Assessment of the TMCP Shipbuilding EH36 Steel Weldability of High Heat Input Submerged Arc Welding Joint

The welding with high heat input is one of the main strategies used by shipyards in the world to increase their productivity in joining operation activities. However, the thermal cycles due to the welding process may affect the microstructure features and be deleterious to the toughness in the heat affected zone (HAZ). The aim of this study was to evaluate the microstructure and the mechanical properties of the HAZ of the EH36 steel produced by controlled rolling and accelerated cooling compared to a conventional steel of the same grade, both welded with submerged-arc welding with two heat inputs: 76 to 130 kJ/cm. It was observed that the presence of a more refined microstructure in the different regions of the HAZ, associated with a fine base metal grain size and lower carbon equivalent value, were the main factors that contributed to the excellent HAZ toughness of the TMCP steel compared to conventional steel. The results of this study showed that it is possible to obtain welded joints with excellent mechanical properties even using high heat input levels by employing TMCP steel, and its use may be a strategy to optimize the production time and cost in the shipbuilding industry.