Abstract:The cause of nonconformity in flaw detection of X65 pipeline steel was determined by analyzing the process of inclusions transformation. Meanwhile, a reasonable calcium treatment process was proposed to control B type inclusions and reduce the rate of flaw detection. The results show that the transformation process of inclusions in primary process was Al2O3→MgO-Al2O3→MgO-Al2O3-CaO→CaO-Al2O3. And final inclusions were mainly calcium aluminate containing high mass percent of CaO in the low melting point area. Inclusion control target in the pipeline steel was proposed by the thermodynamic calculation and a model of the calcium treatment of the molten steel was established. According to the actual condition of molten steel,the reasonable calcium treatment control window was calculated to guide the practical production under the condition of different S and T[O] mass percent, by optimizing the treatment process, the mass percent of calcium in molten steel was reduced from 0.003 0%-0.004 0% to 0.001 0%-0.002 0% for the original process. The type of inclusions was consist of MgO- Al2O3-(CaO)-CaS including the low melting point and the high melting point phase composites. The first pass percent of severity of B inclusions≤2.0 was enhanced to 97.5% from 96.5%. The rate of nonconformity in the flaw detection was reduced from 10.0% to 1.5% and the quality of pipeline steel was improved remarkably.
收稿日期: 2018-04-18
出版日期: 2018-12-24
引用本文:
刘延强,张 鹏,何文远,杨晓山,黄财德,赵长亮. X65管线钢全流程夹杂物转变规律及控制[J]. , 2018, 53(12): 44-53.
LIU Yan-qiang,ZHANG Peng,HE Wen-yuan,YANG Xiao-shan,HUANG Cai-de,ZHAO Chang-liang. Transformation behavior and control of inclusions in X65 pipelinesteel during whole process. Iron and Steel, 2018, 53(12): 44-53.
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