Shielded metal arc welding

About: Shielded metal arc welding is a research topic. Over the lifetime, 4462 publications have been published within this topic receiving 40560 citations. The topic is also known as: manual metal arc welding & flux shielded arc welding.

Physical Phenomena and Porosity Prevention Mechanism in Laser-Arc Hybrid Welding

Abstract: Hybrid welding of stainless steels or aluminium alloys was performed with the heat sources of YAG laser and TIG, or YAG laser and MIG, respectively. The effects of welding conditions and melt flows on penetration depth, geometry and porosity formation were investigated with the X-ray transmission real-time observation method. Melt flows on penetration depth and geometry were consequently confirmed. Concerning porosity suppression, in TIG-YAG hybrid welding of stainless steel, no formation of bubbles was attributed to the absence of pores. On the other hand, disappearance of bubbles from the concave molten pool surface due to the arc pressure played an important role in reducing porosity in YAG-MIG hybrid welding of aluminium alloys at high arc currents.

Pure Ar gas shielded welding MIG flux-cored wire and MIG arc welding method

Abstract: A pure Ar-MIG welding wire for welding steel according to the present invention is formed of a flux-cored wire. The flux-cored wire is formed in the manner that a formation formed by welding a carbon steel hoop into a pipe shape or a seamless pipe is used as an outer sheath, the outer sheath is filled with a flux, and a wire drawing process is performed. The flux accounts for 7 to 27 mass% of the total wire mass. The wire contains graphite in the amount of 0.16 to 2.00 mass% on the basis of the total wire mass and iron powder in the amount of 20 mass% on the basis of the total flux mass. According to the construction, neither expensive metal resource nor a greenhouse effect gas is used, slag and fume generation is inhibited, and a weld joint having a high static tensile strength and fatigue strength can be obtained.

Effects of fume particles from stainless steel welding on sister chromatid exchanges and chromosome aberrations in cultured chinese hamster cells

Abstract: The frequencies of sister chromatid exchanges (SCE) and chromosome aberra-tions were examined in cultured Chinese hamster cells (Don) exposed to two sorts of fume particles collected from different procedures of stainless steel weldingIt was confirmed that the frequencies of SCE and chromosome aberrations in the cells treated with these fume particles increased with increasing fume doses within the range of the fume concentration tested The fume partticles collected from manual metal arc (MMA) welding were more powerful than those from metal inert gas (MIG) welding In order to cause the same increase in SCE frequency the fume particles from MIG welding needed to be about 100 times as much as those from MMA welding The fume particles from MMA welding showed a higher so-lubility of Cr than those from MIG welding The amount of dissolved Cr from the former was about 60 times as much as that from the latter when culture medium was used as a solvent Small amounts of Mn, Ni, Fe and Mg were also detected in the supernatants of both fume suspensions There were no significant differences in the amounts of these metals as was found with Cr when comparing MMA weld-ing with MIG welding The frequencies of SCE and chromosome aberrations were also increased by the addition of the supernatants of these suspensionsFrom these results, it was assumed that dissolved hexavalent Cr may be involved in the cytogenetic effect of the fume particles from stainless steel welding

CO2 laser beam welding of 6061-T6 aluminum alloy thin plate

Abstract: Laser beam welding is an attractive welding process for age-hardened aluminum alloys, because its low heat input minimizes the width of weld fusion and heat-affected zones (HAZs). In the present work, 1-mm-thick age-hardened Al-Mg-Si alloy, 6061-T6, plates were welded with full penetration using a 2.5-kW CO2 laser. Fractions of porosity in the fusion zones were less than 0.05 pct in bead-on-plate welding and less than 0.2 pct in butt welding with polishing the groove surface before welding. The width of a softened region in the-laser beam welds was less than 1/4 times that of a tungsten inert gas (TIG) weld. The softened region is caused by reversion of strengthening β″ (Mg2Si) precipitates due to weld heat input. The hardness values of the softened region in the laser beam welds were almost fully recovered to that of the base metal after an artificial aging treatment at 448 K for 28.8 ks without solution annealing, whereas those in the TIG weld were not recovered in a partly reverted region. Both the bead-on-plate weld and the butt weld after the postweld artificial aging treatment had almost equivalent tensile strengths to that of the base plate.