Temat: weldability - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Weldability of high strength steels in wet welding conditions
Autorzy:: Fydrych, D.
Łabanowski, J.
Rogalski, G.
Tematy:: underwater welding
steel weldability
cold cracking
wet welding
cracks in welds
improving weldability; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258484.pdf Link otwiera się w nowym oknie
Opis:: In this paper are characterized problems of high strength steel weldability in underwater wet welding conditions. Water as a welding environment intensifies action of unfavourable factors which influence susceptibility to cold cracking of welded steel joints. The susceptibility to cold cracking of S355J2G3 steel and S500M steel in wet conditions was experimentally estimated (by using Tekken test). It was concluded that the steels in question are characterized by a high susceptibility to formation of cracks in welds. Usefulness of the proposed Temper Bead Welding technique (TBW) was experimentally verified as a method for improving weldability of the steels in the analyzed conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: The influence of the constraint effect on the mechanical properties and weldability of the mismatched weld joints. Part II
Autorzy:: Ranatowski, E.
Tematy:: weld joint
weldability
weldability analysis
thermal cycle
heat flow analysis
heat-affected zone; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/259003.pdf Link otwiera się w nowym oknie
Opis:: Currently the welding as a technological process is concerned with special processes, the results of which cannot be checked in a complete degree by subsequent control, test of production what finally causes uncertainty of work of welded constructions. The process of welding is related to the local change of the internal energy of welded system and that leads to the local change of state of material expressing by change of microstructure and mechanical properties. This phenomena decide on the assessment of susceptibility of materials under defined welding condition and estimate of the weldability. It is compound relation and the mechanical behaviour of welded joints is sensitive to the close coupling between modules: heat transfer, microstructure evolution an mechanical fields. Welding process in physical meaning it is jointed with three laws govern mass and heat flow the laws of conservation of: mass, momentum and energy. The knowledge of the run of thermo-dynamical process under welding indicates on the possibility of active modelling and control of welding process with use intensive and extensive parameters. As the weld metal cools in the temperature range 2300 to 1800°K, the dissolved oxygen and deoxidising elements in liquid steel react to form complex oxide inclusions of 0.1 to 1 žm size range. In the temperature range 1800 to 1600°K, solidification of liquid to . ferrite starts und envelops these oxide inclusions. After . ferrite transforms to austenite in the temperature range 1100 to 500°K, the austenite transforms to different ferrite morphologies such as ferrite: allotriomorphic, Widmanstättena, and acicular. The macro-mechanical heterogeneity of welded structures is one of their primary features. The heterogeneous nature of the weld joints is characterised by macroscopic dissimilarity in mechanical properties. Numerical weldability analysis is a new powerful research and development tool which is useful for metallurgistics technologist and design engineers. Saying strictly the numerical analysis of weldability comprises thermodynamic, thermomechanical and microstructural modelling of the welding process. The result of this analysis is material susceptibility (SU). The fracture resistance of welded joints is mainly characterised by normalised parameters: SU1 = KIth / KIC for cold cracking or in the exploitation condition by SU2 = ./.C or J/JC, SU1 . SU2. From above-mentioned equations result that does not exist one global parameter which defines the step of susceptibility SU of base materials has been also executed with use of SINTAP program.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Assessing the stregth and weldability of historic structural steel of historic structural steel
Ocena wytrzymałości i spawalności konstrukcyjnych stali historycznych
Autorzy:: Dudkiewicz, J.
Gosowski, B.
Organek, P.
Tematy:: strength of steel
Brinell hardness
weldability
weldability indicators
weldability testing
historical steel
wytrzymałość stali
twardość Brinella
spawalność
wskaźnik spawalności
próba spawalności
stal historyczna; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/395923.pdf Link otwiera się w nowym oknie
Opis:: In practice, in the design stage of revitalization, renovation or reinforcement, there is often a need to determine the strength of steel as well as its weldability. The strength of steel can be determined in two ways: directly through destructive testing or indirectly - by the Brinell hardness test. In the case of weldability, this turns out to be much more difficult, because there are three groups of factors which determine this property, i.e.: local weldability, operative weldability, and overall weldability. This paper presents the results of the verification of the relationship between the hardness and strength of three grades of steel from the early twentieth century. The evaluation of the overall weldability of structural steels is discussed in an analytical approach preceding costly weldability tests. An assessment based on selected indicators of weldability can only lead to confusion.
Często w praktyce inżynierskiej na etapie projektu rewitalizacji, remontu lub wzmocnienia konstrukcji pojawia się konieczność wyznaczenia wytrzymałości stali oraz określenia jej spawalności. O ile wytrzymałość stali można określić na dwa sposoby: bezpośredni, poprzez badania niszczące odpowiednio dużej liczby próbek pobranych z konstrukcji lub pośredni - poprzez badania twardości Brinella, to w przypadku spawalności okazuje się to dużo trudniejsze. Bowiem o tej właściwości decydują trzy grupy czynników: metalurgiczne, konstrukcyjne i technologiczne. W referacie przestawiono doświadczenia związane z zależnością między twardością a wytrzymałością trzech gatunków stali historycznych pochodzących z końca XIX i początku XX wieku. Otrzymane dla nich średnie współczynniki granicy plastyczności oraz wytrzymałości na rozciąganie porównano ze współczynnikami podawanymi w literaturze technicznej dla stali konstrukcyjnych. Omówiono także ocenę spawalności stali konstrukcyjnych w ujęciu analitycznym, poprzedzającą próby spawalności. Na przykładzie przedstawiono, że ocena spawalności jedynie na podstawie kilku wybranych wskaźnikach spawalności, może prowadzić do pomyłek. Należy pamiętać, że wskaźniki spawalności pozwalają wstępnie ocenić jedynie spawalność metalurgiczną (jedną ze składowych spawalności). Wiarygodny wniosek o dostatecznej spawalności stali można wyciągnąć wyłącznie po dodatkowym przeprowadzeniu badań spawalności konstrukcyjnej i technologicznej.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: The influence of the constraint effect on the mechanical properties and weldability of the mismatched weld joints. Part I
Autorzy:: Ranatowski, E.
Tematy:: weld joint
weldability
weldability analysis
thermal cycle
heat source model
heat flow analysis
heat-affected zone; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258976.pdf Link otwiera się w nowym oknie
Opis:: The process of welding has dynamic character and is related with the local change of the internal energy E of welded system and can be defined by general dependence between intensive .j and extensive .j parameters. The knowledge of the run of thermo-dynamical process under welding indicates on the possibility of active modelling of weldability and the control of welding process: .j = .E/..j. Hence, these process can be enhanced by mathematical modelling and numerical analysis of weldability models of, i.e. welding processes of material behaviour in welding and the strength of welded structures. The main attention is focused on the assessment of susceptibility of materials under defined welding conditions using fracture mechanics parameters. The analysis is based on the normalised parameters such as: ./.c, KIth/KIC, as a measure of the susceptibility of materials in welding process. The deformation process and fracture parameters calibrations are influenced by constraint; hence the importance of determining the deformation behaviour and fracture parameters as a function of constraint. Furthermore, there established analytically the condition of welding process in mismatched weld joints for strength equal to base metal. Finally, same analytical examples which present new capabilities of weldability estimates and mechanical properties of mismatched weld joints are presented.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Friction Weldability of UFG 316L Stainless Steel
Autorzy:: Skowrońska, B.
Chmielewski, T.
Pachla, W.
Kulczyk, M.
Skiba, J.
Presz, W.
Tematy:: UFG metals
recrystallization
friction welding
weldability; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355538.pdf Link otwiera się w nowym oknie
Opis:: The broad range applications of Ultra-Fine Grained metals is substantially limited by the lack of a welding method that allows them to be joined without losing the strong refinement of structure. From this point of view, the solid state welding processes are privileged. Friction welding tests were carried out on UFG 316L stainless steel. A joining process at high temperature activates the recrystallization, therefore the friction welding parameters were selected according to the criterion of the lowest degree of weakness due to recrystallization in the heat affected zone. In order to characterize the structure of basic material and selected areas of the obtained joint, were performed SEM, TEM and metallographic examinations in terms of hardness and range of softening of the material and tensile test. Despite the short time and relatively low welding temperature, results of the test by scanning electron microscopy and transmission electron microscopy confirmed the loss of the primary ultrafine structure in the Heat Affected Zone of welded joint.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: The influence of the shape of weld nobs on the fatigue strength of S540Q steel
Autorzy:: Cicholska, M.
Tematy:: weldability
high strength weldable steel
fatigue strength; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/242857.pdf Link otwiera się w nowym oknie
Opis:: The development of weldable steels was discussed together with the methods of obtaining them. The influence of these methods on steel properties was explained. Research was performed on quenched weldable S540Q steel of high strength. Basic mechanical properties of this steel were determined. The results of a static tensile test and technological bending test were given. Next, steel sheets were welded by semi-automatic MAG method. The welds quality was examined and their future suitability was stated. Mechanical properties of the joints welded of this steel were determined. Mechanical properties of native material and welded joints were compared. Joints microstructure was examined in the weld axis, in the heat influence zone and in the native material. Fatigue tests were conducted in the cycle of nonsymmetrical tension – compression of welded joints. The analytical fatigue strength was obtained and it was compared with fatigue strength of welded joints. Tests results were elaborated with the static analysis of linear regression. Wohler diagrams were made after conducting fatigue tests. Finally, weldable joints were melted by TIG method without adding filler metal. The angle and radius of welds nobs entrance into the native material was measured. The increase of fatigue strength is related to the decrease of geometric notch on the edges of weld nobs.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Weldability of Thermomechanically Treated Steels Having a High Yield Point
Spawalność stali obrabianej termomechanicznie o wysokiej granicy plastyczności
Autorzy:: Górka, J.
Tematy:: weldability
TMCP steel
HAZ
spawalność
stal TMCP; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/353588.pdf Link otwiera się w nowym oknie
Opis:: The article concerns the issue of weldability of S700MC steel, treated thermo-mechanically, with high yield point. The weakest area of welded joints of this steel is a high - temperature coarse heat affected zone (HAZ) in which due to the nucleation effect of the dissolved phases, strengthening the matrix and their subsequent uncontrolled separation precipitation in the form of finely disperse and rapid decrease impact strength is observed. Performed arc welding tests here have shown that in order to ensure high quality of welded joints, it is necessary to limit the welding linear heat input. During the welding process of S700MC steel, it is not recommended to use pre heating before the welding process and heat treatment after welding, and the number of repairs should be kept to a minimum, because it leads to a reduction of strength and plastic properties in the HAZ area, as a result of aging processes, dissolution of strengthening phases in the matrix and their subsequent uncontrolled precipitation during cooling.
W pracy przedstawiono problematykę spawalności stali obrabianej termomechanicznie S700MC o wysokiej granicy plastyczności. Najsłabsze miejsce złącza spawanego tej stali stanowi wysokotemperaturowy, gruboziarnisty obszar strefy wpływu ciepła (SWC), w którym na skutek zarodkowania rozpuszczonych faz umacniających w osnowie i ich ponownego, niekontrolowanego wydzielenia w postaci drobnodyspersyjnej, następuje gwałtowny spadek udarności. Przeprowadzone próby spawania łukowego wykazały, że w celu zapewnienia wysokiej jakości złączy spawanych należy ograniczyć energię liniową spawania. Podczas spawania stali S700MC nie zaleca się stosowania podgrzewania wstępnego przed spawaniem oraz obróbki cieplnej po spawaniu, a liczbę napraw należy ograniczyć do minimum, gdyż prowadzi to do obniżenia własności wytrzymałościowych i plastycznych w obszarze SWC, na skutek procesów o charakterze starzeniowym, rozpuszczania faz umacniających w osnowie i ich ponownego, niekontrolowanego wydzielania w czasie chłodzenia.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: The fatigue strength evaluation of S540Q steel and its welded joints
Autorzy:: Cicholska, M.
Tematy:: weldability
fatigue strength
weldable steels of high strength; Pokaż więcej
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Powiązania:: https://bibliotekanauki.pl/articles/245662.pdf Link otwiera się w nowym oknie
Opis:: The research deals with the examination of thermally hardened sheets of weldable S540Q steel of high strength, obtained by thermo mechanical treatment. Conventional rolling and controlled rolling with rapid cooling processes were compared. Example of technological process of high strength sheets production was presented. The basic mechanical properties of this steel were determined (static tensile tests results as well as technological bend tests results were given). Then the steel sheets were welded by a semi-automatic MAG method. The research on the quality of welded joints was performed and their suitability for further research was worked out. Mechanical properties of S540Q steel welded joints were elaborated. The mechanical properties of native material were compared to the properties of welded joints. Joints microstructure was examined in the joints axis, in heat-affected zone and in native material. Fatigue tests were conducted in the non-symmetric tension - compression cycle for the welded joints. The computational fatigue strength was determined and then compared to fatigue strength of the welded joints. The tests results were elaborated statistically by the analysis of linear regression. Wöhler charts were made after conducting fatigue tests. The analysis of increasing the fatigue strength of S540Q steel welded joints was also performed.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Improvement of Weldability of Hot-Dip Galvanized Steel by Anti-Galvanizing Coating with Si-Fe-Al Oxide-Based Micropowder
Autorzy:: So, Seong-Min
Kim, Ki-Yeon
Park, Il-Song
Lee, Seok-Jae
Yoo, Dong-Jin
Kim, Yeon-Won
Oh, Min-Suk
Tematy:: hot-dip galvanizing
anti-galvanizing
oxide micropowder
weldability; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/2203718.pdf Link otwiera się w nowym oknie
Opis:: A Si-Fe-Al ternary oxide-based micropowder coating was used to prevent the formation of a Zn coating on steel during the hot-dip Zn galvanizing process to reduce the welding fume and defects generated during the welding of Zn-galvanized steel. The composition ratio of the oxide powder was optimized and its microstructure and weldability were evaluated. The optimized oxide coating was stable in the hot-dip galvanizing bath at 470°C and effectively inhibited the formation of Zn coating. The Zn residue could be easily removed with simple mechanical impact. The proposed coating reduced Zn fume and prevented the residual Zn from melting in the weld bead during high-temperature welding, thus reducing the number of welding defects. The results indicated that this pretreatment can simplify the manufacturing process and shorten the process time cost-effectively.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Effect of Welding Thermal Cycles on Microstructure and Mechanical Properties of Simulated Heat Affected Zone for a Weldox 1300 Ultra-High Strength Alloy Steel
Autorzy:: Węglowski, M. St.
Zeman, M.
Grocholewski, A.
Tematy:: ultra-high strength steel
weldability
Weldox 1300 steel
physical simulation; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/355256.pdf Link otwiera się w nowym oknie
Opis:: In the present study, the investigation of weldability of ultra-high strength steel has been presented. The thermal simulated samples were used to investigate the effect of welding cooling time t_8/5 on microstructure and mechanical properties of heat affected zone (HAZ) for a Weldox 1300 ultra-high strength steel. In the frame of these investigation the microstructure was studied by light and transmission electron microscopies. Mechanical properties of parent material were analysed by tensile, impact and hardness tests. In details the influence of cooling time in the range of 2,5 ÷ 300 sec. on hardness, impact toughness and microstructure of simulated HAZ was studied by using welding thermal simulation test. The microstructure of ultra-high strength steel is mainly composed of tempered martensite. The results show that the impact toughness and hardness decrease with increase of t_8/5 under condition of a single thermal cycle in simulated HAZ. The increase of cooling time to 300 s causes that the microstructure consists of ferrite and bainite mixture. Lower hardness, for t_8/5 ≥ 60 s indicated that low risk of cold cracking in HAZ for longer cooling time, exists.
Dostawca treści:: Biblioteka Nauki

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