Practical application of high‐power YAG laser welding by optical fibre transmission

Yokoyama, Akira; Nagashima, Tadashi; Matsumoto, Osa; Nagura, Yasumi; Ishide, Takashi

doi:10.1080/09507119209548279

Cited by 3 publications

(5 citation statements)

References 2 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These tubes are generally repaired using some form of plugging or sleeving procedure carried out using a welding process. [1][2][3][4][5][6] However, the sluggish weld metal of nickelbased alloys does not flow out or wet to the same extent as carbon steel or stainless steel weld metals. 7) Therefore, the finished welds commonly exhibit defects such as porosity or solidification cracking.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, Nd-YAG laser welding is a potential candidate for the repair task discussed above. [2][3][4]8) Compared with conventional arc welding processes, the higher power density of laser beam welding increases the depth to width (D=W) ratio of the bead, lowers the heat input, and results in a more rapid solidification. These welding characteristics are beneficial since they minimize distortion and yield excellent mechanical properties.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Kuo

Lin

2007

Mater. Trans.

View full text Add to dashboard Cite

A high power Nd-YAG laser was used to perform bead-on-plate (BOP) welding on high viscosity Inconel 690 alloy plates of 3 mm in thickness with three different shielding gases (Ar, He, and N 2 ). Adopting a rectangular laser power waveform, four different peak-base power differentials (ÁP) were applied with a constant average power of 1.5 kW. A comprehensive investigation was performed into the influences of the shielding gas, the flow rate, and the value of ÁP on the characteristics of the resulting welds, including the weld morphology, the penetration depth, the plume volume, and the porosity formation. The results showed that the weld penetration depth, the depth-to-width ratio, the weld surface roughness and the degree of weld spattering all increased with increasing ÁP. The choice of shielding gas had a significant effect on the porosity ratio (P r ) of the weld. The weld formed under Ar shielding had the highest P r , while that formed under N 2 shielding had the lowest. Under He shielding, the gas flow rate had a significant effect on the porosity ratio. However, under the higher density gases of Ar and N 2 , the porosity appeared to be insensitive to the flow rate. Finally, an increased ÁP yielded a significant reduction in P r for the welds with higher porosity.

show abstract

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Kuo

Lin

2007

Mater. Trans.

View full text Add to dashboard Cite

show abstract

“…A system developed by Ishide et al, 2 shown schematically in Fig. 1, provides an example of coaxial collection of light.…”

Section: Optical Radiationmentioning

confidence: 99%

Progress in real time laser process monitoring: Theory and practice

Farson

2000

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

Real time detection of defects in laser welds has been the subject of substantial research and development efforts. In this review, the state of progress in developing so called emission based monitoring systems is described. These monitors collect and analyse various forms of energy radiated from the laser–material interaction site as the weld is being formed. The most common emissions that have been used for monitoring purposes include optical and near optical wavelength electromagnetic radiation, audible and ultrasonic airborne acoustic waves, and integrated charged particle flux. The various system configurations and the weld quality characteristics that have been measured with these emissions are summarised. As researchers continue to refine these systems, there has been increasing interest in the mechanisms by which the signals are produced and their relationship to the various physical processes occurring in the laser weld keyhole. A review of the current literature pertinent to the sources of electromagnetic, acoustic, and plasma charge emissions is given. Finally, results illustrating the relationships between the various emissions signals are presented.

show abstract

“…If such damage is identified during periodic inspection, the damaged tubes are generally repaired using some form of plugging or sleeving procedure in operation. [3][4][5][6][7] In the sleeving process, a smaller diameter sleeve is inserted into a small diameter tube positioned over the damaged area. The sleeve and tube are then lap welded together from inside the sleeve.…”

Section: Introductionmentioning

confidence: 99%

“…The sleeve and tube are then lap welded together from inside the sleeve. [3][4][5][6][7][8][9] Owing to space constraints and the highly corrosive environment, selection of an appropriate welding process and specification of suitable materials are of crucial concern when repairing the damaged tubes.…”

Section: Introductionmentioning

confidence: 99%

Effects of pulsed and continuous Nd–YAG laser beam waves on welding of Inconel alloy

Kuo¹

2005

Science and Technology of Welding and Joining

View full text Add to dashboard Cite

In the present work a 2 . 5 kW high power Nd-YAG laser is used in the bead on plate (BOP) and butt welding of Inconel 690 plates of thickness 3 mm. Welding is performed using a rectangular laser pulse, for which the peak to base power ratio W r is reduced from an initial value of 10 to a value of 1, maintaining an identical mean power of 1 . 7 kW. Therefore, the welding mode changes from a pulsed wave to a continuous wave. The BOP results indicate that the depth of the weld penetration increases at a lower travel speed and/or a higher value of W r . In the butt welding process, as W r is increased from 1 to 10, the cellular microstructure of the weld remains relatively unchanged, but the macroporosity formation ratio decreases from 7 . 1% to 0 . 6%. At low values of W r , macroporosity is identified primarily in the root region. However, as W r increases, the associated periodic high power increases the agitation of the molten pool and probably causes bubbles to float upwards. Consequently, at higher values of W r , the regions of macroporosity are distributed randomly throughout the weld. Although microcracks are not apparent within any of the welds, each weld exhibits slight microporosity. This microporosity decreases as W r increases. The present results confirm that a pulsed laser beam with an appropriate peak power can be used to achieve a compromise between the mechanical properties and surface roughness of the weld for Inconel 690 in Nd-YAG laser welding.

show abstract

Practical application of high‐power YAG laser welding by optical fibre transmission

Cited by 3 publications

References 2 publications

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Effects of Different Shielding Gases and Power Waveforms on Penetration Characteristics and Porosity Formation in Laser Welding of Inconel 690 Alloy

Progress in real time laser process monitoring: Theory and practice

Effects of pulsed and continuous Nd–YAG laser beam waves on welding of Inconel alloy

Contact Info

Product

Resources

About