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.

Effect of Coating Thickness on Electrode Life in the Spot Welding of Galvanized Steels

Abstract: This study examined the effect of coating thickness on electrode life and nugget strength. Uncoated and galvanized steel sheets supplied from Eregli Iron and Steel Factories Co. (Erdemir) with similar chemical compositions having different coating weights (100, 180, and 275 g/m2) were welded using resistance spot welding under constant welding parameters. Electrode force used during spot welding operation was 7.3 kN under 6.5 kA of constant welding current and 2 s welding time. After welding operations, shearing tests were applied to selected specimens and the nugget diameters were measured. Experimental results showed that as the coating thickness increased the electrode life and the strength of the weld nugget decreased.

Effect of welding consumables on hydrogen induced cracking of armour grade quenched and tempered steel welds

Abstract: Armour grade quenched and tempered (Q&T) steels are susceptible to hydrogen induced cracking (HIC) in the heat affected zone after welding. Austenitic stainless steel (ASS) consumables are selected for welding Q&T steels as they have higher solubility for hydrogen in the austenitic phase and it is the most beneficial method for controlling HIC in Q&T steel welds. Recent studies reveal that high nickel steel and low hydrogen ferritic steel consumables can be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits. In this investigation, an attempt has been made to study the effect of welding consumables on hydrogen induced cracking of Q&T steel welds by implant testing. Shielded metal arc (SMAW) welding process has been used for making welds using three different consumables, namely austenitic stainless steel, low hydrogen ferritic steel (LHF) and high nickel steel (HNS) to assess HIC by implant testing. The high nickel steel consumables exhibited a higher value of lo...

Effect of the welding technique on mechanical properties and metallurgical characteristics of the naval grade high strength low alloy steel joints produced by SMAW and GMAW

Abstract: Naval grade, high strength low alloy (HSLA) steel is designed especially for shipbuilding applications due to its high strength to weight ratio. The conventional fusion welding processes of shielded metal arc welding (SMAW) and gas metal arc welding (GMAW) are employed widely for structural applications. This work reports the influence of welding processes on mechanical properties and metallurgical characteristics of fusion welded DMR249A grade steel. The evaluating tensile, impact, microhardness properties were correlated with microstructures. The maximum recorded transverse tensile strength value of SMAW and GMAW joints were 558 MPa and 578 MPa. The lower microhardness had obtained in the subcritical heat-affected zone than other regions. The weld zone microstructure consists of fine, elongated, and columnar grain structures. From this investigation, it has been concluded that GMAW joints displayed marginally better properties than SMAW joints. But most weld failures has been observed in the subcritical heat-affected region; due to grain deformation and subsequent softening in the weldment.

On the Use of Arc Radiation to Detect the Quality of Gas Metal Arc Welds

Abstract: Gas metal arc (GMA) welding has over the years grown both in stature and strength to become a widely used welding process in the industries related to manufacturing. With sustained and noticeable developments in the technologies related to welding a need to automatically detect and even control the quality of welding has become both essential and desirable. Since defects present in the weld are mainly caused by an instability of the welding process, the overall quality of the welds can be detected from this instability. In order to detect the quality of the weld made by GMA welding, the arc light spectrum was collected and thoroughly analyzed and is the basis of presentation and discussion in this technical manuscript. The instability of the welding process is caused by either an improper selection and use of the welding parameters or the disturbance factors that are introduced during the welding process. Preliminary studies have shown that radiation of arc light comprised of spectral zones each having di...

Hydrogen in welding

Abstract: This chapter discusses the role of hydrogen in welding. The hydrogen content in weld deposits is a function of several variables, namely, welding technique; atmosphere; composition of steel; composition of electrodes and coatings; and cooling rate. During the welding of steel, some parts of the metal attain high temperatures, possibly of the order of 3000°C or more. Under these conditions, the dissociation degree of gaseous hydrogen and its solubility in iron are high. If the air has free access to the metal welded, then oxidation takes place and the metal absorbs little hydrogen. Such a case occurs when bare wires are employed for arc welding of steel. The phenomena caused by hydrogen in weld deposits are consistent with the conclusions drawn from the experimental results concerning other fields of metallurgy. The harmful effect of moisture on welding resembles its effect in steelmaking processes. Under bead cracking of weldments might be related to the formation of hair-line cracks in wrought steels.