热铸坯的高温热修磨工艺

高温热修磨(Casttgrind)工艺通过在线修磨高温热板坯,使得在板坯连铸操作与热轧操作之间真正建立起物理性联机成为可能。在线高温热修磨具有更高的修磨产能;一体化的生产物流特性使产品交货周期(LeadTime)更短;产品质量得到进一步改进。

高强度螺纹钢热送横裂纹控制研究

R8m弧铸机在无结晶器电磁搅拌的情况下,高拉速生产高强度螺纹钢HRB500E系列大规格在热送轧制时,铸坯经过轧机初轧位置,肉眼可见大量角部横裂纹,轧制成品表面有裂纹缺陷,表面质量差。通过生产工艺以及设备条件的研究分析,小弧度铸机高拉速下冷却强度大,铸坯出二冷温度偏低,柱状晶发达,铸坯质量随着钢中V、N元素的含量增加,裂纹敏感性逐步增强,且轧制规格越大,裂纹缺陷造成的质量影响越发严重。结合实际生产情况,对结晶器铜管锥度、振动台参数、热送铸坯入炉温度三个方面做优化设计,解决高强度螺纹钢热送轧制表面横裂纹缺陷。

提高1^(#)连铸机至二棒轧线方坯热送率的工艺实践

通过对炼、轧钢工序开展工艺、设备、参数优化、生产组织等攻关工作,将连铸坯矫直温度提高到了1070℃以上,减少了铸坯在运输过程中的热损失,确保了铸坯进入加热炉时的温度达到850℃,综合铸坯热送热装率平均达到了64.4%,最高达到了80%的设定目标,使吨钢煤气用量得到降低,取得了一定的效果。

连铸坯热送热装实践

介绍铸坯热送热装工艺在理顺炼、铸、轧三工序过程中所采取的措施以及取得的效果。

Characteristics evolution of 6009/7050 bimetal slab prepared by direct-chill casting process

6009/7050 alloy bimetal slab was prepared by a direct-chill (DC) casting process. Homogenizing annealing, hot rolling and T6 treatment were successively performed and their effects on microstructure and properties of the slab were studied. The results reveal that the average diffusion layer thickness of as-cast slab, determined by interdiffusion of elements Zn, Cu, Mg and Si, was about 400 μm. Excellent metallurgical bonding was achieved because all tensile samples fractured on the softer 6009 alloy side after homogenizing annealing. After homogenizing annealing plus rolling, the average diffusion layer thickness decreased to 100 μm, while the network structure of 7050 alloy side transformed to dispersive nubby structure. Furthermore, subsequent T6 treatment resulted in diffusion layer thickness up to 200 μm and an obvious increase of the Vickers hardness for both 7050 and 6009 sides. The layered structure of the as-cast 6009/7050 bimetal is retained after hot rolling and T6 treatment.

Effect of cooling structure on thermal behavior of copper plates of slab continuous casting mold

A three-dimensional finite-element model of slab continuous casting mold was conducted to clarify the effect of cooling structure on thermal behavior of copper plates. The results show that temperature distribution of hot surface is mainly governed by cooling structure and heat-transfer conditions. For hot surface centricity, maximum surface temperature promotions are 30 ℃and 15 ℃ with thickness increments of copper plates of 5 mm and nickel layers of 1 ram, respectively. The surface temperature without nickel layers is depressed by 10 ℃ when the depth increment of water slots is 2 mm and that with nickel layers adjacent to and away from mold outlet is depressed by 7℃ and 5 ℃, respectively. The specific trend of temperature distribution of transverse sections of copper plates is nearly free of cooling structure, but temperature is changed and its law is similar to the corresponding surface temperature.

Area Method Analysis and Thermodynamic Behavior of Nonmetallic Micro-Inclusions in Casting Slab of GCr15 Bearing Steel

The distribution and characteristics of nonmetallic micro-inclusions of GCr15 bearing steel were explored through metallographic area method in virtue of tracer method and electronic microscope.The results show that the micro-inclusions,of which the average value is 0.032%,are mainly the compounds formed via the adsorption/aggregation of multielement deoxidized compounds and secondarily deoxidized products on tundish liquid level.The micro-inclusions of diameters from 0 to 5 μm are 92.5% in total,which basically determines the characteristics of inclusions distribution in casting slab.The inclusions of diameters more than 10 μm only account for less than 1% in total,which have little influence on steel quality.The relationship between equilibrium compositions of the first deoxidation products and molten steel compositions was also calculated based on thermodynamic theory.

鞍钢2150ASP自由程序轧制技术

为了解决鞍钢2150ASP生产线炼钢、连铸和轧制线之间相互影响与相互制约的问题,通过开发LVC工作辊和ASPB支持辊、在精轧机组应用高速钢工作辊和热轧工艺润滑、轧制计划动态编制等一系列相关技术,实现了具有ASP特点的自由程序轧制技术。实际应用效果表明,在保证带钢凸度和平直度精度的前提下,可实现不同钢种、不同厚度和不同宽度带钢的混合轧制,并且同宽轧制长度达到了100km,逆宽轧制达到了300mm。推行自由程序轧制后,连铸坯的直装率达到了60%以上,热装率达到了85%以上。