JP4180492B2 - Carburizing equipment - Google Patents

Description

The present invention relates to a carburizing apparatus used for carburizing a processing material such as a steel part , and in particular, enables the above-mentioned processing material to be carburized at a high speed and used for the carburizing process at a high speed. It is characterized in that a carburizing gas having a high carbon gas concentration can be produced efficiently and stably.

  Conventionally, in order to increase the strength of steel parts such as low carbon steel and low alloy steel, carburizing treatment for diffusing and penetrating carbon from the surface to the inside is performed.

  Various methods are used for carburizing the treatment material such as steel parts in this way. For example, as shown in FIG. 1, the treatment material 1 is introduced into the treatment furnace 2 and this treatment is performed. A carburizing gas containing carbon monoxide gas is supplied from the carburizing gas production apparatus 3 into the furnace 2, and a heating process for heating the processing material 1 in the processing furnace 2, and the processing material 1 heated in this way A carburizing step of imparting carbon to carburize, a diffusion step of diffusing the carbon imparted to the treatment material 1 in this way into the treatment material 1 so that the surface carbon concentration becomes a required value, and thus the carbon Carburizing treatment of the treatment material 1 is performed through a temperature lowering process for lowering the temperature of the treatment material 1 diffused inside.

  Here, as the carburizing gas production apparatus 3 for supplying the carburizing gas containing carbon monoxide gas into the processing furnace 2 as described above, generally a Ni catalyst or a noble metal catalyst such as Rh, Pt is accommodated. A heating device 3b is provided on the outer peripheral side of the catalyst layer 3a, and the catalyst layer 3a is heated by the heating device 3b.

  In the carburizing gas production apparatus 3, the hydrocarbon gas such as LNG and LPG guided by the gas supply pipe 3c and the air guided by the air supply pipe 3d are mixed by the gas mixer 3e. The mixed gas mixed in is introduced into the catalyst layer 3a heated as described above, and the mixed gas is reacted with the catalyst to generate a carburizing gas containing carbon monoxide, and the carburizing gas is treated. The gas is supplied into the furnace 2.

  However, when carburizing gas containing carbon monoxide gas is generated using a mixed gas obtained by mixing hydrocarbon gas such as LNG and LPG and air as described above, the air contains a lot of nitrogen gas. Therefore, in general, the carbon monoxide gas concentration in the carburizing gas is only about 20 to 25% by volume, and thus the carbon monoxide gas concentration is 20 to 25% by volume, and the carburization of the carbon monoxide gas concentration is low. When the working gas is used, there is a problem that the carburizing speed of the treatment material 1 is slow and a long time is required for the carburizing process.

  For this reason, conventionally, the carbon potential in the processing furnace 2 is increased by introducing a hydrocarbon gas such as LNG or LPG in addition to the above carburizing gas into the processing furnace 2 to carburize the processing material 1. Increasing the speed and shortening the processing time are being carried out.

  However, the inside of the processing furnace 2 by introducing hydrocarbon gas such as LNG or LPG into the processing furnace 2 into which the carburizing gas having a carbon monoxide gas concentration of 20 to 25% by volume is introduced as described above. When the carbon potential in the furnace is increased to near the saturation value determined by the temperature and steel type, it is difficult to properly control the carbon potential, the carbon potential in the processing furnace 2 becomes too high above the saturation value, There were problems such as occurrence.

  In addition, it has been known that when the carbon monoxide gas concentration in the carburizing gas is increased, the carburizing speed of the processing material 1 is improved. In recent years, the carburizing treatment of the processing material 1 is performed as described above. It has been studied to obtain a carburizing gas in which the concentration of carbon monoxide gas is increased by using carbon dioxide gas or oxygen gas instead of air in the raw material gas.

  Here, when carbon dioxide gas is used instead of the air in the raw material gas, the reaction between the hydrocarbon gas and the carbon dioxide gas is an endothermic reaction, and therefore the heating device 3b provided on the outer peripheral side as described above. Only by heating, the catalyst layer 3a is not sufficiently heated, the temperature of a part of the catalyst in the catalyst layer 3a is lowered, and the reaction does not proceed sufficiently in the portion where the temperature is lowered. There was a problem that soot was generated and the soot was clogged in the catalyst layer 3a, and the carburizing gas could not be produced stably.

  For this reason, in recent years, a raw material gas obtained by mixing hydrocarbon gas, carbon dioxide gas, and oxygen gas outside the explosive gas mixture range (for example, see Patent Document 1), or hydrocarbon gas is used. Before the raw material gas mixed with carbon dioxide gas and oxygen is introduced into the nickel catalyst layer and reacted, the raw material gas is heated to a temperature lower than the thermal decomposition temperature of hydrocarbons, etc. (For example, refer to Patent Documents 2 to 4.).

  However, even in the case described above, there is a problem that the carburizing gas having a high concentration of carbon monoxide gas cannot be stably produced and the apparatus becomes complicated.

In addition, it is expensive to produce a carburizing gas having a high carbon monoxide gas concentration as described above, and the carburizing gas is always carburized using a carburizing gas having a high carbon monoxide gas concentration. In this case, there is a problem that the running cost is very high.
JP 2000-256824 A JP 2001-1531 2 A JP 2001-152313 A JP 2001-152314 A

  An object of the present invention is to solve the above-mentioned various problems in the case of carburizing a treatment material such as a steel material part, so that a stable carburizing process can be performed at a high speed and at a high speed. An object of the present invention is to enable efficient and stable production of a carburizing gas having a high concentration of carbon monoxide used for carburizing treatment.

In the carburizing apparatus according to the present invention, in order to solve the above-described problems , a carburizing gas containing carbon monoxide gas is supplied into a processing furnace for carburizing the processing material, and heating, carburizing, and diffusion steps are performed. In the carburizing treatment apparatus for carburizing the treatment material, the carburizing furnace in which the catalyst layer is provided between the inner pipe and the outer pipe and the heating device is provided in each of the inner pipe and the outer pipe. A gas production device is attached, a first raw material gas supply device for supplying the carburizing gas production device with a first raw material gas in which at least a hydrocarbon gas and carbon dioxide gas are mixed, and at least a hydrocarbon gas and air A second raw material gas supply device for supplying the mixed second raw material gas to the carburizing gas production device, a raw material gas to be supplied to the carburizing gas production device, and the first raw material gas supply device and the second Raw material It provided a switching device for switching between the supply device.

In the carburizing apparatus, the carburizing gas is supplied from the first raw material gas supply device to the carburizing gas production device with the first raw material gas mixed with at least hydrocarbon gas and carbon dioxide gas. Except for this time, the second raw material gas in which at least a hydrocarbon gas and air are mixed can be supplied from the second raw material gas supply device to the carburizing gas production device.

  Moreover, as a catalyst used for said catalyst layer, generally used Ni catalyst and noble metal catalysts such as Rh, Pt can be used. In order to efficiently react the above raw material gas through the catalyst layer. Is preferably a noble metal catalyst such as Rh or Pt.

In the carburizing apparatus according to the present invention, in the carburizing gas manufacturing apparatus attached to the processing furnace, the catalyst layer is provided between the inner tube and the outer tube as described above, and the inner tube and the outer tube are respectively heated by the heating device. Since the heating is performed, the entire catalyst layer is sufficiently heated through the inner tube and the outer tube.

For this reason, the first raw material gas in which at least hydrocarbon gas and carbon dioxide gas are mixed from the first raw material gas supply device is supplied to the carburizing gas production device, and the carburization having a high carbon monoxide gas concentration is performed. When producing a gas for use, carburizing gas having a high carbon monoxide gas concentration can be prevented from preventing generation of soot due to a decrease in the temperature of a part of the catalyst layer, so that the catalyst layer is not clogged with soot. It becomes possible to manufacture efficiently and stably.

As a result , in the carburizing apparatus according to the present invention, the carburizing gas manufacturing apparatus produces the carburizing gas having a high carbon monoxide gas concentration as described above, and the carburizing gas having a high carbon monoxide gas concentration. Can be stably supplied into the processing furnace, and processing materials such as steel parts can be stably carburized at high speed.

In the carburizing apparatus according to the present invention , a first raw material gas supply device that supplies a first raw material gas in which at least a hydrocarbon gas and a carbon dioxide gas are mixed to the carburizing gas production device, and at least a hydrocarbon. A second raw material gas supply device for supplying a second raw material gas obtained by mixing gas and air to the carburizing gas production device, and a raw material gas supplied to the carburizing gas production device as described above. Since the switching device for switching between the supply device and the second raw material gas supply device is provided , the first raw material gas obtained by mixing at least hydrocarbon gas and carbon dioxide gas from the first raw material gas supply device is used for this carburization. When a carburizing gas is generated by supplying it to a gas production device, a carburizing gas having a high concentration of carbon monoxide gas can be obtained. For example, methane gas is used as a hydrocarbon gas. When the first raw material gas in which the methane gas and the carbon dioxide gas are mixed is supplied to the carburizing gas production apparatus to generate the carburizing gas, the carbon monoxide gas concentration is about 50% by volume. The carburizing gas having the fastest carburizing speed can be obtained.

  On the other hand, when the second raw material gas obtained by mixing at least hydrocarbon gas and air from the second raw material gas supply device is supplied to the carburizing gas production device to generate the carburizing gas, nitrogen gas is generated in the air. Because it is contained in a large amount, the carbon monoxide gas concentration in the obtained carburizing gas is reduced. For example, methane gas is used as the hydrocarbon gas, and the second raw material gas obtained by mixing this methane gas and air is used for carburizing. When the carburizing gas is generated by supplying it to the gas production apparatus, the carburizing gas having a carbon monoxide gas concentration of about 20% by volume can be obtained.

  And when carburizing the processing material in the processing furnace using the carburizing apparatus as described above, the raw material gas supplied to the carburizing gas manufacturing apparatus is changed to the first raw material gas supply apparatus by the switching device. The first raw material gas is supplied from the first raw material gas supply device to the carburizing gas production device so that the carburizing gas having a high carbon monoxide gas concentration is generated. The carburizing gas having a high carbon monoxide gas concentration is generated and supplied to the processing furnace, while the second raw material gas is supplied from the second raw material gas supply device to the carburizing gas production device except during carburizing. Thus, a carburizing gas having a low carbon monoxide gas concentration can be generated, and the carburizing gas having a low carbon monoxide gas concentration can be supplied to the processing furnace.

  In this way, at the time of carburizing, a carburizing gas with a high carbon monoxide gas concentration is supplied to the processing furnace, the carburizing speed of the processing material is increased, the processing time is shortened, and at the time other than carburizing, A carburizing gas having a low carbon oxide gas concentration is supplied to the processing furnace, and the running cost is greatly reduced as compared with a case where a carburizing gas having a high carbon monoxide concentration is always supplied.

Hereinafter, a carburizing gas production apparatus and a carburizing apparatus used in a carburizing apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. Note that the carburizing apparatus according to the present invention is not limited to the one shown in the following embodiment, and can be implemented with appropriate modifications within a range not changing the gist of the invention.

(Embodiment 1)
In the carburizing gas production apparatus 10 in this embodiment, as shown in FIG. 2, a catalyst layer 13 filled with a noble metal catalyst such as Rh or Pt is provided between the inner tube 11 and the outer tube 12. .

  And while providing the heating apparatus 14 which consists of an electric heater which heats this inner pipe | tube 11 inside said inner pipe | tube 11, the exterior body 15 using a heat insulating material is provided in the outer peripheral side of said outer pipe | tube 12, Between the exterior body 15 and the outer tube 12, a heating device 16 including an electric heater for heating the outer tube 12 is provided.

  Here, in producing the carburizing gas Gb having a high carbon monoxide gas concentration by the carburizing gas production apparatus 10 of this embodiment, the heating apparatuses 14 and 16 are heated to produce the inner pipe 11 and the outer pipe. The catalyst layer 13 provided between the inner tube 11 and the outer tube 12 is heated from the source gas supply port 17 provided in the outer tube 12, and at least the hydrocarbon gas and the carbon dioxide gas are mixed with the inner tube 11 and the outer tube 12. It leads to the catalyst layer 13 heated as described above through the pipe 12.

  Then, the raw material gas Ga is reacted in the catalyst layer 13 heated as described above to generate a carburizing gas Gb containing carbon monoxide and hydrogen, and the carburizing gas Gb is provided in the outer tube 12. It is made to supply in the processing furnace (not shown) which performs a carburizing process through the discharge pipe 18. FIG.

  Here, in the carburizing gas production apparatus of this embodiment, the heating devices 14 and 16 are provided in both the inner tube 11 and the outer tube 12 as described above, and the inner tube 11 and the outer tube are respectively provided by the heating devices 14 and 16. Since the catalyst layer 13 is heated through the pipe 12, the catalyst layer 13 is sufficiently heated, and the raw material gas Ga in which at least the hydrocarbon gas and the carbon dioxide gas are mixed as described above. When the reaction is performed through the catalyst layer 13, the temperature of a part of the catalyst layer 13 is prevented from decreasing, so that no soot is generated and the catalyst layer 13 is not clogged, and the carbon monoxide gas concentration is increased. The carburizing gas Gb can be produced efficiently and stably.

  In the carburizing gas production apparatus of this embodiment, an electric heater is used for each of the heating devices 14 and 16, but the type of the heating devices 14 and 16 is not particularly limited, and a known burner or the like is known. The heating device can be used.

  Next, as in the carburizing gas production apparatus in the above embodiment, both the inner tube and the outer tube are heated by the heating device, and only the outer tube is heated by the heating device. In this example, the carburizing gas in which the raw material gas is sufficiently reacted in the catalyst layer to suppress the generation of soot and the concentration of carbon monoxide is increased is efficient. Reveal that it will be well manufactured.

  Here, as the raw material gas, a mixture of 13A city gas and carbon dioxide in a volume ratio of 1: 1.25 is used, and in the example, both the inner tube and the outer tube are heated. While the outer tube temperature is 1000 ° C. and the inner tube temperature is 960 ° C. by heating by the apparatus, in the comparative example, only the outer tube is heated by the heating device, and the outer tube temperature is 1000 ° C. I tried to become.

Then, when the amount of carburizing gas generated through the catalyst layer is 3 m ³ / h and 5 m ³ / h, the ratio (vol%) of each gas component contained in the generated carburizing gas, respectively. The results are shown in Table 1 below.

As is clear from this result, in the example in which both the inner tube and the outer tube are heated by the heating device, the comparative example in which only the outer tube is heated by the heating device is used. In comparison, the ratio of CO ₂ and CH ₄ contained in the generated carburizing gas is greatly reduced, and the above raw material gas is sufficiently reacted in the catalyst layer to suppress the generation of soot, and the carbon monoxide High concentration carburizing gas could be produced efficiently.

(Embodiment 2)
In the carburizing apparatus according to this embodiment, as shown in FIG. 3, the carburizing gas manufacturing apparatus 10 is attached so as to pass through the furnace wall 2 a of the processing furnace 2, and the processing material (see FIG. A heating step of supplying the carburizing gas produced by the carburizing gas production apparatus 10 to the inside of the processing furnace 2 and heating the processing material in the processing furnace 2, and thus heating. A carburizing step in which carbon is imparted to the treated material and carburized, a diffusion step in which the carbon imparted to the treated material is diffused into the treated material, and a treated material in which carbon is diffused in the interior in this way And a temperature lowering step for lowering the temperature.

  Here, in this embodiment, as the carburizing gas production apparatus 10, a device substantially similar to that shown in the first embodiment is used, and between the inner tube 11 and the outer tube 12. Further, a catalyst layer 13 filled with a noble metal catalyst such as Rh or Pt is provided.

  And while providing the heating apparatus 14 which consists of an electric heater which heats this inner pipe | tube 11 inside said inner pipe | tube 11, the exterior body 15 using a heat insulating material is provided in the outer peripheral side of said outer pipe | tube 12, Between the exterior body 15 and the outer tube 12, a heating device 16 including an electric heater for heating the outer tube 12 is provided.

  Here, in this embodiment, when supplying the raw material gas to the carburizing gas production apparatus 10 described above, carbonization of LNG, LPG or the like led through the first gas supply pipe 21 provided with the first electromagnetic valve 21a. Hydrogen gas and carbon dioxide gas guided through the carbon dioxide gas supply pipe 22 provided with the second electromagnetic valve 22a are mixed by the first gas mixer 23, while the third electromagnetic valve 24a is provided. A hydrocarbon gas such as LNG or LPG guided through the second gas supply pipe 24 and the air guided through the air supply pipe 25 provided with the fourth electromagnetic valve 25a are mixed by the second gas mixer 26. ing.

  Then, a first source gas composed of hydrocarbon gas and carbon dioxide gas mixed by the first gas mixer 23 or a second gas composed of hydrocarbon gas and air mixed by the second gas mixer 26. The source gas is guided to the catalyst layer 13 from the source gas supply port 17 provided in the outer tube 12 in the carburizing gas production apparatus 10 and the catalyst layer 13 is heated by the heating devices 14 and 16. In the catalyst layer 13, the first or second source gas is reacted.

  Here, when the first raw material gas composed of the hydrocarbon gas and the carbon dioxide gas mixed by the first gas mixer 23 is reacted in the catalyst layer 13 to generate a carburizing gas containing carbon monoxide gas, As described above, a carburizing gas having a high carbon monoxide gas concentration having a carbon monoxide gas concentration of about 50% by volume can be obtained.

  On the other hand, when the second raw material gas composed of the hydrocarbon gas and air mixed by the second gas mixer 26 is reacted in the catalyst layer 13 to generate a carburizing gas containing carbon monoxide gas, Since a large amount of nitrogen gas is contained, a carburizing gas having a low carbon monoxide gas concentration having a carbon monoxide gas concentration of about 20% by volume as described above can be obtained.

For example, butane gas is used as the hydrocarbon gas, and when the first source gas composed of this butane gas and carbon dioxide gas is reacted in the catalyst layer 13, the reaction formula is
_{C 4 H 10 + 4CO 2 =} 8CO + 5H 2
Since the carbon monoxide gas concentration becomes too high, in this case, for adjusting the carbon monoxide gas concentration in the carburizing gas, although not shown in the drawing, for example, air or Oxygen gas can be supplied.

  And in the carburizing apparatus in this embodiment, when carburizing the processing material such as steel parts, the processing material is introduced into the processing furnace 2, and the processing material is heated in the processing furnace 2, While the first electromagnetic valve 21a and the second electromagnetic valve 22a are closed, the third electromagnetic valve 24a and the fourth electromagnetic valve 25a are opened, and the second gas supply pipe 24 and the air supply pipe 25 are passed through. Hydrocarbon gas and air are led to the second gas mixer 26 to be mixed.

  Then, the second raw material gas in which the hydrocarbon gas and the air are mixed in this manner is reacted in the catalyst layer 13 in the carburizing gas production apparatus 10 so that the carbon monoxide gas concentration becomes about 20% by volume. A carburizing gas having a low carbon monoxide gas concentration is generated, and the carburizing gas is supplied into the processing furnace 2 through the supply port 19 provided in the outer pipe 12, and the processing material is heated to a predetermined temperature. Let

  Next, in the carburizing step in which carbon is added to the treated material thus carburized, the third electromagnetic valve 24a and the fourth electromagnetic valve 25a are closed, while the first electromagnetic valve 21a and the first electromagnetic valve 21a are closed. 2 Open the electromagnetic valve 22a and guide the hydrocarbon gas and carbon dioxide gas through the first gas supply pipe 21 and the carbon dioxide gas supply pipe 22 to the first gas mixer 23 for mixing.

  Then, the first raw material gas in which the hydrocarbon gas and the carbon dioxide gas are mixed in this manner is reacted in the catalyst layer 13 in the carburizing gas production apparatus 10 so that the carbon monoxide gas concentration is about 50% by volume. A carburizing gas having a high carbon monoxide gas concentration is generated, and this carburizing gas is supplied into the processing furnace 2 through the supply port 19 provided in the outer pipe 12 to impart carbon to the processing material. And carburize.

  In addition, after carbon is applied to the treatment material and carburized in this manner, the first electromagnetic valve 21a and the second electromagnetic valve 22a are closed, while the third electromagnetic valve 24a and the fourth electromagnetic valve 25a are closed. In the same manner as in the heating step described above, the second raw material gas in which hydrocarbon gas and air are mixed is reacted in the catalyst layer 13 in the carburizing gas production apparatus 10 to produce carbon monoxide. A carburizing gas having a low carbon monoxide gas concentration having a gas concentration of about 20% by volume is generated, and the carburizing gas is supplied into the processing furnace 2 through the supply port 19 provided in the outer pipe 12. Thus, a diffusion step of diffusing carbon imparted to the treatment material into the inside of the treatment material and a temperature lowering step of lowering the temperature of the treatment material in which carbon is diffused inside are performed.

  Here, in obtaining the effective carburization depth of, for example, 0.9 mm for the processing material such as steel parts, the carbon monoxide gas concentration in which the carbon monoxide gas concentration is about 20% by volume in the carburization step described above. When a low carburizing gas is supplied into the processing furnace 2, the total time required for the carburizing step and the diffusion step is about 300 minutes, whereas in the carburizing step, the carbon monoxide gas concentration is When the carburizing gas having a high carbon monoxide gas concentration of about 50% by volume is supplied into the processing furnace 2, the total time required for the carburizing step and the diffusion step is about 180 minutes, and the carburizing time Will be greatly shortened.

  Further, in the carburizing process as described above, when a carburizing gas having a high carbon monoxide gas concentration having a carbon monoxide gas concentration of about 50% by volume is supplied into the processing furnace 2, the carbon potential in the processing furnace 2 is increased. Appropriate control can be easily performed, and the carbon potential can be prevented from becoming too high to generate soot.

  Further, as described above, only in the carburizing process, a carburizing gas having a high carbon monoxide gas concentration is supplied into the processing furnace 2, and in the processes other than the carburizing process, monoxide is oxidized in the processing furnace 2. If a carburizing gas with a low carbon gas concentration is supplied, the amount of carburizing gas with a high carbon monoxide gas concentration can be reduced, compared to the case of supplying a carburizing gas with a high carbon monoxide gas concentration at all times. , Running costs are greatly reduced.

It is the schematic explanatory drawing which showed the conventional carburizing processing apparatus used in carburizing a process material. It is the schematic explanatory drawing which showed the carburizing gas manufacturing apparatus used for the carburizing processing apparatus which concerns on embodiment of this invention. It is the partial explanatory view showing the carburizing processing device concerning one embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing material 2 Processing furnace 2a Furnace wall 10 Carburizing gas manufacturing apparatus 11 Inner pipe 12 Outer pipe 13 Catalyst layer 14 Heating apparatus 15 Exterior body 16 Heating apparatus 17 Raw material gas supply port 18 Exhaust pipe 19 Supply port 21 First gas supply pipe 21a 1st solenoid valve 22 Carbon dioxide gas supply pipe 22a 2nd solenoid valve 23 1st gas mixer 24 2nd gas supply pipe 24a 3rd solenoid valve 25 Air supply pipe 25a 4th solenoid valve 26 2nd gas mixer Ga Source gas Gb Carburizing gas

Claims (3)

In a carburizing apparatus for supplying a carburizing gas containing carbon monoxide gas into a processing furnace for carburizing the processing material, and carburizing the processing material through the steps of heating, carburizing, and diffusion, the above-mentioned processing furnace includes a catalyst. A layer is provided between the inner tube and the outer tube, and a carburizing gas production device provided with a heating device is attached to each of the inner tube and the outer tube, and at least hydrocarbon gas and carbon dioxide gas are mixed. A first raw material gas supply device for supplying the first raw material gas to the carburizing gas production device, and a second raw material gas obtained by mixing at least a hydrocarbon gas and air to the carburizing gas production device. 2. A raw material gas supply device and a switching device for switching the raw material gas supplied to the carburizing gas production device between the first raw material gas supply device and the second raw material gas supply device. Carburizing treatment equipment . In the carburizing apparatus according to claim 1, while carburizing, while supplying the first raw material gas mixed at least hydrocarbon gas and carbon dioxide gas from the first raw material gas supply device to the carburizing gas production device, A carburizing apparatus characterized by supplying a second raw material gas in which at least a hydrocarbon gas and air are mixed from the second raw material gas supply device to the carburizing gas production device except during carburizing. The carburizing apparatus according to claim 1 or 2, wherein a noble metal catalyst is used as a catalyst of the catalyst layer in the carburizing gas production apparatus.

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