棒材直接轧制工艺改造实践

介绍了国内某带肋钢筋产线进行直接轧制的改造实践。对提高连铸坯温度和降低输送过程中钢坯温度损失的方法等直接轧制工艺中的关键因素进行了讨论;用实际生产中的数据对相关文献中的模拟结果进行了验证。实践表明,采用直接轧制工艺生产抗震带肋钢筋产品,钢坯温度满足轧制需要,轧机轧制负载正常,产品性能满足国标要求。     

A study of the influence of strain path change on the microstructure and mechanical properties of low carbon steel using plate and bar rolling

This paper presents an experimental study of the effect of strain path changes with reference to rolling. The fundamental idea considered is to utilize the characteristics of plate rolling and bar rolling. Plate rolling is characterized as monotonic compressive loading while bar rolling is characterized as cross compressive loading. A four-pass plate rolling and bar rolling experiment was designed so that the material experiences the same amount of strain at each pass during rolling. The rolling experiment was carried out at moderately high temperatures (450, 550 and 650°C). The microstructures and mechanical properties of a low carbon steel acquired from two types of rolling experiments were compared. The results revealed that the differences in strain path attributed to monotonic loading (plate rolling) and cross loading (bar rolling) significantly influenced microstructures and mechanical properties.     

棒线材生产技术的发展前景展望

在分析研究棒线材免加热直接轧制技术优缺点的基础上,讨论了棒线材生产工艺的发展方向。在节能减排、降成本的大趋势下,棒线材免加热直接轧制技术在改造现有生产线及新建生产线方面的应用会越来越多;针对提高产品质量的需求,预计将会出现一种有别于常规加热炉的节能型均温炉,其作用是消除铸坯的头尾温差和表面与芯部温差,同时起到连铸与轧制两个工序间的缓冲作用;从长远看,当方坯拉速达到6 m/min以上时,棒线材生产采用无头轧制技术将成为可能,这将为棒线材的生产带来革命性变化。     

整坯轧制在半连轧生产线上的应用

为降低生产成本,增加经济效益,石横特殊钢厂采用自由活套工艺,使轧件在Φ32 0mm×6与Φ2 80mm×6机组之间形成大活套,并通过采取“设计推套器、侧活套台、切尾剪、夹送辊”等技术创新措施,实现了整坯轧制在半连轧生产线上的应用。应用表明:盘条盘重增加2 80kg ,尾部耳子和直条短尺材减少5 0 % ,直条成材率提高0 93% ;轧制间隙时间缩短,年产量增加4万t。     

棒线材免加热直接轧制的特点和关键技术

介绍了在棒线材生产中连铸坯不经任何加热和补热、进行直接轧制的新技术,分析了免加热技术的特点,介绍了提高铸坯温度的措施和控制技术、把铸坯快速运送到粗轧机的实用技术、轧机负荷分配优化等关键技术。指出了免加热技术的几项负面作用,对使用该技术可取得的节能减排降成本效果进行了分析计算。     

棒线材免加热直接轧制工艺的平面布置

介绍了棒线材免加热直接轧制工艺的平面布置,分析研究了新建机组和对现有车间进行技术改造两种情况下车间平面布置的特点,给出了免加热工艺平面布置应遵循的原则,介绍了在生产线应用棒线材免加热技术平面布置的I字型、b型、Z型、L型和U型等实用方案,为推广应用DROF技术提供了参考。     

青钢半连轧棒材生产线切分轧制工艺初探

针对青钢半连轧棒材生产线生产Φ12、Φ14mm带肋钢筋时制约生产力的问题 ,采用了自行设计的切分轧制方案 ,并对轧辊材质、导卫装置型式进行优选 ,使生产效率明显提高 ,合格率达 98 82 %。     

钛合金棒材三辊螺旋轧制成形数值模拟

利用有限元软件Deform-3D建立钛合金棒材三辊螺旋轧制过程的三维有限元仿真模型,对棒坯轧制从咬入到稳定轧制的全过程进行了模拟分析.研究得出三辊螺旋轧制中棒坯的变形规律,分析了钛合金棒坯成形过程中应力应变情况及轧辊的载荷.该研究对于轧制缺陷控制有着重要的指导意义,为轧机的工艺参数和关键零部件的设计提供了重要依据.     

四切分棒材轧制技术在连轧厂的应用

介绍了广州钢铁集团连轧厂引进的四切分棒材轧制技术和主要设备概况;并针对原工艺设备存在的问题,采取了多项措施:如改进料形,精心进行速度调整,严格切分箱装配及安装制度等。改进后年效益在500万元以上。     

棒材轧制轧件出口断面形状预测及平均轧辊半径的新计算模型

对圆—椭圆—圆孔型轧制合金钢,提出了接触边界临界点的概念,建立了出口断面形状预测模型,推导出临界点的解和新的等效接触断面面积公式,给出了计算平均轧辊半径的新模型。为验证新模型,完成了棒材轧制试验,并且利用刚塑性有限元法对轧制过程进行了模拟。将不同模型得到的理论结果与实验值和模拟值作比较,证明新模型具有很高的精度,因此可以用于精轧孔型设计和轧制工艺参数的设定。     

Φ10mm带肋钢筋三切分轧制工艺的控制要点

分析了合肥钢铁集团有限公司连轧棒材厂Φ10mm带肋钢筋三切分轧制工艺的特点及三切分轧制中的控制要点，并针对生产中存在的问题提出了改进措施。     

Analytical model for prediction of deformed shape in three-roll rolling process

In process design of bar rolling, accurate prediction of deformed shape of the rolled workpiece is important in determining the total number of passes. Thus, development of an approximate analytical model for predicting an accurate rolled shape with less computation time will be beneficial for practical purpose. In the present study, such a model for the three-roll system with multi-passes was developed by deriving spread and geometrical configuration formulae from the finite element (FE) analysis results of a seven-passes sequence rolling. In FE simulations, process parameters such as the initial workpiece geometry and the amount of roll draft and roll speed were varied. By comparing spread ratios of FE simulation results three representative geometry changes (round–curved hexagonal, curved hexagonal–hexagonal, and hexagonal–hexagonal) were identified. For each representative geometry change those two formulae were determined in the present investigation. The formulae determined were further applied to a three-roll process with four-passes sequence. The final workpiece geometry predicted based on the model developed was found to be in good agreement with experimental and FE simulation results. Thus, the analytical model developed in the current approach can be effectively used in the design of multi-pass three-roll rolling processes.     

直接轧制技术在棒材生产中的应用

介绍了我国台湾某钢铁公司棒材生产线采用直接轧制的工艺方案和设备。经生产实践,棒材直接轧制技术提高了成材率,且吨钢可节约成本约300新台币。     

线棒材轧制用冷却器的优化设计与应用

针对棒线材生产用套筒式冷却器存在冷却能力不足，难以满足低温轧制的要求；轧件表面周向温度均匀性较差等问题，对套筒式冷却器结构进行了优化设计，得到旋流式冷却器。其采用圆锥斜齿轮式喷嘴，使冷却管内的水流形成旋流，可以产生较高的压力和速度，大幅度提高冷却能力，同时有效改善轧件表面温度的均匀性。采用SOLIDWORKS软件建模，利用ANSYS CFX软件进行流体仿真，对两种冷却器的流场、压力、流速进行了仿真分析。结果表明，旋流式冷却器可以提高冷却效率，改善轧件温度的均匀性，为实现轧件的超快速冷却创造有利条件。对24 mm圆钢的冷却应用表明，旋流式冷却器对轧件的降温幅度为套筒式冷却器的1.5～2.0倍且冷却均匀性明显改善。     

棒材4线切分轧制技术的开发与应用

介绍了水城钢铁公司二轧厂棒材4线切分轧制工艺的开发情况;重点介绍了Φ12mm带肋钢筋孔型系统的选择、导卫系统和活套等的设计及4线切分轧制中的调整操作要点。该技术的开发成功使小时产量提高50%以上,节省能源25%以上。     

线棒材轧制用冷却器的优化设计与应用

针对棒线材生产用套筒式冷却器存在冷却能力不足，难以满足低温轧制的要求；轧件表面周向温度均匀性较差等问题，对套筒式冷却器结构进行了优化设计，得到旋流式冷却器。其采用圆锥斜齿轮式喷嘴，使冷却管内的水流形成旋流，可以产生较高的压力和速度，大幅度提高冷却能力，同时有效改善轧件表面温度的均匀性。采用SOLIDWORKS软件建模，利用ANSYS CFX软件进行流体仿真，对两种冷却器的流场、压力、流速进行了仿真分析。结果表明，旋流式冷却器可以提高冷却效率，改善轧件温度的均匀性，为实现轧件的超快速冷却创造有利条件。对24 mm圆钢的冷却应用表明，旋流式冷却器对轧件的降温幅度为套筒式冷却器的1.5～2.0倍且冷却均匀性明显改善。     

高温、中应变速率下预测四道次连续轧制力的流变应力方程(英文)

为了计算在应变速率100～400s-1、温度900～1050℃条件下四道次连续线材轧制过程中的轧制力,提出了一个流变应力方程。基本概念是对Shida模型和Misaka模型进行改进。通常用这2种模型建立的流变应力本构方程来描述高温材料在不同应变率下的变形行为。将改进模型与有限元方法相结合来计算应变速率100～400s-1、温度900～1050℃条件下的四道次连续轧制过程中的轧制力。测量材料在每个道次的轧制力和表面温度,并与预测值进行比较。结果表明,在高温、中应变速率条件下,Misaka模型比Shida模型更好。在900℃时,采用Misaka模型的轧制力误差为-5.7%。在1050℃时,采用Misaka模型的轧制力误差为-15.2%,而采用改进的Misaka模型的轧制力误差降低到1.8%。由此可以得出,对于高温、中应变速率的线材轧制过程,改进的Misaka模型能用来预测高温材料的变形行为。     

Mathematical model to simulate thermo-mechanical controlled processing in rod (or bar) rolling

This study presents a mathematical model for computing the thermo-mechanical parameters such as the strain and strain rate at a given pass and the temperature variation during rolling and cooling between inter-stands (pass), to assess the potential for developing “Thermo-Mechanical Controlled Process” technology in rod (or bar) rolling, which has been a well-known technical terminology in strip (or plate) rolling since the 1970s. The model has then been applied to a four-pass (oval-round or round-oval) bar rolling sequence for predicting the pass-by-pass AGS, by incorporating the equation for recrystallization behavior and AGS evolution being widely used in strip rolling. The predicted AGS was compared with those obtained from the hot torsion experiment. Results revealed the proposed model, coupled with the recrystallization behavior and AGS evolution model developed for strip (or plate) rolling, might be applied directly to rod (or bar) rolling. We also found that the recrystallization behavior during rod rolling was significantly influenced by the method for calculating the thermo-mechanical parameters, especially the strain.     

马钢全连续式棒材车间工艺设备设计特点

介绍了马鞍山钢铁股份有限公司新建的年产 60万t全连续棒材生产线的工艺特点及设备设计特点。     

FEM analysis for hot rolling process of AM60 alloy

The rolling of AM60 sheets for 50%reduction was analyzed with DEFORM to investigate the hot deformation process. The simulated results show that the sheet velocities at the entrance(21 mm/s) and at the exit(37 mm/s) are less and larger than roll velocity,respectively.From the entrance to the neutral point,the velocity at the sheet surface is greater than that at the middle point of sheet in thickness,while that from the neutral point to the exit shows the opposite pattern.The effective strain of the shee...