Hot gas quenching devices, and hot gas heat treating system

Abstract

A metal heat treatment method includes quenching a workpiece by blowing an inert gas onto the workpiece, adjusting the temperature of the inert gas to approximately an isothermal holding temperature of the workpiece for transformation of the workpiece, holding the isothermal holding temperature within a margin of error of approximately plus or minus five degrees Celsius for a given period, and performing a metal heat treatment with the isothermal holding temperature kept statically or dynamically by varying the temperature of the hot-gas.

1 . A metal heat treatment method comprising: 
 quenching a workpiece by blowing an inert gas onto the workpiece;    adjusting the temperature of the inert gas to approximately an isothermal holding temperature of the workpiece for transformation of the workpiece;    holding the isothermal holding temperature within a margin of error of approximately plus or minus five degrees Celsius for a given period; and    performing a metal heat treatment with the isothermal holding temperature kept statically or dynamically by varying the temperature of the hot-gas.    
   
   
       2 . A hot-gas quenching apparatus quenching a workpiece preheated at an initial temperature to an intermediate temperature at around the isothermal holding temperature for transformation of the workpiece, and holding the isothermal holding temperature, comprising: 
 a workpiece container configured to contain the preheated workpiece in an inert gas atmosphere;    a flow path provided with the workpiece container;    a first duct and a second duct respectively provided with a control window whose aperture is controlled, the first duct and the second duct diverging from the flow path;    a gas quenching unit provided in the second duct and configured to quench the inert gas to room temperature;    a mixer connected at each end of the first duct and the second duct and configured to mix the inert gases introduced respectively from the first duct and the second duct for equalization of temperature of the inert gases from the first duct and the inert gas from the second duct;    a distributor configured to blow the mixed inert gas evenly onto a surface of the workpiece;    a blower provided between the mixer and the distributor and configured to supply the inert gas under pressure from the mixer to the distributor;    an inert gas introducing unit configured to introduce an required amount of the inert gas to the first duct and the second duct, respectively; and    a controller configured to control the aperture of the control window to hold the temperature of the mixed inert gas at the intermediate temperature.    
   
   
       3 . A hot-gas quenching apparatus quenching a workpiece preheated at an initial temperature to an intermediate temperature at around the isothermal holding temperature for transformation of the workpiece, and holding the isothermal holding temperature, comprising: 
 a workpiece container configured to contain the preheated workpiece in vacuo;    a flow path provided with the workpiece container;    a first duct and a second duct respectively provided with a control window whose aperture is controlled, the first duct and the second duct diverging from the flow path;    a gas quenching unit provided in the second duct and configured to quench the inert gas to room temperature;    a mixer connected at each end of the first duct and the second duct and configured to mix the inert gases introduced respectively from the first duct and the second duct for equalization of temperature of the inert gases from the first duct and the inert gas from the second duct;    a distributor configured to blow the mixed inert gas evenly onto a surface of the workpiece;    a blower provided between the mixer and the distributor and configured to supply the inert gas under pressure from the mixer to the distributor;    an inert gas introducing unit configured to introduce the inert gas preheated at the intermediate temperature to the first duct; and    a controller configured to control the aperture of the control window to hold the temperature of the mixed inert gas at the intermediate temperature.    
   
   
       4 . A hot-gas quenching apparatus quenching a workpiece preheated at an initial temperature to an intermediate temperature at around the isothermal holding temperature for transformation of the workpiece, and holding the isothermal holding temperature, comprising: 
 a workpiece container configured to contain the preheated workpiece in one of an inert gas atmosphere or vacuo;    a flow path provided with the workpiece container;    a first duct and a second duct respectively provided with a control window whose aperture is controlled, the first duct and the second duct diverging from the flow path;    a gas quenching unit provided in the second duct and configured to quench the inert gas to room temperature;    a mixer connected at each end of the first duct and the second duct and configured to mix the inert gases introduced respectively from the first duct and the second duct for equalization of temperature of the inert gases from the first duct and the inert gas from the second duct;    a distributor configured to blow the mixed inert gas evenly onto a surface of the workpiece;    a blower provided between the mixer and the distributor and configured to supply the inert gas under pressure from the mixer to the distributor;    a heat storage contact media provided in the mixer and configured to exchange heat with one of the heated or a non-heated inert gas introduced into the mixer, the heat storage contact media having a gas permeability and a heat capacity;    an inert gas introducing unit configured to introduce the inert gas to the mixer; and    a controller configured to control the aperture of the control window to hold the temperature of the mixed inert gas at the intermediate temperature.    
   
   
       5 . A hot-gas quenching apparatus quenching a workpiece preheated at an initial temperature to an intermediate temperature at around the isothermal holding temperature for transformation of the workpiece, and holding the isothermal holding temperature, comprising: 
 a workpiece container configured to contain the preheated workpiece in one of an inert gas atmosphere or vacuo;    a flow path provided with the workpiece container;    a first duct and a second duct respectively provided with a control window whose aperture is controlled, the first duct and the second duct diverging from the flow path;    a heat storage contact media provided in the first duct and configured to exchange heat with the inert gas introduced into the first duct, the heat storage contact media having a gas permeability and a heat capacity;    a gas quenching unit provided in the second duct and configured to quench the inert gas to room temperature;    a mixer connected at each end of the first duct and the second duct and configured to mix the inert gases introduced respectively from the first duct and the second duct for equalization of temperature of the inert gases from the first duct and the inert gas from the second duct;    a distributor configured to blow the mixed inert gas evenly onto a surface of the workpiece;    a blower provided between the mixer and the distributor and configured to supply the inert gas under pressure from the mixer to the distributor;    an inert gas introducing unit configured to introduce one of the heated or a non-heated inert gas to the mixer; and    a controller configured to control the aperture of the control window to hold the temperature of the mixed inert gas at the intermediate temperature.    
   
   
       6 . A hot-gas quenching apparatus quenching a workpiece preheated at an initial temperature to an intermediate temperature at around the isothermal holding temperature for transformation of the workpiece, and holding the isothermal holding temperature, comprising: 
 a workpiece container configured to contain the preheated workpiece in one of an inert gas atmosphere or vacuo;    a gas extracting inlet provided in the workpiece container;    a distributor configured to blow the inert gas introduced from the gas extracting inlet evenly onto a surface of the workpiece;    a gas circulation duct provided between the gas extracting inlet and the distributor    a blower provided in the gas circulation duct and configured to supply the inert gas under pressure to the distributor;    a heat storage contact media provided in the gas circulation duct; and    a temperature adjuster configured to hold temperature of the inert gas at the intermediate temperature.    
   
   
       7 . A hot-gas heat treatment system quenching a preheated workpiece at initial temperature for a quenching and holding isothermal holding temperature for a heat treatment, comprising: 
 a preheating furnace configured to preheat workpiece at the initial temperature; and    a workpiece transporter configured to transport the preheated workpiece at the initial temperature to a hot-gas quenching unit, wherein the hot-gas quenching unit is configured to accommodate the preheated workpiece transported by the workpiece transporter, quench the preheated workpiece to an intermediate temperature between the initial temperature and room temperature, and hold the intermediate temperature for heat treatment of the workpiece.    
   
   
       8 . The hot-gas heat treatment system of  claim 7 , wherein the workpiece transporter comprises a keep-warm unit configured to hold the preheated workpiece at the initial temperature and a gas pressure regulator configured to regulate a gas pressure in the keep-warm unit, and wherein the workpiece transporter moves automatically from the preheating furnace to the hot-gas quenching unit.  
   
   
       9 . The hot-gas heat treatment system of  claim 7 , wherein 
 the workpiece transporter comprises tunnel structure including a keep-warm unit configured to hold the preheated workpiece at the initial temperature therein and a gas pressure regulator configured to adjust gas pressure in the keep-warm unit, and    the preheating furnace and the hot-gas quenching unit are separately provided in the tunnel structure, respectively.