MICROSTRUCTURE AND MECHANICAL PROPERTIES EVALUATIONS OF HEAT TREATED DISSIMILAR METAL JOINT WELDMENT BETWEEN API 5CT C90 AND ASTM A182 F22

In this research, dissimilar metal welding of API 5CT C90 and ASTM A182 F22 is
used to connect between the upset riser pipe and the riser connector of a marine riser.
API 5CT C90 material is the material have high carbon content that lead to its high
hardness and low weldability. Proper welding parameters need to be qualified so that
the welding process will give desired mechanical properties, less costly and consume
less time. Therefore, post-weld heat treatment (PWHT) is needed to reduce the
hardness and increase the impact energy of the weldment as the intermixture zone at
fusion line between the base metal and weld metal has potential of having high
hardness due to residual stress in the intermixed microstructure after high temperature
welding.