曲线焊缝激光拼焊板胀形成形性研究

拼焊板成形技术是目前汽车车身轻量化的重要手段之一,焊缝形状及位置是影响拼焊板成形极限的两个重要因素,针对此,该文利用圆球胀形试验,对厚度比、焊缝形状对激光拼焊板极限成形高度的影响进行了研究,并对影响规律进行了分析,从而为拼焊板的设计开发开阔了思路。

工艺参数对双层金属保温容器外壳同步液压胀形成形的影响规律研究

基于表面带有浮雕图案的双层金属保温容器外壳同步液压胀形成形技术特点和Dynaform软件,建立了相应的三维弹塑性有限元模型,采用正交试验法对篮球形双层金属保温容器外壳同步液压胀形成形过程进行了数值模拟;根据正交试验所得到的优化工艺参数,对足球及排球形双层金属保温容器外壳同步液压胀形成形过程进行了模拟研究,获得了同步液压胀形成形时,工艺参数对3种不同浮雕图案的成形质量、应力分布的影响规律,分析了影响外壳表面浮雕图案成形质量及产生成形缺陷的原因。结果表明,影响双层不锈钢真空保温容器外壳表面浮雕图案质量因素的主次顺序为:板料厚度、加载时间、加载压力;不同表面浮雕图案成形所需压力大小与图案复杂程度及纹理方向有关。

冲压加工新技术——第六讲 对翻边与胀形成形极限的预测

1.翻边与胀形的基本特点 翻边是将平板坯料或半成品工序件的某一部分沿一定的曲线翻成竖立边缘的成形方法。圆孔翻边是翻边的基本形式,见图1。在冲头的直接作用下,坯料的内环形（外孔径为d1、内径为d0）部分,逐新变成了竖边的直壁部分,冲头所对这个内环形区为变形区;而冲头侧边已成竖边的部分为传力区;

Inconel 601合金胀形成形的显微结构及其性能

Inconel 601合金是一种既耐腐蚀,又抗高温氧化且具有较好热强性的镍基合金,由于其优良的抗氧化性和耐腐蚀性,因而主要用于加热设备、化学工业、环境污染控制、航空、航天以及动力工业中。胀形工艺相对于传统的制造三通工艺来说,具有生产成本低、生产周期短、成形质量好和材料利用率高等优点。实验采用Inconel 601合金通过胀形成形工艺来生产三通、四通等管件。通过对Inconel 601合金胀形成形以后的变形部位进行微观分析,并与变形前的组织对比,研究其变形过程中显微结构的变化、掌握显微结构与性能之间的关系。

聚氨酯橡胶在胀形成形中的应用

采用聚氨酯橡胶成形不锈钢薄壁件，较好的控制了产品的起邹和开裂，解决了钢模难以克服的尺寸精度和表面质量问题，保证了改产品的工艺设计流程。

不锈钢壳体胀形成形模具的设计

通过在中厚度不锈钢壳体胀形成形中采用聚氨酯橡胶作为工作件，简化了模具结构，保证了产品质量。产品加工部位成形轮廓较小，板料较厚、强度高，经固溶时效处理辅助工序保证了产品加工的可行性。

板材超塑性胀形过程的数值仿真

板料超塑性胀形成形是一种全新的金属成形工艺。用Pam-Stamp 2G板料成形数值模拟软件对一个实际成形件的超塑性胀形过程进行了数值仿真,分析了超塑性胀形成形变形过程中成形件的应力、应变、摩擦和厚度分布,研究了超塑性胀形过程中金属变形规律和工艺参数对成形过程的影响。结果表明,Pam-Stamp 2G板料成形数值模拟软件是超塑性胀形成形工艺应用到实践中的有效分析工具。

水胀成形液压系统分析

利用传统拉深成形方法加工真空杯等圆筒状件时存在很多弊端,而采用液压胀形技术则可克服传统工艺的缺陷。介绍液压胀形系统工作原理及特点和此技术在实际生产中的应用。

钛合金球形管接头成形技术

介绍了钛合金球形管接头的弹性介质胀形技术的基本原理和变形特点 ,并通过试验和有限元数值模拟对钛合金球形管接头的成形过程进行了研究 ,对管件胀形时开裂和影响成形质量的工艺因素进行了分析 。

C、N元素对304不锈钢冷冲压成形性能的影响

304不锈钢具有良好的冷加工成形性,但其成分中各元素含量的不同将导致该材料冷加工成形性能差异很大。通过拉伸试验、杯突试验及拉深成形试验,研究分析了C、N元素对304不锈钢冷轧薄板拉深、胀形等冷冲压成形性能的影响。研究结果显示,C、N元素的增加有利于提高304不锈钢材料的延伸率、屈服强度、抗拉强度及硬度,并在适当的范围内可提高冷冲压胀形成形性能,但对冷冲压拉深成形性能不利;同时C元素对材料延伸率及冷冲压成形性能的影响比N元素显著。

内河船舶上层建筑薄板成形加工的研究

为解决内河船舶上层建筑低碳钢薄板加工制作过程中出现的皱纹、裂口等压筋畸变问题,文章研究了在薄板加工过程中如何选取适当的胀形成形极限,通过采取相关的技术与工艺措施,防止拉深成形主要的成形障碍起皱和开裂的产生,避免压筋畸变,提高薄板加工质量.

宝新深冲产品应用分析

为开发深冲用冷轧不锈钢产品(即DDQ产品),扩大宝钢不锈钢在冷冲压制品市场的占有率,在对奥氏体不锈钢形变理论分析及冷冲压制品市场调研的基础上,对304系列钢种中的304Ni8.5、304Ni9及SUS304Cu按不同工艺进行了试制生产,并将试制产品供不同成形方式制品加工试用。试用结果表明:宝新304Ni8.5、304Ni9及SUS304Cu深冲系列产品具有较好的流动性,较适合于热水器内胆等以拉深成形为主要成形方式的冲压加工,其中304Ni8.5及SUS304Cu的极限深冲比在2.4以上、304Ni9的极限深冲比可达2.9以上,而水槽等以胀形为主要成形方式的冲压制品,使用宝新一般冲压类产品更为适合。

Viscous warm pressure bulging process of AZ31B magnesium alloy with different ellipticity dies

Based on the bulging principle of different ellipticity dies, the methyl vinyl silicone rubber with excellent thermal stability and heat transfer performance was chosen as the viscous medium. The finite element analysis and experiments of viscous warm pressure bulging （VWPB） of AZ31B magnesium alloy were conducted to analyze the influence of different ellipticity dies on the formability of AZ31B magnesium alloy. At the same time, based on the grid strain rule, the forming limit diagram （FLD） of VWPB of AZ31B magnesium alloy was obtained through measuring the strain of bulging specimens. The results showed that at the temperature range of viscous medium thermal stability, the viscous medium can fit the geometry variation of sheet and generate non-uniform pressure field, and as the die ellipticity increases, the difference value of non-uniform pressure reduces. Meanwhile, according to the FLD, the relationship between part complexity and ultimate deformation was investigated.

Analysis of bulging process of aluminum alloy by overlapping sheet metal and its formability

The influences of strength coefficient K, work hardening exponent n and thickness t of the overlapping sheet on bulging process are analyzed based on hardening material model. Also, bulging experiments are carried out by taking the aluminum alloy LF21 as formed sheet metal, and selecting overlapping sheet with different thicknesses and material properties, by which accuracy of the above analysis result is verified in the aspects of geometric shape, thickness distribution and limit bulging height. The results show that higher strength coefficient K, larger work hardening exponent n and proper thickness of the overlapping sheet are helpful to improve the formability and forming uniformity of formed sheet metal.

Formability determination of AZ31B tube for IHPF process at elevated temperature

Ring hoop tension test and tube bulging test were carried out at elevated temperatures up to 480 ℃to evaluate the formability of AZ31B extruded tube for internal high pressure forming （IHPF） process. The total elongation along hoop direction and the maximum expansion ratio （MER） of the tube were obtained. The fracture surface after bursting was also analyzed. The results show that the total elongation along hoop direction and the MER value have a similar changing tendency as the testing temperature increases, which is quite different from the total elongation along axial direction. Both the total elongation along hoop direction and the MER value increase to a peak value at about 160 ℃. After that, they begin to decrease quickly until a certain rebounding temperature is reached. From the rebounding temperature, they begin to increase rapidly again. Burnt structure appears on the fracture surface when tested at temperatures higher than 420 ℃. Therefore, the forming temperature of the tested tube should be lower than 420 ℃, even though bigger formability can be achieved at higher temperature.

Friction coefficient in rubber forming process of Ti-15-3 alloy

The forming limit diagram of Ti-15-3 alloy sheet was constituted at room temperature. The effects of different punch and rubber hardness on the limit principal strain distributions were investigated experimentally. Finite element analysis models of the samples with dimensions of 180 mm×180 mm were established to analyze the friction coefficients of different interfaces. Effects of various friction coefficients on the strain distributions were studied in detail. Finally, the friction coefficients in the cold forming were determined by contrasting the strain results between the experimental data and the simulated ones.

钒钛微合金化对建筑用钢成形性能的影响

在Q235建筑用钢中复合添加不同含量的合金元素钒和钛,并进行了准静态拉伸试验、杯突试验、扩孔试验以及显微组织分析。结果表明:复合添加适量的合金元素钒和钛,可以明显改善合金内部组织、提高合金拉伸性能、胀形成形性能和冲压成形性能。合金元素含量过低或过高,均不利于钢板试样获得理想的内部组织和成形性能。与不添加合金元素的Q235建筑用钢相比,当复合添加0.15%V和0.1%Ti时钢的抗拉强度增大了33 MPa、屈服强度增大了35 MPa、断后伸长率增大了2.3%、应变硬化指数增大了0.078、杯突值增大了2.2、扩孔率增大了26.1%。

热轧AZ31镁合金薄板室温成形性能

针对AZ31镁合金板材室温冲压成形较差的特点,采用在不同轧制温度下获得的镁合金板材对其进行拉伸、埃里克森和锥杯试验,并通过光学电镜和X射线衍射仪对其显微组织、织构和成形性能等进行研究。结果表明,AZ31镁合金板材的综合力学性能不仅与晶粒尺寸有关,还与晶粒取向有关;基面织构的减弱可明显提高板材的胀形性能,在基面织构强度相似的强况下,晶粒大小对板材的成形性能起决定性影响。

Chemo-damage modeling and cracking analysis of AAR-affected concrete dams

A chemo-damage model for cracking analysis of concrete dams affected by alkali-aggregate reaction (AAR) is proposed, which combines the plastic-damage model for concrete with the AAR kinetics law. The chemo-damage model is first verified by a stress-free AAR expansion test. The expansion deformation obtained from the simulation is in good agreement with the measurement, demonstrating that the proposed model has a sufficient accuracy to predict the expansion of AAR-affected concrete. Subsequently, the expansion deformation and cracking process of the AAR-affected Fontana gravity dam is analyzed. It shows that permanent displacements in the upstream direction and the vertical direction are gradually increased during the long-term operation period, and that their maximal values reach 1.6 and 3.6 cm, respectively. A crack is observed on the wall in the foundation drainage gallery, and extends towards the downstream face of the dam. With the further development of AAR, another crack forms on the downstream face, and then intersects with the gallery crack to penetrate the downstream side profile of the dam. The third crack occurs in the upstream side wall of the gallery and propagates a short distance towards the upstream face of the dam. The simulated cracking pattern in the dam due to AAR is similar to the in situ observation.