Vol.5, No2, 2005, pp. 59-70
UDC 621.643.2-112.81 669.15-462-112.81

Experience from service of hydroelectrical power plant indicates the possible leakage after stable crack growth or bursting in the case of brittle fracture. Introduction of weldable high strength steels for production of penstock brings important savings, but crack resistance, especially to brittle fracture, of parent metal, weld metal and the heat-affected-zone is required. For the penstock of “Bajina Bašta” hydroelectrical power plant weldable high strength steel is applied (up to 700 MPa nominal yield strength) and investor requested the proof for its resistance to cracks and brittle fracture. The results of testing of penstock model and welded joints are presented, which confirmed acceptable weldability of undermatched weld metal (undermatched effect) and resistance to cracks and brittle fracture.

Keywords: penstock, high strength steel, welded structure, brittle fracture, crack resistance