高频逆变式弧焊机电源的研制初探

弧焊机电源是电弧焊机的重要组成部分,它是对焊接电弧供给电能的装置,它应满足电弧焊所要求的电气特性。弧焊机电源电气性能的优劣,在很大程度上决定了电弧焊机焊接过程的稳定性。没有先进的弧焊机电源,要实现先进的焊接工艺和焊接过程自动化也是难以办到的。弧焊机电源具有较大的短路电流和较高的空载电压等特点。高频逆变式弧焊机电源是近年来世界焊接电源界研究的新技术。它具有控制性能优异、动特性好、焊接工艺性优良、重量轻、效率高、功率因数高、引弧性能好、焊接速度快等优点,是当前国际上焊接电源设备发展的主流和方向。这种电源除了能够用于弧焊机外,还可以用作喷涂等需要大电流,低电压的设备的电源。     

双弧脉冲MIG焊耦合电弧特性的数值模拟研究

针对双弧脉冲MIG焊热源稳定性差的问题,本文对双弧脉冲MIG焊耦合电弧进行瞬态数值模拟,分析了不同脉冲电流参数下耦合电弧形态、温度和压力的分布及变化规律。研究表明：耦合电弧呈驼峰状,脉冲电流发生跳变时,耦合电弧伸展或收缩,并逐渐稳定,峰值电流越小,越快达到稳定;增大脉冲电流,耦合电弧温度和电弧压力随之升高;保持总电流不变,减小主弧电流,增大旁弧电流,主弧温度和电弧压力减小,旁弧温度和电弧压力增大,当旁弧电流足够大时,耦合电弧温度和电弧压力呈双峰分布。数值模拟结果与双弧脉冲MIG焊工艺实验结果吻合良好,模拟结果对调控双弧脉冲MIG焊脉冲电流参数,改善其耦合电弧稳定性及工艺性能具有重要意义。     

新型阴极弧电源研制及脉冲增强电子发射(P3e)效应研究

本文研制了新型脉冲阴极弧电源,并实现了脉冲增强电子发射(P3e)以提高真空室内等离子体密度。该电源核心由脉冲发射和维持电流系统构成,由单片机和触摸屏系统协同控制和管理。对P3e电源进行放电特性和脉冲增强电子发射效应进行了研究。结果表明,在相同平均电弧电流条件下,与直流相比,P3e技术能够显著提高工件(基体)脉冲电流与平均电流。在电弧平均电流90 A时,基体脉冲电流由5 A提高到19.6 A,基体平均电流由2.2 A最大提高到4.6 A,表明脉冲增强了电子发射,进而获得高的等离子体密度,这将有助于增加膜层致密性、降低膜层应力。该新型电源对于阴极弧靶中毒抑制、膜层结构改善、膜层颗粒污染控制具有重要的意义。     

NSA-200交直流氩弧焊机研制

NSA—200交直流氩弧焊机是一种新型的焊接电源。它具有焊接电流调节范围宽;焊接过程电孤稳定等特点。电源采用脉冲稳弧和方波焊接电流对于交流氩弧焊最小电流可稳定在5安,对于直流氩孤焊最小电流可稳定在4安。因此这种电源很适合于黑色及有色金属的薄壁结构件焊接。同时可作为交、直流的手工电弧焊电源。     

利用朗缪尔双探针诊断电弧离子镀等离子体参数

本文利用朗缪尔双探针对电弧离子镀等离子体进行了诊断.双探针具有收集电流小的优点(小于离子饱和电流),可以避免探针在高密度电弧离子镀等离子体中被烧坏.利用离散傅里叶变换(DFT)对测量曲线进行平滑,有效地克服了电弧离子镀等离子体放电所固有的强烈波动.探针端部设计能够避免由薄膜沉积造成的探针与支撑杆短路问题.实验结果表明,等离子体密度随着弧电流和气压的增加而增加,而电子温度随着弧电流和气压变化不明显.另外,使用双靶放电等离子体密度和电子温度高于单靶放电.这些结果提供了电弧离子镀等离子体的基本参数,对于材料涂层工艺研究具有积极意义.     

离子镀膜中的弧电流对膜层质量的影响

论述了电弧电流对多弧离子镀膜层的硬度、厚度及其外观形貌的影响 ,并进一步阐述了电弧电流在实际应用中的作用 ,说明了镀制不同功能的膜层 ,应选择不同弧电流的重要性     

高频逆变真空电弧蒸发电源

高频逆变真空电弧蒸发电源是现代电力电子技术与微电子技术的综合产物，因其具有高效节能、形小体轻、真空电弧稳定等特点，势必发展成为新一代电弧蒸发电源。本文就其主要工作原理、设计计算、实验数据等进行了分析研讨，并举电路实例供参照     

高频逆变真空电弧蒸发电源

高频逆变真空电弧蒸发电源是现代电力电子技术与微电子技术的综合产物，因其具有高效节能、形小体轻、真空电弧稳定等特点，势必发展成为新一代电弧蒸发电源。本文就其主要工作原理、设计计算、实验数据等进行了分析研讨，并举电路实例供参照     

高频逆变真空电弧蒸发电源

高频逆变真空电弧蒸发电源是现代电力电子技术与微电子技术的综合产物，因其具有高效节能、形小体轻、真空电弧稳定等特点，势必发展成为新一代电弧蒸发电源。本文就其主要工作原理、设计计算、实验数据等进行了分析研讨，并举电路实例供参照     

不同弧源电流TiN薄膜的表面形貌及其摩擦学性能研究

本文使用AIP-01型国产多弧离子镀膜设备,采用不同的弧源电流在不锈钢衬底及Si片上制备了TiN薄膜,对其硬度、表面形貌以及摩擦系数等进行了测试,从电弧沉积的物理机制角度详细分析了弧源电流对TiN薄膜表面熔滴的影响,结果表明:随着弧源电流的增大,薄膜沉积速率增大、硬度提高,但薄膜表面熔滴(MP)数量增多、尺寸变大,表面粗糙,摩擦系数增大,因此控制最佳弧源电流来获得最好的薄膜性能是离子镀TiN薄膜的关键问题之一.     

可控硅脉冲等离子弧焊电源的研制

本文介绍了可控硅脉冲等离子弧焊电源的研制成果。在参考国外多种焊机的基础上,设计了比较理想的控制电路。试验结果表明:该电源具有良好的动特性和静特性,能很好地满足脉冲等离子弧焊的要求。     

Dissimilar welding of carbon steel to 5754 aluminum alloy by Nd:YAG pulsed laser

Laser welding of low carbon steel to 5754 aluminum alloy was studied in keyhole welding mode in steel-on-aluminum overlap configuration. In order to decrease formation of intermetallic components during laser welding, effect of laser power, pulse duration and overlapping factor was investigated. Tensile test was performed to identify the effect of each parameter on the weld. The phase composition was characterized by energy dispersive spectrometry and Vickers microhardness test and microstructure by optical and scanning electronic microscopes. Results obtained show that increasing peak power (in constant pulse energy), pulse duration (in constant peak power) and overlapping factor (in constant pulse energy and peak power) will increase percentage of intermetallic components (PIC). On the other hand, decreasing the mentioned parameters will cause destructive effects such as inadequate penetration depth, spattering and cavity formation. Improvement in the tensile strength was attributed to low values of intermetallic components in weld metal. Finally, an optimized peak power, pulse duration and overlapping factor were reported.     

锁孔TIG焊接技术的研究进展

锁孔TIG焊接技术具有不开坡口、单面焊双面成形的特点,尤其适用于中厚板焊接。首先介绍了锁孔TIG焊的基本原理,然后分析了目前锁孔TIG焊接波形控制技术的研究现状,主要包括恒流锁孔TIG焊、单脉冲锁孔TIG焊和高低频双脉冲锁孔TIG焊。针对现有锁孔TIG焊接技术存在热输入量过大、接头组织晶粒粗大等缺点,重点介绍了一种新型的快频脉冲TIG焊接技术,它通过快频脉冲电流产生的电磁场对电弧进行压缩,控制焊接过程的热输入量,达到提高焊接质量的目的。与传统脉冲电弧相比,快频脉冲电弧的收缩效果更为明显,可细化焊接接头组织,将快频脉冲焊接技术应用于锁孔TIG焊是今后研究的热点和主要发展方向。     

TC4合金等离子–MIG复合焊过程温度场的数值模拟

目的 研究TC4合金在等离子-MIG复合焊(Plasma–MIG Hybrid Welding)过程中的温度场特性,探究不同电弧功率对熔池形貌的影响。方法 进行了2组4 mm TC4合金板堆焊试验,根据实验结果提出了一种改进的复合热源模型并进行了相应的仿真分析。结果 仿真与实验获得的焊缝截面相吻合;等离子电流的增大使熔池尺寸增大且余高减小,等离子电弧功率的变化对熔池宽度的影响相对较小。结论 等离子–MIG复合电弧对工件的热作用非常集中,更易实现深熔焊、焊接效率更高;所提出的热源模型适用于TC4合金等离子–MIG复合焊温度场模拟。     

The effect of gas tungsten arc welding and pulsed-gas tungsten arc welding processes’ parameters on the heat affected zone-softening behavior of strain-hardened Al–6.7Mg alloy

The heat affected zone (HAZ) softening behavior of strain-hardened Al–6.7Mg alloy welded by gas tungsten arc welding (GTAW) process was investigated. Increasing the heat input during welding led to formation of a wider HAZ. Moreover, the size of the precipitates was increased at higher heat inputs. Consequently, by increasing the heat input, lower strength was obtained for the welding joints. At the second stage of the study, pulsed-GTAW (PGTAW) process was employed to improve the strength of the joints. It was observed that the overall strength of the welding joints was improved and the fracture during tensile test was moved from the HAZ to the fusion zone. Moreover, the effect of duration ratio and pulse frequency was studied. For the current study, the duration ratio did not have a significant effect on the strength and microstructure of the weld, but increasing the frequency led to higher strength of the weld and finer microstructure.     

TIG电弧热丝对铜、钢堆焊的工艺研究

针对某产品铜带焊接工艺,提出了一种电弧热丝方式应用于TIG堆焊铜、钢工艺的研究。电弧热丝可有效预热低电阻率的焊接材料,如铜;传统的电阻热丝只能加热具有高电阻率的焊接材料,如钢。采用电弧热丝系统,热丝电流小于50A时即可有效预热焊丝,与电阻热丝电流400A相当。在相同焊接电流下,能够大大提高焊接熔敷速度;在相同送丝速度下,降低焊接电流,大大降低焊接设备功率。同时证明2种热丝加热方式对钢基体、铜合金的影响相同,特别是对堆焊层铜合金中泛铁量的影响相当。     

Optimizing the Pulsed Current Gas Tungsten Arc WeldingParameters

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.     

Tri-Arc与Tandem双丝电弧焊的工作原理对比分析

目的 介绍一种称为Tri-Arc的新型双丝电弧焊接方法。方法 将Tri-Arc双丝电弧焊与应用较广的Tandem双丝电弧焊的系统构成和焊接电流波形进行对比分析。结果 Tri-Arc和Tandem两种双丝电弧焊接方法所使用的双丝焊枪相近,双电源相位同步控制和U/I脉冲控制方式类似。Tri-Arc和Tandem两种双丝电弧焊接方法的差异在于:Tandem双丝电弧焊的2个电弧是相对独立的,而Tri-Arc双丝电弧焊的2个电弧是相互耦合的,因此Tri-Arc双丝电弧焊又具有旁路耦合电弧的某些特点。结论 这种新型的Tri-Arc双丝电弧焊不仅具有与Tandem双丝电弧焊一样的高焊丝熔敷率,而且具有比Tandem双丝电弧焊更低的焊接热输入。     

6063铝合金单模光纤激光焊接工艺研究

目的 针对采用脉冲激光点焊的6063铝合金焊点拉力较低,无法满足实际需求的问题,研究6063铝合金激光焊接的最优工艺方案,以提升焊点拉力.方法 采用单模光纤激光对6063铝合金进行焊接,通过极细的线宽组成螺旋点,代替单个脉冲激光点焊.对激光功率、焊接速度及离焦量等工艺参数进行正交实验,得到最佳工艺参数,并通过分析焊缝外...     

Microstructural refinement of 6061 and 5052 aluminium alloys by arc oscillation

The mechanism of the microstructure refinement of metals and alloys (5052 and 6061) by arc oscillating was studied and discussed via the grain size of regular welds and those welded at different oscillation frequencies. In 5052 alloy, fine columnar crystals appeared near the ‘internal fusion line’ during the oscillating arc welding and the grains have been significantly refined by oscillating arc with low and high frequency. However, the grain refinement of 6061 Al alloy was limited during arc oscillating welding due to the different crystal growth pattern at the fusion line and material properties. It is not caused by changing of the grain refinement mechanism but by the difference in the material properties.