| abstract |
Disclosed is a steel for springs, which has the following overall composition (% by mass): C: 0.5 to 0.6%, Si: 1.0 to 1.8%, Mn: 0.1 to 1.0%, Cr: 0.1 to 1.0%, P: 0.035% or less, and S: 0.035% or less, with the remainder being iron and unavoidable impurities, wherein, in the area of the internal structure in an arbitrary cross-section surface of the steel, bainite makes up 65% or more, remaining austenite makes up 6 to 13% and martensite makes up the remainder (including 0%), and wherein the average C concentration in the remaining austenite is 0.65 to 1.7%. The steel for springs can have a tensile strength as high as 1800 MPa or more and high ductility. |