板坯凝固末端不同压下模式对低合金钢内部质量的影响  

The Effects of Different Reduction Modes at Strand Solidification Endpoint on the Soundness of Low Alloy Steel

作　　者：张晓琴[1] 王强 么敬文 李海洋 吴冰 李长华 Zhang Xiaoqin;Wang Qiang;Yao Jingwen;Li Haiyang;Wu Bing;Li Changhua(Tangshan Medium and Heavy Plate Co.,Ltd.)

机构地区：[1]唐山中厚板材有限公司

出　　处：《宽厚板》2023年第5期23-28,共6页Wide and Heavy Plate

摘　　要：提高宽厚板连铸坯的致密度与均质度,是突破传统轧制压缩比、提高宽厚板性能及探伤合格率的重要前提和保障。连铸坯凝固末端重压下能够有效改善铸坯中心凝固缩孔、疏松、中心偏析等缺陷,是生产高品质厚板的重要手段。本研究利用Ansys有限元模拟软件,计算0.85 m/min、0.89 m/min、0.93 m/min拉速时连铸坯固相率,预测固相率的变化趋势,确定了不同拉速下凝固末端位置。考虑现场设备能力及试验安全,选取0.85 m/min作为试验拉速,在0.66~1.0固相率范围内,进行不压下、液相区压下10 mm和液相区+两相区压下20 mm三种模式下的连铸重压下试验。在试验铸坯上取样,对试样的致密度、中心偏析及铸坯组织等进行检测,并分析对比不同压下模式对铸坯内部质量的影响。结果表明:在试验拉速下,压下量在0~20 mm范围内,随着压下量的加大,铸坯致密度提高,中心偏析得到明显改善,铸坯晶粒尺寸显著细化。Improving the soundness and homogeneity of continuous casting slab for wide and heavy steel plate is the critical precondition and guarantee of making a breakthrough in conventional rolling reduction ratio,improving the properties and flaw detection conformity rate of wide and heavy steel plate.Heavy reduction at solidification endpoint of continuous casting strand can effectively improve the defects of strand central solidification shrinkage hole,looseness and central segregation,which is an important means of high quality heavy plate production.The research utilizes Ansys finite element simulation software in computing and predicting its variation trend of solid phase rate for continuous casting slab at withdrawal speeds of 0.85 m/min,0.89 m/min and 0.93 m/min,determines the solidification endpoint position at different withdrawal speeds.Considering the site equipment capability and the test safety,the withdrawal speed of 0.85 m/min is selected for the test,heavy reduction experiment is carried out in the three modes of non-reduction,a reduction of 10 mm at liquid phase region and a reduction of 20 mm at liquid phase region+two phase region within the range of solid phase rate between 0.66 and 1.0.The soundness,central segregation and microstructure of the specimen taken from the continuous casting slab are tested,the effects of different reduction modes on the soundness of the slab are analysed.The results show that at the experimental withdrawal speed and the drafts ranging from 0 to 20 mm,the soundness of slab and the central segregation are improved,the grain size is dramatically refined.

关 键 词：重压下 致密度 凝固末端 疏松 缩孔 偏析 

分 类 号：TG335[金属学及工艺—金属压力加工]