Patent ID: 8038934
Filing Date: 2011-10-18
Classification: C21D,C22C,Y10S

Abstract:
1. A high strength spring steel superior in brittle fracture resistance, comprising the following chemical components in mass %: C: 0.4-0.6%; Si: 1.4-3.0%; Mn: 0.1-1.0%; Cr: 0.2-2.5%; P: 0.025% or less; S: 0.025% or less; N: 0.006% or less; Al: 0.1% or less; O: 0.0030% or less; with the remainder being Fe and inevitable impurities, wherein the amount of solute C is 0.15% or less, the amount of Cr contained as a Cr-containing precipitate is 0.10% or less, a TS value represented by the following equation is 24.8% or more, and the pre-austenite grain diameter is 10 μm or less, and wherein where [X] stands for mass % of element X further comprising, as chemical components, one or more elements selected from the group consisting of: Mg: 0.1-100 ppm; Ca: 0.1-100 ppm; and REM: 0.1-1.5 ppm.