TWI Industrial Member Report Summary 840/2006
By C M Allen
Hybrid laser-arc processes have seen considerable development and application in the past ten years, after renewed interest in a technique that was originally suggested in the late 1970s (1,2). The main benefits claimed over laser welding include improved tolerance to joint fitup, higher productivity, lower distortion, improved weld quality and lower cost (3-5). Hybrid laser-arc welding is now being used in commercial production in the shipbuilding and automotive industries, mainly for the welding of C-Mn steels.
Despite these advances, there are still a number of materials and process combinations for which the hybrid laser-arc process can be further developed. The scope of this report investigates therefore the laser-TIG welding of thick section (=10mm) austenitic stainless steel, with a view to application in the nuclear and power generation industries. Laser sources with output powers of 5kW are selected, as these are typical powers necessary to achieve full penetration in a single pass in this thickness. TIG is selected as the arc process due to the perceived cleanliness of this technique and resultant high quality of welds achievable.
- To characterise CO2 laser-TIG and Yb fibre laser-TIG hybrid welding processes compared with autogenous laser welding of thick section (=10mm) austenitic stainless steel.