Papers by Keyword: Butt Weld

Abstract: Plasma and TIG arc welding they are similar welding processes for the base of plasma welding is tig welding. The main purpose of this paper to come to a detailed conclusion based on a comparative analysis of both welding processes. The analysis is done steel bars each applied with the particular welding technique either plasma or tig welding. The principles of each welding procedure are discussed on how they welding is carried out, the mechanics and the technological functions of the welding devices are also discussed. The time required to complete a weld, the amount of current used. Impact on the steel is investigated caused by each welding processes. The welded joints are tested for bending and how much they elongate when under bending stress. The welded joints are done as butt welds for both of the grouped steel bars. These welding processes are used in industries where precision is of great importance like aerospace, design of industrial machinery, ship construction and Petro chemical industries. The concluded results of this paper will be of great contribution to the manufacturing industries because they would be able to know which welding process is best for which particular case or both must be used in order to achieve an ideal outcome. Keywords: Plasma and Tungsten inert gas TIG welding arc, tensile mild Steel bars, bending, butt weld, Amount of current, elongation.

Abstract: Plasma Arc Welding (PAW) is one of the important arc welding processes used in electronics, medical, automotive and aerospace industries due its high accuracy and ability of welding any hard materials which is more tolerant to joint misalignment than Laser Beam Welding (LBW) at a lower cost. Thickness of 1.6mm plates were used to obtain full penetration and a strong joint with a very narrow Heat Affected Zone. The present study deals with the effect of mechanical and corrosion resistance properties of butt welded 1.6 mm thick martensitic stainless steel-similar (SS410 and SS410) joints made by plasma arc welding technique. Similar butt Welded joints were analyzed by using mechanical (Bend test, Erichsen cup test, Tensile test) characterization methods. Their corresponding corrosion resistance properties were also investigated by potentiodynamic polarization corrosion testing technique. The tensile strength was found to be 341 MPa for similar SS410 weld. During tensile test the failure occurred on the base metal on both similar joints Keywords: SS304; SS410; PAW; Butt weld; Erichsen Cup Test; Microstructure.

Abstract: Plasma Arc Welding (PAW) is more tolerant to joint misalignment than Laser Beam Welding (LBW) at a lower cost [1]. The present study deals with the assessment of mechanical and metallurgical properties of butt welded 1.6 mm thick austenitic stainless steel similar (SS304 and SS304) by using plasma arc welding technique. Similar butt-Welded joints were analyzed by using mechanical (Bend test, Erichsen cup test, tensile test) and metallurgical (Optical macroscopic and microscopic images) characterization methods. The bead width and depth of the butt welded 1.6mm thick butt joined SS304 was analyzed by macroscopic and microscopic images [2]. The Erichsen cup test was conducted on the weld specimens. The indentation was made on the weld specimens. In the similar metal joint the depth of indentation is high, which shows that the similar metal joint has better formability. This makes them appropriate for practicing in the aircraft industries (engine parts), automotive sector (engine-parts and assemblies) chemical processing, food processing, turbine buckets, pumps and valve parts [3]. Keywords: SS304, PAW, Butt weld, Erichsen Cup Test, Microstructure

Abstract: Finite element simulation is utilized in an aluminum alloy 2014 butt weld with the three kinds of welding processes, namely the filler wire Tungsten Inert Gas (TIG) welding, the laser welding and laser-TIG hybrid welding. The simulated results are in good agreement with the weld cross sections for the TIG and the laser welding, and basically in agreement with that for the laser-TIG hybrid welding using the actual welding parameters. Furthermore, the simulated results shown that the longitudinal residual stresses after welding are the largest for the laser welding and the laser-TIG hybrid welding, the maximum of which are approximate to 300MPa and are 1.2 times of that for the TIG welding. However, the residual stresses would be relatively decreased by backing molten with TIG welding and preheating before welding; the maximum longitudinal residual stresses for the laser welding and the laser-TIG hybrid welding could be decreased remarkably by about 50%.

Abstract: Welding is a reliable and efficient joining process in which the coalescence of metals is achieved by fusion. Welding is widely employed in diverse structures such as ships, aircraft, marine structures, bridges, ground vehicles, pipelines and pressure vessels. When two dissimilar plates are joined by welding process, a very complex thermal cycle is applied to the weldment, which further causes inhomogeneous plastic deformation and residual stress in and around fusion zone and heat affected zone (HAZ). Presence of residual stresses may be beneficial or harmful for the structural components depending on the nature and magnitude of residual stresses. In this study, a finite element analysis has been carried out to analyze the thermo-mechanical behaviour and effect of residual stress state in butt-welded in low carbon steel plates. A coupled thermal mechanical three dimension finite element model was developed. Finite element method based software SolidWorks Simulation, was then used to evaluate transient temperature and residual stress during butt welding of two plates. Plate thickness of 8 mm were used which are normally joined by multi-pass operation by Manual Metal Arc Welding (MMAW) process. During each pass, attained peak temperature and variation of residual stresses in plates has also been studied. The results obtained by finite element method agree well with those from X-ray diffraction method as published by Murugan et al. for the prediction of residual stresses.

Abstract: The UUltra -high -strength (UHS) steels are used in booms, transport vechicles and other light weight structures. It is well -known that it is possible to achieve a strong weld statically, as the base material, by using laser welding as a weld method [1]. The design strength of the light weight structure is often rather high. In the case of booms and transport vechilevehicles, there can be very high dynamic forces in the structure. Therefore it is necessary to study how much fatigue stress the weld seam can resist and at the same time find the optimal welding parameters. The 4 mm bainitic-martensitic UHS steel was welded with laser without filler material to lasercut seam edges by using different weld parameters. Argon gas was blown by pipe onr coaxial nozzle near the key hole and through a 60 mm gas nozzle after the keyhole. Also, the root side of the weld was shielded with argon. The welds were tested by using the bending fatigue test. The test stresses were 800 MPa and 700 MPa. The fatigue strength results showed that with the laser welded seams, the number of cycles wereas about three times lower than with the base material. The fatigue strength was slightly better in welds which were welded with lower energy input. In the case of the weld seam which was welded with lowest energy input by using 300 mm optics, there was some incomplete penetration due to tooexcessively high surface roughness ofat the weld seam edges.

Abstract: In the steel-work the rolled coils of low carbon steel plates must be unended before pickling on the continuous mill. This was solved with butt welded joint by laser beam welding at ISD DUNAFERR Dunai Vasmő ZRt. The 8 kW light power, near TEM00 mode laser beam’s final part of optical system is a divided parabolic mirror, which creates two focal spot in the welding region. In the interest of productivity rising, the rolled bands’ ends have to be welded at the highest speed as far as possible. The welded seams have to tolerate the repeated bends on the pickling mill without cracking. The optimum parameters of laser welding technology were determined by metallography and calculation of energetic efficiency.

Abstract: The laser weldability of austenitic stainless steel (ASS) is good because of the material’s high absorptivity and favourable microstructure. There can be a slight possibility of solidification cracking at high welding speeds and low Crekv/Niekv ratios. Test welds were welded with a Yb:YAG disc laser. The test material was 3.2 mm EN 1.4404 2H C700 type stainless steel plate which was work hardened by cold rolling. The test materials were welded with different heat inputs ranging from 0.024 kJ/mm to 0.12 kJ/mm and with 300 mm and 200 mm focal lengths. The weld seams were square-groove welded as butt weld without filler material. The edges of the groove were made by mechanical or laser cutting. The hardness profiles from cross-sections of the welds were measured with a Vickers microhardness tester using 200 g weight. The mechanical properties were tested with tensile tests. The welds were classified with radiographic verification by an accredited laboratory. A number of the welds were fatigue tested with a bending fatigue tester. The mechanical properties (Rp 0.2%, Rm) of the laser welds were almost the same as in the base material except at the highest heat input. In the radiographic classification, the welds which were welded to the laser-cut edge were classified as class B (accepted). The other welds were classified as class D or C (rejected). The main reasons for the rejection of welds made on mechanically cut edges were lack of penetration or undercut of the weld. A problem with mechanically cut edges, and hence the welds, is that they can be non-square and bent edge. Fatigue tests and tensile tests gave no evidence of solidification cracking in the microstructure of the solidified parts of the welds.

Abstract: The purpose of this paper is to develop an estimation formula of stress concentration factors of butt-welded components under tensile loading. To investigate the influence of weld bead profiles on stress concentration factors of double V groove butt-welded joints, butt-welded specimens were made by CO2 gas metal arc welding. And the three main parameters, the toe radius, flank angle and bead height were measured by a profile measuring equipment. By using the measured data, the influence of three parameters on the stress concentration factors was investigated by a finite element analysis. It is shown that the three parameters have similar effects on the stress concentration factors. According to the simulation results, a formula to estimate the stress concentration factors of butt-weld welded structures was proposed and the estimated concentration factors from the formula were compared with the results obtained by the finite element analysis. The two results are in a good agreement.