Section steels produced by welding are essential parts for shipbuilding and offshore plant production. T-type and H-type section steels are produced by handwork for secondary processing, which is a generally difficult and tedious activity. Therefore, automatic welding, with sound welding properties and a high-speed process, is necessary to meet the production demands. Welding conditions can be optimized by controlling various parameters to obtain suitable and highly reliable microstructural properties. In this study, the heat affected zone and weld defects of fillet-welded Angle and T-bar parts were investigated in terms of their microstructural, macrostructural, and mechanical properties to ensure the soundness of AH36 section steel parts joined by continuous welds.

Fusion welding of Ti-Cu is difficult because of big difference of melting points and formation of brittle intermetallic compounds. Friction stir welding is carried out by solid-state joining, thermo-mechanical stirring, and friction heat. Ti-Cu FSW dissimilar welding can supply a very sound joint area with a few intermetallic compounds. Optimized welding process conditions are essential to obtain suitable microstructure and mechanical properties of welded zones. Different welding speeds affect the evolution of microstructure and mechanical properties due to changes of input heat and internal stored deformation energy. The correlation of microstructure and mechanical properties of Ti-Cu welded zone according to welding speeds were investigated and analyzed. As the higher the welding speed, the lower the heat input and the lower the temperature rise. Ti-Cu 75 has the smallest grain size at 13.9 μm, but the optimum mechanical properties and the integrity of welding were shown in Ti-Cu 50.