Heat treatment method and heat treatment apparatus
AssigneeDowa Mining Co., Ltd.
InventorsTakanori Tsuge, Koji Abe
Life of this patent
Estimating the term…
Abstract
In a heat treatment method for supplying transforming gas and enriched gas inside a furnace and heat treating a workpiece inside the furnace, feedback control of carbon potential is performed by operating a supply flow rate of the enriched gas based on carbon potential inside the furnace, the feedback control is stopped before an opening of the furnace is opened and supply flow rates of the transforming gas and the enriched gas are increased from supply flow rates thereof immediately before the feedback control is stopped; and the supply flow rate of the transforming gas is returned to the supply flow rate thereof immediately before the feedback control is stopped and the feedback control is resumed after the opening of the furnace is closed.
Claims14
A heat treatment method for supplying transforming gas and enriched gas inside a furnace and heat treating a workpiece inside the furnace, comprising the steps of:
- performing feedback control of carbon potential by operating a supply flow rate of the enriched gas based on carbon potential inside the furnace;
- stopping the feedback control at any one of before an opening of the furnace is opened, while the opening of the furnace is open, and after the opening of the furnace is closed and before an atmosphere outside the furnace begins to flow into the furnace and increasing a supply flow rate of the transforming gas from a supply flow rate thereof immediately before the feedback control is stopped;
- and
- resuming the feedback control when a furnace pressure reaches a predetermined pressure after the opening of the furnace is closed.
A heat treatment apparatus for supplying transforming gas and enriched gas inside a furnace and heat treating a workpiece inside the furnace, comprising:
- a first regulator for regulating an opening degree of a transforming gas flow regulating valve provided on a supply path of the transforming gas and a second regulator for regulating an opening degree of an enriched gas flow regulating valve provided on a supply path of the enriched gas;
- and
- a feedback control system comprising said second regulator for performing feedback control of carbon potential,
- wherein said first regulator increases the opening degree of the transforming gas flow regulating valve at any one of before an opening of the furnace is opened, while the opening of the furnace is open, and after the opening of the furnace is closed and before an atmosphere outside the furnace begins to flow into the furnace, and decreases the opening degree of the transforming gas flow regulating valve when a furnace pressure reaches a predetermined pressure after the opening of the furnace is closed, and
- wherein said second regulator stops the feedback control at any one of before an opening of the furnace is opened, while the opening of the furnace is open, and after the opening of the furnace is closed and before an atmosphere outside the furnace begins to flow into the furnace, and resumes the feedback control when a furnace pressure reaches a predetermined pressure after the opening of the furnace is closed.
A heat treatment apparatus for supplying transforming gas and enriched gas inside a furnace and heat treating a workpiece inside the furnace, comprising:
- a first transforming gas supply path and a second transforming gas supply path for supplying the transforming gas inside the furnace;
- a first regulator for regulating opening/closing of an open/close valve provided on said second transforming gas supply path and a second regulator for regulating an opening degree of an enriched gas flow regulating valve provided on a supply path of the enriched gas;
- and
- a feedback control system comprising said second regulator for feedback controlling carbon potential,
- wherein said first regulator opens the open/close valve at any one of before an opening of the furnace is opened, while the opening of the furnace is open, and after the opening of the furnace is closed and before an atmosphere outside the furnace begins to flow into the furnace, and closes the open/close valve when a furnace pressure reaches a predetermined pressure after the opening of the furnace is closed, and
- wherein said second regulator stops the feedback control at any one of before an opening of the furnace is opened, while the opening of the furnace is open, and after the opening of the furnace is closed and before an atmosphere outside the furnace begins to flow into the furnace, and resumes the feedback control when a furnace pressure reaches a predetermined pressure after the opening of the furnace is closed.
Dependencies are inferred from the claim text.