Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel

Dissertation

Tommi Jokinen

Research output: ThesisDissertationMonograph

Abstract

Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. Still the process has disadvantages, which are impeding the applicability for the wider industrial use, e.g. tight tolerances in groove manufacturing, fixturing of the pieces against distortions and limited area of thicknesses. Owing to these limiting factors, a great deal of research work has been carried out to overcome these disadvantages by different ways. In many studies it has been pointed out that by using filler metal with laser welding, it is possible to reduce the above-mentioned limitations. The gap bridging ability is then increased strongly and the filler wire plays an important role also when welding thicker sections by using a narrow gap joint configuration and multi pass technique. Recently so-called hybrid welding, which is a combination of the laser beam and arc welding process, has been a target of great interest. A hybrid process seems to be very effective in overcoming the reductions of autogenous laser welding. Not only for the reason of filler wire addition, but also for the extra heat coming from the arc to make the process more effective by increasing the welding speed. In this study filler wire and an arc were used with an Nd:YAG laser in the way of a multi pass technique to weld thick austenitic stainless steel sections. To reduce the welding time and distortions, very narrow grooves were used. The applicability of the laser welding with filler wire was shown, up to a thickness of 20 mm using a 3 kW Nd:YAG laser. Hybrid welding was introduced to the narrow groove by the help of stabilizing, guiding and the contraction effect of the laser beam to the arc discharged. The applicability was shown for a groove angle of 10o and thickness of up to 30 mm.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Lappeenranta University of Technology
Supervisors/Advisors
  • Kujanpää, Veli, Supervisor
Award date4 May 2004
Place of PublicationEspoo
Publisher
Print ISBNs951-38-6361-1
Electronic ISBNs951-38-6362-X
Publication statusPublished - 2004
MoE publication typeG4 Doctoral dissertation (monograph)

Fingerprint

Austenitic stainless steel
Laser beam welding
Welding
Fillers
Lasers
Wire
Filler metals
Electric arc welding
Laser beams
Welds

Keywords

  • laser welding
  • filler wire
  • hybrid welding
  • narrow groove
  • multipass
  • austenitic stainless steels
  • thesis

Cite this

Jokinen, T. (2004). Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Jokinen, Tommi. / Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2004. 120 p.
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abstract = "Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. Still the process has disadvantages, which are impeding the applicability for the wider industrial use, e.g. tight tolerances in groove manufacturing, fixturing of the pieces against distortions and limited area of thicknesses. Owing to these limiting factors, a great deal of research work has been carried out to overcome these disadvantages by different ways. In many studies it has been pointed out that by using filler metal with laser welding, it is possible to reduce the above-mentioned limitations. The gap bridging ability is then increased strongly and the filler wire plays an important role also when welding thicker sections by using a narrow gap joint configuration and multi pass technique. Recently so-called hybrid welding, which is a combination of the laser beam and arc welding process, has been a target of great interest. A hybrid process seems to be very effective in overcoming the reductions of autogenous laser welding. Not only for the reason of filler wire addition, but also for the extra heat coming from the arc to make the process more effective by increasing the welding speed. In this study filler wire and an arc were used with an Nd:YAG laser in the way of a multi pass technique to weld thick austenitic stainless steel sections. To reduce the welding time and distortions, very narrow grooves were used. The applicability of the laser welding with filler wire was shown, up to a thickness of 20 mm using a 3 kW Nd:YAG laser. Hybrid welding was introduced to the narrow groove by the help of stabilizing, guiding and the contraction effect of the laser beam to the arc discharged. The applicability was shown for a groove angle of 10o and thickness of up to 30 mm.",
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author = "Tommi Jokinen",
year = "2004",
language = "English",
isbn = "951-38-6361-1",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "522",
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school = "Lappeenranta University of Technology",

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Jokinen, T 2004, 'Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel: Dissertation', Doctor Degree, Lappeenranta University of Technology , Espoo.

Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel : Dissertation. / Jokinen, Tommi.

Espoo : VTT Technical Research Centre of Finland, 2004. 120 p.

Research output: ThesisDissertationMonograph

TY - THES

T1 - Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel

T2 - Dissertation

AU - Jokinen, Tommi

PY - 2004

Y1 - 2004

N2 - Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. Still the process has disadvantages, which are impeding the applicability for the wider industrial use, e.g. tight tolerances in groove manufacturing, fixturing of the pieces against distortions and limited area of thicknesses. Owing to these limiting factors, a great deal of research work has been carried out to overcome these disadvantages by different ways. In many studies it has been pointed out that by using filler metal with laser welding, it is possible to reduce the above-mentioned limitations. The gap bridging ability is then increased strongly and the filler wire plays an important role also when welding thicker sections by using a narrow gap joint configuration and multi pass technique. Recently so-called hybrid welding, which is a combination of the laser beam and arc welding process, has been a target of great interest. A hybrid process seems to be very effective in overcoming the reductions of autogenous laser welding. Not only for the reason of filler wire addition, but also for the extra heat coming from the arc to make the process more effective by increasing the welding speed. In this study filler wire and an arc were used with an Nd:YAG laser in the way of a multi pass technique to weld thick austenitic stainless steel sections. To reduce the welding time and distortions, very narrow grooves were used. The applicability of the laser welding with filler wire was shown, up to a thickness of 20 mm using a 3 kW Nd:YAG laser. Hybrid welding was introduced to the narrow groove by the help of stabilizing, guiding and the contraction effect of the laser beam to the arc discharged. The applicability was shown for a groove angle of 10o and thickness of up to 30 mm.

AB - Autogenous laser welding has shown many advantages over traditional welding methods in numerous applications. Still the process has disadvantages, which are impeding the applicability for the wider industrial use, e.g. tight tolerances in groove manufacturing, fixturing of the pieces against distortions and limited area of thicknesses. Owing to these limiting factors, a great deal of research work has been carried out to overcome these disadvantages by different ways. In many studies it has been pointed out that by using filler metal with laser welding, it is possible to reduce the above-mentioned limitations. The gap bridging ability is then increased strongly and the filler wire plays an important role also when welding thicker sections by using a narrow gap joint configuration and multi pass technique. Recently so-called hybrid welding, which is a combination of the laser beam and arc welding process, has been a target of great interest. A hybrid process seems to be very effective in overcoming the reductions of autogenous laser welding. Not only for the reason of filler wire addition, but also for the extra heat coming from the arc to make the process more effective by increasing the welding speed. In this study filler wire and an arc were used with an Nd:YAG laser in the way of a multi pass technique to weld thick austenitic stainless steel sections. To reduce the welding time and distortions, very narrow grooves were used. The applicability of the laser welding with filler wire was shown, up to a thickness of 20 mm using a 3 kW Nd:YAG laser. Hybrid welding was introduced to the narrow groove by the help of stabilizing, guiding and the contraction effect of the laser beam to the arc discharged. The applicability was shown for a groove angle of 10o and thickness of up to 30 mm.

KW - laser welding

KW - filler wire

KW - hybrid welding

KW - narrow groove

KW - multipass

KW - austenitic stainless steels

KW - thesis

M3 - Dissertation

SN - 951-38-6361-1

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Jokinen T. Novel ways of using Nd:YAG laser for welding thick section austenitic stainless steel: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2004. 120 p.