STEEL EXCELLENT IN FATIGUE CRACK PROPAGATING PROPERTY IN WET HYDROGEN SULFIDE ENVIRONMENT

摘要

PURPOSE: To provide steel having properties in which fatigue cracks are hard to propagate in the case of use in a wet hydrogen sulfide environment. ;CONSTITUTION: This steel has a compen. contg. 0.01 to 0.2% C, 0.1 to 0.6% Si, 0.3 to 2.0% Mn and 0.01 to 0.1% sol.Al. Its structure is constituted of a mixed one of a primary phase of ferrite and a secondary phase of bainite and/or pearlite, and the average grain size of the ferrite is regulated to ≤20μm. The steel may be incorporated with one or more kinds of components selected from either or both of the following two groups: a primary group; 0.1 to 1.0% Cu, 0.1 to 2.0% Cr, 0.05 to 0.5% Ni and 0.01 to 0.5% Mo and a secondary group; 0.01 to 0.1% Nb, 0.01 to 0.1% Ti and 0.01 to 0.1% V.;COPYRIGHT: (C)1994,JPO