Wyniki wyszukiwania - BazTech

1

Microstructure and properties of FSW joints of 2017A/6013 aluminium alloys sheets

Mroczka K., Dutkiewicz J., Lityńska-Dobrzyńska L., Pietras A.

Archives of Materials Science and Engineering

|

2008

|

Vol. 33, nr 2

93-96

EN

Purpose: The aim of the studies was to analyse the structure and mechanical properties of FSW joints. Experiment were perform in order to study possibilities to join different aluminium alloys 2017A and 6013. The alloys differ one from the other with respect to chemical composition and mechanical properties especially, therefore the ability to perform the correct joints may be useful for special constructions. Design/methodology/approach: The joints were produced applying different parameters and temperatures. The microstructure was studied using optical, scanning electron and transmission electron microscopes. The mechanical properties are discussed with regard to microhardness profiles on the cross-sections of the joints. Findings: No cracks were found in the joints. Weld nuggets were formed in the 2017A alloy which was located on the advancing side during welding. Mixing process of the materials within the joints was observed as a formation of separate regions of the materials being joined. The hardness profiles showed sudden changes of hardness what correlates with structure observations. In the vicinity of the weld nugget higher dislocation density was observed. Lowering the temperature of sheets and welding with intensive cooling caused a decrease in size of the weld nugget. Research limitations/implications: In the further studies, tensile and bending tests are planned. Moreover, an attempt of explaining the influence of precipitates at the regions boundaries on the fracture process. Practical implications: Good quality of the joints can be stated on the basis of structure analysis. The chosen parameters of welding can be considered as proper ones. Originality/value: Comparison of the welding of the alloys2017A and 6013 are not common. The results of studies and conclusions presented in the paper are consecutive data complementing knowledge on FSW of the aluminium alloys. The applied welding parameters ensure good quality of joints with respect to the technology.

2

Effect of post-weld aging on the mechanical and microstructural properties of friction stir welded aluminum alloy 7075

Yeni C., Sayer S., Ertugrul O., Pakdil M.

Archives of Materials Science and Engineering

|

2008

|

Vol. 34, nr 2

105-109

EN

Purpose: of this paper is to investigate the effect of post-weld artificial aging on the friction stir welding of Aluminum Alloy 7075 (AA 7075) for a welding condition of 1600 rpm and 100 mm/min using right and left helical screwed pins for two different shoulder diameters. Design/methodology/approach: The method followed is that first artificial aging has been carried out as 24 hours at 125°C. Afterwards, in order to study the effect of post-weld aging on tool geometry, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. Findings: The results show that left helical screw yields higher mechanical properties and hardness values compared to right helical screw when tested at the same shoulder diameter. It has been observed that post weld aging process compensates the hardness decrease observed in as-welded joints; no significant decrease in hardness is obtained throughout the weld region. Research limitations/implications: For future work it can be suggested to vary the post weld aging condition, such as 12 hours at 125°C. Welding and rotation speeds are other parameters affecting the microstructural and mechanical properties; therefore the effect of varying these parameters should be considered. Practical implications: This study has practical implications and direct applicability. It indicates that helix angle rather than shoulder diameter directly affects the quality of the joint. At certain post weld aging conditions, for obtaining a sound welded joint the right tool selection will be of critical importance. Originality/value: The authors have examined the effect of post weld aging for different helix angles and shoulder diameters. It is believed that examination of the effect of the variation of these parameters on the joint quality provides originality to this study.

3

Własności stopów aluminium serii 5000 zgrzewanych nową technologią FSW

Czechowski M., Pietras A., Zadroga L.

Inżynieria Materiałowa

|

2003

|

R. XXIV, nr 6

264-266

PL

Nową technologię zgrzewania tarciowego z mieszaniem materiału zgrzeiny FSW (Friction Stir Welding) można z powodzeniem stosować do zgrzewania doczołowego blach z różnego rodzaju stopów aluminium. W artykule przedstawiono wyniki badań warunków zgrzewania tarciowego blach wykonanych ze stopów AlMg4,5Mn [5083] i stopu ALUSTAR [5059] prowadzonych w Instytucie Spawalnictwa w Gliwicach. Analiza metalograficzna złączy wykazała poprawną budowę strukturalną zgrzeiny z prawidłowo rozbudowanym jądrem i stosunkowo wąską strefą wpływu ciepła. Przedstawiono wyniki badań własności mechanicznych złączy zgrzewanych tarciowo FSW. Podatność na naprężeniowe pękanie korozyjne badanych złączy zgrzewanych tarciowo mierzono w próbie stałego wolnego odkształcania z szybkością 10 do -6 s do -1 w powietrzu i sztucznej wodzie morskiej. Mierzono wytrzymałość na rozciąganie, wydłużenie, czas do zniszczenia, przewężenie i energię zniszczenia. Stwierdzono małą podatność badanych złączy na naprężeniowe pękanie korozyjne.

EN

Friction Stir Welding (FSW) - a new technology can be successfully used for butt welding of different types of aluminium alloy sheets. The article illustrated the research results concerning the conditions for friction stir welding of sheets made of AlMg4,5Mn [5083] alloys and ALUSTAR [5059] alloy carried out in the Institute of Welding in Gliwice. Metallographic analysis of bonds showed a proper structural construction of the weld with appropriately developed nucleus and a relatively narrow zone of heat influence. The results of examining mechanical properties of friction stir welded bonds were presented. The susceptibility to stress corrosion cracking of the examined friction stir welded bonds was measured during the slow strain rate test at 10 to the -6 s to the -1 in air and in artificial sea water. The tensile strength, elongation, time-to-failure, reduction-in-area and fracture energy were measured. Low susceptibility of the bonds examined to stress corrosion cracking was observed.