Automatic Extraction Method of Weld Weak Defect Features for Ultra-High Voltage Equipment

To solve the problems of low precision of weak feature extraction,heavy reliance on labor and low efficiency of weak feature extraction in X-ray weld detection image of ultra-high voltage(UHV)equipment key parts,an automatic feature extraction algorithm is proposed.Firstly,the original weld image is denoised while retaining the characteristic information of weak defects by the proposed monostable stochastic resonance method.Then,binarization is achieved by combining Laplacian edge detection and Otsu threshold segmentation.Finally,the automatic identification of weld defect area is realized based on the sequential traversal of binary tree.Several characteristic analysis dimensions are established for weld defects of UHV key parts,including defect area,perimeter,slenderness ratio,duty cycle,etc.The experiment using theweld detection image of the actual production site shows that the proposedmethod can effectively extract theweak feature information ofweld defects and further provide reference for decision-making.

Development of welding technology of hydroelectric power equipment

Hydroelectric power equipment consists of a hydro-turbine and a hydrogenerator whose weldments have the features of complicated construction and large bulk as well as some parts operating under water. With the increase of unit rating of the hydroelectric power equipment, the application field of high strength steel and dissimilar steel has been enlarged. What to be introduced in this paper is the development of the welding technology of large hydroelectric generating equipment in China since the 1970s, and the development orientation of its welding construction and procedure in the future.

A new weld repair technique for friction stir welded aluminium structure:inertia friction pull plug welding

The paper gives an analysis on technical characteristics of repair techniques for friction stir welding defects. To overcome the defects,a new repair technique, inertia friction pull plug welding( IFPPW), was researched and its equipment was developed as well. Elementary datum was achieved by investigating the influences of technological parameters on mechanical properties and by analyzing the structural characteristics of repair joint with IFPPW. The study shows that the stability and reliability of welding process of IFPPW can be guaranteed through the constant energy from the flywheel.Integrated with the advantages of friction pull plug welding,the IFPPW,free from back anvil,is considered as a promising technique in repair of termination keyhole of bobbin tool friction stir welding and point-like defects in aluminum alloy welding.

Microstructure and impact mechanical properties of multi-layer and multi-pass TIG welded joints of Al-Zn-Mg alloy plates

The microstructure and mechanical properties of multi-layer multi-pass TIG welded joints of Al-Zn-Mg alloy plates were studied.The phase constituent and microstructure of different regions of the welded joints were characterized by scanning electron microscopy(SEM),X-ray diffraction(XRD),transmission electron microscopy(TEM)and energy disperse spectrum(EDS),while the mechanical properties were evaluated according to the impact test.A dispersively distributed spherical and needle-likeη(MgZn2)phase was obtained in the welding seam.The phase composition of the heat-affected zone(HAZ)wasα(Al)+η(MgZn2)+Al6Mn,and there were a large number of dispersively precipitated nanoscale particles.The welded joint zone had the highest impact toughness as compared with the other parts of the joint.The MgZn2 phase in the weld zone contributed to the improved toughness of the joint.Al2 MgCu phase in HAZ was proven to act as a crack source during fracture.

Numerical simulation of residual stress and deformation for submerged arc welding of Q690D high strength low alloy steel thick plate

The finite element simulation software SYSWELD is used to numerically simulate the temperature field,residual stress field,and welding deformation of Q690D thick plate multi-layer and multi-pass welding under different welding heat input and groove angles.The simulation results show that as the welding heat input increases,the peak temperature during the welding process is higher,and the residual stress increases,they are all between 330–340 MPa,and the residual stress is concentrated in the area near the weld.The hole-drilling method is used to measure the actual welding residual stress,and the measured data is in good agreement with the simulated value.The type of post-welding deformation is angular deformation,and as the welding heat input increases,the maximum deformation also increases.It shows smaller residual stress and deformation when the groove angle is 40°under the same heat input.In engineering applications,under the premise of guaranteeing welding quality,smaller heat input and 40°groove angle should be used.

Diffusion welding process and joint's microstructure behavior of SiC_w/6061Al composite

The rules such as process parameters affecting joint properties and theevolution principle of weld's microstructure have been researched by adopting diffusion weldingprocess to connect SiC_w/6061Al composite. Experimental results show that there exists a criticaltemperature region between solid and liquid phase line of SiC_w/6061Al composite, and the regionwill shrink with the increasing of welding pressure. When diffusion welding occurred under thecritical temperature region, welding joint exhibits bad property of bonding, and the matrix and thereinforcement can't bond effectively. When diffusion welding occurred in the critical temperatureregion, the strength of welding joint changes widely with the variation of welding temperature. Whenwelding temperature varies in 10 deg C, the strength of welding joint will change obviously. Onlywhen welding temperature is higher than the critical temperature region, stable joint properties canbe obtained. Simultaneously the matrix and the reinforcement has better interfacial bonded indiffusion welding interface, and no obvious interface reaction occurred, and thus diffusion weldingof SiC_w/6061 Al composite can be successfully realized.

Research on Radial Friction Welding of 30 mm Shell's Band

A new radial friction welding technology of 30 mm shell's band is introduced.Bands are assembled to shell bodies without notches by using the process.The width of heat-affected zone(HAZ) is small,and the microstructure on steel side is incomplete quenching while that on cooper side is grain refining.The shear-strength of joint exceeds 200 MPa.The result of firing test indicates that radial friction welding can satisfy the assembly requirements of shell bands.

Analysis of Vibration Frequencies of Piezoelectric Ceramic Rings as Ultrasonic Transducers in Welding of Facial Mask Production

The explosive demands for facial masks as vital personal protection equipment(PPE)in the wake of Covid-19 have challenged many industries and enterprises in technology and capacity,and the piezoelectric ceramic(PZT)transducers for the production of facial masks in the welding process are in heavy demand.In the earlier days of the epidemic,the supply of ceramic transducers cannot meet its increasing demands,and efforts in materials,development,and production are mobilized to provide the transducers to mask producers for quick production.The simplest solution is presented with the employment of Rayleigh-Ritz method for the vibration analysis,then different materials can be selected to achieve the required frequency and energy standards.The fully tailored method and results can be utilized by the engineers for quick development of the PZT transducers to perform precise function in welding.

Development of Full Automatic External Welding Machine for Annular Welds of Pipeline

To meet the demands of rapid development of pipeline constructions in China, a complete set of full automatic external welding machine for annular welds of pipeline and welding procedure have been developed thereof. The system has been applied in the “West East Pipeline Project” and its performance is proven. With this welding machine the welding parameters can be either preset before or adjusted in real time during the welding process, which avoids the blemishes of same type domestic and international products. Thus it is best propitious to in situ construction conditions and workers’ technical level in China. In this article the development of mechanical and control systems of this product is introduced and typical welding procedure parameters are provided.

Research on Explosive Welding Technology of Railway Connector

Railway signal transmission is the key to ensure the safe and normal operation of the train. The railway connecting line for signal transmission is important equipment to guarantee the railway signal transmission and reduce the imbalance of electric current. In point of engineering application, the explosive welding technology of railway connecting line is studied theoretically, the appearance, tensile strength, micro configuration of welding junction , welding area are detected after explosive welding. Experimental and detecting results show that the connecting quality of explosive welding is reliable, which lays the foundation for the engineering practice of technology.

大型钻探设备支承底盘焊接工艺优化研究

大型支承底盘作为大型钻探设备的支承平台,通常由大量钢板通过焊接装配而成,焊接残余应力和残余变形会对底盘的强度和刚度产生一定的影响。本文运用有限元分析方法,选取高斯移动热源,针对大型支承底盘中具有代表性的T形焊接接头建立了有限元模型,分别采用4种不同的焊接顺序和焊接速度,分析了其对焊接应力和变形的影响,得到了优化的焊接顺序和焊接速度。在此基础上,对底盘的整体焊接方案做出优化,对比分析了优化前后的焊接应力和变形,结果表明:优化后残余应力减少了约7%,最大变形减少了约26%。研究成果可为焊接工艺的制定提供参考。

机械振动对电弧增材制造2319铝合金微观组织与机械性能的影响

为了解决电弧增材制造试样晶粒粗大、机械性能较差等问题,在电弧增材制造2319铝合金过程中施加机械振动,分析了机械振动频率和幅度对试样微观组织和机械性能的影响。结果显示:机械振动使熔池流动性提高,熔池更加铺展,层宽增加,层高降低;振动破碎了生长过程中的枝晶,使INZ晶粒尺寸减小14.49μm,ITZ晶粒尺寸减小4.68μm;枝晶间隙处的溶质元素含量降低,晶界析出相变得断续且细小,PLC效应间隔增加,材料延伸率显著提高;机械振动频率和机械振动幅度改变时纵向和横向延伸率分别提升了38.2%,15.7%和29.3%,52.5%,而强度变化并不显著。采用机械振动辅助电弧增材制造能够在不影响强度的前提下显著提高试样的塑性,可为机械振动在增材制造领域的广泛应用提供技术参考。

30mm厚EH420船板钢三丝埋弧焊接温度场数值模拟研究

为了减少焊接时产生的高温对热影响区韧性的影响,分别研究了焊接线能量、焊丝功率分配、焊接电压和焊丝间隔对温度场的影响。基于Visual-Environment有限元软件,利用双椭球热源模型,对30 mm厚EH420船板钢三丝埋弧焊接温度场进行了数值模拟。结果表明:1)当线能量从150.26 kJ/cm降低到104.72 kJ/cm时,粗晶区峰值温度降低了322℃;2)当线能量相同时,前丝功率占比从25.00%上升到41.67%,且中丝功率占比不变的情况下,粗晶区峰值温度降低了56.79℃;3)提高焊接电压后,粗晶区峰值温度、熔深和熔宽变化较小;4)焊丝间隔从20 mm增加到45 mm,熔池长度增大了50 mm,并在焊丝间隔40 mm之后出现由单熔池向双熔池转变的现象,粗晶区峰值温度呈现先增大后减小的趋势,焊丝间隔在35 mm达到最高温度1183.62℃;5)从拟合结果得出,在焊接30 mm厚的EH420船板钢“Y”型坡口时,线能量应采用174.54 kJ/cm,在此线能量下前、中、后丝的功率占比采用15∶11∶7且焊丝间隔为20~30 mm,能够有效避免出现焊接缺陷。研究结果既可以保证焊接质量,又可以大幅提高焊接效率,为企业降本增效提供新方法。

核电厂高压蒸汽管道焊缝切割装置的研制

为了修复某核电厂GPV高压缸排汽管膨胀节导流筒焊缝因热处理不当导致的开裂,研发了一款焊缝切割装置,用于将开裂的焊缝切除并加工坡口以进行下一步的自动焊接修复。首先利用SolidWorks对焊缝切割设备进行了机械设计并三维建模,对驱动电机进行了选型计算,设计了控制系统架构,随后制作了设备样机和膨胀节导流筒模拟体,最后在试验室利用模拟体对设备样机的性能进行了连续切削试验,验证了该装备能够高效完成膨胀节导流筒开裂焊缝的切除和坡口加工,且坡口加工质量优良,装置性能稳定。

基于SAConvFormer算法的焊接故障诊断在非平衡数据集上的应用

预测性维护在制造业中扮演着重要角色,而焊接设备的有效维护更是关键,旨在减少企业支出并实现无人车间的目标。然而,焊接领域的研究尚处于初级阶段,而深度学习在此领域的应用也相对较少。针对这一问题,提出一种基于空间注意力卷积Transformer(SAConvFormer)的故障诊断模型,以解决焊接设备故障预测的挑战。通过收集焊接过程中的数据,该算法通过空间注意力机制增强卷积神经网络,从而更准确地预测焊接过程中的各种故障类型。实验结果显示,SAConvFormer模型在预测正常类型故障方面的召回率达到了95%,误差仅为2%。对焊接偏差类型的故障,模型的召回率稳定在80%左右,而不完全熔合类型的故障预测准确性相对较低,但仍保持在70%以上。与传统算法相比,SAConvFormer模型在召回率上表现优异。这一研究成果不仅在技术上取得了进展,也为焊接设备的故障诊断提供了一种新的有效方法,具有重要的理论和实践意义。

机械工程自动化设备安装技术研究

近年来,我国在经济建设和科学技术发展上取得了重大成果,带动了诸多行业的发展。工程自动化行业就是其中之一,基于自动化技术的相关机械设备也在各行业进行了大范围应用,并取得了良好的效果。文章围绕机械工程自动化设备安装技术进行了研究,分析了机械工程自动化设备的性能及常规安装流程,并重点阐述了机械工程自动化设备安装技术要点,包括组装自动化系统、机械设备焊接检测、机械设备安装调整等,旨在提高设备工作效率,减少故障和延长设备的使用寿命。

焊接实训台及辅助设备与场地布局设计优化

针对传统焊接实训车间布局不合理、环境条件差、操作流程不规范、工装缺失、实训设备老化或维修不到位等诸多问题进行了优化设计,改善了实训环境,规范了操作流程,可为学生提供优质的实训平台和环境。

焊接机器人降低空闲损耗的方法研究

焊接机器人的组成部分之一是焊接设备,而随着2019年10月1日欧盟发布的(EU)No 2019/1784《电焊机的生态设计要求》焊接设备空闲损耗概念的引进,焊接机器人也将迎来一次重大的技术革新。本文指出了空闲损耗状态对于焊接机器人的效率制约,从机械臂、控制系统、焊接设备、安全系统四个方面介绍了有效抵消空闲损耗的方法,其中焊接设备部分结合试验数据做了着重分析,从功率器件、主变压器磁芯、控制模块和冷却系统入手,找出了高功耗的原因,提出了相应的解决方案,对焊接机器人的绿色可持续发展有积极推动作用。

X52材质大口径钢制管道全位置自动焊应用总结

针对X52管线钢的全自动焊焊接接头,充分考虑双焊炬的相互影响以及施工环境的影响,对焊接工艺参数进行了调整和优化,通过拉伸试验、弯曲试验、刻槽锤断试验及硬度试验等机械性能试验验证了焊接工艺的可靠性,形成了焊接工艺评定;同时分析并解决了现场焊接中出现的问题,提炼总结了双焊炬自动焊焊接工艺参数优化的要点,形成了适用于X52管线钢的铜衬垫全自动焊工艺。对焊缝进行了金相分析和硬度试验,从微观上分析了焊缝金属组织结构的分布情况,发现X52管线钢焊缝、热影响区及母材硬度分布与对应区域金相组织中珠光体含量呈正相关,进一步验证了该焊接工艺条件下焊缝金属及热影响区金相组织的一致性。结果表明,铜衬垫全自动焊工艺适用于大口径钢制管道的焊接,采用该工艺可以明显提升焊接质量和焊接效率。

市政桥梁钢箱梁梁段安装施工技术分析

为进一步探究市政桥梁钢箱梁安装施工技术要点,文章结合某地市政桥梁工程的实际案例展开研究,讨论了施工准备阶段的地基处理和设备选型,后从节段划分、吊装、合龙与焊接四个环节着手,详细探讨了市政桥梁钢箱梁梁段安装施工技术的具体流程与应当遵循的要点,并对此次施工效果进行评价。结果显示,此次施工作业各项主要指标均符合预期,因此此次施工作业所总结的经验具有一定的参考价值。