论文部分内容阅读
我公司小方坯立式连铸机生产140mm方坯,轧材品种仅限于矿用支掌钢18V和25U,轧制矿用9~#工字钢时则成材率较低。1979年曾两次使用1011t连铸坯试轧矿用9~#工字钢,其成材率平均仅为47.6％,主要缺陷是腿端开裂和小龟裂。据初步分析认为,除由于轧钢因素的影响外,浇注过程中钢液的二次氧化对轧材质量也有很大影响。据国外资料报导,1961年里特耳等人研究了影响铸流空气氧化的诸因素后指出,空气氧化其生成物是成品中夹杂物的主要来源;1967年柯尼进一步证实,用惰性气体保护中间罐到结晶器之间的钢流,可使棒材中的非金属夹杂物减少90％。为了防止钢液二次氧化,提高连铸坯质量,我公司从83年初开始进行中间罐至结晶器之间的钢流氮气保护浇注(以下简称氮封)的探索性试验。通过两年来多次冷、热态试验,除了研制氮封装置之外,还摸索完善了氮封浇注工艺。工业试验和大量数据分析证明,连铸过程中采用DE5型氮封装置进行保护浇注,可获得较好的综合效果。钢流周围气体的含氧量降低到0.55％以下,且浇注工艺基本满足了工业生产的要求,从而确定DF5型装置为我公司一炼钢厂连铸氮气保护浇注的定型装置。
I company billet vertical continuous casting machine to produce 140mm billet, rolled products are limited to the mining support palm steel 18V and 25U, rolling mining 9 ~ # I-beam when the yield rate is lower. In 1979, the 1011t continuous casting slab was used twice to test the rolling mills for 9 ~ # I-beam. The average finished product rate was only 47.6%. The main defects were the crack on the leg end and the small cracks. According to preliminary analysis, in addition to the impact of rolling factors, the secondary oxidation of molten steel during casting also has a great impact on the quality of the rolled material. According to foreign data reported in 1961 Ritter et al studied the impact of casting air oxidation of various factors that the air oxidation of its products is the main source of inclusions in finished products; further confirmed in 1967, Koenig inert gas protection The flow of steel between the tundish and the mold reduces the amount of non-metallic inclusions in the bar by 90%. In order to prevent the secondary oxidation of molten steel and improve the quality of continuous casting slab, our company began exploratory test of nitrogen flow protection (hereinafter referred to as nitrogen seal) of steel flow between intermediate tank and mold from the beginning of 83 year. After several cold and hot tests over the past two years, apart from the research and development of nitrogen sealing devices, the nitrogen sealing process has been explored and improved. Industrial tests and a large number of data analysis show that the DE5-type nitrogen sealing device used in the continuous casting process for protection pouring can achieve better comprehensive effects. Oxygen content of the gas around the steel flow reduced to 0.55% or less, and the casting process basically meets the requirements of industrial production, so as to determine DF5-type equipment for our company a continuous casting nitrogen casting mold casting plant.