Papers by Keyword: Welding Speed

Abstract: Currently, the most promising high-tech and productive process is friction stir welding. An important element of this technology is the determination of the material temperature in the stir zone, which can be determined by calculation based on the amount of heat input introduced into the welding zone. To determine this value, experimental of the dependence of heat input on the tool rotation speed and welding speed were carried out. For this, a scheme of experiments has been selected in which the material to be welded (aluminum alloy AMg5) is modeled as an experimental tube with a diameter of 20 mm, and the tool (made of tool steel R6M5) is modeled as a working plate. On the designed and manufactured stand, studies of the dependence of the heat-liberation value for the speeds of rotation of the experimental tube 42-105 rad/s were carried out. In this case, due to the pressing force of the experimental tube and the working plate, a constant temperature of the place of friction was maintained. The obtained experimental data were used to calculate the heat-liberation value and heat power on each concentric ring 2 mm wide at the end of the working tool with a diameter of 20 mm, as well as the total heat power for different speeds of rotation and welding.When carrying out experiments on the bench, heat losses were determined by thermal conductivity along the rod on which the experimental tube is fixed, as well as from the working plate made of tool steel through the gasket onto the working table and by convection from the surface of the rotating experimental tube into the environment. The calculation results showed that each of these losses does not exceed 3-10%. These losses are taken into account in the heat supply calculations.

Abstract: Nickel-base superalloys are used as a land-base turbine engine due to its excellent properties at elevated temperatures. Nickel base superalloy, grade IN-738. Laser welding is commonly chosen for the refurbishment of the turbine blade. This paper aims to focus on understanding welding speed parameters in laser welding method. With constant power at 400 watts, welding speeds were varied from 1, 3, 5, and 8 mm/s. All of these alloys have no cracks found in fusion zone, HAZ, and bulk area. Increasing welding speed results in less heat energy input, reduces the penetration depth and weld pool area. The 1mm/s, which were subjected to the highest heat energy input, results in very small size of the γ’ precipitates in the fusion zone due to re-precipitation of the γ’ precipitates during the solidification process. The fusion zone also exhibits the highest hardness. The size of the γ’ precipitates in HAZ area are much larger, compared to the fusion zone The bulk areas have no effect from the heat and showed much larger size of the γ’ precipitates, which was caused by microstructural degradation during service, leads to the lowest hardness value among the three zones.

Abstract: Friction stir welding (FSW) is one of the new technique for welding materials in solid state welding process. In this proposed work we are using FSW to join the two dissimilar alloys of aluminium. The 6mm thick aluminum plates of aluminium 5086 and aluminum 7075 plates are considered for welding. These have been considered due to their application in various fields. In this experimental process Taguchi’s L9 orthogonal array method is used for optimizing the three process parameters namely rotational speed, axial force and welding speed. To produce a better joint the tensile strength is predicted for the optimum welding parameters and also their percentage of contribution is calculated, by applying the effect of analysis of variance. Depends upon the experimental study, the rotational speed is found better over the other process parameters, which enhances the quality of the weld. The tensile strength has been found for the optimum parameters and the result found during the experiment was 290Mpa which was higher than the base metal strength of aluminium 5086 alloy. The SEM fractograph analysis was done on the optimum parameters welded joints to show the fracture behaviour of tensile test which justifies the visual inspection results of brittle and ductile failures.

Abstract: The aim of this research is to study the effect of Friction Stir Welding (FSW) process parameters such as tool rotational speed and welding speed on temperature distribution and tensile strength of dissimilar AA5083-O and AA6063-T6 joint welded by FSW. Peak temperature at retreating side was observed lower as compared to advancing side for each experiment. Peak temperature decreases with decreasing the tool rotational speed but vice versa with welding speed. ANOVA indicated that the temperature profile was strongly dependent on the tool rotation speed than the welding speed and it also showed that welding speed is the main process parameter that has highest effect on tensile strength of welded joint.

Abstract: In this paper, the effects of axial force on the mechanical properties of AZ31B magnesium alloy flat plates during the Friction Stir Welding (FSW) process were investigated by carrying out the tensile tests as per the American Society for Testing and Materials (ASTM) E8M-11 standards. The tensile test results indicated that the increase of the axial force greatly improved the tensile shear load (TSL) of the friction stir welded joints at a constant tool rotational speed of 800 rpm and welding speed of 50mm/min. Sound lap joints with low distortion, lack of cavity and high tensile strength were successfully obtained with an axial force of 5kN. However, the TSL of the friction stir welded joints decreased when the axial forces were 3kN and 4kN with the same constant tool rotational and welding speed.

Abstract: Aluminum alloys are mostly used for high strength structural applications utilized in aircraft structure, trucks body, military vehicles, bridges and weapons manufacture. Conventional fusion welding of aluminum alloy produces porosity and hot cracks in the welded joint due to incorrect selection of consumables and parameters, which may lead to lower weld toughness and defects in the mechanical properties. The mostly adopted method for welding AA 2014-T6 is solid state joining process. Friction stir welding (FSW) is an emerging solid state of joining process which avoids bulk melting of the basic material, hot cracking and porosity. The welding parameters and tool pin profile play a major role in deciding weld quality. In this investigation, an attempt has been made to understand the various influences of tool rotational speed, welding speed and pin profile of the tool on friction stir processed (FSP) zone formation in joining of AA2014 aluminum alloy. High Carbon High Chromium steel tool of plain cylindrical pin profile is used to fabricate the joints. The average grey relation grade for each level of each factor are calculated and it was found that the optimal settings of the levels of factors Tool rotation speed (A), Weld speed (B) and Tilt angle (C) are A1-B3-C3. The findings from these investigations will be presented and discussed.

Abstract: In this study, 2024 Al alloy and AZ31B Mg alloy were brazing with mechanical stirring. The effects of brazing speed on microstructure and shear strength were investigated. The results show that oxide films on Al base metal surface broken completely at lower brazing speed. The continuous IMCs layer was broken into thinner one and blocky IMCs distribution in filler metal more evenly at lower brazing speed. The shear strength value near Al and Mg interface up to 53.1Mpa and 41.5Mpa respectively.

Abstract: This article studies the effects of heat source shape parameter and welding speed on the evolution of welding temperature field for Q345 plan carbon steel. The heat input and heat source parameters as well as the welding speed are defined by applying DFLUX subroutine in ABAQUS to simulate the transient welding temperature. The effects of heat resource shape parameters and heat input as well as the welding speed on welding temperature field are investigated by means of finite element analysis. It has been found that heat source parameters and welding speed show strong influence on temperature distribution in FZ (fusion zone) and HAZ (heat-affected zone). Meanwhile, it shows a roughly linear relationship between the changes of heat input and the highest temperature.

Abstract: The laser welding system is used to weld vacuum glass,the organizational structure of welding joint and the combining performance of the laser welding in different speeds are studied in this text. Under the same laser output power,welding combining performance and organizational structure are ideal both in the speed of 5mm/s and 10mm/s. It shows that laser welding is an effective method of the edge welding of vacuum glass. By comparison with experimental results, better solder welding joint organizational structure and combining performance can be obtained when the welding speed is 5mm/s than the welding speed is 10mm/s. It explains that appropriate laser welding speed is one of the effective methods of optimizing vacuum glass welding under certain laser output power.

Abstract: Laser beam welding of aluminum alloys is expected to offer good mechanical properties of welded joints. In this experimental work reported, CO₂ laser beam welding at 3.5 kW incident power was conducted autogenously on 5 mm thick 5083-H321 aluminum alloy plates at different welding speeds. The mechanical properties and microstructural characteristics of the welds are evaluated through tensile tests, micro-hardness tests, optical microscopy and scanning electron microscopy (SEM). Both yield stress and tensile strength of the laser beam welded joint at the optimum welding speed were 88 % of base metal values. Experimental results indicate that the tensile strength and hardness of laser beam welds are affected by the variation of the intermetallic compounds.