Most Japanese shipyards that build general merchant ships use arc welding, but they always have the problem that the accuracy of the hull construction is poor as a result of the thermal deformation ...caused by arc welding. As one method to overcome this problem, it is expected to adopt laser arc hybrid welding that can suppress the total heat input as a result of heat input concentration, but the initial introduction cost is high and this welding method has a poorer gap tolerance than conventional arc welding. In addition, few experiences to apply laser arc hybrid welding for constructing the joints at the plate thickness level used for hull members of general merchant ships. An improved procedure to fabricate a butt joint with a plate with a thickness of 15 to 20mm, which is used as a hull member of a general merchant ships is proposed in this study. Proposed procedure is that the Λ-shaped groove with a very small angle and one-pass welding by laser arc hybrid welding with CO2 gas shielded arc welding to satisfy the weld reinforcement on the front side weld bead. The performance of the joint manufactured by using our proposed procedure was confirmed according to the Guidelines for Laser Arc Hybrid Welding by a classification society Nippon Kaiji Kyokai (ClassNK). It is expected to be introduced as an alternative method of plate joint welding for hull members, especially submerged arc welding with large heat input.
Most Japanese shipyards that build general merchant ships use arc welding, but they always have the problem that the accuracy of the hull construction is poor as a result of the thermal deformation ...caused by arc welding. As one method to overcome this problem, it is expected to adopt laser arc hybrid welding that can suppress the total heat input as a result of heat input concentration, but the initial introduction cost is high and this welding method has a poorer gap tolerance than conventional arc welding. In addition, few experiences to apply laser arc hybrid welding for constructing the joints at the plate thickness level used for hull members of general merchant ships. An improved procedure to fabricate a butt joint with a plate with a thickness of 15 to 20 mm, which is widely applied as a hull member of general merchant ships, is proposed in this study. Proposed procedure is that the Λ-shaped groove with a very small angle and one-pass welding by laser arc hybrid welding with CO
2
gas shielded arc welding to satisfy the weld reinforcement on the front side weld bead. The joint quality manufactured by using our proposed procedure was confirmed according to the Guidelines for Laser Arc Hybrid Welding by a classification society Nippon Kaiji Kyokai (ClassNK). It is expected to be introduced as an alternative method of plate joint welding for hull members, especially submerged arc welding with large heat input.
The paper presents the results of quality assessment of welded joints. The scope of the work was to investigate the non-destructive testing: visual testing (VT), penetration testing (PT) and ...radiological testing (RT). The study included also the survey breaking the macro- and microstructural test on the welded joint section. The research has shown that the use of the welding consumables in form of a wire 4Si1 to joint HARDOX 450® with Strenx 700MC® ensures the required ,,B” quality of welded joints in accordance with regulatory requirements. The analyzed joint was characterized by typical microstructure for native materials used.
We develop a method to improve the quality of welded joints and process performance in arc welding and direct arc growing under the influence of disturbing factors based on the use of artificial ...intelligence.
The method of arc welding under water is based on the ability of the arc to burn steadily in a gas bubble, which is formed by the evaporation and decomposition of water. Water decomposition products ...have a significant effect on the quality of welded joints. To obtain a quality welded joint under underwater arc welding, an external electromagnetic action is used which causes mixing of the liquid metal and changes the crystallization process. To evaluate the effectiveness of electromagnetic mixing of molten metal allows mathematical modeling, which is carried out in two stages: on the first - on the basis of Maxwell's equations in conducting media in terms of vector and scalar potentials, the boundary value problem is formulated; on the second, the obtained boundary value problem reduces to a system of integro-differential equations with respect to the density of eddy currents in the volume of massive bodies and electric charges on their boundaries, as well as magnetization currents at the boundary of ferromagnetic bodies, taking into account the influence of velocity in the liquid conductor. The resulting system of equations makes it possible to increase the accuracy of calculating electrodynamic forces in a liquid metal under any welding regimes.
In this article examinations of hybrid welding technology (laser beam + MAG) of T-joints from thermomechanically worked high strength steel S700MC 10 mm thick were presented. Joints welded from one ...side and both sides were made. Carried examinations enabled to classify joints in quality level B according to ISO 12932 (Welding. Laser-arc hybrid welding of steels, nickel and nickel alloys. Quality levels for imperfections). In case of one sided welding with partial penetration with beam power of 8.5 kW 8 mm of penetration was achieved without noticeable distortion of web. Double sided joints were characterized with correct geometry. Joint metal is bainitic-ferritic in structure and its hardness rises about 40 HV1 in comparison to base metal hardness (280 HV1). In HAZ a slight softening of material in comparison to base metal is present.
The manufacturing process in the automotive industry is in dire need of resistance spot welding machines. Because it was easier to use, highly effective, and effective in functioning. However, there ...were sometimes still connection problems that were still of poor quality, both nuggets and areas that are subject to electrode pressure. To get a quality welding connection, a machine was needed that was able to carry out good material preparation in the form of sanding, able to set the welding current analogously, able to set the time with an automatic timer, able to apply pressure on the electrode measurably during the welding process. The research aimed to design a prototype of resistance spot welding material preparation that could adequately carry out material preparation and welding using a Bluetooth system connected to a mobile phone. The research methods carried out were as follows: first, designing the machine using Autodesk Inventor software, then the device was made with a focus on material preparation prototypes, then the machine elements were made for the material clamping rail, then the machine elements in the control section using Bluetooth connected to the mobile phone, the machine was tested, then the connection quality testing process was carried out on the tensile testing machine. The results showed that the design results had been made using elbows and iron plates with threaded rails with a length of 650 mm, which became material clamping rail grooves with a drive using window motors controlled by Bluetooth on the Arduino circuit. The test results of welded joints show that the roughness is 0.20 μm which has the highest tensile strength.
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