晶内超细夹杂物对钢中铜偏析行为影响的研究

发布时间：2018-06-23 03:41

  本文选题：氧化物冶金 + 铜元素　； 参考：《贵州大学》2016年硕士论文

【摘要】：从“氧化物冶金”理念出发,应用非均质形核理论,研究超细夹杂物对铜元素偏析行为的影响。对MnS、Ti2O3、TiC、Al2O3、SiO2、TiN等夹杂物进行了热力学计算;利用润湿角模型计算了各自的形核功和润湿角,结果表明,这些夹杂物能够促进钢液的非均质形核。基于点阵错错配度理论,对MnS、Ti2O3、TiC、Al2O3、SiO2、TiN等夹杂物进行了晶体学计算,结果表明Al2O3、Ti2O3、MnS、SiO2与?-Cu的错配度较小;TiC、TiN与铜的各种析出相匹配度均较差;氧化物夹杂与硫化铜相之间的匹配度较差;MnS与铜的各种析出相匹配度都较好。实验选取纯铁作为熔炼母料,以真空熔炼炉熔炼的0.6%Cu和Q295GNH耐候钢0.278%Cu等不同含铜量的钢作为实验材料,选取850℃、950℃、1050℃、1150℃的温度梯度段进行热处理,保温时间为120min;采用OM(金相显微镜)、SEM(扫描电镜)、EDS(能谱)等手段观测试样中铜元素析出行为。空白实验组的结果表明,铜元素主要分布在晶界,且温度越高,晶界处的含量越高;对照实验组的结果表明,铜元素主要富集在以MnS为主的超细夹杂物中,形成以MnS为核心的复合夹杂,且温度越高,铜以MnS为形核核心进行非均质形核的数量增加,使得铜在晶内形核,被钉扎在了晶内,降低了铜在晶界处的富集程度。实验结果验证了理论计算结果,说明铜元素能够以钢中超细夹杂物作为形核质点进行非均质形核,为以后寻找能有效诱导铜元素析出的超细夹杂物提供了理论基础。
[Abstract]:Based on the concept of "oxide metallurgy", the effect of ultrafine inclusions on the segregation behavior of copper elements was studied by using heterogeneous nucleation theory. The thermodynamic calculation of inclusions such as MNS Ti2O3TiC2O3Al2O3SiO2TiN and their nucleation work and wetting angle were carried out by using the wetting angle model. The results show that these inclusions can promote the heterogeneous nucleation of molten steel. Based on the theory of lattice mismatch, the crystallographic calculation of the inclusions such as MnSTi2O3TiC2O3TiC2O3Al2O3SiO2TiN and other inclusions has been carried out. The results show that the mismatch between Al _ 2O _ 3-Ti _ 2O _ 3O _ 3mn _ 2O _ 3 Sio _ 2 and Cu is smaller and the mismatch of the precipitated phases between tin and copper is poor. The matching degree between oxide inclusions and copper sulphide phases is worse than that between MNS and copper precipitates. Pure iron was selected as the master batch, 0.6Cu and Q295GNH weathering steel 0.278Cu were selected as experimental materials, and the temperature gradient of 850 鈩，

本文编号：2055599