TWI

The development of friction stir welding (FSW) as a potential low distortion, cost-effective joining method for HSLA-65 steel T-joints is presented with reference to application in the ship building industry. Experiments were carried out on steel (0.09%C, 1.39%Mn, 0.24%Si, 0.35%Ni, 0.06%Mo, 0.16%Cr, 0.25%Cu, 0.06%V, 0.01%Ti, 0.02%Nb, 0.018%Al), 6.25 mm thickness, with the objectives of: evaluating the feasibility of FSW T-joints from a single side using W-Re tool materials; performing macro and microstructural evaluation of selected welds; and mapping microhardness values from cross-sections of selected T joints and evaluating the fatigue performance of selected weldments. The T joints consisted of two flat plate sections: a flange and web section. The majority of tools were made of W, 25%Re, 2%HfC and others were made of W, 25%Re. Welding parameters including tool design, taper angle on shoulder, rotational and tool speed, load and heat input were all varied during the welding trials. Fatigue testing was performed at four different stress levels and results were compared with results of GMA welded cruciform test specimens of HSLA 80. Tool wear and weld microstructure were observed.

8th International Symposium, 18-20 May 2010, Session 2A: Steel, Paper 03