不同强度级别帘线钢中钛夹杂性质的探索

Exploration on the properties of titanium inclusion in tire cord steel of different strength grades

为了实现高强度帘线钢中钛夹杂的有效控制,通过热力学理论分析结合真空感应炉实验,探究了不同强度级别帘线钢中钛夹杂的性质。结论如下:1)不同强度级别的帘线钢中钛夹杂析出的驱动力有差异,帘线钢强度级别越高,钛夹杂形成元素的过饱和度也越高,其形核-析出-长大的驱动力也就越大,从而加剧钛夹杂的析出和长大。2)帘线钢中同时存在钛的碳化物和钛的氮化物夹杂。随着帘线钢强度级别的提高,钛夹杂中碳化钛所占的摩尔分数呈增加的趋势,其析出的钛夹杂在金相显微镜下的颜色也随之变化。3)帘线钢强度级别越高,凝固过程中析出的钛夹杂平均尺寸增大,大颗粒钛夹杂的数量也越多。为有效控制超高强度级别帘线钢中的钛夹杂,必须对炼钢和连铸工艺进行更为苛刻的控制。

In order to achieve the effective control of titanium inclusion for the high strength tire cord steel, the properties of titanium inclusion in tire cord steel of different strength grades were explored by thermodynamic analysis combined with vacuum induction furnace experiment. The results are as follows： 1 ） The driving force of titanium inclusion precipitated in tire cord steel of different strength grades are different. The higher strength of the tire cord steel, the greater supersaturation of the titanium inclusion formed elements, thus the driving force of ＂nucleation-precipitation-grow up＂ becomes greater, and more helpful for the precipitation and grow up for titanium inclusion. 2） Titanium carbide and titanium nitride inclusions are existed simultaneously in the tire cord steel. The molar fraction of titanium carbide in titanium inclusion phase increased with the increasing of strength grade, and the color of titanium inclusions under the metallographic microscope are also changed. 3） The higher strength grade of tire cord steel, the larger average size of titanium inclusion precipitated during solidification, and the number of large titanium inclusions are also more. In order to effective control the precipitation of titanium inclusion in the super high strength grade tire cord steel, more strict measures of steelmaking and continuous casting process must be implemented.