钛稀土复合处理对C-Mn钢粗晶热影响区组织及韧性的影响

发布时间：2018-07-25 18:49

【摘要】：利用Gleeble-1500D热模拟机进行焊接热影响区热循环模拟实验,研究了在焊接热输入为65 kJ·cm~(-1)时稀土单独处理和钛稀土复合处理对C-Mn钢粗晶热影响区组织及冲击韧性的影响,并利用扫描电镜观察和分析了实验钢中的夹杂物和冲击断口形貌,利用光镜观察了热循环模拟后实验钢中的微观组织.实验结果表明:稀土单独处理和钛稀土复合处理的试样微观组织分别主要是晶界铁素体+块状铁素体+针状铁素体和晶界铁素体+晶内针状铁素体.经稀土单独处理的试样中夹杂物为La_2O_2S+锰铝硅酸盐+MnS复合夹杂;钛稀土复合处理的试样中的夹杂主要是La_2O_2S+TiO_x+锰铝硅酸盐+MnS复合夹杂.钛稀土复合处理钢中的复合夹杂更细小,有利于形成细小的晶内针状铁素体.钛稀土复合处理极大地改善了实验钢的焊接热影响区低温冲击韧性,比稀土单独处理对试样的冲击性能提升效果更好.
[Abstract]:The thermal cycle simulation experiment of welding heat affected zone (HAZ) was carried out by using Gleeble-1500D thermal simulator. The effects of rare earth alone treatment and titanium rare earth composite treatment on the microstructure and impact toughness of coarse grained heat affected zone (HAZ) of C-Mn steel were studied when the welding heat input was 65 kJ / cm ~ (-1). The morphology of inclusion and impact fracture in experimental steel was observed and analyzed by scanning electron microscope. The microstructure of experimental steel after thermal cycling simulation was observed by light microscope. The experimental results show that the microstructure of the samples treated with rare earth alone and titanium rare earth complex is mainly grain boundary ferrite block ferrite acicular ferrite and grain boundary ferrite intracrystalline acicular ferrite respectively. The inclusions in the samples treated by rare earth alone are La_2O_2S manganese-aluminosilicate MnS complex inclusions, and the main inclusions in Ti rare earth treated samples are La_2O_2S TiO_x manganese-aluminosilicate MnS complex inclusions. The composite inclusions in Ti-RE composite treated steel are finer, which is favorable for the formation of fine intragranular ferrite. Titanium rare earth composite treatment greatly improved the low temperature impact toughness of welding heat affected zone of experimental steel, which was better than that of rare earth treatment alone.
【作者单位】：北京科技大学冶金与生态工程学院;北京科技大学钢铁冶金新技术国家重点实验室;武汉科技大学耐火材料与冶金国家重点实验室;
【基金】：国家自然科学基金资助项目(51274269)
【分类号】：TG457.11

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