Microwave carburizing furnace and carburizing method

Abstract

A microwave carburizing furnace comprising: a microwave heat source for conducting carburization in plasma generated in atmosphere without electrodes; a microwave irradiating chamber into which the microwave is introduced; a atmospheric gas supply mechanism for supplying atmospheric gas containing Ar and O 2 into the irradiating chamber; and a rapid quenching mechanism for quenching a specimen after carburizing treatment with a quenching medium; wherein a steel material as the specimen and a carbon source necessary for carburization are placed in the carburizing chamber.

1 . A microwave carburizing furnace comprising:
 a carburizing chamber for placing a specimen of a steel material to be treated therein and a carbon source and for confining a atmosphere gas containing Ar and O 2 ;   a microwave heat source for generating a microwave;   a guide for guiding the microwave into the carburizing chamber for conducting carburization of the specimen with plasma generated in the atmosphere; and   an atmosphere gas supply mechanism for supplying the atmosphere gas into the carburizing chamber.   
   
   
       2 . The microwave carburizing furnace according to  claim 1 , wherein the chamber has a port through which the carburized specimen is transferred to a quenching medium is a quenching container. 
   
   
       3 . The microwave furnace according to  claim 1 , wherein the chamber is connected with a quenching container. 
   
   
       4 . The microwave carburizing furnace according to  claim 1 , wherein a frequency of the microwave is 300 MHZ to 300 GHZ. 
   
   
       5 . A microwave carburizing furnace comprising:
 a microwave heat source for conducting carburization in plasma generated in atmosphere comprising:   a microwave irradiating chamber into which the microwave is introduced;   a atmospheric gas supply mechanism for supplying atmospheric gas containing Ar and O 2  into the irradiating chamber; and   a rapid quenching mechanism for quenching a specimen after carburizing treatment with a quenching medium;   wherein a steel material as the specimen and a carbon source necessary for carburization are placed in the carburizing chamber.   
   
   
       6 . The microwave carburizing furnace according to  claim 5 , wherein a quenching room is provided next to the microwave irradiating chamber as the rapid quenching mechanism. 
   
   
       7 . The microwave carburizing furnace according to  claim 5 , wherein a quenching gas supply mechanism for supplying gaseous quenching medium into the microwave irradiating chamber as the rapid quenching mechanism. 
   
   
       8 . The microwave carburizing furnace according to  claim 5 , wherein at least one of CO and hydrocarbon gases is supplied into the irradiating chamber from the ambient gas supply mechanism in addition to Ar and O 2 . 
   
   
       9 . The microwave carburizing furnace according to  claim 5 , wherein H 2  is supplied into the irradiating chamber from the atmospheric gas supply mechanism in addition to Ar and O 2 . 
   
   
       10 . The microwave carburizing furnace according to  claim 5 , wherein H 2  is supplied into the irradiating chamber from the atmospheric gas supply mechanism in addition to Ar and O 2 . 
   
   
       11 . The microwave carburizing furnace according to  claim 5 , wherein the specimen having a solid carbon source in the surface thereof is placed in the irradiating chamber. 
   
   
       12 . The microwave carburizing furnace according to  claim 5 , wherein a frequency of the microwave is 1 to 30 GHz. 
   
   
       13 . The microwave carburizing furnace according to  claim 5 , which is provided with the microwave irradiating mechanism that is built in the microwave irradiating furnace as the microwave irradiating chamber. 
   
   
       14 . The microwave carburizing furnace according to  claim 13 , wherein the microwave irradiating furnace is provided with a fan for dispersing the microwave therein. 
   
   
       15 . The microwave carburizing furnace according to  claim 13 , wherein the microwave irradiating furnace is provided with a susceptor therein. 
   
   
       16 . The microwave carburizing furnace according to  claim 5 , wherein a part of the microwave irradiating furnace is provided with a window for introducing microwave. 
   
   
       17 . The microwave carburizing furnace according to  claim 5 , wherein the carburizing chamber is provided with a specimen holder with a high thermal conductivity and a susceptor capable of having a carbon source whereby the specimen holder and the susceptor holds the specimen therebetween. 
   
   
       18 . A method of carburizing a specimen made of steel material with a microwave as a heating source, which comprises:
 irradiating the specimen to be treated with the microwave in the presence of a carbon source and an atmospheric gas containing Ar and O 2 ;   generating plasma by reacting the carbon source and O 2  to produce and excite CO thereby generating Ar plasma to produce carbon ions; and   carburizing the specimen with the iron ions.   
   
   
       19 . The method according to  claim 18 , which further comprises, after the carburizing the specimen, rapid-quenching the treated specimen with a quenching medium thereby annealing the specimen. 
   
   
       20 . The method according to  claim 18 , wherein the frequency of the microwave is 300 MHZ to 300 GHZ. 
   
   
       21 . The method of carburizing the specimen with the microwave according to  claim 18 , wherein the atmospheric gas is Ar, O 2  and at least one of CO and hydrocarbon gas. 
   
   
       22 . The method of carburizing the specimen with the microwave according to  claim 18 , wherein the atmospheric gas contains Ar, O 2  and H 2 . 
   
   
       23 . The method of carburizing the specimen with the microwave according to  claim 18 , wherein the atmospheric gas further contains H 2 . 
   
   
       24 . The method of carburizing the specimen with the microwave according to  claim 18 , wherein the carbon source is a solid or gas, the solid being carbon powder and the gas being CO or hydrocarbon. 
   
   
       25 . The method of carburizing the specimen with the microwave according to  claim 18 , wherein the specimen is a steel material having a crystal grains of 1 μm or more and a tensile strength of 1000 MPa or more. 
   
   
       26 . The method of carburizing the specimen with the microwave according to  claim 18 , wherein a frequency of the microwave is 1 to 30 GHz. 
   
   
       27 . The method of carburizing the specimen according to  claim 18 , wherein a selected portion of the specimen is in contact with the carbon source.