Ti含量对0Cr25Al5电热合金凝固组织和夹杂物的影响  

Effect of Ti content on solidification organization and non-metallic inclusions in 0Cr25Al5 electrothermal alloy

作　　者：苏耀 郭汉杰[1,2] 郭靖 罗乙娲[1,3] 李刚 杨庆松 郑晓丹 SU Yao;GUO Hanjie;GUO Jing;LUO Yiwa;LI Gang;YANG Qingsong;ZHENG Xiaodan(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;Beijing Key Laboratory of Special Melting and Preparation of High-End Metal Materials,Beijing 100083,China;State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China;Beijing Shougang Jitaian New Material Co.,Ltd.,Beijing 102206,China)

机构地区：[1]北京科技大学冶金与生态工程学院,北京100083 [2]高端金属材料特殊熔融与制备北京市重点实验室,北京100083 [3]绿色低碳钢铁冶金全国重点实验室,北京100083 [4]北京首钢吉泰安新材料有限公司,北京102206

出　　处：《有色金属科学与工程》2025年第1期8-16,84,共10页Nonferrous Metals Science and Engineering

基　　金：国家自然科学基金资助项目(52374350)。

摘　　要：合金微合金化是改善钢锭性能的重要手段之一,为了进一步研究Ti元素对0Cr25Al5牌号电热合金铸锭凝固组织和其非金属夹杂物对铸锭性能的影响,首先利用热力学软件Thermo-Calc对Fe-Cr-Al-Ti-N-C六元体系中Ti含量分别为0.08%、0.10%和0.12%(指质量分数,下同),和N含量分别为0.009%、0.012%、0.017%和0.020%,在凝固前沿中AlN和TiN等析出相行为进行计算,并给出不同Ti含量对应N含量的控制水平。实验结果表明,该牌号电热合金凝固组织随着Ti含量的增高等轴晶率降低,当铸锭Ti含量为0.082%时,其纵剖面等轴晶率达到最高值为69.56%,相反平均晶粒尺寸达到最低值为1.96 mm,因此,适当添加Ti元素进行微合金化,可以改善0Cr25Al5号电热合金的凝固组织。与此同时,对3种不同Ti含量的金相样品分别进行夹杂物自动分析系统检测,结果表明当Ti含量为0.082%时,夹杂物数目、夹杂物尺寸、夹杂物面积分数以及数量密度均为最小值。除此之外,对其金相样品侵蚀后进行扫描电镜(SEM)及能谱仪(EDS)观察分析,发现含Ti夹杂物在钢锭存在形式主要有Ti(C,N)、TiO_(x)、TiN-稀土复合夹杂物和含Ti稀土氧化物。当Ti含量为0.110%时,发现大量尺寸为1~2μm的TiN夹杂物在晶界处富集,对电热合金的疲劳性能与机械性能造成较大危害。综上所述,通过对铸锭添加0.082%Ti,可以明显改善其凝固组织,且减少铸锭中存在的含Ti夹杂物对铸锭性能产生的不利影响。Alloy microalloying is one of the most important means of improving the performance of ingots.In order to further investigate the effect of Ti element on the solidification organization and non-metallic inclusions of 0Cr25Al5 electric heating alloy ingots on their properties,the thermodynamic software Thermo Calc was first used to calculate the behavior of AlN and TiN precipitates in the solidification front of Fe-Cr-Al-Ti-N-C hexagonal system with different Ti contents(mass fractions,the same below,0.08%,0.10%,and 0.12%,respectively)and different N contents(mass fractions,the same below,0.009%,0.012%,0.017%,and 0.020%,respectively),and the control level of N content corresponding to different Ti contents was given.The results of experiments show that the isometric crystal rate obviously reduces for the solidification organization of this alloy with increasing Ti content,and when the content of Ti is 0.082%,the equiaxed crystal rate of lengthwise section reaches the maximum value of 69.56%,on the contrary,the average grain size is the minimum value of 1.96 mm.Thus,the appropriate addition of Ti elements for micro-alloying can improve the solidification organization for this alloy.Meanwhile,automatic inclusion analysis systems were used to detect inclusions in three different Ti content metallographic samples.The results indicate that when Ti content is 0.082%,the number,size,area fraction,and quantity density of inclusions are all at their minimum values.In addition,scanning electron microscopy(SEM)and energy dispersive spectroscopy(EDS)were used to observe and analyze the metallographic samples after erosion.It is found that Ti containing inclusions mainly exist in the form of Ti(C,N),TiO_(x),TiN rare earth composite inclusions,and Ti containing rare earth oxides in the steel ingot.In addition,when the content of Ti is 0.110%,it is also found that a large number of non-metallic inclusions TiN,the size is about 1-2μm,are found to be enriched at grain boundaries,which causes greater harm to the fatigue properties

关 键 词：Scheil模型 凝固前沿 等轴晶 晶粒尺寸 含Ti夹杂物 

分 类 号：TF704.7[冶金工程—钢铁冶金]