Kawasaki Jukogyo Kabushiki Kaisha

Satoshi Furuitsu

Mizuo Edamura

Satoru Kunise

Akio Tanaka

Toshiaki Katayama

Takashi Kajikawa

Shyunji Takamoto

Minoru Makimura

Norikatsu Bekku

This invention relates to a retort type apparatus for ion-nitriding treatment which is so designed as to effect heating and nitriding of a workpiece at high thermal efficiency, with excellent uniformity and in a short time, by using both glow discharge and heat produced by a heating element.

Ion-nitriding apparatus

Engine cylinder block made of an aluminum alloy containing in weight 4 to 14% of Si, 1 to 5% of Cu and 0.2 to 0.8% of Mg. Method for manufacturing the cylinder block includes a heat treatment step after moulding of such aluminum alloy.

Method for manufacturing engine cylinder block

Disclosed is an improved ion-nitriding process comprising ion-nitriding a workpiece at a high voltage level of glow discharge in a gas atmosphere resulting from the introduction of a gas mixture containing a specific amount of ammonia into a nitriding reactor, and then, further ion-nitriding the same workpiece at a lower voltage level of glow discharge in a gas atmosphere resulting from the introduction of a gas mixture not containing ammonia into the reactor.

Ion-nitriding process

An ion-nitriding process in which workpieces are subjected to a two-step glow discharge in a nitrogen and hydrogen atmosphere, there being a larger nitrogen to hydrogen ratio in the second step.

Ion-nitriting process

The present invention provides an ion-nitriding process wherein a workpiece having at least one aperture is subjected to a DC voltage in an atmosphere of nitrogen-containing gas, characterized in that a first nitriding step is carried out under a vacuum which is strong enough to suppress arc discharge on the workpiece, and a second nitriding step is carried out under a weaker vacuum as compared to that in the first step so that glow discharge is produced even in the aperture of the workpiece.

An ion-nitriding apparatus which is designed so that in heating and nitriding a workpiece by the combined use of glow discharge and heat generated by a heat-producing element, uniform temperature distribution of the workpiece during glow discharge can be obtained, thereby preventing overheating of the workpiece and realizing uniform heating and uniform nitriding of the workpiece.

Apparatus for ion-nitriding treatment

An ion-nitriding apparatus wherein heating and nitriding of workpieces can be carried out at high thermal efficiency, with excellent uniformity and in a short time by the combined use of glow discharge and heat generated by a heat-producing element. Heating efficiency can be raised in heating of workpieces by lessening the heat value to be released out of the furnace, and overheating of workpieces can be prevented in nitriding of them by increasing the heat value to be released out of the furnace in proportion to the increase of glow discharge output, and thus the nitriding efficiency can be raised.

Growing community of inventors

Kakogawa, Japan

Satoshi Furuitsu