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.

Fume and gas emission during arc welding: Hazards and recommendation

Abstract: Welding is the principal industrial process used for joining metals, but at the same time, it’s the significant source of toxic fumes and gases emission. With the advent of new types of welding procedures and consumables, the number of welders exposed to welding fumes is growing constantly in spite of the mechanisation and automation of the process. Having in mind that, in some cases, toxic fumes and gases can be over the respective limits for toxic substances, one of the most important requirements for chosen welding procedure is its harmlessness to the environment. The health aspects associated with welding are complex and the industry is continuing its research to evaluate the effects of the welder’s exposure to typical constituents of welding fumes and gases, as well as its impact on what concerns climatic changes. The aim of this paper is to estimate the influence of the type of filler material on the emission of toxic substances, and to show the potential hazards. In order to determine that effect, microalloyed steel has been welded using two different filler materials (metal cored wire and self-shielded wire). The concentrations of emitted total dust, CO 2 , CO, SO, Mn, Ni, Al, Cr, Cr(VI), Ca and P were measured. By comparing results for both filler materials, it was established that the special attention must be paid to the high concentration of manganese and CO in metal cored wire, as well as high concentrations of phosphorus and aluminum in self-shielded wire. Also, conducted experimental measurements of emission of certain elements did not show higher toxicity of self-shielded wire compare to metal cored wire, what is in the contrast with previous studies.

The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

Abstract: In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

Effects of Nb on the microstructure and corrosive property in the Alloy 690–SUS 304L weldment

Abstract: A study of the microstructure and corrosion of dissimilar weldments of Alloy 690 and SUS 304L with various additions of niobium (Nb) (0.1, 1.03, 2.49, and 3.35% by weight) in the flux of coated electrodes is presented. With identical welding parameters and procedures, the weldments were butt-welded in three layers by shielding metal arc welding (SMAW), with each layer being deposited in a single pass. The results show that the dendritic microstructure in the fusion zone changed from a cellular to columnar dendrite and equiaxed dendrite with increasing Nb addition. Furthermore, the interdendritic phase increased in volume and changed in composition from an Al–Ti oxide to a mixture of Nb–Si phase and Nb-rich phase. Nevertheless, it was clearly observed that Cr 7 C 3 precipitated at the grain boundaries of the low Nb weldment root pass. Finally, the results revealed that corrosion occurs primarily at the grain boundaries and within the interdendritic regions of the weldements irrespective of the level of Nb addition. For the region of abundant formation of Nb-rich phase, the high-Nb weldment had a relatively low corrosion resistance.

The effect of joint shape geometry on the microstructural evolution, fracture toughness, and corrosion behavior of the welded joints of a Hadfield Steel

Abstract: Effect of joint shape geometry on properties of Hadfield steels welded via Shield Metal Arc Welding (SMAW) was studied. Fracture toughness, tensile strength, hardness and corrosion behavior were ex...