Denso Corporation

Daido Steel Co., Ltd.

Makoto Haritani

Takahiro Miyazaki

Yuuki Tanaka

Tadashi Nishiwaki

Toshimasa Ito

Tomomitsu Fukuoka

Koji Morita

Kazuyoshi Kimura

Yoshihiro Tanimura

Kouji Morita

Ayumi Yamazaki

Hiroki Terada

Tomohiro Andoh

Keisuke Inoue

Yusuke Yoshimi

A workpiece for a fuel injection component is made of a steel having compositions, by mass %, of C: 0.08 to 0.16%, Si: 0.10 to 0.30%, Mn: 1.00 to 2.00%, S: 0.005 to 0.030%, Cu: 0.01 to 0.30%, Ni: 0.40 to 1.50%, Cr: 0.50 to 1.50%, Mo: 0.30 to 0.70%, V: 0.10 to 0.40%, s-Al: 0.001 to 0.100%, and Fe and unavoidable impurities as remaining components. After heating the workpiece to a temperature of 950&#xb0; C. or more and 1350&#xb0; C. or less, the workpiece is subjected to a hot forging, and thereafter cooled at an average cooling rate of 0.1&#xb0; C./sec. or more in a temperature range from 800&#xb0; C. to 500&#xb0; C., and at the average cooling rate of 0.02&#xb0; C./sec. or more and 10&#xb0; C./sec. or less in the subsequent temperature range from 500&#xb0; C. to 300&#xb0; C. to set an area ratio of a bainite structure after hot forging to 85% or more.

Method for manufacturing fuel injection component

The present invention provides an age hardening type bainitic microalloyed steel having a composition which includes, in terms of mass %: 0.06-0.35% of C; 0.01-2.00% of Si; 0.10-3.00% of Mn; 0.001-0.200% of S; 0.001-2.00% of Cu; 0.40-3.00% of Ni; 0.10-3.00% of Cr; 0.10-1.00% of Mo; 0.10-1.00% of V; and 0.001-0.100% of s-Al, with the remainder being Fe and unavoidable impurities, and which satisfies a value of the following expression (1) to be 20 or larger and a value of the following expression (2) to be 0.82 or larger:3&#xd7;[C]+10&#xd7;[Mn]+2&#xd7;[Cu]+2&#xd7;[Ni]+12&#xd7;[Cr]+9&#xd7;[Mo]+2&#xd7;[V]&#x2003;&#x2003;expression (1);1.66&#xd7;[C]+0.18&#xd7;[Si]+0.27&#xd7;[Mn]+0.09&#xd7;[Ni]+0.32&#xd7;[Cr]+0.34&#xd7;[Mo]+0.44&#xd7;[V]&#x2003;&#x2003;expression (2),in which each [ ] in the expression (1) and the expression (2) indicates a content of the element shown therein in terms of mass %.

Age hardening non-heat treated bainitic steel

The present invention relates to a part obtained from an age hardening type bainitic microalloyed steel, a process for producing the part, and the age hardening type bainitic microalloyed steel. In particular, the present invention relates to a part which has been controlled so as to have higher values of strength than conventional parts, a process for producing the part, and the age hardening type bainitic microalloyed steel.

Part obtained from age hardening type bainitic microalloyed steel, process for producing part, and age hardening type bainitic microalloyed steel

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Aichi, Japan

Makoto Haritani