Heavy Section Steel Plates for Reactor Pressure Vessels Produced by Basic Oxygen Process

Low alloy steel plates with heavy sections for pressure vessels of direct desulfurization unit and nuclear reactor were produced by basic oxygen process instead of the conventional electric furnace process. There was a decrease of impurity and residual elements which increase susceptibility to neutron irradiation embrittlement and temper embrittlement. Productivity also increased by this process. Various properties of the plates thus manufactured were evaluated in comparison with those of electric furnace plates. It was found as a result that the basic oxygen process produces an improved notch toughness for use in nuclear reactor pressure vessels, and approximately the same levels of properties for application to desulfurization-purpose pressure vessels, compared with the electric furnace process in which BOP return scrap was also used especially.