焊条成形工艺对手工自蔓延焊接的影响
Effects of forming process of combustion welding rod on manual SHS welding
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摘要: 系统研究了焊条成形工艺对手工自蔓延焊接燃烧过程和焊接质量的影响.结果表明,粉末粒度、装药密度和混料时间均对焊接有显著影响.粉末粒度增大,焊缝出现大量气孔,强度降低;粉末粒度减小,燃烧速度加快,焊接可控性降低;粒度在-260~+300目时,焊接效果最佳.焊条燃烧速度随装药密度呈先增后减并逐渐趋于平稳的变化趋势,当药粉密度ρ>2.7 g/cm3时,焊条燃烧平稳,焊接可控性好.混料时间增长,燃烧合成反应加剧,燃烧速度加快,焊接飞溅增大;混料时间不足,粉末混合不均,焊接热量不足,制作燃烧型焊条以30 min混料时间为宜.焊条直径对于燃烧影响较小,宜根据焊件厚度选择合适的焊条直径.Abstract: The influence of forming process of the combustion rod on manual self-propagating high-temperature synthesis(SHS) welding was investigated systematically,and the optimum parameters were obtained.Results showed that the particle size,the forming density and the mixing time had significant effects on the combustion reaction and the welding quality.As the particle size of the powder increased,welding spatter became severe and a lot of stomata generated in the seam.As the particle size decreased,the combustion velocity increased and the rod was difficult to operate.The optimum particle size to make combustion rod was -260 to +300 mesh.It was showed that there was a peak in the forming density and combustion velocity curve.The optimum forming density was between 2.74 and 3.05 g/cm3.Results also showed that when the mixing time increased,the reaction and spatter became violent.But if the mixing time was too short,the powder could not contact adequately and the heat generated was not enough to melt the metal.The optimum mixing time was 30 min.It was showed that the diameter of the rod had not obvious effect on the combustion,and it could be determined by the thickness of the weldment.