁素体和珠光体的热轧Q345B无缝钢管为原料,通过中频感应热处理工艺,开发出基体组织为铁素体和马氏体的双相钢无缝钢管,并通过循环处理工艺得到基体为超细晶组织的双相钢无缝钢管。介绍了对这种双相钢无缝钢管进行中频感应热处理的工艺设计,热处理工艺试验的过程及试验结果。研究表明:中频感应淬火热处理工艺应用于双相钢无缝钢管的开发是完全可行的。 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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Mechanical properties of high-density powder metallurgy (PM) steels have been evaluated using standard tests, and a theoretical
model using the artificial neural network (ANN) has been developed. Various heat treatments were carried out to study their
influence on mechanical properties, viz. endurance limit (EL), yield strength (YS), and hardness, and also on the carbon content in PM steel. The material containing
0.47% C that was quenched and tempered at 503 K (QT 503 K) showed the optimum combination of yield strength/ultimate tensile
strength (YS/UTS) and EL. The ANN-based model showed excellent agreement with experimental results. Prediction models based
on the ANN are demonstrated for YS as well as for the EL as a function of heat treatment (ranging from QT 400 K to QT 900
K) and percent carbon (%C) (between 0.1 and 0.5). This would help the materials engineer suitably design the heat-treatment
schedule to obtain the desired/best combination of fatigue and strength properties. 相似文献
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Shipin Wu Dongpo Wang Zhi Zhang Chengning Li Xiuguo Liu Xianqun Meng 《Science & Technology of Welding & Joining》2013,18(2):112-120
ABSTRACTThe as-welded low-transformation-temperature (LTT) weld metal with martensite/retained austenite (RA) dual phase exhibits high toughness and ductility, but the yield strength (YS) is very low. After low-temperature postweld heat treatment at 300°C, the YS, toughness and ductility of dual-phase LTT weld metal increase dramatically, while there is a slight effect on mechanical properties of full martensite LTT weld metal. During the low-temperature postweld heat treatment, carbon atoms diffuse from martensite into RA, which increases the stability of RA. The improvements of mechanical properties for dual-phase LTT weld metal after low-temperature postweld heat treatment are attributed to the increased stability of RA and enhanced transformation-induced plasticity effect. 相似文献
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《中国有色金属学会会刊》2020,30(6):1439-1451
The relationship between the microstructure and mechanical properties of the spark plasma sintered AA2024−Y composites subjected to cryo-rolling was investigated. Yttrium addition enhances the mechanical properties of the composites by promoting grain refinement and precipitation. However, there is a clear trend of initial increase and later decrease in the properties. Also, it is observed that 0.3 wt.% of yttrium is the optimum amount of reinforcement content to obtain the highest mechanical properties. To further improve the tensile strength of the composites, cryo-rolling was performed on the composites under standard cryogenic conditions by several passes up to a reduction of 25%. The mechanical properties and the corresponding microstructures of composites after cryo-rolling were correlated. The SEM and TEM microstructures reveal that the samples exhibit dual size grains, i.e., nanograins are formed as sub-grains within the actual grain. Due to the grain size reduction and the increase in the dislocation density, the tensile properties are remarkably improved compared to those of the composites before cryo-rolling. The highest mechanical properties like hardness, YS and UTS are found to be 153 HV, 539 MPa and 572 MPa, respectively, with a reasonable ductility in the composite with 0.3 wt.% Y. 相似文献
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Bake-hardening behaviour of carbon steel with different martensite morphologies and volume fraction was investigated.The specimens with fibrous and bulky martensite were prestrained in tension by 4%.After this,they were unloaded and bake hardened at 180 °C for 10–160 min.It was found that dual-phase steel samples which were bake hardened at 180 °C for 20 min showed an increase in the yield stress(YS) and ultimate tensile stress(UTS) but a decrease in ductility.Further increase in the bake-hardening time of 80 or 160 min has reduced the YS and UTS,but increased the ductility.Dr(increase in stress due to bake hardening),YS and UTS values are higher for the microstructure containing fibrous martensite compared to the microstructure-containing bulky martensite.It was also observed that at a given baking temperature Dr,YS and UTS increased by volume of martensite. 相似文献
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The aim of this investigation was to evaluate the microstructural change after laser welding and its effect on the tensile
properties and strain hardening behavior of DP600 and DP980 dual-phase steels. Laser welding led to the formation of martensite
and significant hardness rise in the fusion zone because of the fast cooling, but the presence of a soft zone in the heat-affected
zone was caused by partial vanishing and tempering of the pre-existing martensite. The extent of softening was much larger
in the DP980-welded joints than in the DP600-welded joints. Despite the reduction in ductility, the ultimate tensile strength
(UTS) remained almost unchanged, and the yield strength (YS) indeed increased stemming from the appearance of yield point
phenomena after welding in the DP600 steel. The DP980-welded joints showed lower YS and UTS than the base metal owing to the
appearance of severe soft zone. The YS, UTS, and strain hardening exponent increased slightly with increasing strain rate.
While the base metals had multi-stage strain hardening, the welded joints showed only stage III hardening. All the welded
joints failed in the soft zone, and the fracture surfaces exhibited characteristic dimple fracture. 相似文献
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Nb和Cr对冷轧低碳低硅双相钢组织性能的影响 总被引:2,自引:0,他引:2
研究了在不同双相处理工艺条件下加Nb(0.033%)和加Cr(0.44%)两种低碳低硅冷轧双相钢的组织演变规律和性能特点。分析了合金元素Cr和Nb对双相组织中马氏体体积分数、马氏体形态和铁素体晶粒尺寸的影响。结果表明,Nb的作用主要是通过NbC粒子的析出阻碍再结晶晶粒的长大,从而在同样较低温度热处理工艺条件下,加Nb双相钢中的铁素体晶粒较细。随着处理温度的升高,当相变先于再结晶发生时,NbC对细化晶粒的作用不明显,因而加Nb和加Cr钢具有相近的铁素体晶粒尺寸。Cr提高奥氏体形成温度,导致双相处理时奥氏体的体积分数以及淬火后马氏体的体积分数的减少。力学性能分析表明,在同样的双相处理条件下,加Nb钢具有较高的强度和较低的屈强比;而加Cr钢则表现出较好的塑性。 相似文献