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Title: High power laser welding in hyperbaric gas and water environments

Abstract

As the exploitation of oil and gas reserves moves into deeper water (>500 m), advanced welding techniques will have to be developed for installation and repair as current commercially available arc welding processes can no longer be utilized at depths greater than 300 m due to the detrimental effect of pressure on arc stability. In addition, systems relying on diver intervention are unlikely to be viable due to health and safety considerations. Here, a hyperbaric laser welding facility has been constructed and the feasibility of high power CO{sub 2} and Nd:YAG laser welding in both high pressure gas and water environments, to simulated water depths of 500 m, has been established. From initial trials on welding through water at atmospheric pressure, it was found that the different absorption characteristics of water to 10.6 {micro}m (CO{sub 2} laser) and 1.06 {micro}m (Nd:YAG laser) radiation proved crucial. The Nd:YAG laser was totally unsuitable as the beam was largely diffused in the water, whereas the CO{sub 2} beam was readily absorbed and, using high speed video equipment, was found to form a high irradiance channel and a dry region around the weld area. Welding under a high pressure gas environment produced a highlymore » energized plume which prevented keyhole welding at pressures over 1 {times} 10{sup 6} Pa. An investigation carried out into the efficacy of a gas jet delivery system to alleviate the extent of the plume showed that argon blown horizontally across the weld was the optimum configuration, extending the welding range up to 5 {times} 10{sup 6} Pa. A limited investigation into high pressure underwater welding showed porosity to be a problem although sound welds were produced at pressures up to 2 {times} 10{sup 6} Pa.« less

Authors:
 [1];  [2]; ;  [3]
  1. Univ. of Liverpool (United Kingdom). Dept. of Mechanical Engineering
  2. Howden Lasers, Dundee (United Kingdom)
  3. Univ. of Aberdeen (United Kingdom). Dept. of Engineering
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
500925
Resource Type:
Journal Article
Journal Name:
Journal of Laser Applications
Additional Journal Information:
Journal Volume: 9; Journal Issue: 3; Other Information: PBD: Jun 1997
Country of Publication:
United States
Language:
English
Subject:
03 NATURAL GAS; 02 PETROLEUM; 36 MATERIALS SCIENCE; LASER WELDING; STEELS; PETROLEUM INDUSTRY; NATURAL GAS INDUSTRY; OFFSHORE OPERATIONS; CARBON DIOXIDE LASERS; NEODYMIUM LASERS; EXPERIMENTAL DATA; DEPTH

Citation Formats

Shannon, G J, McNaught, W, Deans, W F, and Watson, J. High power laser welding in hyperbaric gas and water environments. United States: N. p., 1997. Web. doi:10.2351/1.4745452.
Shannon, G J, McNaught, W, Deans, W F, & Watson, J. High power laser welding in hyperbaric gas and water environments. United States. https://doi.org/10.2351/1.4745452
Shannon, G J, McNaught, W, Deans, W F, and Watson, J. 1997. "High power laser welding in hyperbaric gas and water environments". United States. https://doi.org/10.2351/1.4745452.
@article{osti_500925,
title = {High power laser welding in hyperbaric gas and water environments},
author = {Shannon, G J and McNaught, W and Deans, W F and Watson, J},
abstractNote = {As the exploitation of oil and gas reserves moves into deeper water (>500 m), advanced welding techniques will have to be developed for installation and repair as current commercially available arc welding processes can no longer be utilized at depths greater than 300 m due to the detrimental effect of pressure on arc stability. In addition, systems relying on diver intervention are unlikely to be viable due to health and safety considerations. Here, a hyperbaric laser welding facility has been constructed and the feasibility of high power CO{sub 2} and Nd:YAG laser welding in both high pressure gas and water environments, to simulated water depths of 500 m, has been established. From initial trials on welding through water at atmospheric pressure, it was found that the different absorption characteristics of water to 10.6 {micro}m (CO{sub 2} laser) and 1.06 {micro}m (Nd:YAG laser) radiation proved crucial. The Nd:YAG laser was totally unsuitable as the beam was largely diffused in the water, whereas the CO{sub 2} beam was readily absorbed and, using high speed video equipment, was found to form a high irradiance channel and a dry region around the weld area. Welding under a high pressure gas environment produced a highly energized plume which prevented keyhole welding at pressures over 1 {times} 10{sup 6} Pa. An investigation carried out into the efficacy of a gas jet delivery system to alleviate the extent of the plume showed that argon blown horizontally across the weld was the optimum configuration, extending the welding range up to 5 {times} 10{sup 6} Pa. A limited investigation into high pressure underwater welding showed porosity to be a problem although sound welds were produced at pressures up to 2 {times} 10{sup 6} Pa.},
doi = {10.2351/1.4745452},
url = {https://www.osti.gov/biblio/500925}, journal = {Journal of Laser Applications},
number = 3,
volume = 9,
place = {United States},
year = {Sun Jun 01 00:00:00 EDT 1997},
month = {Sun Jun 01 00:00:00 EDT 1997}
}