Papers by Author: Krzysztof Dudzik

Abstract: The results of corrosion properties research of aluminum alloy AW 7020 (AlZn5Mg1) welded by friction stir welding (FSW) and MIG were presented. Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. In the paper, the parameters for friction stir welding of sheets made of AlZn5Mg1 [7020] alloy were presented as well as parameters for MIG. Metallographic analysis of bonds showed a proper structural construction of both, the FSW and MIG welded 7020 aluminum alloys.The study was carried out in accordance with the requirements of the ASTM G 106. EIS measurement was performed in three-electrode system in artificial seawater (3.5% NaCl). Impedance studies were carried out at the corrosion potential. Changed voltage signal amplitude in the range ±10 mV and frequency range of changes was as follows: 100 kHz – 0.1 Hz. Atlas 0531 EU & IA potentiostat was used for studies.The results of electrochemical impedance spectroscopy are presented in the form of parameters characterizing the corrosion process. Obtained results were statistically analyzed.The electrochemical impedance spectroscopy studies have shown that the joint welded by FSW has better electrochemical corrosion resistance than the joint welded by MIG and the native material – AW-7020 alloy.Original value are received results of the corrosion properties of new method friction stir welded AlZn5Mg1 alloy compared with traditional MIG method and the native material.

Abstract: The paper presents the research results on the mechanical properties of aluminum alloy 7020 and its FSW and MIG welded joints. For comparison, alloy 5083 – the most currently used in shipbuilding alloy was chosen as well as 5059 – the new high-strength alloy. Besides, the native material alloys there were investigated their joints welded by FSW and MIG – the same methods as alloy 7020. Welding parameters used for the connection of the sheets made of 7020, 5083 and 5059 alloys were presented. Metallographic analysis showed the correct construction of structural bonded joints.Friction Stir Welding (FSW) – a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. FSW method can be an alternative to traditional arc welding methods, especially MIG, which is the most common method of joining aluminum alloys used in shipbuilding. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standards PN-EN ISO 4136:2011 and PN-EN ISO 6892-1:2010. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of +20 oC.Friction stir welded joints of tested alloys have higher strength properties as compared to MIG welded joints. The 7020 alloy has higher strength properties then alloys 5083 and 5059. The yield stress is higher by 14.8% as compared to alloy 5083, and by 11.7% as compared to the alloy 5059. Plastic properties of alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by FSW of alloy 7020 have the highest strength properties of all researched joints – higher then alloys 5083 and 5059 joints welded by FSW and joints of all alloys welded by MIG.

Abstract: The article presents the research results of hardness values distribution of friction stir welded joint (FSW) alloy AW 7020 (AlZn5Mg1). FSW is a method of welding in the solid state, mechanical properties of joints welded by that method can be higher than that for arc welding techniques (MIG, TIG). The parameters of friction stir welding (FSW) used to join 7020 alloy were presented. Metallographic analysis showed the correctly structured FSW welded 7020 alloy. The study was carried out using Vickers hardness HV5 in accordance with the requirements of the Polish Standard PN-EN 6507 using a hardness testing machine HPO-10. The location of measurement points in the butt joint was determined in accordance with PN-EN 1043-1:2000. The indenter load was 49 N. In order to determine the effect of bonding method on structure change of the material microscopic examination was performed using an optical microscope ZEISS Axiovert 25.The test specimens were polished and then etched with KELLER reagent. This enabled the precise identification of zones present in the joint, such as: weld nugget, thermo-mechanically affected zone, native material. To determine the grain size in the different zones of joints bonded by FSW AxioVision 4.8.2 software was used. Hardness testing in across researched joints showed that the highest value of hardness is in the weld and the lowest is in the native material.

Abstract: The results of corrosion properties research of aluminum alloy AW 7020 (AlZn5Mg1) welded by friction stir welding FSW were presented. Friction Stir Welding (FSW) a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. In the article the parameters for friction stir welding of sheets made of AlZn5Mg1 (7020) alloy was presented. The study was carried out in accordance with the requirements of the ASTM G 106. EIS measurement was performed in three electrode system in an artificial seawater (3.5% NaCl). Impedance studies were carried out at the corrosion potential. Changed voltage signal amplitude in the range ± 10 mV and frequency range of changes was as follows: 100 kHz - 0.1 Hz. Atlas 0531 EU & IA potentiostat was used for studies. The results of electrochemical impedance spectroscopy are presented in the form of parameters characterizing the corrosion process. Obtained results were statistically analyzed. The electrochemical impedance spectroscopy studies have shown that the joint welded by FSW has better electrochemical corrosion resistance than the native material - AW-7020 alloy. Original value are received results of the corrosion properties of new method friction stir welded AlZn5Mg1 alloy compared with the native material.