Wyniki wyszukiwania - BazTech

1

Investigation of process stability and weld quality of underwater wet flux-cored arc welding of low-alloy high-strength steel with oxy-rutile wire

Li Hongliang, Liu Shixiong, Ma Qiang, Wang Pengfei, Liu Duo, Zhu Qiang

Polish Maritime Research

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2021

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nr 3

100--109

EN

The paper described the experimental findings of underwater wet welding of E40 steel using self-shielded flux-cored wire with a TiO2 -FeO-MnO slag system. The arc stability, weld quality and corrosion resistance with different heat inputs were studied. The results showed that the wet welding process of the designed wire displayed good operability in the range of investigated parameters. The microstructure and mechanical properties of the weld metal depended on the heat input. Due to the high fraction of acicular ferrite in the weld metal, the mechanical properties of the weld metal under low heat input had better tensile strength and impact toughness. Fracture morphologies at low heat input had uniform and small dimples, which exhibited a ductile characteristic. The diffusible hydrogen content in the deposited metal obtained at a heat input of 26 kJ/cm significantly reduced to 14.6 ml/100g due to the combined effects of Fe2 O3 addition and the slow solidification rate of molten metal. The microstructure also had a significant effect on the corrosion resistance of the weld metal. The weld metal with high proportions of acicular ferrite at low heat input exhibited the lowest corrosion rate, while the base metal possessed a reduced corrosion resistance. These results were helpful to promote the application of low alloy high strength steel in the marine fields.

2

Susceptibility for extrusion welding of AlMg alloys

Leśniak Dariusz, Wassermann Alicja, Dziki Mateusz, Zaborowski Krzysztof, Jurczak Henryk

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 1

20--31

EN

The extrusion of hollow profiles from high strength aluminium alloys through porthole dies causes serious problem in practice. Mainly, this is due to low weldability of these alloys and high extrusion force. The present paper discusses the investigations undertaken to determine the weldability of hard AlMg alloys using the original method and device. Main advantage of the proposed method is that it allows for the reflection of real welding conditions occurring in a welding chamber of the porthole die. Weldability tests were performed for alloys: 5754 (3.5% Mg), 5083 (4.5% Mg), 5019 (5.6% Mg) and 5xxx (7.1% Mg) in a wide range of temperature, unit pressure (normal compressive stress) and duration of welding. Microstructure and strength properties of the welds were examined. Most favourable welding conditions for the tested alloys, allowing for obtaining high strength welds were defined. To validate the laboratory experiments the extrusion trials were performed in the industrial conditions, in which the round tubes from 5754 alloy were produced using the porthole dies. The tensile strength of the welds in the extruded tubes is comparable to that for the solid material. Strength of the welds as well as of the solid material strongly increases with magnesium content in the alloy.

3

Wpływ kształtu narzędzia w metodzie zgrzewania FSW stopu Al na jakość zgrzein

Mazurkiewicz K., Bober M.

Przegląd Spawalnictwa

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2018

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R. 90, nr 8

13--17

PL

W pracy przedstawiono wyniki badań zgrzewania metodą FSW (ang. Friction Stir Welding) stopu aluminium typu 6082. Analizowano wpływ kształtu narzędzia na jakość zgrzein. Zaprojektowano i wykonano modułowe narzędzia o różnej geometrii zarówno powierzchni tarcia oprawki, jak i narzędzia roboczego. Testy zgrzewania wykonano dla złączy nakładkowych i doczołowych na podkładce przy zmiennych parametrach procesu. Wykazano, iż zarówno geometria powierzchni tarcia, jak i kształt narzędzia roboczego istotnie wpływają na wygląd lica oraz jakość połączenia zgrzewanego.

EN

The paper presents the results of Friction Stir Welding Al 6082 alloy. The research focused on the influence of the tool shape on the quality of welds. Modular tools with different geometry for the shoulder surface and the probe were designed and made. Welding tests were performed for overlap and strapped butt joints and variable process parameters. Studies concluded that both the geometry of the shoulder and the probe significantly affect the appearance of the face and the quality of the welded connection.

4

Ocena jakości zgrzewów rur z trudnoodkształcalnych stopów aluminiowych wyciskanych na matrycach mostkowo-komorowych

Zasadziński J., Galanty M., Leśniak D., Grzyb J.

Rudy i Metale Nieżelazne

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2010

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R. 55, nr 11

762-766

PL

W dotychczasowej praktyce nie stosowano technologii wyciskania kształtowników pustych na matrycach mostkowych lub komorowych z powodu głównej przeszkody, jaką jest niska podatność do zgrzewania mającego miejsce podczas tej operacji, zwłaszcza dla stopów aluminium serii 2xxx. Badania autorów pozwoliły określić ogólną procedurę projektowania technologii wyciskania zgrzewającego kształtowników pustych [1, 2], w szczególności pozwoliły zaprojektować odpowiednią matrycę mostkowo-komorową. Potwierdzenie możliwości uzyskania dobrego wyrobu odbyło się w oparciu o próby wyciskania na prasie 25MN w rzeczywistych warunkach przemysłowych. Uzyskane wyroby (rury phi 50 × 4 mm ze stopu 2024) poddano ocenie jakości zgrzewów w próbach rozciągania pierścieni i próbie roztłaczania końców rur oraz poprzez obserwacje makrostruktury wyrobu. Uzyskane rezultaty badań potwierdzają możliwość wyciskania na gorąco kształtowników pustych ze stopów trudnoodkształcalnych aluminiowych.

EN

Demand for long hollow sections, i.e. those that have one or more holes in the cross-section made of highly durable and simultaneously difficult to form aluminium alloys, is still rising. The existing technology of producing this type of profiles based on hot extrusion with piercing the ingot is inefficient, and significantly limits the range and quality of produced shapes. As far, the newer technology based on extrusion through porthole dies is not applied, mainly due to low weldability of 2xxx series alloys, but also 5xxx and 7xxx series alloys. Undertaken a comprehensive study on this issue helped provide a general procedure for design the technology of welding extrusion based on the experimental determination of the required minimum welding stress [1]. On the way to further compare these data with the values of unit pressure in the welding chamber of porthole die (obtained by FEM calculations [2]), the extrusion die design is possible for the specific case of extrusion. Confirmation of the possibility of obtaining a good product must take place in real industrial conditions. This latter issue is presented in this paper and is tantamount to performing the extrusion trials and evaluation of obtained tubes in terms of welds quality. The tubes with phi50x4 mm extruded from 2024 alloy through experimental porthole die on the 25 MN press were investigated. These products were then assessed quality welds in tensile tests and expanding tests of tube rings, and by observing the macrostructure of the product. The obtained results of research confirm the possibility of hot extrusion of hollow profiles from hard deformable aluminium alloys (2xxx series).

5

Weld transference modes identification through sound pressure level in GMAW process

Cayo E. H., Absi Alfaro S. C.

Journal of Achievements in Materials and Manufacturing Engineering

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2008

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Vol. 29, nr 1

57-62

EN

Purpose: One of the most used processes in the industry is GMAW, in this welding process there is physical phenomena such as the temperature, electromagnetic field, luminosity and sound pressure. It is known that GMAW weld specialized techinicisian combine visual and sound at the work to garantee the process stability. It is important to improve the final weld quality; therefore, the quantification of electrical and acoustical behaviour-within the audible bands, offer an information that is important to comprehend his impirical rules. Design/methodology/approach: With these he can identify the transfer mode, instabilities in the process, determine defects and evaluate the weld quality along the weld bead. The sound signal is captured simultaneously with the arc voltage and current signals. Was proved that first derived from the instantaneous power of the electrical arc presents a behaviour similar to the acoustical with a delay, because the measured sound is airborne. Findings: This relation was corroborated by the comparison between the sound pressure level calculated by electrical signals and by acoustical signals. This relation presented a similarity between the calculated signals greater than that between the sound and the power first derived. Practical implications: Besides that, with the sound pressure level it is possible to identify process instabilities that is not so trivial to realize with the sound pressure signal. In spite of it, the identification of instabilities for the globular and spray tranfer modes displays greater difficulty than that for the short circuit transfer mode. It was shown that the acoustical weld sensing offers information about the behaviour of the tranfer mode and the process stability. Originality/value: The sound quantification would be applied as a control variable for the weld process. Thus, it would be possible to develop similar control strategies as those applied by specialized workers.

6

Ocena wpływu warunków technologicznych procesu napawania zrobotyzowanego metodą GMA na kształt i jakość napoin

Klimpel A., Górka J., Czupryński A., Miler T.

Zeszyty Naukowe Politechniki Poznańskiej. Budowa Maszyn i Zarządzanie Produkcją

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2004

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Nr 1

15-26

PL

W artykule przedstawiono wyniki badań wpływu podstawowych parametrów napawania i parametrów ruchu palnika GMA zamocowanego na kiści manipulatora spawalniczego Reis SRV6 na kształt i jakość napoin wykonanych drutem proszkowym samoosłonowym. Odpowiednio dobrane parametry programowe ruchu i oscylacji przestrzennej palnika wraz z parametrami technologicznymi pozwalają na uzyskanie najwyższej jakości napoin z zachowaniem dużej dokładności i całkowitej powtarzalności procesu. Wyznaczone pole parametrów optymalnych napawania zroboty-zowanego pozwala na osiągnięcie określonych założeń technologicznych (np. odpowiedniej szerokości napoiny, wysokości nadlewu, chropowatości lica, twardości, odporności na ścieranie itp.) zależnych od takich czynników, jak: oscylacja palnika i pochylenie palnika, prędkość napawania itp. Robotyzacja napawania eliminuje również wpływ czynnika ludzkiego na jakość uzyskiwanych napoin oraz ogranicza niekorzystny wpływ napawania drutem proszkowym samoosłonowym na organizm ludzki.

EN

Results of the influence of basic parameters of SSA surfacing process and path of torch motion on shape and quality of welds done on robotized welding stand with Reis SRV6 manipulator will be discussed. The choose of torch motion and oscillation variables together with technological parameters allows to get the highest possible quality of welds as well as a good accuracy and repeatability. The obtained range of optimal SSA surfacing parameters makes possible to achieve some presumed technological objectives (given width of welds, reinforcement high, smoothness, hardness or wear resistance) depending on number of variables, such as: oscillation pattern, amplitude and frequency, torch angle, surfacing velocity etc. The use of robot eliminates the influence of human factor on welds quality and protects the welder from direct and undesirable impact of SSA welding process on human body.