Product Code: ICAL07_P503

The Effect of Output Fibre Diameter when Welding Austenitic Stainless Steel with a Fibre Laser
Authors:
Ian Pashby, The University of Nottingham; Nottingham Great Britain
Jongkol Iammi, The University of Nottingham; Nottingham Great Britain
Guijun Bi, The University of Nottingham; Nottingham Great Britain
Presented at ICALEO 2007

Fibre lasers are attractive for use in welding process because of their combination of properties which include high power and a good beam quality. However, the use of fibre lasers as a power source to join stainless steel has not been extensively researched. The aim of this research is to establish suitable parameters for fibre laser welding of austenitic stainless steel and to investigate the effect of laser power, welding speed and diameter of the delivery fibre. Specific aspects investigated include the relationships between process parameters, weld bead shape, dimensions and microstructure. Bead on plate welds were made on grade AISI 304 austenitic stainless steel using a fibre laser with a maximum power output of 2 kW using delivery fibres of diameters 200, 400 and 600 μm. The bead shape and microstructure of steel welds were observed by optical microscopy and the hardness of welds at different process parameters was measured. The results show that the penetration width and depth are related to the welding speed and power density. The weld bead shapes are different at different delivery fibre diameters. The penetration depth and width were much deeper and narrower at higher laser power density i.e. when using the smaller diameter delivery fibre.