Numerical modelling of optimum microstructure behaviour in duplex stainless steel weldments

• Main Author: Payares Rios de Asprino, M. C.
• Published: Swansea University 2005
• Subjects: 671
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638433

A comprehensive study of DSS SAF 2205 weldments and nature of weld metal and heat-affected zones has been undertaken. Several DSSs SAF 2205 welds were fabricated using GMAW welding process at different welding conditions. The investigation focuses on the effect of the welding parameters are current, arc voltage, welding speed and heat input on the weld geometry, microstructure and mechanical properties. Also, the technique of the determination of “Response Surface” for the welding parameters was focused to optimise the effects on them each dependent. Variable. All weldments had the UTS, the yield strength and elongation in the range of weld mechanical according to ASTM A240. The welding parameters appeared to have much effect on the tensile properties of DSS weldments tested along transverse direction than the weldment tested along rolling direction. The hardness values vary with welding parameters employed. The trends show that HAZ hardness is slightly lower than base metal when 0.53 to 1.19 kJ/mm is used. However, the hardness in WM is higher than base metal for welding conditions with HI lower than 1.30 kJ/mm. DSS weldments showed no ductile to brittle transition. The fracture location for weld TST with head-off varied between HAZ and base metal. On the contrary, the fracture location along LT was generally at the base metal. SEM photographs shows that the mode of fracture of DSS welds is because microvoids coalescence (simples). Hence the fracture is ductile in DSS specimens. AS the heat input increases the simple size also increases.