高強度クランク・シャフト用軟窒化鋼の開発

概要

論文の詳細を見る
Alloy-designing of a nitrocarburizing steel for crank shafts of automobile engines was studied in order to increase the fatigue strength.This crank shaft has been made of a free-machining carbon steel, and it was required to increase the fatigue strength by 20%.It has been known that fatigue strength of nitro-carburized steels was controlled by mainly surface hardness and case depth, so contents of Cr and Al were optimized in view points those two factors. Through the laboratory experiments, optimum compositions were determined as follows;0.2%C-0.7%Si-1%Mn-1%Cr-0.15%Al-0.08%S-0.1%S-0.1%Pb.This new steel was produced in an industrial quantity and practical properties such as hot-forgeability, machinability, fatigue strength of a crank shaft after nitrocarburizing and so on were investigated in an automobile producers shop. As a result, the new steel was found to satisfy the above requirements.
大同特殊鋼株式会社の論文