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Mechanical properties of 5083, 5059 and 7020 aluminium alloys and their joints welded by MIG

Dudzik K.

Journal of KONES

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2011

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Vol. 18, No. 3

73-77

EN

The article presents the research results on the mechanical properties of aluminum alloy 7020 and its 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 MIG -the same method 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. The arc welding method - MIG is the most common method of joining aluminum alloys used in shipbuilding. It replaces the TIG method of providing equally high quality of joints with a much higher performance. The research was carried out using a static tensile test in accordance with the requirements of the Polish Standard PN-EN 10002:2004. Flat samples cut perpendicular to the direction of rolling were used. The research was conducted at the temperature of + 20 centigrade. The 7020 alloy has higher strength properties then alloys: 5083 and 5059. The yield stress is higher by 14.8% compared to 5083 alloy, and by 11.7% compared to the alloy 5059. Plastic properties of an alloy 7020 are the lowest, but with reserves meet the requirements of classification societies. The joints welded by MIG of 7020 alloy have higher strength properties then joints of alloys: 5083 and 5059. Plastic properties of alloy 7020 compared to 5083 alloy are smaller and at the same level as the connector alloy 5059.

2

Influence of joining method for hardness distribution in joints of AlZnSMg1 alloy

Dudzik K.

Journal of KONES

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2010

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Vol. 17, No. 4

137-141

EN

The article presents the research results of hardness values distribution of friction s tir welded joint (FSW) alloy AW 7020 (AlZn5Mg1). The joints welded by traditional MIG method of the same aluminium alloy were chosen as reference points. Friction stir welding (FSW) - a new technology can be successfully used for butt welding of sheet metal with different types of aluminium alloys. The parameters of friction stir welding (FSW) and MIG welding used to join metal alloy AlZn5Mg1 (7020) were presented. Metallographic analysis showed the correct structured both MIG welded joints and FSW welded aluminum alloy 7020. The study was carried out using Vickers hardness HV5 accordance with the requirements of the Polish Standard PN-EN 1043-1:2000. The study was conducted in three rows, and the indenter load was 50 N. In order to determine the structural changes in the bonded joints, the samples were polished and then micro-etched KELLER reagent. Metallographic examination was carried out using optical microscope Axiovert ZAISS 25. Metallographic examination revealed the existence of an explicit heat affected zone of HAZ in case of MIG welded joints and virtually lack there of, in case of FSW welded joints. In case of FSW welded joint, maximum hardness was observed in the middle of joint, but at a distance of approximately 25 mm from the middle of the weld there is a hardness decrease of about 10% relative to the base material. In the MIG weldedjoint lowest hardness of the weld occurred in the middle of the joint.

3

Influence of friction stir welding on impact resistance of AlZn5Mg1 alloy joints

Dudzik K., Czechowski M.

Journal of KONES

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2009

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Vol. 16, No. 3

93-98

EN

The paper presents the research results on impact resistance of friction s tir welded aluminum alloy A W 7020 [AlZn5MglJ. The joints welded by traditional MIG method of the same aluminium alloy were chosen as reference points. Friction Stir Welding (FSW) - a new technology can be successfully used for butt welding of different types of aluminum alloy sheets. The parameters for friction stir welding of sheets made of AlZn5Mgl [7020] alloy were introduced in the article. Metallographic analysis of bonds showed proper structural construction of the friction stir welded 7020 aluminum alloys. The impact resistance was examined via the Charpy test according to PN-EN 10045-1. During test the hammer angle of deflection beta after hitting was noted and next the brake work "L " and impact resistance "U" were determined. The tests were carried out on typical specimens of cuboids shape (55x10x10 mm), with "V" notch. The research was conducted at the temperature of + 20°C. After impact resistance test the failure surface of specimens was analyzed by scanning with electron microscope SEM Philips XL30. The research of impact resistance showed that the values of 7020 alloy welded by FSW method were higher compared to the properties of 7020 alloy joints welded by traditional MIG method — the average impact resistance was about 18% higher in case ofFSW then in MG.

PL

W artykule przedstawiono wyniki badań udarności złączy zgrzewanych tarciowo (FSW) stopu AW 7020 (AlZn5Mgl). Jako punkt odniesienia wybrano zlącza tego samego stopu spawane tradycyjną metodą MIG. Nową technologię zgrzewania tarciowego z przemieszaniem materiału zgrzeiny FSW (Friction Stir Welding) można z powodzeniem stosować do zgrzewania doczołowego blach z różnego rodzaju stopów aluminium. Przedstawiono parametry zgrzewania tarciowego (FSW) zastosowane do połączenia blach ze stopu AlZn5Mgl (7020). Analiza metalograficzna wykazała poprawną budowę strukturalną złączy zgrzewanych stopu aluminium 7020. Badania udarności przeprowadzono metodą Charpy'ego zgodnie z wymaganiami Polskiej Normy PN-EN 10045-1. Podczas badań odczytano kąt wychylenia młota po uderzeniu beta a następnie wyznaczono pracę łamania L oraz udarność U. Próbki do badań udarności wykonano jako standardowe, w kształcie prostopadłościanu o wymiarach 55x10x10 mm z zalecaną przez normę dokładnością š0,1 mm, w których wycięto karb w kształcie litery V. Próbę przeprowadzono w temperaturze + 20°C. Po badaniach udarności przeprowadzono analizę powierzchni przełomów próbek za pomocą mikroskopu elektronowego (SEM) Philips XL3O. Badania udarności złączy stopu 7020 wykazały wyższą wartość udarności w przypadku zastosowania zgrzewania tarciowego FSW w porównaniu do tradycyjnej metody spawalniczej MIG - średnio udarność była wyższa o ok. 18%.