共查询到18条相似文献,搜索用时 171 毫秒
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对Fe-1.5C-1.5Cr-1.5Al超高碳钢碳化物的球化工艺及力学性能进行了研究.扫描电镜观察表明,加入铝,可抑制锻后空冷条件下先共析网状碳化物的析出;利用铝合金化作用和成分不均匀化奥氏体加热控制,提出了2种无形变球化处理工艺:①离异共析等温球化;②预冷淬火 高温回火.2种球化处理工艺均能获得良好的球化组织和良好的综合力学性能:Rm≥1 000 MPa,Re≥700 MPa,A10=10%~14%.拉伸断口具有明显的缩颈,断口形貌呈具有典型的韧窝特征. 相似文献
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对Fe 15C 15Cr 15Al超高碳钢碳化物的球化工艺及力学性能进行了研究。扫描电镜观察表明,加入铝,可抑制锻后空冷条件下先共析网状碳化物的析出;利用铝合金化作用和成分不均匀化奥氏体加热控制,提出了2种无形变球化处理工艺:①离异共析等温球化;②预冷淬火+高温回火。2种球化处理工艺均能获得良好的球化组织和良好的综合力学性能:Rm≥1 000 MPa,Re≥700 MPa,A10=10%~14%。拉伸断口具有明显的缩颈,断口形貌呈具有典型的韧窝特征。 相似文献
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离异共析转变(DET)是高碳钢实现快速球化退火的重要理论依据。为了深入理解离异共析转变机理,采用定量金相方法,通过奥氏体中断淬火和等温转变试验对Fe-1C钢离异共析转变行为进行研究。结果表明,在共析温度以下,Fe-1C钢中离异共析转变与珠光体转变存在竞争, DET相体积分数与奥氏体化后残留的渗碳体粒子间距Lθ以及珠光体片层间距λ有关,DET相体积分数随λ/Lθ值的增加而增大。用基于JMAK方程的离异共析转变动力学模型计算了DET相体积分数随λ/Lθ的变化关系并与试验结果进行了比较拟合,试验测量值与计算拟合曲线吻合较好。λ/Lθ的值越大,离异共析转变时碳原子扩散所需距离相对于珠光体转变越短,就越有利于离异共析转变的发生。 相似文献
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离异共析转变(DET)是高碳钢实现快速球化退火的重要理论依据。为了深入理解离异共析转变机理,采用定量金相方法,通过奥氏体中断淬火和等温转变试验对Fe-1C钢离异共析转变行为进行研究。结果表明,在共析温度以下,Fe-1C钢中离异共析转变与珠光体转变存在竞争, DET相体积分数与奥氏体化后残留的渗碳体粒子间距Lθ以及珠光体片层间距λ有关,DET相体积分数随λ/Lθ值的增加而增大。用基于JMAK方程的离异共析转变动力学模型计算了DET相体积分数随λ/Lθ的变化关系并与试验结果进行了比较拟合,试验测量值与计算拟合曲线吻合较好。λ/Lθ的值越大,离异共析转变时碳原子扩散所需距离相对于珠光体转变越短,就越有利于离异共析转变的发生。 相似文献
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轴承钢棒材超快速冷却新工艺的应用研究 总被引:2,自引:0,他引:2
针对国内某钢厂连轧生产线上出现的网状碳化物严重析出问题,提出高温终轧后超快速冷却与缓冷相配合技术,在精轧机后安装超快速冷却器,对60 mm棒材高温终轧后超快速冷却到一定温度后缓冷,从而抑制了网状碳化物的析出,使过冷奥氏体完全发生伪共析转变而得到细片层间距的珠光体型组织-索氏体,并促进珠光体形核减小珠光体球团直径,减小C原子扩散能力细化了珠光体片层间距,得到了利于球化退火的理想组织。 相似文献
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为探究奥氏体化温度和冷却速率对40Cr钢球化过程的影响,采用双相区球化退火研究了热轧态40Cr钢的球化退火行为和力学性能.奥氏体化温度从760℃提高到800℃,冷却速率从10℃·h-1上升到30℃·h-1,组织硬度随冷却速度呈V形变化,碳化物球化率随冷却速度变化正好与前者相反.奥氏体化温度为760℃,冷却速率为20℃·h-1所得到的球化组织球化率高,且碳化物细小,具有良好的冷成形性能,可大幅度缩短球化退火时间,显著提高生产效率.提出了球化退火过程中离异共析转变机制,控制好球化过程中奥氏体化温度、冷却速率及保温时间有利于离异共析转变的发生. 相似文献
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A new spheroidizing process of ultra-high carbon steel (UHCS) containing C 1.55%, Cr 1.45%, and Al 1.5% in mass percent has been proposed. The effect of processing parameters on the microstructure was analyzed. The UHCS produced by this new process has a microstructure with recrystallized ferrite matrix and fine and uniform carbide particles. After this spheroidizing, the UHCS exhibits good mechanical properties at ambient temperature, for example σb= 1 100 MPa, σs =915 MPa, δ=8% and high ratio of σs/σb. 相似文献
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SUN Yan-Kun 《钢铁研究学报(英文版)》2009,16(5):61-61
The ultra-fast cooling technology of large-section bars GCr15 bearing steel was researched connected with industry practice, the microstructure in different cooling patters were researched by optical microscopy、transmission electron microscopy and energy spectrometer, it was concluded that: the large-section bars of GCr15 bearing steel passed the zone of secondary carbide precipitation quickly through the ultra-fast cooling technology(UFC) the instantaneous cooling rate of which was about 200℃/s, the finishing cooling temperature was higher than Ms, the lamellar spacing of pearlite was thinner and thinner and the micro-hardness was bigger and bigger along with the reduction of re-reddening temperature,the precipitation of network carbide was restrained when re-reddening temperature was 690℃, and fine laminated pearlite was obtained through transformation of pseudopearlition which induced the reduction of the diamond of pearlite grain and refinement of the lamellar spacing of pearlite, ideal microstructures promoting spheroidizing annealing were obtained. 相似文献
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14MnVTiRE钢[/%:0.10~0.15C、0.30~0.60Si、1.20~1.60Mn、0.03~0.09V、0.07~0.16Ti、0.10~0.15RE(加入量)]4 mm薄板的生产流程为180 t顶底复吹转炉-180 mm×1 260 mm连铸板坯-连轧-卷取工艺。在连铸时由结晶器喂φ2.5 mm RE丝。试验研究了950℃正火,950℃正火+690℃1~5 h回火对薄板组织和力学性能的影响。结果表明,正火后钢的组织为铁素体+细珠光体,在正火+690℃回火1~3 h钢中的珠光体片层碳化物发生球化,分布在晶界和晶粒内部,随回火时间进一步增加,碳化物呈点状和三角形,全部分布在晶界,材料的强度降低很大。14MnVTiRE钢薄板的最佳热处理工艺为950℃正火+690℃1~2 h回火,其屈服强度为510~610MPa,抗拉强度630~680 MPa,伸长率22%~25%。 相似文献
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The role of the divorced eutectoid transformation in the spheroidization of 52100 steel 总被引:1,自引:0,他引:1
J. D. Verhoeven 《Metallurgical and Materials Transactions A》2000,31(10):2431-2438
Austenite containing fine particles of carbides may undergo the eutectoid transformation by either the pearlite reaction or
the divorced eutectoid transformation (DET) reaction. The latter reaction automatically produces a spheroidized structure,
while the pearlite reaction produces a structure that resists spheroidization. This study has evaluated the heat treatment
conditions that promote the DET in 52100 steel. The results show that the DET is dominant over the pearlite reaction for austenitization
at temperatures of 830 °C and below and for cooling rates of 500 °C/h and below. This information should be useful in the
design of more energy efficient heat treatment processes for spheroidization annealing than the very long time processes currently
recommended in the literature. 相似文献
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Ata Kamyabi-Gol 《钢铁研究学报(英文版)》2010,17(4):45-52
When processing parts made from medium carbon steel, toughness and flexibility are of importance. Therefore, to achieve these properties, the cementite in the steels is spheroidized through heat treatment. Different parameters such as the time and temperature of spheroidizing and the initial microstructure of the steel affect the amount of spheroidized cementite. In the present work, the percent of contribution of two parameters, i.e. initial microstructure and spheroidizing time, on the percent of spheroidization in CK60 steel was investigated using Taguchi robust design. Based on the number of parameters (two) and the number of their levels (four), a L16 orthogonal array, which consists of 16 experiments, was chosen. The initial microstructures consisted of Martensite (M), Coarse Pearlite (C. P.), Fine Pearlite (F. P.), and Bainite (B) and the chosen spheroidization times were 4, 8, 12, 16 hours. Spheroidizing was done at the constant temperature 700 oC. After spheroidizing was completed, the samples were prepared in order to view their microstructure under an optical microscope and to determine the spheroidized percent using MIP? (Metallographic Image Processing) software. It was found that the spheroidizing time had the most influence (58.5%) on spheroidized percent and the initial microstructure only had a 31.1% contribution. Finally, the instantaneous growth rate of the carbide was also deduced. 相似文献