六斜辊管材矫直过程精度解析

摘要：以管材六斜辊矫直过程为研究对象,推导了管材经一次反弯后,弹复曲率及残余曲率的演变过程。根据管材旋转一圈弯曲2次,计算了管材全流程矫直微元段的反弯次数;借助三次样条函数,以管材与矫直辊接触点为特征点,拟合出了管材在辊系中的弯曲形态。基于所获得的函数,可以获得任意位置处的弯曲曲率;对某一微梁段的反弯弹复过程进行循环迭代,计算出管材微梁段的最终残余曲率,进而得到最终的管材矫后的直线度精度。通过与现场矫直数据对比,证明该模型能够可靠地预测六斜辊矫直精度,为科学合理的设定矫直参数奠定了理论基础。     

六斜辊管材矫直过程精度解析

以管材六斜辊矫直过程为研究对象,推导了管材经一次反弯后,弹复曲率及残余曲率的演变过程。根据管材旋转一圈弯曲2次,计算了管材全流程矫直微元段的反弯次数;借助三次样条函数,以管材与矫直辊接触点为特征点,拟合出了管材在辊系中的弯曲形态。基于所获得的函数,可以获得任意位置处的弯曲曲率;对某一微梁段的反弯弹复过程进行循环迭代,计算出管材微梁段的最终残余曲率,进而得到最终的管材矫后的直线度精度。通过与现场矫直数据对比,证明该模型能够可靠地预测六斜辊矫直精度,为科学合理的设定矫直参数奠定了理论基础。     

拉矫机带钢反弯曲率的计算方法

对于拉伸矫直机,带钢在矫直机辊子上的曲率半径的计算尤为重要,只有确定了该曲率半径,才能进一步计算带钢的反弯曲率、弹复曲率和残留曲率,进一步计算带钢的平直度。假定带钢在矫直辊上的曲线为抛物线,给出带钢反弯曲率半径的计算方法,并且进一步讨论矫直辊辊子直径的计算方法。     

中厚板热矫直机压下模型

矫直机压下模型主要由入、出口矫直辊的压弯量设定和矫直辊的弯辊量设定组成.根据梁的弹塑性弯曲理论,矫直辊的压弯量应该由作用在板材上的反弯挠度来确定,即通过确定弹复挠度、残余挠度而得到反弯挠度,从而得到矫直辊的压弯量;矫直辊的弯辊量由最大原始曲率及入口板件厚度的塑性变形层深度来确定.研究结果表明计算值与实际设定值较吻合.     

棒材二辊矫直过程曲率的全流程定量解析

为了摸清棒材斜辊矫直过程中各曲率的变化规律,应用小曲率平面弯曲弹复理论以及棒材弯曲弹复的曲率方程式,实现棒材一次反弯弹复的计算模型,基于棒材每旋转半周反弯一次的规律以及上一次弹复后的残余曲率认为是下一次弯曲的原始曲率,建立棒材全流程二辊矫直过程弯曲弹复模型,获得整个矫直过程中原始曲率、弯曲曲率、弹复曲率以及残余曲率的演变过程,得到棒材最终的残余曲率.应用该理论模型对现场生产过程进行了计算,与现场结果一致,验证了理论模型的正确性.应用所建立的理论模型对不同直径、不同材料屈服强度、不同原始挠度的棒材矫直过程分别进行分析,获得了不同来料参数情况下矫直过程的变形规律.该模型可以为二辊矫直机辊型优化设计与工艺参数计算提供理论依据.      

Zr-4成品包壳管矫直工艺的优选研究

采用压力矫直和弯曲矫直两种矫直工艺进行Zr-4成品包壳管加工,并对矫直后管材的直线度、外径变化量和氢化物取向因子进行对比分析,重点研究了纯反弯弯曲矫直法对管材矫直质量的影响,探讨适合实际生产的矫直工艺。研究表明,在适当的弯曲量下,采用纯反弯弯曲矫直工艺能够确保氢化物取向因子控制在标准范围内,同时获得良好的直线度和管材表面质量。     

基于虚拟支点与曲线拟合的板带矫直机力能参数模型

 反弯曲率是矫直力计算过程中关键且难以确定的参数,矫直力的确定需要反弯曲率。根据虚拟支点概念,确定了力能参数理论模型;再利用中性层上下顶点处的位置,用曲线拟合的方法确定出了板材在矫直过程中的反弯曲率;将反弯曲率导入理论计算模型可得出矫直力。使用此方法并依据某钢厂热轧横切生产线中2号矫直机（11辊辊式矫直机）的工艺参数,计算出了矫直力的大小。结果表明利用该方法可以比较准确地计算矫直力。     

连铸多点弯曲多点矫直与连续弯曲连续矫直辊列设计计算

从理论上讨论了多点弯曲多点矫直和连续弯曲连续矫直辊列的设计计算，提出了多点弯曲多点矫直辊列的弯曲半径和矫直半径计算公式，推导了连续弯曲连续矫直辊列的理想曲线方程，举例说明了两种不同辊列形式在弯曲区和矫直区的应变规律．     

基于压力弹塑性变形中性层偏移模型的构建与验证

大截面棒材矫直过程中性层偏移明显,对二辊矫直辊辊型及棒材直线度的影响较大.依据三点弯曲理论建立了棒材矫直过程中基于压力弹塑性变形的中性层偏移量理论计算模型,结合室温拉伸和弯曲试验,研究了棒材矫直过程中性层偏移规律.结果表明:反弯半径和棒材力学性能对中性层偏移值的影响显著,反弯半径越小,则中性层偏移量越大;强度较低、塑性较强的材料,中性层偏移量较大.通过弯曲试验,验证了该模型的可靠性及其适用范围.      

簿板(带)连续拉伸弯曲矫直技术

本文根据拉伸弯曲矫直原理,论述了拉弯矫直各因素对板形的影响和拉弯矫直工艺参数的控制技术;给出了国产500 mm连续拉伸弯曲矫直机组各工艺参数的计算公式和有关的控制数据。     

Setting and realizing process plan for straightening thin- walled tube by multiple cross rolls of equal curvature

Since it was difficult to setting the plan and the unifying curvature- radius precisely when the thin- walled tubes were straightened continuously by the rolls of equal curvature. Therefore, based on the mechanism of unifying- straightening for the multiple cross- rolls straightening machine, the judgment method of the unifying curvature- radius was presented firstly in view of the bending and springback equation of the thin- walled tube, and then the searching method of the minimum unifying curvature- radius was presented subsequently, finally the straightening plans were drawn up for different thin- walled tubes with different initial curvature radii, especially for the thin- walled tube with the large initial deformation which could not be unified by the two cross rolls, the new method was pre- bending, unifying, and straightening, and it was also presented whether a thin- walled tube could be straightened. Some procedures were developed by VB to calculate the example, which is shown that the methods are effective, meanwhile it is found that if the unifying curvature- radius exist for an initial curvature- radius, it will not be sole and will be within a scope, and it is also found that there must be a scope of the initial curvature- radius within which the thin- walled tubes can??t be unified by the two cross rolls.     

Continuous bending and straightening technology of Q345c slab based on high-temperature creep deformation

A new continuous bending and straightening casting curve with the aim of full using of high-temperature creep deformation was proposed.The curvature of bending and straightening segment varies as sine law with arc length.The basic arc segment is shortened significantly so that the length of bending and straightening area can be extended and the time of creep behavior can be increased.The distance from solidifying front in the slab was calculated at 1 200°C by finite element method.The maximum strain rate of new casting curve at different locations inside the slab is 6.39×10~(-5) s~(-1) during the bending segment and it tends to be 3.70×10-5 s~(-1) in the straightening segment.The minimum creep strain rate is 7.45×10~(-5) s~(-1)when the stress is 14 MPa at 1 200°C.The strain rate of new casting machine can be less than the minimum creep strain rate.Thus,there is only creep deformation and no plastic deformation in the bending and straightening process of steel continuous casting.Deformation of slabs depending on creep behavior only comes true.It is helpful for the design of the new casting machine and improvement of old casting machine depending on high temperature creep property.     

辊式矫直过程弯辊量对边浪影响的仿真分析

针对辊式矫直过程建立具有边浪特征的带钢有限元仿真模型,通过对比现场工况实测矫直力与有限元模型计算所得的矫直力,得到二者误差在10%以内,验证了有限元模型的精度。分别采用原始曲率补偿法和塑性变形层增加法确定了4种弯辊量设定方案。采用上述方案对浪高为20 mm的带钢进行矫直,对比矫直后带钢平直度情况,得出按最高浪采用原始曲率补偿法计算得到的弯辊量矫直效果最优。同时随着弯辊量的加大,矫直力也随之增加,为现场边浪矫直过程提供了依据。     

Simplified calculation of the bending torques of steel sheet and the roller reaction in a straightening machine

In the straightening of steel sheet, it is necessary to calculate the optimal reduction of the steel blank by the working rollers of the straightening machine so that the sheet produced has the minimum residual stress and curvature. In the simulation of sheet straightening in multiroller machines, the curvature and bending torques of the steel sheet at contact points with the working rollers are first calculated and then the straightening forces are determined. In straightening steel sheet, it is important to calculate the forces in the multiroller straightening machine. Such calculations are based on determination of the reaction of the roller bearings and the forces at the upper and lower working-roller cassettes in straightening. With insufficient bending torque, it is impossible to eliminate harmful residual stress and surface defects in the sheet. Extreme roller torques and forces at the roller cassettes often lead to defects of the sheet, fracture of the working and supporting rollers, and failure of the straightening machine. In the present work, an approximate method is proposed for calculation of the optimal cold-straightening parameters of the steel sheet in a multiroller machine. The calculations permit determination of the curvature of the neutral plane in the sheet on straightening, the residual curvature of the sheet after straightening, the bending torque and the reaction of the working-roller bearings, the residual stress in the sheet, the penetration of the plastic deformation into the depth of the steel sheet, and the relative deformation of the longitudinal surface fibers of the sheet on straightening as a function of the radius of the working rollers, the distance between the rollers of the straightening machine, the reduction of the sheet by the upper rollers, the sheet thickness, and its properties (Young’s modulus, yield point, and strengthening modulus). The results may be widely used at manufacturing and metallurgical plants.     

薄壁管矫直过程中性层位移解析

为进一步揭示薄壁金属管材矫直变形机理,基于薄壁构件弹塑性理论及相关假设建立了薄壁管材矫直变形区的应力应变关系模型,基于此完成了矫直过程应变中性层位移模型的解析,通过对模型变化趋势的分析,证明了位移量随相对反弯半径的增大而减小,并给出了不同金属材料位移模型的应用方法,为深入研究薄壁管材的矫直机理和变形过程提供了理论依据。     

棒材二辊矫直机辊型曲线与矫直精度分析

 为了改进二辊棒材矫直机矫直质量,从弹塑性弯曲理论出发,用Matlab求解双曲线和三曲率二辊矫直机辊型曲线,并绘制相应的辊型图。分别计算了双曲线和三曲率辊型曲线的矫直精度,结果表明三曲率辊型曲线矫直精度高于双曲线辊型曲线的矫直精度。综合考虑棒材的弹塑性变形,基于有限元MARC平台,根据具体实例建立了棒材二辊矫直弹塑性模型,并对其矫直过程进行模拟,分析了棒材在矫直过程中各种参量的变化。对比分析不同辊型下棒材矫直效果,三曲率辊型矫直效果要好于双曲线辊型,可为实际生产提供理论指导。     

Principle of Multi-roller Straightening Process and Quantitative Resolutions of Straightening Strategies

The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening process and clear- ly reveal the principle of the multi-roller straightening process. The principle can be described as~ the initial curva- tures are reduced by several times anti-bendingl meanwhile the initial curvature differences are diminished and the residual curvatures are unified~ finally, the member after curvature unification is straightened by the last anti-ben- ding. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curva- tures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.     

连铸坯弯曲矫直时的变形行为

 连铸机的弯曲矫直曲线的确定属于铸机辊列设计的重要内容之一。通过对不同的弯曲矫直方法的比较分析,提出了关于铸坯弯曲矫直原理的一些新的看法,指出确定铸机的弯曲矫直曲线时应综合考虑铸坯的变形速率、剪切力和矫直反力3个因素。同时对目前铸机设计中广泛使用的连续矫直曲线进行了分析,理论推理并结合实例验证了该曲线的正确性,并对该曲线下铸坯的变形规律和力学特征进行了分析和讨论,从理论上说明了该曲线的合理性。