中频加热推制弯管的成形过程及成形机理初探

本文提出了一种研究弯管成形过程的单元模型及分析方法，并用该方法对中频热推弯管成形过程和成形机理进行了研究，为中频热推弯管工艺参数的选定和这一新工艺的进一步理论研究奠定了基础。     

中频热推弯管工艺参数自动控制

提出了中频热推弯管工艺加热温度与推制速度两个工艺参数的自动控制方案。该方案采用两个单片机协同完成管坯推制成形过程中的感应加热温度检测和中频电源整流逆变控制 ;采用一个单片机完成热推弯管机液压系统推制速度控制。因此 ,使这两个工艺参数在给定的优化域内自动实现合理匹配 ,工艺过程实现自动控制     

等强度弯管成形工艺及工艺参数CAD系统

介绍了基于等壁厚弯管理论的中频热推弯管新工艺及新开发的中频热推弯管工艺参数CAD系统。该系统在实际生产中产生了明显的经济和社会效益。     

中频热推弯管工艺参数自动控制

提出了中频热推弯管工艺加热温度与推制速度两个工艺参数的自动控制方案。该方案采用两个单片机协同完成管坯推制成形过程中的感应加热温度检测和中频电源整流逆变控制；采用一个单片机完成热推弯管机液压系统推制速度控制。因此，使这两个工艺参数在给定的优化域内自动实现合理匹配，工艺过程实现自动控制。     

等强度弯管成形工艺及工艺参数CAD系统

介绍了基于等壁厚弯管理论的中频热推弯管新工艺及新开发的中频热推弯管工艺参数CAD系统。该系统在实际生产中产生了明显的经济和社会效益。     

中频热推弯管工艺参数优化设计与实验研究──加热温度与推制速度的试验优化

采用试验优化方法，对中频热推弯管工艺参数加热温度和推制速度，进行了优化设计和实验研究，给出了优化结果和可行性分析。     

精密弯管工艺

介绍国内外精密弯管技术的发展及在研制新产品中遇到制做精密弯管制品的工艺论证和工艺参数选择,从而改善了精密弯管工艺,提高了弯管制品质量。     

直缝焊管(UOE)热煨弯管最佳工艺参数的研究

通过弯制工艺试验、力学性能试验、金相及硬度试验,对直缝焊管(UOE)热煨弯管弯制工艺进行了分析研究,并且提出了最佳的工艺参数范围。现场实际验证表明,采用本文提出的最佳工艺参数制造的热煨弯管,符合Q/SYXQ16—2002《西气东输工程用感应加热弯管技术条件》等技术标准的质量要求,从而保证了弯管的整体质量。     

Φ1422 X80高钢级大口径长输管道用热煨弯管制造工艺

通过对φ1 422 mm、X80级弯管母管的成分设计、管体及焊缝的力学性能以及热加工性能的研究,对比试制多个工艺参数,优化必选合理的推制和热处理工艺参数,实现了弯管管体、焊缝力学性能和金相组织等性能匹配,试制出满足CDP-S-OGP-PL-016-2014-3《油气管道工程感应加热弯管通用技术条件》要求的φ1 422 mm×25.7 mm、X80大口径长输管道用热煨弯管样品,并通过了国家型式试验认证。     

中频热推弯管工艺参数优化设计与实验研究—加热温度与推制速率的试验优化

采用试验优化方法，对中频热扒弯管工艺参数加热温度和推制速度，进行了优化设计和实验研究，给出了优化结果和可行性分析。     

Effects of process parameters on numerical control bending process for large diameter thin-walled aluminum alloy tubes

Numerical control(NC) bending experiments with different process parameters were carried out for 5052O aluminum alloy tubes with outer diameter of 70 mm, wall thickness of 1.5 mm, and centerline bending radius of 105 mm. And the effects of process parameters on tube wall thinning and cross section distortion were investigated. Meanwhile, acceptable bending of the 5052O aluminum tubes was accomplished based on the above experiments. The results show that the effects of process parameters on bending process for large diameter thin-walled aluminum alloy tubes are similar to those for small diameter thin-walled tubes, but the forming quality of the large diameter thin-walled aluminum alloy tubes is much more sensitive to the process parameters and thus it is more difficult to form.     

管和板的热应力弯曲工艺

热应力弯曲是一种特殊的成形方法 ,具有无外力、无模具、便于现场操作等不可替代的优点。本文对管和板的热应力弯曲的工艺方案、变形规律及工艺参数的影响进行了试验研究 ,据此制定了具体的弯管和圆柱面的成形工艺 ,并达到了预期的目的。     

非轴对称管件缩径旋压的数值模拟与参数优化的研究

针对具有两个回转轴线的三维非轴对称薄壁空心管件,通过数值模拟与正交试验相结合的方法,研究主要成形工艺参数(偏移量、倾斜角、名义压下量、进给比、旋轮圆角半径、旋轮直径)对成形尺寸精度(壁厚偏差、椭圆度和直线度)的影响显著性的主次顺序;根据影响规律给出了几组较好的工艺参数组合,然后利用灰色决策理论进行了效果测度,分别得到了偏心类和倾斜类管件缩径旋压成形的最优工艺参数组合。     

复合材料齿轮弯曲强度仿真与试验研究

三维编织复合材料的性能与编织参数密切相关,为了研究碳纤维编织复合材料齿轮的弯曲性能及其与编织参数的关系,提出复合材料及齿轮弯曲性能预测模型。基于代表性体积单胞法和均质化思想建立复合材料的细观、宏观双尺度模型,采用体积平均法、借助有限元手段预测复合材料及齿轮的弯曲性能。并且,采用四步法编织及模压成型方法制备两对碳纤维编织复合材料齿轮,通过试验获得特定编织参数下复合材料及齿轮的弯曲性能。预测结果与试验结果吻合良好,验证了预测模型的准确性。最后,进行了多组编织参数下复合材料及齿轮弯曲性能的预测,得到了编织角和纤维体积分数对复合材料及齿轮弯曲性能的影响规律,并给出了使复合材料齿轮弯曲性能最佳的编织参数。     

钢管六角打包成型机构的设计

通过分析无缝钢管六角形堆放的原理， 提出了钢管六角形打包的简易机构设计方案。生产实践表明， 该成型机构设计合理， 使用方便； 采用该成型机构打出的钢管六角包， 在运输过程中散捆、压弯的比率大大降低。     

中频感应加热纯钛弯管成形过程中的有限元模拟

在MSC／Autoforge有限元模拟软件和弹塑性有限元理论的基础上，建立纯钛弯管成形过程中的计算机模拟系统。采用中频感应加热方法，通过对模具设计参数和推制速度的优化，获得环形管成形最佳的参数为；a=1．0～1．1、V=3．5～4．0mm／s。模拟和实际结果表明，采用上述参数可获得壁厚均匀，等强度，轻重量的薄壁钛环形管。     

Prediction of spring-back and side-wall curl in 2-D draw bending

Accurate prediction of spring-back is essential for the design of tools used in automotive sheet-stamping operations. The 2-D draw bending operation presents a complex form of spring-back occurring in sheet-metal forming since the sheet undergoes stretching, bending and unbending deformations. These three sets of deformation can create complex stress-strain states in the sheet which result in the formation of side-wall curls after the sheet is allowed to unload. Accurate prediction of the side-wall curl requires using finite-element shell models which can account for curvature and stress variation through the thickness caused by bending and unbending of sheet. Since such models are generally computationally intense, an alternative and efficient method of predicting side-wall curls is desirable. This paper describes a novel and robust method for predicting spring-back and side-wall curls in 2-D draw bending operations, using moment-curvature relationships derived for sheets undergoing plane-strain stretching, bending and unbending deformations. This model makes use of the membrane finite-element solution to calculate spring-back. The accuracy of the model is verified by comparison with finite element (ABAQUS) and experimental results.     

钢管热镀锌机组中螺旋的设计缺陷分析

分析了引进的钢管热镀锌机组中螺旋的原始设计，从理论上证明其设计存在的缺陷。针对各缺陷提出了改进措施，从而在实际浸渍中避免了钢管发生弯曲现象，提高了镀管的质量、产量及合格品率．     

Numerical and experimental study on in-plane bending of microchannel aluminum flat tube

Microchannel aluminum flat tubes have attracted more and more attention in recent years, especially in ACR (air conditioning and refrigeration) industry. Rotary-draw bending is a versatile and precise method in forming of tubes. Compared with traditional out-of-plane bending method, in-plane bending can cause different forming defects. During the process, wall thinning, sectional distortion, wrinkling, and channel shape degradation are the main defects that affect tube quality in industrial applications. In this paper, an experimental apparatus for flat tube in-plane bending is manufactured, and experiments are performed to examine the forming quality of tubes. Considering the characteristics of the bending process, based on the LS-DYNA software environment, a 3D elastic–plastic finite element model is established and validated by experiment. Using the validated FE model, the forming quality of microchannel flat tube bending process is evaluated quantitively. Furthermore, the influence mechanism of process parameters, such as bending radius, tool–tube clearance, and channel diameter, has been revealed. The results indicate that the degradation of the tube channels is relatively small under common process conditions; bending radius is the main factor which influences the forming quality of the flat tube; the tool–tube clearance mainly affects the wrinkling of the flat tubes; channel diameter has little effect on the formability of tube.