连铸厚板坯几何形状的热机建模
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摘要
奥钢联林茨公司为了生产厚355 mm、宽1 600 mm的特厚板坯,升级改造了第3炼钢厂的5号连铸机。该弧形连铸机最初设计生产的板坯最大厚度为285 mm,弧形半径为10 m,配置了直结晶器,对带液芯的铸坯进行弯曲和矫直。在这种类型的连铸机上生产厚度为355 mm铸坯的主要问题是板坯的几何形状。由于弯曲时铸坯角部变形,铸坯可能出现小的皮下热裂纹。为了模拟在浇注过程中结晶器液面到弧形段开始位置的连铸板坯变形,使用ABAQUS软件开发了有限元3D模型。该热力学模型结合材料的粘弹性定律计算浇注过程凝固坯壳的张应力和压应力。据观测,模拟计算出的浇注过程凝固坯壳的张应力和压应力的分布与小热裂纹的外形大致相符。还将抽样测量的板坯几何形状与有限元计算结果进行了比较。采用热机建模计算结果,通过优化结晶器锥度和强化出结晶器后铸坯窄面的冷却,改进了板坯的几何形状。
Voestalpine Stahl Linz upgraded in the LD3,caster no. 5 in order to produce 355 mm thick and 1600 mm wide slabs. The caster with a radius of 10 m,initially designed to produce a maximum of 285 mm thick slab is a bow-type with straight mould and liquid core bending and straightening. The main problem to this caster type at 355 mm thickness is the slab geometry. Due to bending the slab corner are deformed and small hot cracks can appear near to the slab surface. Using ABAQUS software a FEM 3D-Model was developed in order to simulate the deformation of slab during casting,between mould level and begin of caster bow. The thermo-mechanical model,couplet with viscoelastic materials law calculates the tensions and strains in the solidified shell during casting. A good agreement between calculated tensions and strains distribution respectively the appearance of small hot cracks was observed. Also the geometry of slab measured on sample is comparable with the results of FEM computation. Using the results of computation the geometry of slab can be improved by means of mould taper optimization and intensively cooling of narrow face below the mould.
Voestalpine Stahl Linz upgraded in the LD3,caster no. 5 in order to produce 355 mm thick and 1600 mm wide slabs. The caster with a radius of 10 m,initially designed to produce a maximum of 285 mm thick slab is a bow-type with straight mould and liquid core bending and straightening. The main problem to this caster type at 355 mm thickness is the slab geometry. Due to bending the slab corner are deformed and small hot cracks can appear near to the slab surface. Using ABAQUS software a FEM 3D-Model was developed in order to simulate the deformation of slab during casting,between mould level and begin of caster bow. The thermo-mechanical model,couplet with viscoelastic materials law calculates the tensions and strains in the solidified shell during casting. A good agreement between calculated tensions and strains distribution respectively the appearance of small hot cracks was observed. Also the geometry of slab measured on sample is comparable with the results of FEM computation. Using the results of computation the geometry of slab can be improved by means of mould taper optimization and intensively cooling of narrow face below the mould.
引文
[1]Hodnik P,Fürst Ch,Ilie S,et al.Operational results on casting 355 mm thickness slab on a bow-type caster at voestalpine Stahl Linz[C]//6thEuropean Conference on Continuous Casting.Italy,2008.
[2]Pennerstorfer P,Stiftinger M,Hodnik P,et al.Production of 355 thick slabs on a straight mould,bowtype caster[J].Millenium Steel,2008:125-130.
[3]Mittinen J,Louhenkilpi S,Laine J.IDS Solidification Analysis Package V1.3.2 Helsinki University of Technology.
[4]Harste K,Schwerdtfeger K.Thermomechanical properties of iron:viscoplasticity of ferrit and of austenit-ferrit mixtures[J].Materials Science and Technology,1996,13:381.
[5]Schwerdtfeger K.Metallurgie des Stranggieens-Gieen und Erstarren von Stahl,Düsseldorf:Verlag Stahleisen mbH,1992.
[2]Pennerstorfer P,Stiftinger M,Hodnik P,et al.Production of 355 thick slabs on a straight mould,bowtype caster[J].Millenium Steel,2008:125-130.
[3]Mittinen J,Louhenkilpi S,Laine J.IDS Solidification Analysis Package V1.3.2 Helsinki University of Technology.
[4]Harste K,Schwerdtfeger K.Thermomechanical properties of iron:viscoplasticity of ferrit and of austenit-ferrit mixtures[J].Materials Science and Technology,1996,13:381.
[5]Schwerdtfeger K.Metallurgie des Stranggieens-Gieen und Erstarren von Stahl,Düsseldorf:Verlag Stahleisen mbH,1992.