Patent ID: 9598752
Date: 2017-03-21
CPC Classifications: C21D,C22C,F16C

Claim:
1. A steel comprising: iron, C: 0.9 to 1.10 mass %, Si: 0.05 to 0.49 mass %, Mn: 0.1 to 1.0 mass %, P: more than 0 but at most 0.05 mass %, S: more than 0 but at most 0.05 mass %, Cr: 0.03 to 0.40 mass %, Al: more than 0 but at most 0.05 mass %, N: 0.002 to 0.025 mass %, Ti: more than 0 but at most 0.0030 mass %, and O: more than 0 but at most 0.0025 mass %, wherein an average aspect ratio of cementite is at most 2.00, an average circle-equivalent diameter of cementite is 0.35 to 0.6 μm, and a number density of cementite having a circle-equivalent diameter of at least 0.13 μm is at least 0.45 μm