Characteristics and formation mechanism of #br# sulfide in the slab of pipeline steel
CHANG Jinbao1,YANG Wen2,ZHANG Lifeng2,REN Ying2
(1. Research and Development Institute, HBIS Group Co., Ltd., Shijiazhuang 050023, Hebei, China;2. School
of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China)
Abstract：The characteristics of sulfide in the slab of pipeline steel was analyzed and the formation mechanism was discussed in the current work. It was found that from the molten steel in tundish to the slab, inclusions transformed from liquid CaOAl2O3 to CaSAl2O3 type, and the smaller the size of inclusions, the more complete the transformation in the cooling process. According to the morphology, sulfide containing inclusions could be classfied into partial precipitation of sulfide on oxide surface, semiencapsulation of oxides by sulfide, complete encapsulation of oxides by sulfide, pure sulfide, and sulfide precipitated on TiN. The transformation of inclusion phases during the cooling of pipeline steel was calculated employing FactSage software. It was indicated that with the decrease of temperature, liquid calcium aluminates transform along the path of CaO·Al2O3→CaO·2Al2O3→CaO·6Al2O3→Al2O3. Phases of CaS and MnS will also precipitate during the cooling process, and the precipitation temperature of MnS was lower than that of CaS, which could explain the characteristic and formation of sulfide in the slab.
常金宝，杨文，张立峰，任英. 管线钢铸坯中硫化物特征及形成机理[J]. 钢铁, 2019, 54(8): 154-160.
CHANG Jinbao,YANG Wen,ZHANG Lifeng,REN Ying. Characteristics and formation mechanism of #br# sulfide in the slab of pipeline steel. Iron and Steel, 2019, 54(8): 154-160.
