基于药芯焊丝飞溅率模型决策分析的药芯配方的评判

在简要介绍了定量指标模糊综合决策方法的基础上，提出并建立了二级定量指标模糊综合决策模型，并将该模型应用于药芯焊丝药芯粉配方对飞溅率影响的评判问题中，试验结果表明，模糊决策模型的评判结论与试验结果吻合良好，这说明该模型能够较为准确地通过对药芯焊丝飞溅率的评判来确定药芯粉配方的优劣，从而也证明了模糊决策方法应用于焊接领域中的可行性与有效性。     

减少药芯焊丝飞溅的途径

对降低金属芯型药芯丝飞溅的途径进行了研究和探讨。结果表明，金属芯药芯焊丝中加入适当数量的K、Na化合物时，可以明显降低焊接飞溅。     

造渣剂组分对507Mo型药芯焊丝脱渣及飞溅性能的影响

通过改变药芯焊丝中金红石、镁砂、硅灰石、萤石等造渣剂的配比进行试验,研究造渣剂在药芯焊丝中的含量变化对507Mo型药芯焊丝脱渣率及飞溅率的影响。试验表明,在507Mo型药芯焊丝中,金红石含量不超过6%时,增加金红石含量能够改善焊丝的脱渣及飞溅性能;镁砂能提升药芯焊丝的全位置焊接性,使药芯焊丝能够进行横焊及立向上焊接,镁砂的加入量超过1.0%时焊丝的脱渣及飞溅开始变差;硅灰石能够改善焊丝的脱渣及飞溅性能,随着硅灰石的增加,熔渣在焊道表面覆盖更加均匀,但是过量的硅灰石会使焊道表面出现压铁水现象;萤石能够降低熔渣的熔点,改善熔渣的流动性,有利于熔渣在焊道表面的铺展及覆盖,萤石电离产生的F-和熔池中的H+结合生成HF气体,提高了熔滴的爆破力,使焊接飞溅率增加,萤石含量超过1.0%时会大幅增加焊丝飞溅率。     

药芯焊丝电弧焊熔滴过渡与焊接飞溅

针对不同焊接参数下SQJ501型、SQJS07型和SQJ50MX型药芯焊丝电弧焊的熔滴过渡行为进行了拍照,并对焊接飞溅进行了测量,研究药芯焊丝电弧焊的熔滴过渡行为及其焊接飞溅的基本规律.试验结果表明:三种药芯焊丝随着焊接参数的增大,均依次发生短路过渡、大滴排斥过渡和细颗粒过渡.SQJ501型和SQJS0MX型药芯焊丝电孤焊电弧形态呈锥形,SQJS07型电弧形态接近于钟形.SQJ507型药芯焊丝出现细颗粒过渡的焊接参数比其他两种焊丝大.焊接工艺参数以及焊丝种类影响了熔滴过渡行为进而影响焊接飞溅,细颗粒过渡时产生的飞溅最小.     

自保护药芯焊丝飞溅的形成机理及其影响因素

详细研究了自保护药芯焊丝飞溅的形成机理及其影响因素.高速摄影观察表明,自保护药芯焊丝在焊接过程中的飞溅主要有以下三种形式,电弧力引起的大颗粒飞溅、气泡放出型飞溅和气体爆炸引起的飞溅.通过混料回归试验分析了药粉中氟化物、氧化物、碳酸盐、脱氧剂、合金元素对焊接飞溅的影响规律.结果表明,氟化物和碳酸盐对飞溅的影响较大,氧化物、脱氧剂和合金元素对飞溅的影响较小.     

“滞熔”现象对碱性气保护药芯焊丝飞溅的影响

在大量工艺性试验的基础上，讨论了碱性气保护药芯焊丝特有的药芯滞熔现象及其对滴过渡形式的影响，并对药芯滞熔的因素（药芯填充率、矿物成分和金属粉）进行了正交试验，分析了探讨这些因素对药芯滞熔程度和飞溅的影响规律，提出控制芯滞熔程度是减小飞溅的有效５措施。     

金属粉芯型药芯焊丝熔滴过渡及飞溅观察分析

采用高速摄影技术对金属粉芯型药芯焊丝的熔滴过渡及飞溅进行观察分析,总结了金属粉芯型药芯焊丝在试验参数下的熔滴过渡类型和特征以及飞溅类型和特征,阐述了熔滴过渡特征以及飞溅特征产生的原因．结果表明,采用100％CO2气体保护时,焊接过程中电弧电压波动较大,熔滴过渡不稳．以排斥过渡为主,少量细颗粒过渡和爆炸过渡,焊接飞溅大;采用5％CO2＋95％Ar保护时,熔滴过渡为单一射滴过渡,熔滴过渡平稳,电弧稳定,焊接飞溅小;金属粉芯型药芯焊丝飞溅形式主要包括：气泡放出型飞溅、缩颈飞溅、熔滴爆炸飞溅以及电弧力引起的飞溅．     

自保护药芯焊丝熔滴过渡及飞溅分析

电弧物理特性是影响电弧行为和焊接飞溅的重要因素。利用高速摄像技术和汉诺威弧焊分析仪观察分析自保护药芯焊丝的电弧行为、熔滴过渡特征与飞溅形式的关系。研究发现,自保护药芯焊丝电弧在滞熔渣柱周围环绕旋转、熔滴过渡的模式以及焊接冶金反应是形成焊接飞溅的主要原因。焊接过程中自保护药芯焊丝主要有五种飞溅形式:爆炸飞溅、电弧力引起的飞溅、气泡放出型飞溅、颗粒偏飞和熔池飞溅。统计结果表明,爆炸飞溅是数量最多的飞溅。     

不锈钢药芯焊丝E308LT1-1对防飞溅剂的适应性改进

通过对不锈钢药芯焊丝E308LT1-1在使用防飞溅剂时,焊接后容易产生气孔进行分析,发现防飞溅剂污染焊接坡口后焊接时产生了大量的气体,导致不锈钢药芯焊丝E308LT1-1焊缝容易产生氢气孔。合理控制氟化物和氧化物的加入量能够提高不锈钢药芯焊丝对防飞溅剂的适应性,使焊缝不产生气孔;合理加入氧化铁和氧化铈不会对该药芯焊丝工艺性能和力学性能产生不良影响。     

高铬铸铁型药芯焊丝熔滴过渡及飞溅试验研究

通过高速摄影技术及焊接飞溅率测试试验,详细阐述了金属粉型高铬铸铁自保护硬面药芯焊丝的熔滴过渡过程以及飞溅产生的原因及特点。结果表明,高铬铸铁自保护硬面药芯焊丝的熔滴过渡模式主要是大滴排斥过渡,熔滴可以长大到焊丝直径的2倍左右;其飞溅率较低,在1%左右;绝大部分飞溅产生于熔滴脱离焊丝端部瞬间、熔滴落入熔池的瞬间、熔滴爆炸以及熔滴形成的初期。其中,对焊接过程影响不大的直径小于1 mm的小颗粒飞溅占较大比例,存在少量的直径在1~2 mm之间的中等大小颗粒飞溅,而直径大于2 mm的大颗粒飞溅在试验中出现的频率较低。     

Opportunistic maintenance based on fuzzy modelling of component proximity

Conventional maintenance strategies on a single component are being phased out in favor of more predictive maintenance actions. These new forms of maintenance are emerging today for better controlling the global performances of the whole system all along its life cycle. They are anticipative in nature allowing developing non-already-planned maintenance actions or to move earlier or later a planned maintenance action. It leads to investigate opportunistic interventions by considering, for example, the direct environment of a given component to be maintained in order to run additional maintenance actions on other components considered enough closed (proximity principle). Thus, this paper presents a new fuzzy methodology to assess component proximity in the design phase to impact design out maintenance. The methodology is applied on an industrial case study.     

Study on metal transfer modes and welding spatter characteristics of self-shielded flux cored wire

Abstract

The metal transfer behaviour of self-shielded flux cored wire and the resultant welding spatter were investigated by using a high speed camera. Three modes of metal transfer were found, i.e. bridging transfer without arc interruption in explosive form or by surface tension, globular repelled transfer and droplet transfer, while the former two modes played a key role in the weld metal transfer. Correspondingly, the bridge explosion, discontinuous globular repelled process and the misalignment of droplets transfer were the main factors causing the welding spatter.     

基于有限元分析的摩擦系数测定

在塑性体积成形有限元模拟中,摩擦模型和摩擦系数的确定是一个关键问题.本文采用圆环镦粗法研究体积成形中摩擦系数的确定.利用有限元分析确定一组摩擦系数标定曲线,用圆环镦粗试验确定圆环内径变化率百分比与圆环高度压缩百分比关系曲线.通过曲线对比得到模具材料和成形材料之间的摩擦系数.针对6A02CZ材料在钢模具中体积成形时6A02CZ材料与钢之间的摩擦系数进行确定,6A02CS材料在无润滑剂和润滑油做润滑剂两种情况下的摩擦系数分别为0.325和0.3.研究表明,采用有限元方法和圆环镦粗试验相结合的方法更适合塑性体积成形中的有限元分析.     

冲压成形仿真数据的主成分与模糊聚类分析

冲压成形数值仿真结果中隐含着大量的领域知识。文章将主成分分析与模糊聚类方法应用于基于仿真模型与模拟结果数据的冲压件相似性判别与成形性能判别。通过对油箱冲压成形有限元仿真结果数据进行处理,分析了压边力、拉延筋设置参数、摩擦系数等工艺参数对成形性能的相对重要程度;构造了油箱成形性能的模糊概念,描述其破裂、起皱程度。通过对汽车覆盖件有限元模型数据的分析,对汽车覆盖件进行模糊分类及相似性判别。结果表明,面向有限元仿真结果的数据挖掘技术,可以为冲压成形领域知识发现提供一种有效的新途径。     

基于有限元模拟的极限拉深系数优化

结合0.618优化算法,运用ANSYS分析软件,通过改变坯料尺寸的方法,对板料的成形过程进行模拟,对板材的极限拉深系数进行逼近优化,并将模拟和优化结果与物理拉深试验结果进行了比较。     

基于模糊算法的7050铝合金微观结构自动分析

晶粒度是高强度铝合金微观组织分析的关键参数。通常是由人工手动获得,整个过程耗时且容易出错。目前随着数字图像处理技术和模式识别技术的快速发展为定量金相分析提供了一种新的方法。利用人工智能实现自动金相分析可以克服手工工艺的缺点。在本文中提出了确定的金相图像的晶粒尺寸的数字图像处理的一种新方法。基于模糊逻辑的边缘检测算法的提取晶界。并对不同方法的金相图像提取方法进行了对比,验证了该方法的有效性。并基于美国材料试验学会（ASTM）标准获得了晶粒度等微观组织参数。     

A coefficient clustering analysis for damage assessment of composites based on pulsed thermographic inspection

This paper introduces a coefficient clustering analysis method to detect and quantitatively measure damage occurring in composite materials using pulsed thermographic inspection. This method is based on fitting a low order polynomial model for temperature decay curves, which (a) provides an enhanced visual confirmation and size measurement of the damage, (b) provides the reference point for sound material for further damage depth measurement, (c) and reduces the burden in computational time. The performance of the proposed method is evaluated through a practical case study with carbon fibre reinforced polymer (CFRP) laminates which were subjected to a drop impact test with varying energy levels. A novel method for reducing an entire thermogram sequence into a single image is introduced, which provides an enhanced visualisation of the damage area.     

Dynamic character analysis for the arc welding power source based on fuzzy logic

A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic reasoning method, a dynamic character assessing model for the arc welding power source was established and used to analyze the dynamic character of the welding power source. Three different types of welding machine have been tested, and the characteristic information of the electrical signals such as re-striking arc voltage, low welding current and so on of the welding process were extracted accurately by using a self-developed welding dynamic arc wavelet analyzer. The experimental results indicate that this model can be used as a new assessing method for the dynamic character of the arc welding power source.