Finish heat treatment method and finish heat treatment apparatus for iron powder

Patent metadata

Field	Value
Publication number	US-9321103-B2
Application number	US-201113984409-A
Country	US
Kind code	B2
Filing date	Dec 15, 2011
Priority date	Mar 23, 2011
Publication date	Apr 26, 2016
Grant date	Apr 26, 2016

Abstract

In a finish heat treatment method and finish heat treatment apparatus for an iron powder, a raw iron powder is placed on a continuous moving hearth and continuously charged into the apparatus. In the pretreatment zone, the raw iron powder is subjected to a pretreatment of heating the raw iron powder in an atmosphere of hydrogen gas and/or inert gas at 450 to 1100° C. In decarburization, deoxidation, and denitrification zones, the pretreated iron powder is subsequently subjected to at least two treatments of decarburization, deoxidation, and denitrification. In the pretreatment zone, a hydrogen gas and/or an inert gas serving as a pretreatment ambient gas is introduced separately from an ambient gas used in the at least two treatments is introduced from the upstream side of the pretreatment zone and released from the downstream side so as to flow in the same direction as a moving direction of the moving hearth.

First claim

What is claimed is:

1. A finish heat treatment method for an iron powder comprising:
placing a raw iron powder on a continuous moving hearth;
subjecting the raw iron powder to a pretreatment of heating the raw iron powder in an atmosphere of a hydrogen gas and/or an inert gas; and
then continuously subjecting the pretreated iron powder to at least two treatments selected from decarburization, deoxidation, and denitrification to obtain a product iron powder, wherein:
the hydrogen gas and/or the inert gas is used as ambient gas in the pretreatment and is introduced separately from ambient gas used in the at least two treatments, and
the hydrogen gas and/or the inert gas in the pretreatment is introduced from an upstream side of a region where the pretreatment is performed and released from a downstream side of the region so that the gas flows in the same direction as a moving direction of the continuous moving hearth.

2. The method according to claim 1 , wherein the heating in the pretreatment is performed at an ambient temperature of 450 to 1100° C.

3. The method according to claim 1 , wherein the at least two treatments include the decarburization.

Assignees

• Sakaguchi Yasuhiko
• Maetani Toshio
• Jfe Steel Corp

Inventors

• Sakaguchi Yasuhiko
• Maetani Toshio

Classifications

• B22F1/142

  Thermal or thermo-mechanical treatment · CPC title

• B22F1/145

  Chemical treatment, e.g. passivation or decarburisation · CPC title

• B22F1/00

  Metallic powder; Treatment of metallic powder, e.g. to facilitate working or to improve properties · CPC title

• B22F1/14

  Treatment of metallic powder (mixing with lubricating or binding agents or with organic material B22F1/10) · CPC title

• F27B9/243

  Endless-strand conveyor · CPC title