Carburizing method for high Si carburizing steel

摘要

PROBLEM TO BE SOLVED: To provide a novel carburizing method capable of securing a stable surface carbon concentration of high-Si case-hardened steel after carburized.SOLUTION: A steel containing C: 0.10 to 0.30 mass%, Si: 0.50 to 2.00 mass%, Mn: 0.30 to 1.50 mass%, P: 0.035 mass% or less, S: 0.035 mass% or less, Cr: 0.80 to 3.00 mass%, Mo: 0.80 mass% or less (including 0-impurity range), Al: 0.020 to 0.060 mass%, N: 0.0080 to 0.0250 mass%, and the remainder consisting of Fe and inevitable impurities, is used. The steel is worked into a final part shape, then heated in an oxygen-containing atmosphere to form an Fe oxide film of a thickness of 1.5 μm or more on its surface, before carburized, and then it is subjected to a gas carburization treatment.