Experiments have been performed for the butt welding of 160 mm x 90 mm x 2 mm sheets of EN AW 5754 aluminium alloy, where the friction stir welding (FSW) has been used.Referring to the parent metal, the chemical composition and the form of wrought products of the aluminium alloy EN AW 5754 is presented, according to the standard EN 573-1:2005, respectively EN 573-3:2013. The mechanical properties of EN AW-5754 (Al Mg3) sheets are presented, according to EN 485-2:2016. The experiments have been conducted on the own equipment for friction stir welding, type FSW-4kW-10kN, to execute 8 (eight) FSW test pieces, according to EN ISO 25239-4. A quenched FSW tool, own-made of C 45 grade steel, EN 10083, has been used. The parameters of the FSW tests are shown. As main parameters, the rotational speed of the FSW tool was in the range n = 800 – 1200 rev/min, respectively the travel speed was in the range v = 50 – 200 mm/min. The run of the joining experiments is described and the joining test pieces are presented in figures. The ultimate tensile strength of the parent metal (σmin,pm) is based on the specified minimum tensile strength of the ”O” condition of the parent material, respectively this value is also required for the weld, that is σmin,w = 190 MPa. The specimens T1.0, T1.1, T2.1, T2.2, T3.1, T3.2, T4.1, T4.2, T5.1, T5.2 și T6.1 are adequate and accepted by this tensile test. The specimens T1.2, T6.2, T7.1, T72. and T8.1 can be accepted, if higher properties are achieved with a full postweld treatment. Another possibility is a lower extent of the minimum tensile strength of the weld that shall be in accordance with another design specification, for example σmin,w = 145 MPa. By the correlation of the FSW parameters with the results of the tensile test, the ranges for the main parameters with adequate values of the ultimate tensile strength are established: n = 800 – 1000 rev/min and v = 50 – 100 mm/min. By the conclusions, the main aspects of the execution of the FSW test pieces, as well as the results of the tensile tests are selected. The involved industrial areas of the applications are: electro-technique, electronics, manufacturing, shipbuilding and automotive industries. The FSW process is ecological, because it neither uses, nor produces hazardous substances. The references consist of 12 titles.

For the examination of noxious emissions, cladding tests were performed according to EN ISO 6847. The filler materials were 1.2 mm diameter wire-electrodes, made of tin bronze, aluminium bronze, austenitic stainless steel, duplex stainless steel and nickel alloy.The low-energy metal transfer welding process, named CMT (cold metal transfer) was examined, on the welding source type Trans Puls Synergic 2700 CMT, of 270 A, produced by the company Fronius, Austria. For sampling welding smoke particles, an Apex type pump was used. For measuring the concentration of gases emitted by welding, a Triple Plus type multi-gas detector was applied.The particulate emission rate is 0.500 mg / m3 in the breathing zone, according to ISO 10882-1. For comparison, the measured emission rate is from 0.877 to 2.513 mg / m3 in the welding zone, according to ISO 15011-1. The concentration of the emitted gases is in the ranges: 0.14 to 0.16% CO2; 0.1-0.2 ppm NO2; 0-15 ppm H2; 0-5 ppm CO. These concentration levels are below the exposure limits (8 hours per day, five days a week): 5% CO2; 1.0 ppm NO2; 30 ppm CO. In conclusion, the emissions from the CMT welding process are without health risk for the welder.

In the paper are presented some preliminary results regarding the possibilities of using of the friction stir welding process (FSW) and FSW assisted with TIG (FSW – TIG) welding for joining of the electrical components in the automotive industry. Couples of dissimilar materials approached in experiments were Aluminium EN AW 1200 and Copper Cu99, with thicknesses in conformity with real cases in the production process. The results obtained for butt welding an overlap welding of different thicknesses of materials (aluminium thickness s1 = 2mm and copper thickness s2 = 5mm) are presented. There are some general conclusions regarding the possibilities of joining the two materials under the specified conditions.

There are various base metals that might be subjected to friction stir welding (FSW). They have different yield strength, ultimate tensile strength and other mechanical characteristics that influence the complex phenomena of the FSW process. The nature, mechanical characteristic and other properties of the base metals introduce also certain requirements for the FSW equipment, because FSW is a mechanical process.Experimental data of the FSW of the following materials are presented and compared:- similar overlapped sheets of aluminium alloy EN AW 5754, having the thickness 1.0 mm; - dissimilar overlapped sheets of 3 - 6 mm thickness of the base metal couples: aluminium alloy EN AW 1200 / copper Cu 99 ET, aluminium alloy EN AW 5754 / copper Cu 99, aluminium alloy EN AW 6082 / copper Cu 99 ET;- sheets of nickel alloy, inconel 718, thickness 8 - 10 mm, by friction stir processing. The characteristics of the FSW tool are described and the main technology parameters are mentioned: overlap, rotational speed of the FSW tool, rotational direction, travel speed, thrust force, as well as electric current of the motor for the rotating motion of the tool.Other important factors are also taken into account: sizes and positioning of the sheets (up or down), rolling direction of the sheets, room temperature, temperature of the sheets, material and temperature of the support plate.The linear energy of the FSW process is the main parameter. This is an indirect parameter, because it must be calculated, based on the previous mentioned parameters. According to the definition, the linear energy depends directly on the mechanical power developed during the stirring process, respectively it depends indirectly on the travel speed.On the other hand, the heat input is directly proportional to the linear energy and the thermal efficiency of the transfer of the heat produced by the friction of the shoulder and pin, to the nugget zone, where the weld metal is produced. These quantities are also analysed.For these materials the power developed by the motor for the rotational movement is determined, as well as the mechanical torque applied to the FSW tool. All these data are important for the design of the FSW equipment, in order to realize its main technical characteristics, depending on the base metals.Conclusions on the results are exposed, with important consequences for the industrial applications of the FSW process.