Experience with shipyard installation of a hybrid pipe welding system
Laser-Gas Metal Arc (GMA) hybrid welding is fast making the transition from laboratory to production, in industries as diverse as shipbuilding to automobile manufacture. For the past 3 years, our team has striven to both develop a hybrid welding process for steel pipe, and to specify, build, and install a hybrid pipe welding system in a General Dynamics NASSCO shipyard. In March 2007, the system was successfully installed into the shipyard. This work presents a summary of our continued experimental explorations into various practical aspects of hybrid welding, discusses the system design, and provides an overview of the installation of the system into the shipyard. Test results are presented, as well as lessons learned throughout the project.
Experimental analysis of practical aspects of hybrid welding of thick sections
Laser-Gas Metal Arc (GMA) hybrid welding is fast making the transition from laboratory to production, in industries as diverse as shipbuilding to automobile manufacturing. However, many aspects of hybrid laser welding are not well understood. This work presents a summary of recent experimental explorations into various practical aspects of hybrid welding, such as joint design, gap tolerance, welding through conventional tack welds, and others. An assortment of analyses are run, including metallurgical analysis and radiographic testing, weld formation analysis via macroscopy, mechanical properties evaluations using tensile and bend testing, and process analysis using high speed imaging.Laser-Gas Metal Arc (GMA) hybrid welding is fast making the transition from laboratory to production, in industries as diverse as shipbuilding to automobile manufacturing. However, many aspects of hybrid laser welding are not well understood. This work presents a summary of recent experimental explorations into various practical aspects of hybrid welding, such as joint design, gap tolerance, welding through conventional tack welds, and others. An assortment of analyses are run, including metallurgical analysis and radiographic testing, weld formation analysis via macroscopy, mechanical properties evaluations using tensile and bend testing, and process analysis using high speed imaging.
Heat transfer model for cw laser material processing
(Received 19 September 1979; accepted for publication 12 October 1979)A three‐dimensional heat transfer model for laser material processing with a moving Gaussian heat source is developed using finite difference numerical techniques. In order to develop the model, the process is physically defined as follows: A laser beam, having a defined power distribution, strikes the surface of an opaque substrate of infinite length but finite width and depth moving with a uniform velocity in the positive x direction (along the length). The incident radiation is partly reflected and partly absorbed according to the value of the reflectivity. The reflectivity is considered to be zero at any surface point where the temperature exceeds the boiling point. This is because a ’’keyhole’’ is considered to have formed which will act as a black body. Some of the absorbed energy is lost by reradiation and convection from both the upper and lower surfaces while the rest is conducted into the substrate. That part of the incident r...