共查询到19条相似文献,搜索用时 109 毫秒
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不同成分系列微合金负抗奥氏体晶粒长大能力研究 总被引:3,自引:0,他引:3
研究了Nb-V,Nb-Ti,Nb-V-Ti三种成分系列微合金钢的抗奥氏体晶粒生大能力,以及含氮量对Nb-V-Ti微合金钢抗奥氏体晶粒长大能力的影响。试验结果表明,微合金钢中加入微量钛可大大提高钢抗奥氏体晶粒长大能力,Nb-V-Ti微合金钢中含氮量增多抗奥氏体晶粒长大能力增强,但含氮量过高会影响焊接热影响区韧性。 相似文献
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微合金钢焊接粗晶区晶粒长大的热模拟研究 总被引:2,自引:0,他引:2
采用焊接热模拟方法,研究了不同的焊接热循环参数Tmax和tmax/8对Ti、Nb和N复合加入的两种成分系更的微合金钢昌区奥氏体晶粒尺寸长大的影响。结果表明,奥氏体晶粒尺寸随Tmax增大而增大;并且Tmax恒定时,随着时间延长,长大倾向不岑i低的Ti-Nb-N钢的(BB503)长大倾向严重。tmax/8增大时,两种成分系列钢奥氏体晶粒尺寸变化平缓,但含Ti低的Ti-N钢(1^#)和Ti-Nb-N钢( 相似文献
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采用热模拟方法研究了焊接热循环对Nb-V-Ti微合金钢组织和韧性的影响。研究结果表明,焊接热影响区组织和韧性与t8/5和热循环类型有关。Nb-V-Ti微合金钢母材组织为P+F。经1320℃焊接热循环,t8/5冷速较小时,组织为B+F+P;冷速较大时,组织为B;冷速继续增大,组织为B+M。冷速过大或过小都会降低韧性。经1320℃、1320℃+1320℃和1320℃+780℃三种热循环后,韧性均有较大下降,以1320℃+780℃热循环韧性最低。 相似文献
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通过模拟焊接热循环,在GLeeb-1500装置上模拟了v-Ti-N和V-N钢焊接热影响区粗晶区(GC-HAZ)的组织,并用示波冲击法测定了不同△(从800℃到500℃的冷却时间)试样的Akv值、解理裂纹形核功(Ei)和扩展功(Ep)。用光学显微镜、SEM和TEM对这两种钢高温奥氏体的晶粒尺寸、过冷奥氏体转变产物和各△条件下的冲击断口进行了定量分析和观察,探讨了加微量钛对焊接GC-HAZ的组织和韧性的影响。试验结果表明,与V-N钢相比,V-Ti-N钢由于含有适量的钛,使奥氏体晶粒及其转变产物显著细化,并且奥氏体转变产物的形态和分布也得到改善,这使V-Ti-N钢GC-HAZ的韧性显著高于V-N钢。 相似文献
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研究了在非平衡态,即焊接热循环条件下,Nb-V-Ti微合金化C-Mn钢中总含氮量(以下简称含氮量一译者注)对焊接热影区(HAZ)韧性,显微组织和地为的影响。HAZ韧性随含氮量增加而提高,含氮量高达80ppm时,100J的转变温度最低。随含氮量增加,显微组织细化,固溶Nb,Ti减少,因而改善了HAZ韧性,经焊接热循环后,在Nb-V-Ti钢中观察到了Nb,Ti 事沉淀相。随含氮量增加,这些沉淀9粒子变 相似文献
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本文介绍了形变热处理使含(微)Ti、Nb钢高强化的机理;微Ti钢板的高强化是因Ti碳化和折析出。铁素体(F)晶粒的细化和贝氏体(B)体积的增中所致;微Nb钢板的高强度化则是因Nb碳氮化物的析出,F晶粒的细化及B体积增中的结果。快冷微Ti微Nb钢板以增加B含量是其高强化的主要原因。 相似文献
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摘要:以往研究表明Nb析出相钉扎和固溶Nb溶质拖曳作用共同阻碍奥氏体晶粒长大。采用高温共聚焦显微镜研究了Nb对一种高碳含Nb钢奥氏体晶粒长大的影响,对含Nb钢加热过程组织演变进行原位观察。结果表明,Nb在没有钉扎作用下(即高温条件下)仍能起到阻碍奥氏体晶粒长大的作用,该阻碍效果主要是固溶Nb的溶质拖曳作用引起的。采用2种模型对奥氏体晶粒长大行为进行拟合,给出了不同加热温度下Nb微合金化高碳钢的Beck长大方程,同时考虑到加热温度和保温时间的共同影响,根据原位观察结果得到实验钢的奥氏体晶粒长大动力学模型,该模型能够较准确地预测Nb微合金化高碳钢奥氏体晶粒长大行为。 相似文献
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It was reported in previous studies that the growth of austenite was inhibited by the pinning effect of Nb containing precipitates and the solute dragging effect of solute Nb. The effect of Nb on austenite grain growth of high carbon steel was investigated by laser scanning confocal microscope (LSCM). Microstructure evolution during heating process of the tested steel was observed by in situ observation. The results show that even without the pinning effect of Nb containing precipitates (at high temperatures), Nb can hinder the growth of austenite grains due to the solute dragging effect of Nb. Two models were used to fit the austenite grain growth process, and the Beck growth models of Nb microalloyed high carbon steels at different heating temperatures were established. The austenite grain growth kinetics model considering the influence of heating temperature and holding time can accurately predict the austenite grain growth process of Nb microalloyed high carbon steels. 相似文献
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一种Nb-Ti微合金钢微合金碳氮化物析出行为的研究 总被引:8,自引:1,他引:7
利用热模拟和TEM技术研究了Nb—Ti微合金钢中微合金碳氮化物的析出行为,研究结果表明,高温奥氏体区析出的微合金碳氮化物数量随变形量的增大而增加,尺寸随着变形温度的升高稍有增大。铁素体区析出的微合金碳氮化物尺寸比在形变奥氏体中析出的更为细小,数量随着保温时间的增加而增多,但尺寸变化不大;当温度较低的时候,微合金碳氮化物主要在位错线等晶内缺陷处析出。 相似文献
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AbstractThis paper analyses the effect of carbon and nitrogen content on the austenite microstructural homogeneity before transformation in the thin slab direct rolling of Nb and Nb–V microalloyed steels. The study was made with the help of a microstructural hot working model adapted to the metallurgical peculiarities associated with thin slab direct rolling. The results show that an increase in carbon content from 0·04 to 0·09% in 0·05%Nb microalloyed steels requires a significant increase in the initial rolling temperature in order to avoid the presence of isolated as cast austenite grains prior to transformation. Similarly, an increase in nitrogen content from 30 to 120 ppm does not imply changes as drastic as in the case of carbon. In both situations the changes required in the rolling temperature can be explained by the interaction between post-dynamic softening mechanisms and strain induced precipitation kinetics. In this context, the incidence of different final gauge thicknesses on microstructural homogeneity is evaluated. 相似文献
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Hans-Joachim Klaar Klaus Braag Radko Kaspar Josef Siegfried Distl Ulrike Zeislmair 《国际钢铁研究》1987,58(12):559-564
The influence of various reheating temperatures and times on austenite grain growth and dissolution behaviour of precipitates was investigated in three different microalloyed steels. The characteristics of these steels were compared with those of a non-microalloyed steel of similar basic composition. Then, the interrelationships between precipitate distribution, precipitate dissolution and austenite grain growth were discussed. 相似文献