电子束焊接焊缝气孔缺陷分析及预防

在电子束焊接过程中,密集气孔是一种常见的焊接缺陷。现从电子束焊接成型理论入手分析了气孔缺陷产生的内因,从跟踪试验入手研究了焊缝间隙与焊接面表面质量对焊接质量的影响,并采取相应措施,有效控制了气孔缺陷产生。     

压力容器常用几种有色金属焊接产生气孔的分析和对策

1引言随着工业的发展，一些具有特殊性能的有色金属广泛地应用于制造压力容器。但是，这些有色金属在焊接过程中容易产生一些缺陷，特别是气孔，而气孔的存在会大大降低焊接接头疲劳强度，甚至无损探伤检查不出的小气孔对疲劳强度都会产生明显的不利作用。实验表明，气孔能使接头疲劳强度降低一半甚至四分之三。有鉴于此，必须分析这些有色金属焊接易产生气孔的原因，从而采取相应的措施加以防范。2造成工业纯钛焊接气孔的主要原因气孔是工业纯钛焊接时最常见的焊接缺陷，往往在熔合线附近形成。而这些气孔的形成主要是氢引起的。因为氢在钛…     

CO_2气体保护焊技术问答?

31.CO_2焊接时为什么会产生气孔?如何防止? [答]CO_2焊接时,由于熔池上没有较厚的熔渣覆盖和CO_2气流对熔池有较大的冷却作用,因此熔池凝固得较快;另外由于焊缝窄而深,在熔池内部存在CO、H_2、N_2等溶解不了的或者过饱和的气体来不及在熔池凝固前逸出时,焊缝中就产生了气孔。CO_2焊接时产生气孔的气体来源、气孔类     

铝合金车体用6005A—T6焊接气孔的防止

研究了城轨车辆铝合金车体用6005A—T6在MIG焊接生产过程中气孔产生的原因，总结并分析了其对气孔的敏感性及焊接工艺方法和保护气体对铝合金焊缝中气孔的影响，最后提出了防止措施。结果表明：在实际生产中主要采取提高保护气体纯度、保护气中增加He气含量的比例、焊前烘烤等手段来防止焊缝气孔，此外增加工艺垫板、控制焊接参数、改善焊接手法等对减少焊缝气孔也有一定的帮助。     

2A12铝合金真空电子束焊接气孔缺陷分析

在电子束焊接试验的基础上,研究了真空电子束焊接2A12时焊缝接头的力学性能;探讨了电子束焊接2A12时,影响焊缝强度的主要因素是在焊接过程中产生的气孔缺陷,同时分析了2A12铝合金焊缝气孔产生的倾向和表面焊前清理、焊接参数、预热以及重熔方法之间的关系.结果表明,在采取一定的焊接工艺措施后,接头中的气孔缺陷可得到很好地控制,保证了焊缝所需的力学性能,满足设计使用要求.     

板状对接仰焊时气孔的产生及预防

本文着重分析了板状对接仰焊时产生气孔的原因、形态、性质及其对焊接质量的影响。探讨了焊缝中气孔形成机理以及冶金学的影响因素,提出了控制气孔产生的对策。     

焊缝气孔的形成原因及防治措施

论述焊缝气孔缺陷的类型及形成条件,如何限制熔池溶入或产生气体以及排除熔池中存在的气体,选用与母材匹配的焊接材料,制定并控制焊接工艺条件,可以有效地控制焊接过程中的气孔缺陷的产生.     

全位置焊接真空舱拼接焊缝

全位置焊接真空舱拼接焊缝过程中主要是按照焊接工艺要求操作,控制焊接过程中产生的缺陷。本文主要介绍了真空舱拼接焊缝的焊接工艺,气孔和未焊透缺陷的产生原因及预防措施,控制缺陷产生几率在控制范围内,降低成本。     

铝合金管道焊接气孔产生原因分析及克服措施

正2011年,第十届全国工程建设系统焊工职业竞赛,增加了铝镁合金Al5A06小口径φ80mm×5mm管道2G位置固定交流TIG焊接项目。但比赛中,87名选手铝管焊接RT探伤有50人气孔超标得0分,20分以下9人,一级无缺陷满分只有2人,于是比赛结束后,我们针对铝管气孔的各个因素,通过反复调研和试验,找到了气孔产生原因,使焊接气孔得到有效遏制,并在2013年第十一届全国焊工竞赛中获得优异成绩,为避免铝管焊接气孔积累了经验。     

小口径耐热合金钢管钨极氩弧焊气孔探讨

在中高压锅炉过热器中使用15CrMoG耐热合金钢管,在使用手工TIG焊管子对接时,产生气孔及夹渣缺陷.文中根据材料性能、焊接方法、焊接材料、焊接技能等提出解决焊接气孔及夹渣缺陷的工艺方法.     

AW-600型弧焊机器人操作机设计

本文着重介绍了 Ａ Ｗ ６００ 型弧焊机器人机械本体的设计。     

薄铌板电子束焊接工艺研究

超导铌腔是高能加速器的重要组成部分,采用高真空电子束焊接工艺对超导铌腔进行加工制造时,铌板焊接试验可以为超导铌腔的制造提供可行的焊接参数。据此,主要研究了薄铌板的焊接试验流程。在不同焊缝质量要求下,通过改变聚焦电流和焊接电流大小的方式,快速找到符合要求的参数值,然后对这些参数进行试验,观察其焊缝是否可行。结果表明,试验方法切实可行,效率高,焊缝质量可以达到预期目标。     

CO2气体保护焊产生飞溅的原因及控制措施

熔滴飞溅是CO2气体保护焊影响生产效率、焊接稳定性和焊缝质量的主要因素。大滴过渡和短路过渡都会产生飞溅。分析飞溅的成因,采取有针对性的控制飞溅的有效措施,采用合理的焊接工艺、选择合理的焊接工艺参数降低飞溅率,对CO2气保焊有着十分重要的意义。     

Reduction of fume and gas emissions using innovative gas metal arc welding variants

New environmental, health and safety legislation, both in the EU and in the USA, is driving the need for the study of new welding processes, and the selection of the operational procedures that will reduce fume emissions and will promote a healthier, safer and more productive work environment. Actually, there are a significant number of publications related with gas metal arc welding hazards. However, for the new gas metal arc welding hazards variants, especially cold metal transfer, there is no data available concerning fumes and gases emissions. This paper attempts to point out ways of reducing the harmful effects of gas metal arc welding processes using different filler materials, different shielding gases, different operational welding procedures and three welding processes: gas metal arc welding process and two variants, pulsed gas metal arc welding and cold metal transfer. The effect of nitrogen oxide addition to the shielding gas composition on the amount of welding fumes and gaseous emissions produced during welding is also analysed. The amount of fume and gases generated during welding was measured over a range of current intensity and arc voltages, using the standard procedures contained in EN ISO 15011-2 [1]. The data presented give a summary of the different gas metal arc welding variants and their relations to fume generation rates and gases emitted. The results obtained give indications on measures to be taken in order to reduce fume and gas emissions. In general, the minimisation of fume formation rate can be achieved by using lower energy gas metal arc welding variants, gas shielding with low CO₂ and O₂ contents and “green” wires.     

Mathematical models for control of weld bead penetration in the GMAW process

This paper presents the effects of welding process parameters on weld bead penetration for the gas metal arc welding (GMAW) process. Welding process parameters included wire diameter, gas flow rate, welding speed, arc current and welding voltage. The experimental results have shown that weld bead penetration increased as wire diameter, arc current and welding voltage increased, whereas an increase in welding speed was found to decrease the weld bead penetration. However, the weld bead penetration is not affected significantly by gas flow rate changes. Mathematical equations for study of the relationship between welding process parameters and weld bead penetration have also been computed by employing a standard statistical package program, SAS.     

煤气加压机大回流系统的节能研究及其在宝钢的应用

基于加压机大回流系统压力－流量特性的讨论,提出并实现了利用风机入口流量预调装置ＶＳＲ－ＲＡ一间接改变风机特性的变流量自动恒压控制系统。结合宝钢工程实际,简述了系统结构及主要功能,并对该系统的节能原理作了重点分析,试验及实际运行结果均充分显示出该系统在节能、恒压供气和防喘振上具有优异的性能。     

智能型气压焊设备人机界面的设计

本文论述人机界面在智能型气压焊设备系统中的应用.通过对钢轨气压焊工作参数的分析,提出了系统主体结构,设计出人机界面的工作画面.简要讨论了系统的安全保护设计和通讯组态.现场应用表明.该产品提高了铁路钢轨焊接接头的质量.使我国气压焊准备水平迈上了自动化台阶.     

Effects of shielding gas control: welded joint properties in GMAW process optimization

One function of shielding gases used in welding processes, such as hydrogen (H₂), oxygen (O₂), carbon dioxide (CO₂), nitrogen (N₂), helium (He), argon (Ar) and their mixtures, is protection of the weld pool against harmful contamination that could generate defects. In addition to this primary function, shielding gases significantly affect the shape of the weld, weld geometry, seam appearance, metallurgical and mechanical properties, welding speed, metal transfer, arc stability or beam and fume emissions. The shielding gas is thus a key factor in determining weld joint properties and welding process efficiency. As welding processes have become enhanced and welding research has advanced, different combinations of shielding gas mixtures have become available under a wide variety of trademarks, each claiming to offer the best efficiency. The shielding gas flow rate in GMAW welding is usually set according to empirical experiment. The flow generally remains unchanged throughout the entire welding process and is set at maximum values of the welding parameters so that there is sufficient gas cover. This setting means, however, that unnecessarily large quantities of shielding gas may be consumed in other phases of the welding process. In view of constantly increasing prices and shortfalls in helium supply, there is a need to optimize the use of shielding gas. Consequently, an ability to closely monitor the shielding gas blend and reduce waste can provide valuable cost savings. This paper examines the effects of shielding gas mixtures and their components, presents a cross-comparison of shielding effects in fusion welding and suggests guidelines for adaptive controllability of shielding gas in advanced adaptive fusion welding. The study reviews scientific case studies and experiments from the point of view of the effect of the shielding gas on the process efficiency and process outcome. The study considers shielding gases for welding of both ferrous metals (i.e. carbon steels, stainless steels, high-strength steels) and non-ferrous metals (i.e. aluminium and its alloys, nickel and its alloys and copper and its alloys). Appropriate choice of shielding gas and use of an optimum flow rate results in better quality in terms of increased productivity, reduced gas consumption and improved weld geometry properties, microstructure and mechanical properties. Although some blends can be used effectively in many different processes, other blends appear process-dependent; they produce far poorer results when utilized in non-appropriate processes. Particle image velocimetry (PIV) and Schlieren techniques can be used for visual sensing of gas flow during fusing welding. Moreover, an adaptive alternative gas supply can improve welding performance and weld quality and reduce harmful fume emission.     

熔化极气体保护焊熔滴过渡光谱信号模式识别系统的研究

为实现熔化极气体保护焊熔滴过渡类型的自动识别,开发了熔滴过渡光谱信号模式识别系统,利用此系统,获得了大量各种熔滴过渡类型的光谱信号。以此为样本,根据模式识别的原理和方法,在Windows环境下,以Visual Basic为开发语言,设计了熔滴过渡光谱信号模式识别软件,成功地对各种熔滴过渡类型进行了自动识别。     

C-276合金的特性及其焊接工艺

简要介绍了C-276合金的焊接特点，给出了TIG焊的推荐焊接工艺参数，指出了该材料在焊接时应采取的特殊工艺措施和注意事项。