【摘要】：利用熱模擬試驗(yàn)機(jī)、SEM、HRTEM及EDS研究了Ti-Mo和Ti-Mo-Nb低碳微合金鋼的連續(xù)冷卻轉(zhuǎn)變規(guī)律,探討了Nb對Ti-Mo微合金鋼組織及性能的影響。結(jié)果表明:Nb元素能夠提高鋼的Ac1和Ac3溫度,降低冷卻過程中奧氏體的分解溫度,縮小鐵素體-珠光體相區(qū),使貝氏體相區(qū)向左下方移動。此外,Nb的添加能夠細(xì)化Ti-Mo-Nb微合金鋼中的組織,提高硬度。利用HRTEM對冷速為50℃/s的樣品進(jìn)行分析,發(fā)現(xiàn):Ti-Mo和Ti-Mo-Nb微合金鋼中均存在少量應(yīng)變誘導(dǎo)析出的碳化物,分別為(Ti,Mo)C和(Ti,Nb,Mo)C粒子,呈隨機(jī)分布。2種析出物均為Na Cl型結(jié)構(gòu),其晶格常數(shù)分別為0.432和0.436 nm,平均粒徑分別為12.11和8.69 nm。TiMo-Nb微合金鋼中析出相體積分?jǐn)?shù)更多,尺寸更小,是其組織細(xì)化、硬度提高的主要原因。
[Abstract]:The continuous cooling transformation of low carbon microalloyed steel (Ti-Mo and Ti-Mo-Nb) was studied by means of thermal simulation test machine, SEM,HRTEM and EDS. The effect of Nb on microstructure and properties of Ti-Mo microalloyed steel was discussed. The results show that the Nb element can increase the Ac1 and Ac3 temperatures of the steel, decrease the decomposition temperature of austenite during cooling, reduce the ferrite-pearlite phase region, and make the bainite phase region move to the lower left. In addition, the addition of Nb can refine the microstructure and improve the hardness of Ti-Mo-Nb microalloyed steel. The samples with 50 鈩，

本文編號：2276941