Komatsu Corporation

Osaka University

Koji Hagihara

Koji Yamamoto

Yusuke Hiratsuka

Shohei Ikurumi

Takeshi Fujimatsu

Yoritoshi Minamino

Toshiyuki Sugimoto

A steel with high hardness and excellent toughness contains, in mass %, 0.40-1.00% C, 0.10-2.00% Si, 0.10-1.00% Mn, 0.030% or less P, 0.030% or less S, 1.10-3.20% Cr, 0.010-0.10% Al, and 0.15-0.50% V, and further contains at least one or two of 2.50% or less Ni and 1.00% or less Mo, with an amount of (C+V) being 0.60% or more in mass %, with the balance consisting of Fe and unavoidable impurities. The steel has a microstructure which is a martensitic structure with finely dispersed Fe-based &#x3b5; carbides, with its prior austenite grain size being 20 &#x3bc;m or less.

Steel with high hardness and excellent toughness

Growing community of inventors

Suita, Japan

Koji Hagihara