Two-pass laser welding of galvanized high-strength dual-phase steel for a zero-gap lap joint configuration

Ma, Jingsen; Kong, Fang; Carlson, Blair E.; Kovacevic, Radovan

doi:10.1016/j.jmatprotec.2012.10.019

Cited by 60 publications

(31 citation statements)

References 16 publications

(20 reference statements)

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“…Reisgen et al [26] measured approximately 380 hv in the fusion zone. on the other hand the hardeness of the DP980 steel (with a higher strength level than the investigated dP800 steel) reaches 430-450 hv [27].…”

Section: Hardness Profilesmentioning

confidence: 73%

Microstructural Aspects of Twin-Spot Laser Welding of Dp-Hsla Steel Sheet Joints

Stano

Grajcar²,

Wilk³

et al. 2016

Archives of Metallurgy and Materials

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The article presents the possibility of using twin-spot laser welding (i.e. laser welding with focusing a laser beam on two spots) for making overlap joints made of 0.8-1 mm thick HSLA and DP type high strength steel sheets. joints were made using a Yb:YAG disc laser having a maximum power of 12 kW and a welding head by means of which it was possible to focus a laser beam on two spots, 0.6 mm and 1 mm away. The angle between focuses amounted to 0° or 90°, whereas the power distribution was 50%-50%. With settings as presented above it was possible to obtain high-quality overlap joints. The geometrical parameters of the joints were primarily affected by beams positions (in relation to each other) and, to a lesser degree, by the distance between the focuses. It was possible to obtain a 10% hardness reduction in the fusion zone of the DP-HSLA steel joints if the angle between the beams amounted to 90°. The tests also involved microstructural examinations of individual zones of the joints.

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Section: Hardness Profilesmentioning

confidence: 73%

Microstructural Aspects of Twin-Spot Laser Welding of Dp-Hsla Steel Sheet Joints

Stano

Grajcar²,

Wilk³

et al. 2016

Archives of Metallurgy and Materials

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“…A defocused laser beam has been used for preheating. Afterwards, partial penetration welding was carried out by using a focused laser beam [21]. The main disadvantage of that strategy is the additional process step of preheating and as a result the extension of the process time.…”

Section: Introductionmentioning

confidence: 99%

Decreasing pore formation in multiple-sheet laser joining with interfacial polymeric contaminations

2015

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Deep-penetration laser welding is an efficient joining technology for overlap joints nowadays. However, contaminations usually having a lower vaporization temperature can cause seam defects like pores and melt ejections during the process. Many approaches have been investigated, e.g., for the industrially interesting case of welding zinc-coated steel sheets. Suitable techniques for sufficient reduction or avoidance of porosity require additional process steps or timeconsuming preparations. In this paper, three-sheet joints having polymeric interlayers as exemplary extensive contaminations are investigated. Seams feature extreme porosity after standard single-pass welding. The porosity can be decreased significantly when repeating the welding process (double-pass welding). This effect on formation of porosity is modified in this paper. Instead of two processes, longitudinal beam oscillation is applied. The center porosity in longitudinal sections, used as indicator for the porosity of seams, can be reduced significantly from more than 50 to 20 % by using the beam oscillation technique. As the main reason, the increased degassing time due to the lengthening of the melt pool depending on oscillation parameters is identified. Simultaneously, the results indicate that the seam width must not increase similarly to avoid that further evaporation of contamination material cancels out the achieved benefit by lengthening.

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“…Sheets of this type are used in the manufacture of automobile bodies in high volume production because of excellent corrosion resistance and relatively low costs [1][2][3][4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

“…Both joining methods mentioned above are still used but the extent of their use systematically decreases [1,7]. The reason for this is the continuous introduction of new materials such as advanced automotive steels, galvanized high-strength dual-phase steel, trip steels, increase use of aluminium and composites, "sandwich" steel, and tailored blanks [2][3][4]. The conventional resistance and arc welding methods are not proper for welding of new materials and joints of dissimilar materials [38][39][40][41][42].…”

Section: Introductionmentioning

confidence: 99%

“…2-4%, to argon gas mixture can effectively reduce the tendency of zinc to evaporation. J. Ma et al proposed two-pass laser welding of galvanized steel [2]. The first pass is based on a defocused laser spot that scans across the top of the overlapped sheets and heats the zinc coating at the faying surface to be melted and vaporized, while the second pass is executed with a focused laser spot in order to perform the welding.…”

Section: Introductionmentioning

confidence: 99%

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Disk Laser Welding of Car Body Zinc Coated Steel Sheets / Spawanie Laserem Dyskowym Blach Ze Stali Karoseryjnej Ocynkowanej

Lisiecki¹,

Burdzik²,

Siwiec³

et al. 2015

Archives of Metallurgy and Materials

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Autogenous laser welding of 0.8 mm thick butt joints of car body electro-galvanized steel sheet DC04 was investigated. The Yb:YAG disk laser TruDisk 3302 with the beam spot diameter of 200 µm was used. The effect of laser welding parameters and technological conditions on weld shape, penetration depth, process stability, microstructure and mechanical performance was determined. It was found that the laser beam spot focused on the top surface of a butt joint tends to pass through the gap, especially in the low range of heat input and high welding speed. All test welds were welded at a keyhole mode, and the weld metal was free of porosity. Thus, the keyhole laser welding of zinc coated steel sheets in butt configuration provides excellent conditions to escape for zinc vapours, with no risk of porosity. Microstructure, microhardness and mechanical performance of the butt joints depend on laser welding conditions thus cooling rate and cooling times. The shortest cooling time t8/5 was calculated for 0.29 s.Keywords: car body steel, DC04, laser welding, disk laser, zinc W artykule opisano wyniki badań procesu spawania laserowego bez materiału dodatkowego złączy doczołowych blach karoseryjnych ocynkowanych DC04 o grubości 0.8 mm. W procesie spawania zastosowano laser stały Yb:YAG TruDisk 3302 z wiązką laserową o średnicy ogniska 200 µm. Badano wpływ parametrów i warunków technologicznych spawania na kształt i głębokość ściegu spoiny, stabilność procesu spawania, mikrostrukturę i właściwości mechaniczne złączy. Stwierdzono, że wiązka laserowa zogniskowana na górnej powierzchni blach wykazuje tendencję do przenikania przez szczelinę złącza, szczególnie przy niskich energiach liniowych i dużych prędkościach spawania. W całym zakresie parametrów złącza były spawane z utworzeniem kanału parowego, a metal spoiny był wolny od porowatości. Wskazuje to, że konfiguracja złącza doczołowego stwarza dogodne warunki do ujścia par cynku, bez ryzyka porowatości spoin. Mikrostruktura, mikrotwardość i właściwości mechaniczne złączy zależą wyraźnie od warunków spawania, a więc szybkości stygnięcia i czasów stygnięcia. Najkrótszy wyznaczony czas stygnięcia t8/5 był równy 0.29 s.

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Two-pass laser welding of galvanized high-strength dual-phase steel for a zero-gap lap joint configuration

Cited by 60 publications

References 16 publications

Microstructural Aspects of Twin-Spot Laser Welding of Dp-Hsla Steel Sheet Joints

Microstructural Aspects of Twin-Spot Laser Welding of Dp-Hsla Steel Sheet Joints

Decreasing pore formation in multiple-sheet laser joining with interfacial polymeric contaminations

Disk Laser Welding of Car Body Zinc Coated Steel Sheets / Spawanie Laserem Dyskowym Blach Ze Stali Karoseryjnej Ocynkowanej

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