共查询到20条相似文献,搜索用时 15 毫秒
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ZHANG Qiyun LIU Shuqi LAN Tie FU Yuchuan Peking University Beijing China ZHANG Qiyun Professor Department of Chemistry Peking University Beijing China 《金属学报(英文版)》1990,3(7):54-58
A study on the interfacial activity behavior of flux during aluminium brazing has been madeby using metallography,SEM and electron prob techniques.The results show that the activity,of a flux is caused by the wetting of base metal with the liquid heavy metal reduced from theflux,thus,some regions of liquid alloy created,at which no aluminium oxide film covers on thesurfaces.The reduced metal drops are finally trapped in the fillet.The size of the metal dropsincreases with the decrease of brazing temperature. 相似文献
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The effect of the chemical activity of flux on the properties of deposited metal of Mn–Ni–Mo–V steels, produced by electroslag welding and electroslag remelting, is discussed. It is shown that an increase in the chemical activity of flux by increasing its silica content to 16–24% (FTs-21 flux) in the remelted metal increases the fraction of easily deformed non-metallic oxide inclusions and the number of zones with reduced hardness in the structure of the metal. This increases the elasticity properties and strain capacity of the metal in the process of relaxation of welding stresses and in the formation of the required mechanical properties of the welded joints after final heat treatment. Also, the risk of formation of reheat cracks in the electroslag welded joints is reduced. 相似文献
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Yu. S. Volobuev O. S. Volobuev A. G. Parkhomenko E. I. Dobrozhela O. S. Klimenchuk 《Welding International》2013,27(8):649-653
The composition of a new general-purpose ceramic flux for welding of carbon steels is described. The flux is not susceptible to hydration, has low chemical activity in relation to deposited metal ensuring minimum oxidation of the alloying elements, with easy separation of the slag layer immediately after welding. Consequently, no labour-consuming operations are required for the removal of the slag from the surface of the welded joint. The flux ensures efficient melting with the edges of the welded components and prevents the formation of unacceptable defects in the weld metal. 相似文献
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Zhang Qiyun 《中国焊接》1994,(1)
ReductionofmetalionsonaluminiuminmoltenfluxduringaluminiumbrazingZhangQiyun(BeijingUniversity)Abstract:Themechanismofactivity... 相似文献
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《Science & Technology of Welding & Joining》2013,18(7):550-555
AbstractThe investigation on the influences of the KCl, TiO2 and CaCl2 fluxes on the metal transfer and the spatter loss in metal inert gas (MIG) welding of magnesium alloy is carried out. The results indicate that KCl flux favours the stability of metal transfer and reduces the spatter loss, whereas the extension of the period of metal transfer and the aggravation of the spatter loss are produced by CaCl2 flux, compared with MIG welding. For TiO2 flux, the metal transfer behaviour and the spatter loss are similar to those of MIG welding. The reason for promoting the metal transfer on KCl flux is that the increased electromagnetic force resulted from the enhancement of the welding current. In addition, for MIG welding with the KCl or CaCl2 flux, the arc conductivity is affected together by the metallic atoms and the chlorine atoms contained in the two fluxes. 相似文献
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Effects of flux composition on the element transfer and mechanical properties of weld metal in submerged arc welding 总被引:1,自引:0,他引:1
Kook-soo Bang Chan Park Hong-chul Jung Jong-bong Lee 《Metals and Materials International》2009,15(3):471-477
Submerged arc welding was performed using metal-cored wires and fluxes with different compositions. The effects of wire/flux
combination on the chemical composition, tensile strength, and impact toughness of the weld metal were investigated and interpreted
in terms of element transfer between the slag and the weld metal, i.e., Δ quantity. Both carbon and manganese show negative Δ quantity in most combinations, indicating the transfer of the elements
from the weld metal to the slag during welding. The amount of transfer, however, is different depending on the flux composition.
More basic fluxes yield less negative Δ C and Δ Mn through the reduction of oxygen content in the weld metal and presumably
higher Mn activity in the slag, respectively. The transfer of silicon, however, is influenced by Al2O3, TiO2 and ZrO2 contents in the flux. Δ Si becomes less negative and reaches a positive value of 0.044 as the oxides contents increase. This
is because Al, Ti, and Zr could replace Si in the SiO2 network, leaving more Si free to transfer from the slag to the weld metal. Accordingly, the Pcm index of weld metals calculated
from chemical compositions varies from 0.153 to 0.196 depending on the wire/flux combination, and it almost has a linear relationship
with the tensile strength of the weld metal. 相似文献
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为认识超窄间隙焊接母材熔化特性及熔池形成机制,在放置焊剂带的I形坡口中进行熔化极电弧焊接试验,采用一种快速中断电弧的方法,保留焊接过程中焊剂带、坡口底部和侧壁的熔化形态.结果表明,电弧区焊剂带热收缩效应和固壁约束作用能有效约束坡口中电弧作用范围.当选择合适的侧壁根部焊剂带裸露高度时,电弧加热区域控制在坡口底部和侧壁根部,熔滴过渡的冲击作用及电弧力集中在熔池前端,使熔融金属产生有利于排出熔池中气体和熔渣的流动,形成无缺陷焊缝.当侧壁根部焊剂带裸露高度大于一定值时,电弧所受约束减小,加热区域扩展到较大范围的坡口侧壁上,熔滴过渡分散在坡口底部和侧壁,熔融金属难以形成贯穿熔池的流动,焊缝存在较多孔洞. 相似文献
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An effect of heat flux on initiation and propagation of pitting corrosion of austenitic stainless steel in chloride environment has been studied using electrochemical and exposure methods. The experiments were performed at constant surface temperature of 60°C and heat flux from ? 15 to + 74 kW m?2. The presence of heat flux from metal to solution shifted the breakdown potential towards noble values and lowered the pit density, whereas the pit propagation rate increased. Presence of maximum heat flux caused, in comparison with isothermal conditions, increase of the breakdown potential by approx. 100 mV, reduction of pit density by 30% and increase of the average pit depth by 40%. The positive effect of heat flux from metal to solution was given mainly by improving the protective ability of the passive film, as the amount of oxygen available at the metal surface increased. With a smaller significance, the effect of intensified mass transfer, which made accumulation of the chloride ions on the surface more difficult, occurred. 相似文献
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向Ag30CuZnSn药芯银钎料药粉中添加Ga2O3,研究了Ga2O3对Ag30CuZnSn药芯银钎料钎缝组织的影响及钎焊接头性能的影响. 结果表明,微量Ga2O3可以显著提高Ag30CuZnSn药芯银钎料的润湿铺展性能且可以减少药芯中钎剂的添加量. Ga2O3添加量为0.4%(质量分数)时,钎料润湿铺展性能和钎焊接头抗剪切强度达到最佳值. 这是因为Ga2O3属于表面活性物质,可以显著降低熔融钎料和母材之间的界面张力,从而提高了钎剂粉末的去膜效果,进而提高银钎料的润湿铺展性能. 药芯银钎料基体及钎缝组织主要由以CuZn相为主的固溶体、银基固溶体和铜基固溶体构成. 火焰钎焊时,添加0.4%Ga2O3(质量分数)时作用效果最佳,钎缝组织的细化与钎着率的提高(钎着率提高至95%以上)使得钎焊接头抗剪强度提高了11%以上,钎焊接头断口组织的形貌证明了上述结果. 相似文献
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0 IntroductionSelf-shielded flux cored wire is a newly developedwelding material used without gas protection. Use of suchcored wires has grown rapidly in developed countriesbecause of the following advantages: simple use, goodwind resistance ability, lower cost resulted from highproductivity and strong desulfurization ability[1]. Self-shielded flux cored wires are preferred for on-site weldingsuch as ship and barge building, storage tank, bridge,offshore oil platform buildings and so on[2 -3].… 相似文献
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简述了药皮钎料环研制的背景及意义,详细介绍了药皮成分选定原则和药皮制造技术,对比了药皮钎料环和实心钎焊焊条在节约环保、生产自动化等方面的优势,并阐述了其应用领域。研究结果表明:环保型药皮钎料环实现了钎料和钎剂定量、高效的添加,且不含有机粘结剂,有效减少了焊剂的使用量,节约环保;药皮钎料环在提高生产效率、保证产品钎焊质量、减少环境污染等方面发挥重要作用,这使得药皮钎料环有非常广阔的应用前景。 相似文献
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针对铝合金交流A-TIG焊、FB-TIG焊和FZ-TIG焊,研究活性剂与熔池表面金属或表面氧化膜之间的化学反应,对于确定这些焊接方法的可行性和指导活性剂配方开发具有重要意义.通过焊缝表面焊渣XRD分析,并采用物质吉布斯自由能函数法进行反应热力学计算分析了熔池表面发生的化学反应.发现采用FZ108+SiO2的FZ-TIG焊发生了活性剂FZ108与熔池金属之间的吸热反应,能起到收缩电弧增加熔深的作用;对于采用FZ108的A-TIG焊,反应所吸收或放出的热量少,对收缩电弧的作用也很小;对于采用SiO2的FB-TIG焊,未发生活性剂与熔池金属和表面氧化膜之间的化学反应,不会通过该反应过程影响电弧. 相似文献
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采用铝硅钎料进行了铝/钢异种合金TIG熔-钎焊试验,开发出了适用于TIG电弧热源下的特种钎剂,通过高速摄影观察了液态钎料的润湿铺展行为,并分析了接头特性.结果表明,特种钎剂能够显著促进钎料的润湿铺展,钎剂成分(质量分数,%)为:改性的Noclock钎剂(KAlF4:K3AlF6,65:35)55~78,Zn10~20,Sn10~20,K2SiF62~5.液态钎料的铺展包括两部分:一是通过成形槽,沿钢背面进行铺展,获得良好的背面成形;二是沿坡口表面进行"上坡"铺展,实现焊缝正面成形.铝/钢TIG熔-钎焊接头具有熔焊与钎焊的双重性质,接头抗拉强度可达115.5MPa,断裂于焊缝/不锈钢界面层. 相似文献
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为了提高铝合金对激光的吸收率,改善焊缝表面成形,对1.8mm厚的6013铝合金板进行活性剂CO2激光焊接。活性剂主要采用的是对激光具有较高吸收率的氧化物和氟化物,将其焊前预涂覆于铝合金板上,然后施焊。结果表明:活性剂在提高CO2激光吸收率,增加母材金属熔化量方面具有明显的效果;氧化物活性剂对促进激光能量吸收的效果要强于氟化物,但氧化物形成熔渣的脱渣性较氟化物熔渣的差;在氧化物活性焊接过程中,气孔敏感性比较大,而氟化物活性剂在焊接过程中很少出现气孔。 相似文献
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V.N. Matviyenko L.K. Leshchinskiy K.K. Stepnov E.N. Schebanits N.I. Omelyanenko 《Welding International》2013,27(1):65-69
The composition of 20KhN4MFB coldrolled strip for hardfacing rolling rolls was determined and production started. The deposited layer is characterized by high impact toughness, plasticity and resistance to cyclic heat changes. Additional alloying to increase the hardness and wear resistance of the metal is carried out through a ceramic flux. The composition of the new ceramic flux is characterized by improved welding and technological properties and relatively low chemical activity. Hardfacing of the hot rolling rolls increases the volume of rolled material per 1 mm of the reduction of the roll diameter. 相似文献