管线钢X65连铸过程絮流原因分析

Analysis of the Causes of Flocculent Flow in the Continuous Casting Process of Pipeline Steel X65

通过对低碳低硫低氧铝镇静钢X65连铸过程絮流原因的分析,得出引起塞棒絮流的原因是高Ca的钙铝酸盐粘附在塞棒头部。浇注初期,塞棒头部吸热使周围钢液温度急剧下降,析出高熔点钙铝酸盐被粘附在塞棒头部,引起塞棒曲线上行。另外,通过热力学计算,在低碳低硫低氧铝镇静钢X65中,1 540℃时,形成12CaO·7Al_(2)O_(3)需要的w[Ca]为16×10^(-6),过量的Ca进一步反应形成高熔点钙铝酸盐。在中间包工作层、塞棒、水口、碗口等与钢水接触部位全部使用镁质耐材的条件下,在低碳低硫低氧的铝镇静钢生产时,向钢液中喂入的Ca含量越多,塞棒上行程度越严重。采用高碱度渣系和Al降低钢中的O和S,将Ca喂入量控制在0.065 0~0.071 5 kg/t,中间包w[Ca]控制在(10~15)×10^(-6),可以有效控制塞棒絮流。

This article analyzes the causes of flocculent flow in the continuous casting process of low-carbon, low sulfur, and low oxygen aluminum killed steel X65, and finds that the cause of flocculent flow in the stopper rod is the adhesion of high Ca calcium aluminate to the head of the stopper rod. In the early stage of pouring, the head of the stopper absorbs heat, causing a sharp decrease in the temperature of the surrounding steel liquid, and the precipitation of high melting point calcium aluminate is adhered to the head of the stopper, causing the stopper curve to rise. In addition, by thermodynamic calculations, the Ca content required to form 12CaO·7Al_(2)O_(3) in low-carbon, low sulfur, and low oxygen aluminum killed steel X65 at 1 540 ℃ is 16×10^(-6), excess Ca further reacts to form high melting point calcium aluminate. Under the condition that magnesium refractory materials are used in all areas in contact with the molten steel, such as the working layer of the intermediate ladle, stopper rods, nozzles, and bowl mouths, and in the production of low-carbon, low sulfur, and low oxygen aluminum killed steel, the more Ca content is fed into the molten steel, the more severe the upward movement of the stopper rods. Using high alkalinity slag system and Al to reduce O and S in steel, and then controlling the Ca feeding amount between 0. 065 0~0. 071 5 kg/t, and controlling the calcium content in the tundish between(10~15)×10^(-6) can effectively control flocculent flow.