A Mn-Mo-Ni BASED STEEL FOR PRESSURE VESSEL HAVING SUPERIOR TOUGHNESS

摘要

The present invention relates to a boiler, material Mn-Mo-Ni-based carbon to be applied to such pressure vessel of the power plant, by adding a small amount of B, Ti, etc. to the Mn-Mo-Ni-based by fine precipitation of carbides and nitrides increasing the tensile strength to be manufactured for a can improve toughness by Sikkim employs B on the base material steel pressure vessels, it is an object.; The present invention for achieving the above object, in weight%, C: 0.10 ~ 0.14%, Si: 0.1 ~ 0.4%, Mn: 1.0 ~ 1.5%, Mo: 0.4 ~ 0.6%, Ni: 0.4 ~ 0.7%, B: 0.0005 ~ 0.003%, Ti: 0.005 ~ 0.02%, Al: 0.01 ~ 0.03%, P: 0.010% or less, S: 0.003% or less, N: 0.005% or less, the balance Fe and other inevitable excellent toughness that the composition to impurities Mn -Mo-Ni-based and the steel for pressure vessels with the technical gist.