方矩形管连续辊弯成型金属的流动规律

 为了研究方矩形管辊弯成型时金属的流动规律,结合某厂实际生产工艺,建立了方矩形管辊弯成型的三维弹塑性非线性有限元模型,基于该模型得到的仿真结果与现场轧制结果基本一致,通过对仿真结果的分析分别得到了方矩形管辊弯成型时长边、角部、短边和纵向上的内、中、外层的金属流动规律。研究结果表明：在厚度方向稳定段处,从外层到内层的金属流动规律是不一致的,长边处的不一致性要比短边处明显;在纵向上前、中、后段处,外层上的金属流动规律存在较大的差异,前段与后段的外、内层上的金属流动规律是相反的。分析结果为预测最终成型尺寸精度与辊弯成形工艺参数的制定提供了理论依据。     

H型钢万能轧制过程中金属流动的有限元分析

采用显示动力学有限元软件LS-DYNA,结合生产实际,对H型钢万能轧制进行了仿真计算.在仿真结果的基础上,根据轧制平面内的节点位移矢量分布情况,分析了轧件断面内金属流动规律.仿真结果显示轧件断面内在立辊和平辊压下方向上存在\     

全浮动芯棒连轧管机的竹节形成机理

利用宝钢竹节攻关组的实测数据，对咬、抛钢阶段的前、后竹节形成过程作全面具体的讨论，阐述了竹节的形成机理及造成前、后竹节显明形态差异之根由。     

内螺纹铜管成型的工艺设计

内螺纹铜管成型的工艺比较复杂,共涉及到17个主要的工艺参数。文章介绍了内螺纹成型工艺的设计方法,利用该方法,使复杂的工艺设计变得简单直观,对关键参数的优化使工艺更合理。     

内螺纹铜管成形工艺研究

阐述了内螺纹铜管成形的两种生产工艺：拉拔旋压成形法和铜带滚压成形焊接法。对两种工艺的优劣进行了研究分析，并指出了应用前景。     

半固态金属制备原理与应用

综述了半固态金属加工的特点以及主要制备方法。从金属凝固原理出发，结合实验结果论述了半固态金属组织的几种生成机制以及这些生成机制在工程实施中将遇到的困难。     

钢中白点及其形成机理

白点是热轧钢坯和大型锻件中比较常见的低倍缺陷。白点的破坏性极大，作为钢中的显微裂纹，可能成为疲劳裂纹源，降低钢的强度。为此，研究了钢中白点的形成机理，找出消除白点的根本措施。     

Mixed Finite Element for Three-Dimensional Nonlinear Dynamic Analysis of Rectangular Concrete-Filled Steel Tube Beam-Columns

A beam finite-element formulation following Euler-Bernoulli beam theory is presented for geometrically and materially nonlinear analysis of rectangular concrete-filled steel tube (RCFT) beam-columns. The formulation is geared for conducting transient dynamic analysis of composite steel/concrete frame structures. The element stiffness and internal forces were derived through adopting a mixed finite-element approach based on the Hellinger-Reissner variational principle. The load transfer between the steel and concrete constitutive materials was provided through steel and concrete interface via friction and interlocking. Six extra translational degrees-of-freedom (DOFs) were added to the conventional 12 DOF beam element to quantify the differential displacement between the two media. The formulation was verified for a range of geometrically nonlinear test problems and geometrically and materially nonlinear RCFT experimental test specimens from the literature. Strong correlation and convergence characteristics were achieved compared to the published results.     

工业纯锆三通液压胀形优化新工艺

通过对工业纯锆三通一次液压胀形后的成品率、壁厚分布情况和残留变形应力进行分析,提出工业纯锆三通液压胀形优化新工艺,即两次成形,两次热处理,并将三通下模内芯棒端头改为内半球形或内椭圆形。采用新工艺得到的工业纯锆三通内外表面光滑,外形美观,经100%PT探伤检测,符合JB/T 4730.5—2005Ⅰ级标准,外形尺寸均满足GB/T 27684—2011要求,合格率提高到90%以上,能够满足石油化工等领域中耐腐蚀性能要求较高的工况条件。     

Effect of Various Field Shapers on Magnetic Pressure in Electromagnetic Inward Tube Forming

In this paper,the influence of various field shapers and their shapes on the distribution of the magnetic flux densities and applied forces on the work-piece in the electromagnetic inward tube forming are studied numerically using the FEA software MAXWELL.First the model was verified with experimental results and thereafter four kinds of field shapers(conical,cylindrical,concave and convex)were considered.Effects of their geometries,such as air gap between field shaper and tube work-piece,height of the step in single and multiple stepped field shaper on magnetic flux densities and magnetic pressures were studied.The results of this research can be applied to design field shaper,tube compression technology,and improve the efficiency of the coil.It is seen that magnetic force decreases if height of step in convex field shaper increases but effective forming region enlarges.Decreasing air gap has also a positive influence on magnetic field increase.Though the object of this research is limited to field shaper for inward tube forming,the results can also be applied to the field shaper for tube bulging.     

铜铝双金属管连续衬拉复合成形的研究

采用连续衬拉复合工艺线路对铜铝双金属管成形规律进行研究 ,全面探讨了变形量和后序的热处理工艺对界面强度的影响 ,以及在成形过程中组元金属的变形规律。界面强度受变形量及热处理工艺影响较大 ,且组元金属存在不均匀变形规律 ,这为合理制订铜铝双金属管拉伸复合工艺提供了依据。     

Prediction of Stress and Strain Based Forming Limit Diagram During Tube Hydroforming Process

Hydroforming process is most widely used in automotive industries. The current work involves the formability evaluation of DQ Steel and Al 5182 tubular blanks using the bulge test simulation done on PAM-STAMP 2G solver. The dependence of stress based forming limit diagrams are also evaluated in complex loading paths in case of hydro-forming as they are independent of strain paths.