Abstract: | In general, at the choice of metallic materials it is taken into consideration both the reliability and the price. The steam boilers are under pressure at high temperature industrial equipments. Being given the operation risks presented by steam boilers, at the used metallic materials choice has priority the aspects bound to reliability as follows: mechanical resistance, corrosion resistance. The metallic materials used in construction of main elements of steam boilers show a multitude of types, which have to correspond to some very severe requirements. In general, the greatest part of metallic materials of main elements of steam boilers made in Romania are described by Romanian standards (STAS), but the rest of materials by soviet (GOST), German (DIN) or American (ASTM) standards as well by foreign norms, as for example, Mannesmann, Sandvik, Marrel Freres, Hoesch, Creusol- Loire, Uddeholm. At Central Heating-and-Power Plant from Bacau, the metallic materials of main elements of 420 t/h steam boiler are described by Romanian and soviet standards as well by Marrel Freres norms, inspired from American norms. From economic reasons, all these metallic materials were made at Iron and Steel Works from Galati. This paper presents some aspects concerning choice criteria of metallic materials used at manufacturing of 420 t/h steam boiler main elements from Central Heating-and-Power Plant from Bacau, taking into consideration chemical composition, the influence of some alloying elements, some mechanical characteristics and the design stipulated standards. |
