摘要
应用热力学、动力学原理和试验检测方法,研究了帘线钢凝固过程中钛夹杂的析出规律及其性质,钢水成分(C、N、Ti含量)及凝固冷却速率对凝固析出钛夹杂组成和颗粒尺寸的影响,以及帘线钢铸坯高温加热过程中钛夹杂分解、固溶和再析出的热力学条件和影响因素。研究表明:1)帘线钢中的Ti(CxN1-x)夹杂在钢水凝固前期就开始析出,而Ti N夹杂在凝固末期才析出。2)帘线钢碳含量越高,钛夹杂析出温度越低,溶质元素的过饱和度越大,钛夹杂析出越早,析出的碳氮化钛(Ti(CxN1-x))夹杂中的x值越高。3)钢水凝固冷却速率对析出钛夹杂的尺寸影响十分显著。钢水初始氮含量越低,析出的钛夹杂尺寸越小,但钢水初始钛含量对析出钛夹杂尺寸影响不大。4)铸坯中的钛夹杂在热加工前的高温加热过程中能发生分解和固溶。帘线钢碳含量对钛夹杂热分解温度影响不大,但钢中氮和钛含量对钛夹杂热分解温度影响很大。钛夹杂分解出的溶质原子通过扩散发生固溶,使小颗粒夹杂溶解消失,较大颗粒夹杂逐渐变小。5)若铸坯在高温加热后缓冷,过饱和的溶质原子会再次析出使钛夹杂长大。铸坯在轧后的快速冷却过程中,因溶质原子过饱和再次析出的钛夹杂没有机会长大。
It has been studied that：（ 1） The law of precipitating titanium inclusions during the solidification of tire cord steel and titanium inclusions ＇ characteristics;（ 2） The effect of the composition（ C、N、Ti） in tire cord steel and cooling rate of solidification on the titanium inclusions＇ composition and its size;（ 3） The thermodynamic conditions and the factors influencing the decomposition,solid solution and reprecipitation of titanium inclusions during heating of billets at high temperature,by means of thermodynamics,dynamics and experimental detection. The results show that ：（ 1） The inclusions of Ti（ CxN1-x） start to precipitate in earlier stage of the solidification of molten tire cord steel,while the inclusion of Ti N precipitates at the end period of the solidification.（ 2） The higher the carbon content of tire cord steel is,the lower the temperature of precipitating the titanium inclusions,the greater the supersaturation of solute elements,the earlier the precipitation of titanium inclusions at solidification front,the larger the value of x in Ti（ CxN1-x） inclusions is.（ 3） The cooling rate has a remarkable influence on the size of titanium inclusion precipitated during molten steel solidification. The lower the initial nitrogen content of molten steel,the smaller the size of titanium inclusion. But the initial titanium content of molten steel has little influence on the size of titanium inclusion.（ 4） The titanium inclusions in billets can be decomposition and then solid solution during heating at high temperature before hot working. The carbon content in tire cord steel has a little influence on the temperature of thermal decomposition of titanium inclusion, but the contents of nitrogen and titanium have great influence on the temperature of thermal decomposition of titanium inclusion. The solute atoms originated from decomposition of titanium inclusion are dissolved in austenite by diffusion,which make the small inclusion dissolve and disappear,the larger inclusion become smaller and smaller gradually.（ 5） If the billets are slow cooling after heating at high temperature,the solute atoms in a supersaturation could reprecipitate to make the titanium inclusion grow up. During the quick cooling after hot rolling,the supersaturated solute atoms can reprecipitate to form titanium inclusion,but have no opportunity to grow up.
出处
《炼钢》
CAS
北大核心
2016年第4期23-32,共10页
Steelmaking
关键词
帘线钢
钛夹杂
碳氮化钛夹杂
凝固析出
固溶
tire cord steel
titanium inclusions
titanium carbonitride inclusions
precipitation during solidification
solid solution
