No abstract

No abstract

No abstract

No abstract

This work presents the results of studying harmful substances in the air, released in the case of tungsten inert gas (TIG) and metal inert gas (MIG) welding of 1460 aluminum alloy (Al-Cu-Li). It is shown that the TIG process is accompanied by smaller evolution of the solid component and gas component of welding fumes than in MIG welding. Ozone concentrations during TIG and MIG welding are significantly (1.3 and 7.4 times, respectively) higher than the maximum permissible concentration. It is found that ultraviolet radiation, accompanying the welding process, is the main factor of toxic gas generation in the working zone of the studied aluminum-lithium alloys. Also, this paper presents analyses of microstructure, hardness, strength characteristics and fatigue behavior of 1460 TIG weld joints.

Comparative studies were performed of microstructure, degree of softening, ultimate strength, crack initiation and propagation susceptibility and fatigue resistance of welded joints of wrought aluminium alloys AMg5M andAMg6M 1.8 mm thick, produced by nonconsumable-electrode argon-arc welding and friction stir welding, as well as of the levels of residual longitudinal stresses developing in them. It is shown that application of FSW enables formation of permanent joint with minimum level of stress concentration in weld-to-base metal transition areas, and allows avoiding defects in the form of pores, oxide film macroinclusions and hot cracks in welds due to metal melting and solidification in fusion welding. Intensive plastic deformation of metal results in formation of a uniform disoriented structure under the tool shoulder and in the weld nugget with grain size of 3-4 μm and disperse (not more than 1 μm) phase precipitates, and grain elongation and distortion in the direction of plasticized metal displacement occur in the adjacent areas. This leads to increase of metal hardness in the joint zone, sample ultimate strength at uniaxial tension, their fatigue strength and lowering of crack initiation and propagation susceptibility. Lowering of temperature of welded edges heating leads to lowering of maximum level of residual longitudinal stresses in welded joints by 25 %, compared to TIG welding. 16 Ref., 8 Figures.

No abstract

This research paper presents hardness, structure and tensile strength analysis of 1460 alloy of Al-Cu-Li system, welded joints made by Tungsten Inert Gas (TIG) welding and Friction Stir Welding (FSW). Characteristics of acoustic noise at the welding operator workplace during mechanized TIG and FSW of aluminium-lithium alloy with the purpose to develop recommendations for the improvement of health and safety during welding processes were studied. Analyzing results, we concluded that during TIG welding the values of welding noise at the workplace, are much higher than the admissible noise level limit. Results showed that the values of the welding nose reach 95 dB. The noise level at the workplace for FSW is also dangerous and reaches up a value of 84.3 dB. Also, this paper presents hardness, structure, and tensile strength measurements of 1460 alloy welded joints made by TIG and FSW welding.