Thick steel sheet having superior fatigue resistance properties in direction of sheet thickness method for producing same and fillet welded joint using said thick steel sheet

摘要

Provided are: a thick steel sheet that has superior fatigue resistance properties in the direction of sheet thickness and that is favorable for welded steel structures such as pressure vessels; a method for producing the thick steel sheet; and a fillet welded joint using the thick steel sheet. Specifically the thick steel sheet has a composition that in a range from one or both of the rolled surfaces of the steel sheet to 4 mm in the direction of sheet thickness has a compressive residual stress perpendicular to the direction of steel thickness of at least 100 MPa and preferably contains by mass%: 0.03 0.15% of C no greater than 1.0% of Si and 1.0 2.0% of Mn; 0.005 0.05% of Ti and/or 0.001 0.05% of Nb; and one or at least two of Cu Ni Cr Mo V W Zr Ca B and no greater than 0.1% of Al.