Abstract
The applicability of 100 kgf/mm2 grade high tensile strength steel developed for penstock was evaluated in this paper. Firstly, five kinds of weld-cracking tests were performed and it was demonstrated that the 100 kgf/mm2 grade steel, including its weld metal, has a good resistance for cold cracking. Secondly, mechanical properties and fracture toughness were investigated and evaluated the safety of the weldment against brittle fracture. As a result, it is confirmed that the 100 kgf/mm2 grade steel weldment has enough toughness to prevent the brittle fracture. Finally, the corelation between fracture toughness and absorbed energy obtained by Charpy-V test was investigated, and Charpy-V values required to prevent the brittle fracture was proposed.
