Optimization design of resistance spot welding parameters of magnesium alloy

By means of the quadratic regression combination design process, the regression equations of nugget diameter and tensile shear load of spot welded joint were established. Effects of welding parameters on the nugget diameter and the tensile shear load were investigated. The results show that effect of welding current on nugget diameter is the most evident. And higher welding current will result in bigger nugget diameter. Besides, interaction effect of electrode force and welding current on tensile shear load is the most evident compared with others. The optimum welding parameters corresponding to the maximum of tensile shear load have been obtained by programming using Matlab software, which is 4, 7 kN electrode force, 28 kA welding current and 4 cycle welding time. Under the condition of the optimum welding parameters, the joint having no visible defects can be obtained, nugget diameter and tensile shear load being 6. 8 mm and 3 256 N, respectively.

Subsection method of fatigue design for welded joints treated by ultrasonic peening

Concerning the notable difference between the S-N curve slope of welded joints treated by ultrasonic peening treatment （UPT） and that of as-welded joints, the subsection method is put forward for fatigue design of welded joints treated by UPT, using the design method of nominal S-N curves. Results show that, in medium life zone, strength grade of the fatigue design curves for UPT welded joints is two grades higher than that for as-welded joints. Furthermore, in medium life zone, strength grade of the fatigue design curves for UPT welded joints is three grades lower than that in long life zone. Conclusion of the comparison is that as for different joint types in different life zones, fatigue design should be processed according to different S-N curves respectively.

Design strategy of intelligent CAD for welding positioner scheme design

Traditional CAD technique does not support the design processes such as function definition, conceptual design and preliminary design, which are most creative and play significant roles on the design quality. Because scheme design has close relationship with product structure, performance and technology cost, it is important for applying the intelligent CAD of scheme design to improve the quality and competitive level of the product. The definition and function of welding positioner are discussed in this paper. The new definition of welding positioner extends the research scope of welding positioner to welding fixture and welding positioning motion mechanism. The design process of welding fixture and positioning motion system is described, and the cased based and knowledge based design strategy of welding positioner scheme design intelligent CAD is then put forward, which lays foundation for developing proto type system of welding positioner scheme design.

COMPUTER-AIDED DESIGN OF ADAPTIVE PULSED ARC WELDING OF ROOT WELDS BY MELTING ELECTRODE

The purpose of computer-aided design of new adaptive pulsed arc technologies of welding is: to de- sign optimum algorithms of pulsed control over main energy parameters of welding.It permits:to in- crease welding productivity, to stabilize the welding regime, to control weld formation,taking into ac- count its spatial position, to proveal specie strength of the welded and coatings. Computer- aided design reduces the time of development of new pulsed arc technology:provides the optimization of technological referes according to the operating conditions of welded joints,the prediction of the ser- vice life of the welds.The developed methodology of computer-aided design of advanced technologies, models, original software, adaptive algorithms of pulsed control, and spend equipment permits to regulate penetration,the weld shape, the sizes of heat - affected zone; to predict sired properties and quality of welded joints.

Design method for transistor-inverted welding power supplies

From the viewpoint of reliability and practicability, a general design method and the related considerationsfor transistor- inverted welding power supplies are proposed in this paper. The detail contents are composed of the choice ofinverters, the choice and protection of transistors, the determination of inverting frequency, the design of transformers,and the choice of output rectifiers and rectifying diodes. Besides, a concrete design example of the transistor-invertedpower supply for plasma arc cutting is introduced.

Nonlinear Finite Element Analysis and Optimum Design of Spot-Welded Joints and Weld-Bonded Joints

Resistance spot welding and hybrid weld bonding have wide applications in the body work construction within the automobile industry. The integrity of the spot welds and applied adhesives determines the body assembly rigidity and dynamic performance. Incorporating contact nonlinearity and geometric nonlinearity, finite element analysis (FEA) have been carried out to investigate the structural stiffness and strength of both spot-welded and weld-bonded assemblies. Topology optimization has been performed to reveal the distributions of material effectiveness in the overlap regions and suggest a feasible method for removing underutilized material for weight reduction. Design optimization has been conducted with an aim to reduce the maximum von Mises stress in the assembly to minimum by choosing optimum values for a set of design variables, including the weld spacing, weld diameter and overlap width.

Prediction of Weld Bead Geometry in Plasma Arc Welding using Factorial Design Approach

The effect of various process parameters like welding current, torch height, welding speed and plasma gas flow rate on front melting width, back melting width and weld reinforcement of plasma arc welding on aluminum alloy is investigated by using factorial design approach. Variable polarity plasma arc welding is used for welding aluminum alloy. Trail experiments are conducted and the limits of the input process parameters are decided. Two levels and four input process parameters are chosen and experiments are conducted as per typical design matrix considering full factorial design. Total sixteen experiments are conducted and output responses are measured. The coefficients are calculated by using regression analysis and the mathematical models are constructed. By using the mathematical models the main and interaction effect of various process parameters on weld quality is studied.

Optimum design of welding transformer

Welding transformer is widely used in industry manufacturing, depleting a large portion of electricity energy.Based on modern computer technology and mathematical programming, optimum design of electro-magnetic devices leads to highly efficient use of energy and materials. Are welding transformer is optimized here. A mathematical model,considering both productive cost and operating losses, which is called or Economical-through-Life transformer, is established. Mixed penalty function method, mixed dispersing variable method and improved orthogonal method have been applied to carry out the optimization calculations. Result shows that the power factor is quite important in an Economi-cal-through-Life transformer, and that some principles must be followed in the design work. Also discussed are the advantages and disadvantages of the three methods. In the end, the prospect of optimum design of welding transformer is forecast.

Case-based intelligent computer aided design system of welding machinery

The procedure during complex system plan design of welding position-locating machine is studied in this paper. The main difficulties in designing welding position-locating machine utilizing computer are discussed as well. A method of case-based intelligent CAD system for welding position-locating machine ( WMICAD) is put forward through wide research on design methodology. Object-oriented programming method is also applied to Ms system. The basic idea and realizing method are described.

基于Design-Expert V7设计的不锈钢激光非熔透搭接焊工艺优化研究

在保证焊接接头的力学性能的前提下,采用Design-Expert V7软件对厚度为0.8 mm/1.5 mm的SUS301L奥氏体不锈钢激光搭接焊接试验进行设计,并通过优化焊接参数来减少焊缝背面微凸变形。为了获得最佳的激光焊接工艺参数,建立一套与每个焊缝特征相关的焊接参数的数学模型。并通过验证试验检验所建立的数学模型的准确性,其误差范围小于5%,可以被用于后续的优化分析。根据优化方案得到最佳的焊接条件是激光功率、焊接速度、激光入射角度和离焦量分别为3.50～3.79 kW、7.40～8.00 m/min、65°和0 mm。同时,通过试验研究和优化分析得出,离焦量只对最优区域的偏移有影响,对最优区域的宽度影响不大,而激光入射角度对最优区域的偏移和宽度均有较大影响。

基于Cognex Designer的对接焊和堆焊焊缝成形尺寸测量方法研究

通过对焊缝尺寸测量方法的分析,针对Q345E钢板对接焊和304不锈钢平板堆焊两种焊缝检测要求,以康耐视DS1100系列3D位移传感器作为图像采集设备,通过VEXTA PK569-NA步进电机和KH-01型步进电机控制器搭建滚轴丝杠直线匀速位移平台,采用宜科EB50B8编码器进行速度反馈,并在基于.NET的Cognex Designer2.5视觉工具软件上完成图像处理及尺寸测量。视觉传感器DS1100集成了2D CMOS传感器和线激光发射器,根据激光三角法原理采集图像,并通过以太网连到计算机,将采集的图像传送到计算机Designer软件上。在Designer中进行图像处理系统的搭建、相机参数的设定以及运动平台参数的设置,再借助移动平台扫描运行,获取焊缝成形图像,最后通过计算工具对图像横截面关键点进行标定和测量,得到焊缝尺寸信息。经验证,该系统的检测精度达到检测要求,检测效率大大提高。

采用Process Designer的白车身焊装生产线工艺规划研究

白车身焊装生产线工艺规划是决定汽车整车生产周期的重要环节。以先进的数字化工厂技术软件——ProcessDesigner为平台,通过创建制造信息模型和工艺过程模型,实现对白车身焊装生产线的生产信息管理和工艺过程规划,构建了白车身焊装生产线工艺规划系统,并详细描述了其工艺规划实现的具体方法和步骤,最后以某型白车身底板焊装线为例,生成了基于规划系统的数字化三维工厂,对规划结果进行了验证。结果表明,利用该系统进行焊装工艺规划能显著缩短工艺规划时间,提高工艺规划的准确性。

应用Designer与HFSS对激光焊接工艺的联合仿真

应用Designer与HFSS联合仿真技术研究激光焊接工艺对连接性能的影响。首先,在HFSS中建立一个标准的BGA焊点模型,通过改变其尺寸参数仿真,得到使回波损耗最小的参数组合;随后,在Designer中建立激光模型,把HFSS中的焊接连接工艺模型以N端口元件的形式嵌入到Designer建立的激光中,进行联合仿真;最后,对嵌入焊接连接工艺前后的仿真结果进行对比分析,得出焊点及焊点尺寸的改变对激光性能的影响。在高频段,随着焊点高度的增加,焊点的回波损耗随之减小,当焊点高度为0.50 mm时,回波损耗最小,因而应优先选择0.50 mm的焊点高度。

Welding technique studies on the “West-East” pipeline project

This paper described the work of welding process design for the ＂ West-East＂ pipeline project, which is high pressure, large diameter and heavy wall thickness. According to the different geographical situation, climate, culture and the flexibility of the welding methods, this work recommended the semi-automatic process at the east and middle sections and automatic process at the west section of the pipeline project. The manual process is recommended on the tie-in joints and repairs. The double joint pipe and the 3 joint pipe are recommended at the water net place and some in-ditch welding place to reduce the welding volume. Also the special redesigned bevels are recommended for the automatic process and the semiautomatic process. Through all destructive tests, the results shows the welds are meet the requirements of related standards, specifications and design documents.

Optimizing the Pulsed Current Gas Tungsten Arc Welding Parameters

The selection of process parameter in the gas tungsten arc （GTA） welding of titanium alloy was presented for obtaining optimum grain size and hardness. Titanium alloy （Ti-6Al-4V） is one of the most important non-ferrous metals which offers great potential application in aerospace, biomedical and chemical industries, because of its low density （4.5 g/cm^3）, excellent corrosion resistance, high strength, attractive fracture behaviour and high melting point （1678℃）. The preferred welding process for titanium alloy is frequent GTA welding due to its comparatively easier applicability and better economy. In the case of single pass （GTA） welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. Many considerations come into the picture and one needs to carefully balance various pulse current parameters to reach an optimum combination. Four factors, five level, central composite, rotatable design matrix were used to optimize the required number of experimental conditions. Mathematical models were developed to predict the fusion zone grain size using analysis of variance （ANOVA） and regression analysis. The developed models were optimized using the traditional Hooke and Jeeve＇s algorithm. Experimental results were provided to illustrate the proposed approach.

Optimization of process parameters of the activated tungsten inert gas welding for aspect ratio of UNS S32205 duplex stainless steel welds

The activated TIG(ATIG) welding process mainly focuses on increasing the depth of penetration and the reduction in the width of weld bead has not been paid much attention.The shape of a weld in terms of its width-to-depth ratio known as aspect ratio has a marked influence on its solidification cracking tendency.The major influencing ATIG welding parameters,such as electrode gap,travel speed,current and voltage,that aid in controlling the aspect ratio of DSS joints,must be optimized to obtain desirable aspect ratio for DSS joints.Hence in this study,the above parameters of ATIG welding for aspect ratio of ASTM/UNS S32205 DSS welds are optimized by using Taguchi orthogonal array(OA)experimental design and other statistical tools such as Analysis of Variance(ANOVA) and Pooled ANOVA techniques.The optimum process parameters are found to be 1 mm electrode gap,130 mm/min travel speed,140 A current and 12 V voltage.The aspect ratio and the ferrite content for the DSS joints fabricated using the optimized ATIG parameters are found to be well within the acceptable range and there is no macroscopically evident solidification cracking.

高参数垃圾电站锅炉防腐涂层体系的设计策略与评价

随着国家“双碳”战略目标的提出,垃圾发电成为城市垃圾处理的主流方式。针对高参数垃圾电站锅炉管道腐蚀减薄到一定程度时,造成泄漏甚至爆管的严重安全问题,本文在简介了高参数对锅炉腐蚀影响规律的基础上,评述了高参数条件下管道的基材特性及主流涂层防护技术,重点论述了Inconel堆焊、感应熔焊、HVOF等技术及性能。因为涂层系统设计主要是对管道基体和涂层材料与工艺进行选配,同时匹配参数也是对涂层系统的主要评价指标,所以本文对热膨胀系数、导热系数、结合强度、孔隙率、服役寿命以及经济性等参数进行了系统评价,并阐述了涂层结构设计策略,包括防腐涂层的厚度设计、涂层结构设计、涂层材料组分设计等内容。根据涂层防护技术现存的主要问题,提出粉末合成设计-涂层结构设计-服役性能评价一体化研究的重要性;针对目前主要的材料体系设计比较集中于高Cr含量的FeCr系和NiCr系合金的现状,指出应开发以NiCr基辅以W、Mo等元素涂层材料,使其兼具优异的耐腐蚀和抗磨损的综合性能。最后对涂层防护技术的发展前景进行展望。

Effect of Welding Parameters on Dilution and Weld Bead Geometry in Cladding

The effect of pulsed gas metal arc welding （GMAW） variables on the dilution and weld bead geometry in cladding X65 pipeline steel with 316L stainless steel was studied. Using a full factorial method, a series of experiments were carried out to know the effect of wire feed rate, welding speed, distance between gas nozzle and plate, and the vertical angle of welding on dilution and weld bead geometry. The findings indicate that the dilution of weld metal and its dimension i.e. width, height and depth increase with the feed rate, but the contact angle of the bead decreases first and then increases. Meantime, welding speed has an opposite effect except for dilution. There is an interaction effect between welding parameters at the contact angle. The results also show forehand welding or decreasing electrode extension decrease the angle of contact. Finally, a mathematical model is contrived to highlight the relationship between welding variables with dilution and weld bead geometry.

Research on CAD system of lever-hinge style welding fixture

A computer aided design system of welding fixture (called WFCAD system) is introduced in this paper. The microcomputer graphics software AutoCAD has been used as the supporting software of WFCAD system. By means of programming, 2-D and 3-D parameterized graphic libraries of components of welding fixture are established. With the aid of AutoCAD ' s advanced development system (ADS), menus and dialogs are constructed for convenient use of graphic library, and it also makes the system has a good man-machine interface.

Effect of details of vertical stiffener on fatigue behavior of welding plate beams

The design of the vertical stiffener details is important in the anti-fa- tigue design of the welded steel plate beams.There still exist different opinions on the selection of the design parameters and the effect of the shear stress.In the present study,the effects of the welding process(semi-automatic welding, manual welding)and the connecting location of vertical stiffener(welded to the web or to the flange)on the fatigue behaviour in the regions subjected to the pure bending and subjected to the bending and shearing are investigated by test- ing the simulation beams of large scale.The analysis of the fatigue test results shows that the normal bending stress is the governing factor to the fatigue strength.