News & Views

Laser welding thick sections

By Kirk Cooper on Friday, August 27th, 2010

Nuclear power plant components are huge – and they take a long time to put together.  I realized this when I traveled recently to a facility which fabricates pressure vessels and steam generators for nuclear applications.  Wall thicknesses can reach ten inches or more, and the fixturing and manipulation of a single welded joint can take days.  A welding technique which could fuse large vessel weld joints without having to rotate the part would be revolutionary. 

Single-pass, autogenous laser welding of thick section material was recently demonstrated at EWI.  Butt-welds on 5/8” thick 316L stainless steel were made using a 15kW fiber laser.  The figure below shows a cross-section of one of these welds made at a travel speed of 80-inches/minute.  Testing is underway to evaluate weld quality, but preliminary investigations did not reveal cracking or lack of fusion.   While this weld was produced using flat plate in the 1G position, out-of-position welding of vessel walls is very achievable.  Laser welding, either alone or coupled with gas metal arc welding, could prove to be a game-changing technology for large nuclear vessel fabrication.

If you are interested in exploring how EWI could assist you in using lasers to weld heavy section components, contact Brad Nagy at or 614.688.5093.

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