400MPa级超级钢不同焊接方法焊接接头组织性能分析

采用手工电弧焊，二氧化碳气体保护焊，等离子弧焊焊接400MPa级超级钢，并对焊接接头显微组织及力学性能作了分析研究，结果表明，实际生产中可以应用二氧化碳气体保护焊焊接400MPa级超细晶粒钢。     

400MPa级超细晶粒钢电弧焊焊接接头组织与性能

采用普通电弧焊方法（手工电弧焊、二氧化碳气体保护焊、埋弧焊）对400MPa级超细晶粒钢进行焊接,并对不同工艺条件下的焊接接头的组织与性能进行了分析。结果表明,400MPa级超细晶粒钢电弧焊焊接接头热影响区存在着明显的晶粒长大现象;手工电弧焊和埋弧焊焊接接头性能明显下降,而二筘化碳气体保护焊焊接接头性能下降不明显。根据试验结果,实际生产中可以利用二氧化碳气体保护焊方法焊接400MPa级超细晶粒钢。     

400MPa级超细晶粒钢电弧焊接头组织性能分析

采用普通电弧焊方法(手工电弧焊、二氧化碳气体保护焊、埋弧焊)对400MPa级超细晶粒钢进行焊接,并对不同工艺条件下的焊接接头进行了组织性能分析.研究结果表明:400MPa级超细晶粒钢电弧焊焊接接头热影响祆区存在着明显的晶粒长大现象;手工电弧焊和埋弧焊焊接接头性能明显下降,而二氧化碳气体保护焊焊接接头性能下降不明显.根据试验结果,实际生产中可以利用二氧化碳气体保护焊方法焊接400MPa级超细晶粒钢.     

高强度耐候钢焊接性研究

本文针对新型400MPa级高强度耐候钢材,采用CO2气体保护焊,通过化学成分、焊接裂纹试验、对接接头力学性能试验,对其焊接性能进行检验,结果表明该钢焊接性能优良,能够得到优质的焊接接头。     

不同焊接工艺对超级钢焊接接头组织性能影响

采用普通电孤焊方法(手工电弧焊、钨极氩弧焊、埋弧焊)对400MPa级超细晶粒钢进行焊接，并对不同工艺条件下的焊接接头进行了组织性能分析。结果表明，使用钨极氩弧焊方洼焊接400MP。级超细晶粒钢优于手了电弧焊和埋弧焊焊接方法。     

焊接方法对C-Mn超细晶粒钢接头低温韧性的影响

采用焊条电弧焊及CO2+Ar混合气体保护焊方法分别对厚6mm的400MPa级超细晶粒钢钢板进行了焊接试验,采用系列冲击试验方法对焊接接头的低温韧性进行了研究,并对接头组织进行了分析.试验结果表明,气体保护焊减小了焊缝及热影响区组织粗化,其焊接接头的低温韧性优于焊条电弧焊接头的低温韧性,是一种可行的超细晶粒钢焊接方法.     

喷水冷却对400MPa级超细晶粒钢焊接接头组织和性能的影响

采用手工电弧焊焊接400MPa级超细晶粒钢，并对不同冷却条件下的焊接接头显微组织及力学性能进行分析。结果表明，400MPa级超细晶粒钢手工焊焊接接头热影响区存在着严重的晶粒长大和强度下降现象；焊接过程中采用喷水冷却可明显提高焊接接头强度，实际生产中可以应用手工电弧焊水冷处理方法焊接400MPa级超细晶粒钢。     

400 MPa超细晶粒钢焊接接头的强化工艺研究

分别通过表面机械强化和深冷处理对400 MPa级超细晶粒钢焊条电极手工焊焊接接头进行了强化处理,并对强化处理前后焊接接头进行了组织和性能分析.研究结果表明:400 MPa级超细晶粒钢焊条电极手工焊焊接接头确实存在着晶粒严重长大和强度下降现象;经表面机械强化后,400 MPa级超细晶粒钢焊接接头表面组织得到重新细化,焊接接头强度和韧性均有明显提高;经深冷处理后,焊接接头强度和韧性均有所提高,但效果不明显.     

MAG焊接法

二氧化碳气体保护焊是一种高效率焊接法,也是我国目前正在大力推广的焊接新技术。但是,由于二氧化碳气体保护焊有种种缺点,因此,一种新的MAG焊接法——即活性气体保护焊接法得到了人们的重视和注意。 MAG焊接法和以氩气、二氧化碳气和氧气等混合气体作为保护气体的焊接方法。 MAG焊接法与二氧化碳气体保护焊接法相比,有如下优点:     

焊接热过程和冶金过程

间断焊温度场的试验研究；铝合金双丝焊应力场的数值模拟；双电极焊条单弧焊飞溅的研究；400MPa级超级钢焊接热影响区晶粒尺寸的预测；全焊接阀门的焊接温度场拟合分析；[编者按]     

CO2短路过渡焊电弧电压自寻优模糊控制系统

CO2 短路过渡焊机一元化控制是通过单旋钮将影响短路过渡频率的主要规范参数电弧电压和焊接电流有机结合在一起 ,通过单旋钮调节焊接电流 ,电弧电压随电流相应变化 ,形成最佳匹配而获得最高短路过渡频率。但由于CO2 短路过渡过程目前尚难以用精确数学模型来描述 ,所以通过一般控制方法所实现的一元化控制并未真正实现单旋钮调节。针对这一不足 ,研究了一种以 16位 80C196KC数字单片机为核心器件通过软件方式实现的CO2 短路过渡焊电弧电压自寻优模糊控制系统。系统以操作者所选择的焊接电流为唯一设定参数 ,自动对电弧电压进行以实现最高短路频率为目标的自寻优 ,可使此类焊机实现真正单旋钮调节为特征的一元化控制     

Phenomena in GTA and GHTA welding in Mars-like atmosphere

NASA is advancing the project of manned Mars exploration. In the future, Martian outposts and structures will be constructed. To realize this, welding technology is expected to be applied. The main atmospheric component of Mars is carbon dioxide, and the atmospheric pressure is approximately 700 Pa. In this study, welding experiments were carried out in a simulated Mars atmosphere of 99.5% carbon dioxide and a pressure of 700 Pa. Conventional gas tungsten arc (GTA) welding and gas hollow tungsten arc (GHTA) welding, in which arc operating gas is allowed only to flow out from the electrode tip of a hollow tungsten electrode, were investigated. The arc discharge behaviour and the melting characteristics in the simulated Mars atmosphere were studied. As a result, it was shown that GTA welding and GHTA welding might be applicable even in the Mars atmosphere.     

Investigation of the effect of SF6 gaseous halide on the process of MAG welding S235JR carbon steel

The results of investigation of the process of MAG welding S235JR carbon steel with the addition of SF₆ gaseous sulphur hexafluoride with concentrations from 1.6 to 6.4% carbon dioxide are described. The aim of the investigations was to improve the droplet metal transfer and the formation of the welded joint in MAG CO₂ welding in carbon dioxide. The addition of the SF₆ sulphur hexafluoride to the carbon dioxide changes the process of melting of the electrodes, decreases the extent of splashing and shortens the short-circuiting time. The droplet transfer frequency increases by up to 1.6 times, the depth of penetration increases to 66% and the width of the welded joint decreases to 36%. The welding current increases in a wide range of the welding conditions, the arc voltage decreases, together with the amplitude of the deviation of the current and arc voltage     

Effects of shielding gas composition on arc characteristics and droplet transfer in tandem narrow gap GMA welding

The effects of shielding gas composition in tandem narrow gap gas metal arc welding were studied. The shielding gas included argon, carbon dioxide and helium. The arc characteristics and droplet transfer process were analysed. The results show that in the same welding parameters, the trail wire welding current is higher than the lead wire welding current. With the increase of carbon dioxide content, the welding currents of two wires decrease, and the trail wire droplet transfer mode transforms from spray transfer to projected transfer. With the increase of helium content, the welding currents increase and the lead wire droplet transfer mode transforms from projected transfer to spray transfer. The weld width is the largest when the shielding gas mixture is 80%Ar10%CO₂10%He.     

A Study on Factors Influencing Toughness of Basic Flux-Cored Weld of Modified 9Cr-1Mo Steel

Flux-cored arc welding (FCAW) is relatively a new process for joining of modified 9Cr-1Mo (P91) steel. In this study, effect of shielding gas composition, inclusion content, gas tungsten-arc welding (GTAW) surface remelting, and postweld heat treatment (PWHT) on toughness were investigated. The high amount of silicon resulted in the formation of δ-ferrite in basic flux-cored weld. A mixture of 80% argon + 20% (80A) carbon dioxide shielding gas during welding resulted in the required toughness of 47 J at room temperature. The 95% argon + 5% carbon dioxide (95A) gas-shielded welds have lower toughness due to higher amount of δ-ferrite (4%) than 80% argon + 20% carbon dioxide welds (2%). In essence, most desirable shielding gas medium to achieve optimum toughness was 80% argon + 20% carbon dioxide in basic flux-cored arc welding.     

16000 kN卧式双动挤压机活动横梁修理

挤压机活动横梁下部发生断裂并产生裂缝,丧失功能需进行修理。采用自制的、具有锁紧装置的液压顶紧装置将其复位后,在裂缝上面、下面和侧面分别采用二氧化碳气体保护焊和直流弧焊的方法进行焊接。采用焊前预热、焊中保温、焊后低温回火和每焊一层后振动打击的方法消除焊接应力。焊接修理后恢复了活动横梁的功能,经过几年的使用证明,满足压机的功能要求。     

单片机控制多外特性的焊接电源

本文介绍一种由单片计算机构成的晶闸管整流弧焊控制系统以及用ＰＩ算法实现恒流、恒流外拖、斜外特性的控制软件。设计中充分利用单片机的软硬件资源，使控制系统简单、、、用。研制的ＺＸ５－８００Ｄ电源在进行钨极氩弧焊、手工电弧焊、碳弧气刨及埋弧焊时均获得满意的性能。     

CO2焊、MAG焊焊接对比试验及其在工程机械制造中的应用

通过对CO2焊、MAG焊、焊条电弧焊三种焊接方法的焊接工艺对比试验，表明CO2焊具有成本低、效率高、焊接质量好等优点。介绍了CO2焊、MAG焊对接焊缝工艺和角焊缝工艺在工程机械制造中的应用