首页|铸坯头尾温差模拟及直接轧制棒材力学性能分析

铸坯头尾温差模拟及直接轧制棒材力学性能分析

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直接轧制工艺中常存在铸坯头尾温差大的问题,控制铸坯温度的均匀性有利于减小棒材性能波动,对棒材生产具有重要意义.利用数值模拟研究了铸坯切断后不同部位的温度场变化,发现3 m/min拉速下,铸坯切断后头尾表面温差约为85 ℃,且其随运输时间增加而减小,但运输时间过长会导致铸坯温度无法满足轧制要求.针对铸坯头尾温差大的问题,提出了在连铸切割机后增设阶段冷却装置,同样利用数值模拟研究了增设阶段冷却装置对铸坯温度场的影响.结果表明,增设阶段冷却装置可有效减小连铸坯头尾温差,水流密度与铸坯长度基本呈抛物线关系,出冷却装置时的连铸坯头尾温差降低至约35 ℃,粗轧机入口处铸坯中部的芯表温差减小约9 ℃,尾部的芯表温差增大约19 ℃,阶段冷却装置对芯表温差的影响基本消除.根据计算结果对阶段冷却装置的关键工艺参数进行设计,利用某企业生产线进行阶段应用试验,对棒材屈服强度和抗拉强度等力学性能进行研究,发现屈服强度和抗拉强度的波动范围为30 MPa,棒材性能均匀性得到有效控制,同时棒材屈服强度远高于415 MPa的要求,为减少炼钢过程的合金消耗提供了有利条件.研究结果为阶段冷却装置实际应用提供参考和依据,同时为钢铁企业控制铸坯头尾温差和棒材性能均匀性提供了新思路.
Simulation of temperature difference between head and tail of casting strand and analysis on mechanical properties of direct rolling bar steel
The direct rolling process has the problem of large temperature difference between the head and tail of casting strand.Controlling the temperature uniformity of the casting strand is beneficial to reduce the fluctuation of mechanical properties for bar steel,which is of great significance to the production of bar steel.The temperature field changes of different parts in casting strand after cutting off were studied by numerical simulation.It is found that at the casting speed of 3 m/min,the temperature difference between the head and tail surface of casting strand after cutting off is about 85 ℃,and it decreases with the increase of transportation time.However,if the transpor-tation time is too long,the slab temperature cannot meet the rolling requirements.Aiming at the problem of large temperature difference between the head and tail of casting strand,a stage cooling device was added after the continu-ous casting cutting machine.The influence of device on the temperature field of casting strand was also studied by numerical simulation.The results show that adding the device can effectively reduce the temperature difference be-tween the head and tail of casting strand,and the relationship between water flow density and length of casting strand is basically parabolic.When the casting strand leaves the device,the temperature difference between the head and tail is reduced to about 35 ℃.The temperature difference between the center and the surface for middle of the casting strand is reduced by about 9 ℃ and the temperature difference between the center and the surface of casting strand tail is increased by about 19 ℃ at the entrance of the roughing mill.The effect of stage cooling device on cen-ter and surface temperature difference is basically eliminated.According to the calculation results,the key process parameters of the stage cooling device were designed,and the application test was carried out using the production line of an enterprise.The mechanical properties such as yield strength and tensile strength of the bar steel were studied.It is found that the fluctuation range of yield strength and tensile strength is 30 MPa,and the uniformity of product performance is effectively controlled.At the same time,the yield strength of bar steel is much higher than the requirement of 415 MPa,which provides favorable conditions for reducing alloy consumption in steelmaking process.The research results provide reference and basis for the practical application of stage cooling device,and provide a new idea for the iron and steel enterprises to control the temperature difference between the head and tail of casting strand and the bar steel mechanical property uniformity.

billet castingdirect rollingnumerical simulationtemperature difference between head and tailme-chanical property

吕明、薛魁、习晓峰、郭红民、梁少鹏、张朝晖

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西安建筑科技大学冶金工程学院,陕西西安 710055

陕西龙门钢铁有限责任公司,陕西韩城 715405

方坯连铸 直接轧制 数值模拟 头尾温差 力学性能

国家自然科学基金面上基金项目资助陕西省教育厅服务地方专项计划项目陕西省自然科学基础研究计划联合基金项目陕西省创新能力支撑计划资助项目

5237434622JC0442021JLM-322023-CX-TD-53

2024

中国冶金
中国金属学会

中国冶金

CSTPCD北大核心
影响因子:0.907
ISSN:1006-9356
年,卷(期):2024.34(2)
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