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Deep drawability of tailor welded blank of dual phase steel DP 600 affected by laser weld

Brusilova Alena, Schrek Alexander, Pokusova Marcela

Hutnik, Wiadomości Hutnicze

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2019

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Vol. 86, nr 8

238--244

EN

The advanced high-strength steels are used as a part of tailor welded blanks (TWB) or engineering blanks (EB) for the parts production with special properties applied in cars body constructions. The individual parts are laser welded because of narrow heat-affected zone of base material. Also, these structural changes in this area affect strain characteristics of using materials. During forming, there is a danger of cracks creating leading to technological fracture. At analysis, the attention was focused on Dual-phase steel DP600 that is applied very often for tailor welded blanks of front beams of device system, B-pillars reinforcement etc. Erichsen cupping test was used for determination of effect of speed, laser output power and protective atmosphere on a deep drawability change of the weld bead.

PL

Zaawansowane stale wysoko wytrzymałe są wykorzystywane jako elementy składowe wsadów spawanych (WS) oraz złożonych wykrojów wsadowych o specjalnie zaprojektowanych właściwościach. Wsady te stosuje się do produkcji tłoczonych elementów konstrukcji pojazdów. Poszczególne części składowe wykrojów są najczęściej spawane laserowo z powodu wąskiej strefy wpływu ciepła powstającej przy tego typu spawaniu. Nawet wąska strefa wpływu ciepła posiada zmiany strukturalne, które mają decydujący wpływ na charakter odkształcania się WS. Podczas ich formowania istnieje większe niebezpieczeństwo powstawania pęknięć w obszarze spoiny prowadzących do dyskwalifikacji wytłoczek na skutek pęknięć technologicznych. W przedstawionej pracy analizie poddano dwufazową stal DP600, z której produkuje się WS do tłoczenia takich elementów jak: wzmocnienia przednich belek, słupki B itp. Próbę Erichsena wykorzystano do określenia wpływu parametrów spawania laserowego: prędkości spawania, mocy wyjściowej lasera oraz atmosfery ochronnej na zmiany właściwości tłocznych w obszarze spoiny, a tym samym podatności WS do głębokiego tłoczenia.

2

Numerical study of the mechanical behavior and fatigue in a weld bead by friction stir for a 6082-T6 aluminum alloy

Kambouz Y., Benguediab M., Bouchouicha B.

Mechanics and Mechanical Engineering

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2017

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Vol. 21, nr 1

67--83

EN

The process of friction stir welding is a significant advance in the field of research on the Friction welding technique known for several decades. This assembly technique has obvious originality since welding is performed in the solid state, which can help eliminate birth defects related to solidification phase compared to conventional welding. The numerical modeling of this type of process is complex, not only in terms of the variety of physical phenomena which must be considered, but also because of the experimental procedure that must be followed in order to verify and validate numerical predictions. In this work, a finite element model is proposed in order to simulate the crack propagation under monotonic loading in different areas of the weld seam of a specimen CT-50 aluminum alloy 6082-T6. Microhardness tests were performed to characterize the Vickers hardness profile in the vicinity of the weld area. Friction stir welding process leads to a decrease of the static mechanical properties relatively to base material. Detailed examination revealed a hardness decrease in the thermo mechanically affected zone and the nugget zone average hardness was found to be significantly lower than the base alloy hardness. Welded specimens show significantly lower lives than base material.

3

Relationship between geometrie welding parameters and optical-acoustic emissions from eleetrie are in GMAW-S proeess

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

Journal of Achievements in Materials and Manufacturing Engineering

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2011

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Vol. 46, nr 1

79--87

EN

Purpose: Show the relationship between geometrie characteristics of the weld bead and the optical-acoustic emissions from electric arc during welding in the GMAW-S process. Design/methodology/approach: Bead on plate welding experiments was carried out setting different process parameters. Every welding parameter group was set aiming to reach a high stability level what guarantee a geometrical uniformity in the weld beads. In each experiment was simultaneously acquired arc voltage, welding current, infrared and acoustic emissions; from them were computed parameters as arc power, acoustic peaks rate and infrared radiation rate. It was used a tri-dimensional LASER scanner for to acquire geometrical information from the weld beads surface as width and height of the bead. Depth penetration was measured from sectional cross cutting of weld beads. Findings: Previous analysis showed that the arc emission parameters reach a stationary state with different characteristic for each experiment group which means that there is some correlation level between them. Posterior analysis showed that from infrared parameter is possible to monitoring external weld bead geometry and principally its penetration depth. From acoustic parameter is possible to monitoring principally the external weld bead geometry. Therefore is concluded that there is a close relation between the arc emissions and the weld bead geometry and that them could be used to measuring the welding geometrical parameters. Research limitations/implications: After analysis it was noticed that the infrared sensing has a better performance than acoustic sensing in the depth penetration monitoring. Infrared sensing also sources some information about external geometric parameters that in conjunction with the acoustic sensing is possible to have reliable information about weld bead geometry. This method of sensing geometric parameters could be applied in other welding processes, but is necessary to have visibility of the arc, it means that for example this method cannot be used in the submerged arc welding - SAW process. Originality/value: The using two or more sensors for monitoring welding parameters increases the performance and reliability of the measurements. In this case, the monitoring of the weld bead geometric parameters could be possible from sensing arc emission and potentially it could be used as an on-line monitor, avoiding any complex electric connections of sensors into the welding process.