针对SS400铝镇静钢连铸板坯的角横裂纹缺陷问题，研究了铸坯的高温力学性能、铸坯在矫直区内的角部温度，同时对铸坯角横裂纹缺陷试样进行了金相分析并对裂纹表面进行了SEM观察。研究分析认为对于SS400铝镇静钢，在800 ℃左右，奥氏体向铁素体转变引起的晶间脆化以及在更高温度开始析出的AlN对晶界的脆化降低了钢的延塑性，使得铸坯在这一温度附近矫直时导致角部出现沿晶开裂。在对连铸机二冷喷嘴水量分布研究的基础上，通过更改二冷喷嘴的位置和排布方式，减弱了对铸坯角部的冷却，从而有效地避免了角横裂纹缺陷的发生。
To investigate corner cracking of Alkilled SS400 slab, the high temperature mechanical properties and corner temperature of slab in straightening zone were measured.The samples were studied by metallography and the surface of crack was analyzed by SEM.The conclusions are: intergranular embrittlement at 800 ℃ is caused by austeniteferrite transition and the precipitation of AlN.So straightening near 800 ℃ is the reason of intergranular corner cracking of slab.The distribution of secondary cooling water in width direction of slab was studied. Based on the results of test, the nozzle arrangement in secondary cooling zone was changed to increase corner temperature and avoid corner cracking.
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