张力减径机组孔型设计简介

张力减径机孔型设计最关键的两个因素是减径系列的分配和椭圆度的选取。一个减径系列可以生产多个规格的成品管,不同的成品管规格可以通过改变减径系列的总减径率来获得。孔型椭圆度的计算尤为重要,如果椭圆度过小,在轧制薄壁钢管时,钢管的外壁容易挤入辊缝,形成轧折缺陷;而椭圆度过大,钢管横向受力不均,形成内多边形。孔型设计时椭圆度选取一般根据宽展系数和实际轧制经验确定。     

小口径无缝管275减径机孔型设计及改进

对热轧小口径无缝钢管22架次275集中差速传动减径机微张力减径机设计单架次减径率为4.38%、孔型椭圆度为1.0671-1.0624逐渐递减,可以有效节省机架数量。生产径壁比大于10.67的无缝管且内孔壁厚均匀;对于径壁比小于10.67,采用微张力减径机设计单架次减径率为3.20%、孔型椭圆度为1.0347,内孔壁厚均匀。     

张力减径机不同孔型横向壁厚分布的有限元模拟分析

借助有限元分析软件模拟钢管张力减径的轧制过程,由3种不同张力减径机孔型轧制的同一规格钢管产品的横向壁厚分布的比较表明,采用宝钢专有技术设计的新孔型轧制的钢管与原有的德国传统孔型轧制的钢管相比,其横向壁厚较为均匀,并对钢管"辊印"缺馅的产生有抑制作用.     

冷辊轧制状态下钢管横向壁厚不均的变化

引用了在60—120冷循环辊轧制机上轧制时管子横向壁厚不均,沿工作锥长度的变化实验研究结果。获得了荒管及其所轧管子的横向壁厚不均数据,以及对于最小厚始值情况而言,管子沿工作变形锥长度的变化数据和特点。     

用异型孔轧制消除钢管定减径内多边形缺陷

就钢管定减径中普遍出现的内多边形缺陷进行了分析 ,提出用孔型适当变异的轧制方法并给出计算公式 .结果表明 ,通过异型孔定减径可使内多边形缺陷得到有效缓解     

无缝钢管张力减径过程内六方产生的模拟分析

根据无缝钢管张减过程的变形特点,利用MSC.Marc软件建立了三维热力耦合有限元分析模型,对18机架张力减径试轧产品进行数值模拟,模拟结果与实测数值的对比表明建立的分析模型实用可靠,精度较高.通过研究各机架出口断面不同点的壁厚变化,得出减径后钢管横向壁厚分布不均,探讨了内六方缺陷产生的原因.该模型的建立为分析产品缺陷、指导工艺设计提供了依据.     

用异型孔轧制消除钢管定减径内多边形缺陷

就钢管定减径中普遍出现的内多边形缺陷进行了分析，提出用孔型适当变异的轧制方法并给出计算公式。结果表明，通过异型孔定减径可使内多边形缺陷得到有效缓解     

自动轧管横向壁厚精度研究

摘要：针对自动轧管机轧制薄壁不锈钢管中出现的严重横向壁厚不均问题,借助于三维有限元分析软件Simufact,对X10CrNiTi18不锈钢管典型规格112mm×4.5mm自动轧管过程进行数值模拟。研究了不同轧辊孔型结构参数、芯棒润滑状态、轧辊孔型磨损及穿孔毛管偏心对自动轧管横向壁厚精度的影响。结果表明：随着芯棒摩擦因数的增大,所轧荒管横向壁厚精度明显恶化;偏心毛管轧制所轧荒管依旧偏心,延伸轧制对穿孔毛管偏心壁厚纠偏能力有限;磨损的孔型修模后,采用负芯补轧制较增大芯棒直径轧制所轧荒管横向壁厚不均度增大;采用三段式圆弧孔型,所轧荒管横向平均壁厚更接近目标壁厚,横向壁厚不均度由原孔型的13.55%下降到9.94%,横向壁厚精度明显改善。     

微力张减径的工艺参数选定

介绍了微张力减径工艺中单机架减径率、孔型椭圆度、张力系数工艺参数的选定原则和选定范围，认为其最佳范围是单机架减径率３％～５％，宽度系数０．９７５～１．０２５，张力系数０．２５～０．４５。     

微张力减径的工艺参数选定

介绍了微张力减径工艺中单机架减径率、孔型椭圆度、张力系数工艺参数的选定原则和选定范围，认为其最佳范围是单机架减径率３％～５％，宽度系数０．９７５～１．０２５，张力系数０．２５～０．４５。     

圆孔型系统张力减径后钢管横向壁厚不均匀性的模拟

用有限元法模拟152．5BR圆孔型系统主变形四机架连轧过程发现：张力减径后钢管的横向壁厚分布不均匀,产生内六方趋势,内六方趋势的大小与主变形机架的数量呈直线关系。利用这种关系可预测152．5BR圆孔型系统生产的各种规格钢管的横向壁厚不均匀程度。实际生产轧制试验证明了该有限元模拟结果的正确性。     

Method for Improving Transverse Wall Thickness Precision of Seamless Steel Tube Based on Tube Rotation

The tube rotation method(TRM) refers to the rotational movement of steel tube about its axis as well as translation in rolling direction in stretch reducing rolling process.The influence of the TRM on transverse wall thickness precision of seamless steel tube was studied.Thickness distribution of the TRM was obtained by superimposing the thickened amount of single pass rolling.Results show that the TRM can effectively improve the evenness of thickness distribution.In order to analyze the influence mechanism of the TRM,the finite element method was adopted to simulate the thickness distribution in stretch reduction process.Results show that the TRM changes the roundtrip flow between two fix places of conventional stretch reducing and inhibits the directional accumulation of metal.In addition,the TRM has a correction effect on thickness cusp.All these advantages of the TRM help to improve the transverse wall thickness precision of seamless steel tube.     

Study on transverse wall thickness accuracy of tube rolled by automatic plug mill

In view of serious uneven transverse wall thickness of thin walled stainless steel tube rolled by automatic plug mill，the automatic tube rolling process of X10CrNiTi18 stainless steel tubes with typical specification of 112mm×4.5mm was numerically simulated by using 3D finite element analysis software Simufact. The influence of different roll pass structure parameters, different mandrel lubrication state, roll pass wear and eccentricity of pierced shell on transverse wall thickness accuracy of automatic rolling tube was analyzed. The results show that as the friction coefficient of the mandrel increases, the accuracy of transverse wall thickness of the rolled tube deteriorates obviously. The hollow tube rolled by eccentric pierced shell is still eccentric, and it shows that the elongation rolling has a limited ability to correct the eccentric wall thickness of the pierced shell. With repaired the worn pass, the unevenness of the transverse wall thickness of the rolled tube increases using the negative mandrel compensation rolling compared with the increase of mandrel diameter. The average transverse wall thickness of the rolled tube is closer to the target wall thickness by using three section arc groove, and the transverse wall thickness unevenness decreases from 13.55% of the original groove to 9.94%, and the transverse wall thickness accuracy is obviously improved.     

The PQF pass parametric design system of heavy calibre seamless tube

According to the characteristics of PQF continuous rolling pass,the relationship between spread coefficient,wall thickness coefficient and elongation are analyzed.The section shape of tube in each stand outlet,the efficient working radius and the rotational speed of each roll are obtained,therefore,the pass parametric design is completed.A thermal-mechanical coupled model of continuous rolling tube’ s forming process is established by the three-dimensional elasto-plastic finite element method,the section shape and area of tube in each stand outlet are forecasted,which is used to modify the pass.The rolling force of each roller is predict too,which provides a guidance for pass design.In addition,a visual software of PQF pass parametric design system on heavy calibre seamless tube is generated with Visual Basic.The forming dimension of tube and the rolling force of each roller are successfully obtained,by simulating the forming process of a certain series heavy calibre seamless tube.This system posses practical utilization value.By using this system,the development cycle of new product can be shortened,the reliability of pass design can be improved,and the energy consumption of rolling mill and production cost can be decreased.     

钢管连轧过程中机架孔型参数优化

为了优化某限动芯棒连轧管机的孔型参数,利用正交试验参数优化方法,结合钢管热连轧有限元模拟分析,研究轧辊孔型参数(脱离角、脱离比、过渡圆角半径、辊缝值)对轧制所得钢管的尺寸精度和轧制过程中力能参数的影响,分析各参数影响的显著性,确定各因素的优化组合.结果表明:辊缝值对外径椭圆度、壁厚不均度和轧制力矩的影响最为显著,脱离角的影响居于次位,而脱离比对外径椭圆度、轧制力、轧制力矩的影响最小.根据影响规律获得较优参数组合:脱离角35°、脱离比2.25、过渡圆角半径5mm、辊缝值35 mm.对比仿真结果,优化后的钢管尺寸精度较优化前有明显提高.     

Mathematical Modelling on the Microstructure Evolution of X60 Line Pipe Steel during CSP Hot Rolling

 An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and mechanical properties prediction technology. Thermo-mechanical coupled finite element models for simulating hot strip rolling have been developed and the distribution of equivalent plastic strain through the thickness direction in the rolled material of CSP rolling was carried out. Thus the distribution of temperature, strain and strain rate through the thickness of the steel stocks, as well as the microstructure evolution during hot rolling of X60 line pipe steel strip have been investigated by using the developed integrated process modelling system. In addition the determination and optimization of controllable process parameters during CSP hot strip rolling for the Nb-microalloyed X60 line pipe steel have been implemented, and control strategies such as adopting larger pass reduction in the first stand, and arranging appropriate pass interval times and proper rolling speed, to reduce or eliminate mixed-grains microstructure of Nb microalloyed strip in CSP processing have been proposed.     

Mathematical Model of Microstructure Evolution of X60 Line Pipe Steel During CSP Hot Rolling

An integrated process modelling system for simulating the microstructure evolution of Nb-microalloyed HSLA steel produced in CSP hot rolling process has been developed on the basis of the microstructure simulation and mechanical properties prediction technology. 3-D thermomechanical coupled finite element models for simulating hot strip rolling have been developed and the distribution of equivalent plastic strain through the thickness direction of the rolled material by CSP roiling was obtained. Thus the distribution of temperature, strain and strain rate through the thickness of the steel stocks, as well as the microstructure evolution during hot rolling of X60 line pipe steel strip has been investigated by using the developed integrated process modelling system. In addition, the determination and op-timization of controllable process parameters during CSP hot strip rolling for the Nb-microalloyed X60 line pipe steel have been implemented, and control strategies such as adopting larger pass reduction in the first stand, arranging ap-propriate pass interval times and proper rolling speed, to reduce or eliminate mixed grain microstructure of Nb micro-alloyed strip in CSP processing have been proposed.     

厚壁无缝钢管张减过程横向壁厚不均研究

为解决热轧厚壁无缝钢管横向壁厚分布不均的问题,建立三维热力耦合有限元模型,对张力减径轧制过程进行了动态模拟,并结合工业试验验证仿真模型.根据仿真结果分析了轧制过程中温度、应变和摩擦力的分布,研究了单道次轧制时金属的径向和周向流动规律,并结合整个轧制过程对金属的横向流动及壁厚不均的形成过程进行了分析,研究了轧制过程中温度对金属流动行为的影响,从而总结出横向壁厚分布不均的原因.结果表明:(1)在经过单道次轧制时,金属的周向流动为从孔型顶部流向辊缝,对应孔型角±30°位置处金属的周向流动最活跃,靠近孔型顶部和辊缝位置的金属周向流动性较差.但从整个轧制过程来看,金属总的周向流动为从孔型顶部和辊缝向孔型角±30°位置处流动,从而导致孔型角±30°位置处的壁厚比孔型顶部和辊缝位置要厚.(2)温度分布对金属横向流动有重大影响.由于塑性功换热的原因,孔型角±30°位置处金属的温度比辊缝和孔型顶部处高,此处金属较软,阻力较小,孔型顶部和辊缝处金属向此处的流动性增强,导致钢管截面呈内边方形.      

全浮动芯棒连轧管机组孔型修改效果初探

 针对全浮动芯棒连轧管机组孔型系统的修改过程,通过生产实验实时记录力能参数,并离线抽取荒管获得钢管壁厚分布曲线,随后进行对比,得到如下结论：连轧钢管壁厚分布具有螺旋形特征,纵向上最大和最小壁厚以波峰与波谷形式交替出现;孔型修改后,钢管壁厚精度降低,力能参数有所升高。分析其原因,孔型修改后,第3、5机架孔型椭圆度增大,加大了钢管压扁变形与金属横向壁厚增厚,并且机组的张力状态未能有效减弱金属横向流动趋势,最终导致壁厚不均率及力能参数升高。