共查询到17条相似文献,搜索用时 156 毫秒
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通过建立的实验中厚板轧制过程宽展计算模型,对Q345钢(/%:≤0.20C,≤1.60Mn,≤0.55Si)中厚板210 mm铸坯经10道次轧成48 mm板的各粗轧道次轧制压力进行预算,分析试验宽展模型和Besse宽展模型对中厚板轧制压力的影响。结果表明,在中厚板轧制开始23道次和终止910道次,实验宽展模型轧制压力预算精度较高,相对误差为0.26%~0.68%;轧制48道次,Besse宽展模型轧制压力预算精度较高,其相埘误差为0.33%~11.79%,两模型第1道次的相对误差均为18.00%。 相似文献
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通过对钢板表面边部裂纹进行宏观观察和微观分析,通过控制Al、S和N的含量,避免高温浇注,需用合适保护渣,控制矫直温度,保持铸机状态良好,改善铸坯的表面质量;减小横轧展宽量,提高板坯加热均匀性,保证轧制压下量,减小轧件边部不均匀变形,保持圆盘剪状态良好,可大大降低中厚板边裂的发生率,可有效的减少边部裂纹的发生。 相似文献
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特厚模具钢因具有卓越的性能和可靠的使用寿命,在制造大型模具中起着不可替代的作用。然而,在连铸过程中,铸坯内部可能形成的缺陷对模具钢的力学性能和使用寿命造成严重影响。设计合理轧制工艺提高芯部变形是改善芯部缺陷的重要途经之一。针对大直径椭圆连铸坯轧制成特厚钢板的开坯粗轧、平整成型及精轧3个过程,采用有限元数值模拟的方法研究了不同轧制工艺对42CrMo特厚钢板不同位置的累积变形量、单道次变形量以及钢板成材率的影响。利用材料性能计算软件JMatPro计算了42CrMo钢的高温变形行为和热导率、比热容、密度、弹性模量、泊松比等物理参数,采用ABAQUS软件进行轧制有限元模拟分析了轧制道次压下量对椭圆坯内部疏松压合的影响规律。结果表明,开坯粗轧的前3道次压下量变化对芯部变形影响不大,芯部变形量主要取决于精轧阶段单道次压下量。采用前3道次较小压下量开坯加后5道次较大压下量精轧,芯部累积变形量最大,达1.5,且最后5道次中每道次的应变量均大于0.14,可以有效提高大规格椭圆坯轧制的特厚板芯部变形渗透率,有利于芯部裂纹和疏松等铸坯缺陷的改善。 相似文献
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粗轧板坯侧翻变形的数值模拟 总被引:1,自引:0,他引:1
针对板带热轧过程中易产生各种边部缺陷的问题,利用有限元法对粗轧可逆道次轧制过程进行了数值模拟,分析了不同立轧和平轧道次中轧件变形的情况,特别是角部金属由侧面逐渐翻转到轧件上表面的变化过程。结果表明,平轧道次轧件主要产生宽展和侧翻,且其角部金属呈拉应力状态,有可能诱发各种缺陷的产生,而立轧道次处于具有修复缺陷的压应力状态,因此优化立轧压下制度是改善带钢边部缺陷的一个重要方法。通过单元的变形过程可跟踪坯料和轧件位置之间的对应关系,这对分析带钢表面缺陷的成因并消除缺陷具有重要意义。 相似文献
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分析了板材边裂的形貌及其金相组织,认为连铸坯角部横裂纹是形成板材边裂缺陷的主要原因。在此基础上,提出了改进铸坯角部横裂纹的有效措施,即控制钢中N、S和P等有害元素含量,优化二冷配水,有效控制了铸坯角部横裂纹缺陷,板材边裂比例由2010年的1.25%降至2011年的0.80%。 相似文献
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边部裂纹是中厚板常见的表面缺陷之一.通过铸坯钻孔、倒角、翻面轧制及金相分析,确定了连铸坯边角部表面微裂纹是边裂产生的主要原因.通过减弱结晶器冷却,控制结晶器锥度,避免高温浇注,优化二次冷却,保持铸机状况良好,改善铸坯角部的表面质量,45#板边部裂纹得到有效控制. 相似文献
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《钢铁研究学报(英文版)》2016,(6):539-546
To improve the straight edge seam defect on hot-rolled steel plates,the deformation and temperature distribution of rectangular slabs and chamfered slabs during rolling in a pilot rolling experiment were analyzed in detail using the finite element method.The results showed that the crease formed on the lateral side near the edge of the plate as a result of uneven stress during broadside rolling.The creases rose to the surface with unrestricted spread and evolved into a straight edge seam during the subsequent straight rolling.To eliminate the straight edge seam defect,chamfered slabs were developed and investigated for rolling.The use of the chamfered slabs provided two advantages for rolling:the distribution of the temperature near the edge was ameliorated,and the deformation shape was improved by the chamfered shape.As a result,the risk of forming a straight edge seam defect was reduced by the use of a chamfered slab. 相似文献
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夹杂物是影响IF钢表面质量的重要因素。对某厂生产的IF钢连铸坯和热轧板取样, 采用光学显微镜、扫描电镜、能谱、大样电解等多种检测分析方法, 分析了夹杂物的形貌、尺寸、数量、分布以及成分等。研究发现, 热轧工艺的轧制作用使连铸坯宽度方向1/4处聚集的夹杂物向边部迁移, 最终造成热轧板边部夹杂物指数最高, 说明夹杂物聚集带在轧制过程中具有遗传性。热轧板中20 μm以下夹杂所占百分比与连铸坯中夹杂相比稍有增大, 50 μm以上夹杂所占百分比稍有降低。热轧工艺的轧制作用将连铸坯中大颗粒氧化铝夹杂挤压变形为热轧板中的长条状, 容易形成表面条状缺陷。夹杂物在连铸坯距内弧侧30 mm处存在聚集现象, 热轧板中距内弧侧0.5 mm处夹杂物指数最高, 这是由于等效应变不同使夹杂物聚集带向表层迁移。IF钢连铸坯和热轧板中主要有4类显微夹杂, 分别为Al2O3类、TiN、Al2O3-TiOx和SiO2类复合夹杂, 且两者中各类夹杂物所占百分比差别不大。 相似文献
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The systematic investigation of the formation of edge defects on hot strips resulting from slab corner cracks generated in continuous casters, affords the development of model‐based concepts for the identification of such initial slab cracks. This enables the reduction of material losses during trimming of defective edges. Utilizing the commercial finite element package Deform‐3D, systematic massive forming simulations of several consecutive flat and edging passes were performed. The main simulation challenges result from the occurrence of different length scale values in the slab and strip models including edge cracks. The numerical results clearly point out the significant morphological changes of the cracks during rolling and afford valuable indications for a deeper understanding of the underlying process details. The results from metal forming simulations coincide very satisfactorily with the unetched cross‐sectional micrographs obtained from an experimental rolling mill. Systematic variation of geometry data enables the identification of the topology of initial slab corner cracks from edge defects detected after hot rolling. 相似文献
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《钢铁冶炼》2013,40(9):656-664
AbstractOn the basis of Shagang Group’s 5000 mm heavy plate mills, conventional rolling processes with different broadside rolling ratios were simulated by the three-dimensional rigid plastic thermomechanical finite element (FE) model developed in the author’s previous work. By analysing the simulation results, it was found that the final plate plan view patterns after hot rolling processes were bound closely to the broadside rolling ratio and the finishing rolling ratio. Then, predictive models for plate end edge shapes and side edge shapes were formulated by nonlinear regressive analysis of the simulation results and modified by the lengths of the uneven shapes for higher accuracy. The validity of the prediction models was confirmed by comparing the predicted concavity and convexity lengths with those measured from industrial tests. The predicted plate edge shapes were in good agreement with those of the FE simulation. On the basis of the plate plan view pattern prediction models, methods to improve the plate plan view pattern are discussed. 相似文献
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