A review on tailored blanks—Production,applications and evaluation

Tailored Blanks is the collective for semi-finished sheet products which are characterised by a local variation of the sheet thickness, sheet material, coating or material properties. With these adaptions the tailored blanks are optimised for a subsequent forming process or the final application. In principle four different approaches can be distinguished to realise tailored blanks: joining materials with different grade, thickness or coating by a welding process (tailor welded blanks), locally reinforcing the blank by adding a second blank (Patchwork blanks), creating a continuous variation of the sheet thickness via a rolling process (tailor rolled blanks) and adapting the material properties by a local heat treatment (tailor heat treated blanks). The major advantage of products made from tailored blanks in comparison to conventional products is a weight reduction. This paper covers the state of the art in scientific research concerning tailored blanks. The review presents the potentials of the technology and chances for further scientific investigations.     

ST14钢激光拼焊板焊缝组织及成形性能分析

对1.5mm和0.8mm两种规格的ST14钢等厚激光拼焊板焊缝部位进行杯突试验,比较焊缝与母材杯突值;再对由这两种规格组合拼焊的不等厚激光拼焊板进行单向拉伸试验,检验拼焊板经拉伸后的断裂部位;分析焊缝区组织及其硬度变化,研究激光焊接参数变化对ST14钢拼焊板成形性能的影响.结果表明,焊缝深冲性能低于母材,焊缝杯突值受焊接速度影响,随焊接速度增加而增加;激光焊缝抗拉强度高于母材;对于1.5 mm拼焊板,提高焊接速度,加快焊缝冷却,有利于生成细小的针状铁素体,可提高激光拼焊板的成形性能;而0.8 mm板焊缝生成晶粒细小的粒状贝氏体组织,可使焊缝区材料成形性能接近母材;焊缝及其热影响区的硬度高于母材硬度.     

镁合金拼焊板冲压成形过程数值模拟

借助MSC-Marc模拟软件,采用大变形弹塑性有限元法,建立了镁合金拼焊板筒形件冲压成形有限元模型,对相同厚度、不同成分的镁合金拼焊板冲压成形过程进行了数值模拟。得到了筒形件底部及侧壁法兰处焊缝移动规律;分析了压边力及板料初始温度对焊缝移动情况的影响。对于拼焊板冲压成形的研究具有一定意义。     

A microscopic study of the effects of particle size and composition of atmospheric aerosols on the corrosion of mild steel

A novel approach to measure the corrosion effects of aerosols as a function of their aerodynamic size and chemical composition was used to study the effects of atmospheric aerosols on mild steel at a rural coastal site. The technique uses collocated micro-orifice uniform deposition impactor samplers to deposit ambient atmospheric particles on exposure steel coupons and collect aerosol samples for ionic analyses. Rusts were found on the coupons with aerosols but none on the blank coupons even the blanks were incubated at the same conditions. FTIR analysis shows that the composition of rusts changes gradually with the aerosol particle size.     

激光拼焊门外板拉延成形有限元分析

门板是拼焊板在汽车车身上应用的典型零件之一,本文通过数值模拟研究了不同厚度组合及不同材质拼焊板应力、应变和厚度分布等成形结果的影响.研究结果表明,对不同材质和不同厚度的拼焊板,零件的变形取决于两种材料的强度比和厚度比.     

半滑动式液压胀形汽车桥壳的模具设计及成形

提出了半滑动式液压胀形模具的设计原则,并针对某小型汽车桥壳设计了终胀形模具和两种结构方案的预胀形模具;使用ANSYS软件数值模拟桥壳的液压胀形成形过程,重点分析模具型腔对成形的影响,比较了两种预胀形模具对成形管坯的壁厚变化及成形性的影响;在普通液压机上试制出汽车桥壳样件。     

管壁异形渐进翻孔及其变形特征分析

结合数值模拟和物理实验,实现了圆管、方管管坯上不同孔形、不同翻孔方向的管壁异形渐进翻孔成形.通过模拟验证了圆管管壁异形渐进翻孔成形过程的受力情况与方管翻孔时不同,各个部分的成形力大小大致相同;在方管中有:圆弧端成形力>过渡端成形力>直壁端成形力的关系.研究发现,破裂、金属堆积、划痕严重、底端凸起等是渐进翻孔可能出现的缺...     

变截面板方盒形件成形参数的正交试验分析

以影响变截面板方盒形件成形的板料厚度比、板料形状与尺寸、压边力及凹模圆角半径等为参数,以成形深度和过渡区移动量为考核目标,通过数值模拟和利用正交优化方法对比分析不同方案下成形深度、过渡区移动量,调整危险点应变路径,确定最优方案,可提高变截面板成形性能。     

A study on laser bending of tailor machined blanks with various irradiating schemes

In this work, laser bending of tailor machined blanks has been investigated, both experimentally and numerically. Due to thickness variations in tailor machined blanks, laser bending of these blanks is more complicated than monolithic plates. In these blanks, bending angles and curvatures are different in various sections. Also, multi-curvature bending phenomenon in other words, non-uniform bending in the transverse direction can appear more seriously in tailor machined blanks than monolithic plates. In this paper, a study on laser bending of tailor machined blanks with various irradiating schemes has been performed. For this purpose, three different irradiating schemes i.e. variable speed method (VSM), variable power method (VPM) and variable beam diameter method (VBDM) have been considered. In each method, relevant variable parameter was changed in various sections of tailor machined blank. The results show that using these irradiating methods can reduce differences in bending angles and curvatures of two sections in tailor machined blanks. However, the results show that for the cases investigated in this paper, VSM is a better irradiating scheme than VPM and VBDM. After VSM, the VPM is a suitable choice. It is also concluded that for investigated conditions, VBDM is not a suitable method for laser bending of tailor machined blanks in comparison with VPM and VSM. In other words the results of bending angles and curvature uniformities are not satisfactory with VBDM.     

乌克兰的钢管生产技术近况

笔者一行 7人重点考察了乌克兰用离心浇铸空心坯轧制不锈钢无缝钢管的技术。介绍了乌克兰近年来钢管生产的概况,主要钢管企业的装备;乌克兰国家冶金学院在离心浇铸合金钢和高合金钢空心管坯方面的研究成果,几种特殊异型钢管及管件的生产方法。     

拼焊板等离子体弧柔性成形数值模拟

采用等离子体弧作为热源对低碳钢差厚拼焊板进行弯曲成形研究,并利用有限元分析软件ANSYS对差厚拼焊板进行弯曲成形模拟。通过分析匀速恒功率热源、变速恒功率热源及匀速变功率热源扫描差厚拼焊板的温度梯度和应力分布,给出了一种较好的拼焊板热成形方法,最后通过试验对有限元分析结果进行了验证。     

Combined tube and double sheet hydroforming for the manufacturing of complex parts

Modern lightweight construction, especially in the automotive industry, requires more and more complex components, which can be manufactured in one process step using the hydroforming technology. The combination of the tube and double sheet hydroforming is a new forming process, where a tube and two blanks are formed simultaneously in a die cavity, combining the advantages of both hydroforming variants. This paper deals with the fundamental considerations and investigations related to connection between tube and double sheet. The finite element analysis and laboratory trials were used in order to design the shape of the die cavity and to avoid wrinkles, material tearing and the collapse of the tube section during forming. The paper will also illustrate an analytical model for the prediction of the edge shape in the constrained bulging of a rectangular cup together with several technical solutions, which enabled a complete forming of the investigated part. Finally, the definition of a hydroforming material factor based on the analytical model of the hydraulic bulging process enables the right choice of sheets with different material strength and thickness for the hydroforming of hybrid components.     

拼焊板V形自由弯曲成形及回弹过程

采用数值模拟和试验方法,对拼焊板V形自由弯曲及其回弹过程进行分析。采用壳单元,对横、纵向拼焊板基板和焊缝在不同参数条件下V形自由弯曲及回弹过程精确建模,并与试验进行对比分析,得到了拼焊板V形自由弯曲时,焊缝移动及模具参数、材料性能参数、板料厚度比和摩擦等对回弹的影响规律,为进一步开展拼焊板V形自由弯曲回弹控制的研究奠定了基础。     

Experimental and numerical study of machined aluminum tailor-made blanks

In this paper, the effects of the thickness difference and machining on the mechanical behavior of machined aluminum tailor-made blanks are studied from both experimental and numerical viewpoints. A variety of tensile test specimens with different thickness ratios are machined from Clad and bare AA2024-T3 monolithic sheets and are used for the experimental study. Two different machining processes, i.e. milling and grinding, are applied for preparation of the samples. A numerical study is also conducted to understand the effects of the thickness difference on the mechanical behavior of machined tailor-made blanks. FEM simulations are carried out by using a FEM package (ABAQUS). The stress concentration phenomenon, bending caused by the thickness difference, and the effects of the thickness ratio on the stress and strain fields are studied numerically. It is shown that both the machining process and thickness difference have significant impact on the forming behavior and failure mechanism of the specimens. It is also concluded that stress concentration and strain localization are two competing failure mechanisms in the tensile testing of machined tailor-made blanks.     

耐热马氏体不锈钢1Cr5Mo管坯的生产试制

1Cr5Mo耐热马氏体不锈钢管具有良好的抗氧化性、耐腐蚀性和组织稳定性,被广泛应用于石油精炼厂的炉管、热交换器管及管道。通过严格控制钢锭表面质量,延时热送、甩坑缓冷、锻后去氢等工艺措施成功生产出1Cr5Mo管坯。     

不等厚拼焊管轴向压缩变形的数值模拟研究

采用两种焊缝建模方法对拼焊管的轴向变形进行了数值模拟和实验研究,分析了不同建模方法和料厚比对拼焊管轴向变形的影响。研究结果表明,随着料厚比的增加,差厚同材拼焊管和传统等厚管的载荷-位移曲线形貌、折叠铰数量和折叠波长存在差别;焊缝位置和料厚比适当的拼焊管轴向力学性能优于等厚管。正确估算不等厚紧排折叠铰的折叠波长,设计适当的料厚比和焊缝位置,对于差厚同材拼焊型吸能管结构设计具有较为重要的意义。     

基于BP-GA的拼焊板拉深成形工艺优化

基于BP神经网络与遗传算法建立了多目标优化模型,对拼焊板拉深质量评价指标进行详细分析,提出了一种改进的拼焊板拉深成形多目标优化函数。将所建立的BP-GA模型用于某车型中柱拼焊板拉深成形,将有限元分析结果作为训练样本,得到模型最大厚度、最小厚度(拼焊板两侧),以及焊缝移动最大误差3.23%、6.16%、0.47%、2.64%、6.65%。利用遗传算法寻找最佳的工艺参数,实验证明,基于BP-GA的拼焊板拉深成形工艺优化模型,能够对生产实践提供有效指导。     

An extrusion−shear−expanding process for manufacturing AZ31 magnesium alloy tube

A new severe plastic deformation method for manufacturing tubes made of AZ31 magnesium alloy with a large diameter was developed, which is called the TCESE (tube continuous extrusion?shear?expanding) process. The process combines direct extrusion with a two-step shear?expanding process. The influences of expanding ratios, extrusion temperatures on the deformation of finite element meshes, strain evolution and flow velocity of tube blanks during the TCESE process were researched based on numerical simulations by using DEFORM-3D software. Simulation results show that the maximum expanding ratio is 3.0 in the TCESE process. The deformation of finite element meshes of tube blanks is inhomogeneous in the shear?expanding zone, and the equivalent strains increase significantly during the TCESE process of the AZ31 magnesium alloy. A extrusion temperature of 380 °C and expanding ratio of 2.0 were selected as the optimized process parameters from the numerical simulation results. The average grain size of tubes fabricated by the TCESE process is approximately 10 µm. The TCESE process can refine grains of magnesium alloy tubes with the occurrence of dynamic recrystallization. The (0001) basal texture intensities of the magnesium alloy tube blanks decrease due to continuous plastic deformation during the TCESE process. The average hardness of the extruded tubes is approximately HV 75, which is obviously improved.     

差厚拼焊板自由弯曲力的计算

根据弯曲理论,推导出了焊缝方向平行于弯曲线的差厚拼焊板弯曲力的近似计算公式;对质量相同,料厚比不同的差厚拼焊板的自由弯曲进行了计算并同模拟结果进行了对比。所得理论计算模型对研究差厚拼焊板的弯曲回弹及模具设计具有指导意义。     

Drawing of conical cups with friction actuated blank holding

Aluminum and copper blanks were drawn to cups in the shape of a frustum of a cone using the friction actuated blank holding technique. Variations of the total punch force with stroke were measured for several draw ratios. The maximum draw ratios possible with aluminum and copper blanks of thickness 1 mm were determined experimentally. Strains on the cup, including the thinning of the wall of the cup, measured with blanks of two sizes are presented. Other factors affecting the process are discussed.