JPS62290860A - Carburizing and hardening apparatus - Google Patents

Abstract

PURPOSE:To considerably improve the quality of a treated product and the efficiency of treatment by separately placing a plasma carburizing furnace provided with a high frequency coil for diffusion heating and a high frequency hardening furnace side by side so that carburization and hardening can be carried out in parallel with each other. CONSTITUTION:A body W to be treated is conveyend into a plasma carburizing furnace 1 provided with a high frequency coil 14 for diffusion heating. In the furnace 1, the body W is subjected to plasma carburization by high frequency heating. The body W is then taken out of the furnace 1 in a way reverse to the conveying way and conveyed into a high frequency hardening furnace 2 placed separately from the furnace 1 side by side. The body W hardened in the furnace 2 is taken out of the furnace 2 in a way reverse to the conveying-in way.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an apparatus for sequentially performing plasma carburizing treatment and induction hardening treatment.

(Prior Art) Conventionally, as shown in FIG. 3, after gas carburizing treatment is performed in a heating chamber 21, a fan 23
The crystal grains of the object W to be processed are made fine by cooling, and then the object W to be processed is returned to the heating chamber 21, heated again, and then lowered into the tank 24 for oil quenching treatment.

(Problem to be Solved by the Invention) However, there is no heating chamber 21 in one sealed furnace 25.
and a cooling section 22 are provided, and the high-temperature gas in the heating chamber 21 flows into the cooling section 22 after gas carburizing, so fan cooling in the cooling section 22 takes time to cool down the workpiece W, resulting in coarse particles after carburizing. Since grain refinement in the core of the carburized core becomes insufficient, high-quality quenching cannot be performed, gas carburizing and oil quenching cannot be performed at the same time, and the workpiece W is heated twice between the heating chamber 21 and the cooling section 22. Since it is necessary to repeat heating and cooling by reciprocating the heating and cooling, the processing efficiency is inevitably low.

(Object of the Invention) The present invention was made to solve the above-mentioned conventional problems, and it enables plasma carburizing and induction hardening to be performed independently of each other, thereby achieving the advantages of plasma carburizing (high-speed processing and The aim is to significantly improve processing quality and efficiency by effectively utilizing the uniformity of the steel and by performing carburizing and quenching in parallel.

(Means for Solving the Problems) The carburizing and quenching treatment apparatus of the present invention includes a plasma carburizing furnace and an induction quenching furnace that are installed independently in parallel, and a diffusion heating high-frequency coil provided in the plasma carburizing furnace. It is characterized by this.

(Example) An embodiment of the present invention will be described below with reference to FIG.

In the figure, 1 is one or more plasma carburizing furnaces, 2 is one or more induction hardening furnaces, and they are arranged independently and in parallel above a common transfer chamber 3. On the bottom wall of the hearth,
An opening 5 that can be opened and closed by a lid 4 is provided.

On the floor of the transfer chamber 3, there are a plurality of elevating rams 6 that can be raised and lowered independently from each other by cylinders (not shown) located directly below the openings 5 of the upper chambers 1 and 2, and a plurality of elevating rams 6 that run on the floor of the transfer chamber 3. One or more carts 7 are installed which are capable of moving and through which the lifting ram 6 can pass. This truck 7 is provided with a jack 7A for raising and lowering the truck 7.
! A metal cylindrical cover 9 having a diameter of 8.8' can be placed thereon. This cover 9 includes a gas filling device (not shown) and a gas curtain generating device (not shown) that curtain-seals the ram elevating port at the bottom of the container. In addition, the transfer chamber 3
Transport conveyors 10 and 11 are provided outside the loading/unloading port of the transport chamber 3, and a vacuum suction device and a gas supply device (not shown) are connected to the transport chamber 3.

On the floor of the plasma carburizing furnace 1, around the opening 5, there is provided a conductive pedestal 12 which also serves as a cathode and which can be moved forward and backward toward the center of the opening 5 by means of a moving device (not shown). , an anode 1 formed of a cylindrical plate or a porous plate, etc.
A high-frequency coil 14 surrounding the anode 13 and the anode 13 is arranged between the opening 5 and the pedestal 12 and the anode 13.
An AC power source for high frequency generation (not shown) is connected to. Further, a gas supply device, a vacuum suction device, and an exhaust device (not shown) are connected to the plasma carburizing furnace 1, and a cooling coil 16 and a fan 17 that can supply cold air into the furnace are provided at the top of the furnace. ing.

On the floor of the induction hardening furnace 2, around the opening 5, there is provided a pedestal 18 that can move forward and backward toward the center of the opening 5 by a moving device (not shown). High frequency coil 19 connected to the same power source as 14
is arranged between the opening 5 and the high frequency coil 19.
A quenching liquid spray device (not shown) is incorporated in which the inside of the coil is formed as a liquid supply path and a large number of pores are bored. Furthermore, a gas supply device and a vacuum suction device (not shown) are connected to the induction hardening furnace 2.

(Function) The workpiece W is placed on the conductive support base 20, and! 8.8' is placed in the cover 9 and is transported by the transport conveyor 10, and after being transferred together with the cover 9 onto the trolley 7 in the transport chamber 3, the trolley 7 moves it to the plasma carburizing furnace 1.
is transported to a predetermined position directly below.

Next, when the upper part M8 of the cover 9 is removed and the elevating ram 6 is raised by the cylinder's rond extension operation, the elevating ram 6 passes through the trolley 7 and the bottom lid 8' of the cover 9 and rises. The workpiece W is transferred onto this elevating ram 6 together with the support table 2o and ascends, and is carried into the plasma carburizing furnace 1 through the opening 5.

When the elevating ram 6 reaches the ascending end position, the gantry 12 is moved to the lower part of the support stand 2o supported by the elevating ram 6. Therefore, when the elevating ram 6 is lowered by the cylinder Rondo shortening operation, the support stand 20 is supported on the hearth surface via a pedestal 12, and the workpiece W is supported by an anode 13 and a high frequency coil 14.
It is placed at the center surrounded by. Lifting ram 6
is lowered and returned to its original position, and the opening 5 is closed with M4 (carrying into the furnace).

Next, as shown in FIG. 2, the pressure inside the plasma carburizing furnace 1 is reduced by operating the vacuum suction device to increase the degree of vacuum, and nitrogen gas is supplied by the gas supply device, so that the degree of vacuum is approximately 5 X 10 Torr. When the vacuum level is reached, an AC voltage is applied to the high frequency coil 14 while maintaining this degree of vacuum, and the workpiece W is heated by high frequency heating.
The workpiece W is heated to a plasma generation temperature of about 900 to 1000°C (maximum 1100°C) after the stress during machining is removed at the A3 transformation point.

Next, the degree of vacuum is set to approximately 0.1 to 1 of the plasma generation vacuum degree.
．． While lowering the pressure to 0 Torr and supplying hydrogen gas as a reducing gas and propane as a carburizing gas,
When a DC voltage is applied between the (cathode) and the positive pole 13, a negative glow discharge with high ionization density is stably generated under the above degree of vacuum and temperature, converting the gas into plasma, making it possible to perform plasma carburizing. possible (carburizing stage).

After carburizing, the discharge is stopped, the degree of vacuum is raised again, and only high-frequency heating is continued to diffuse and penetrate more carbon into the surface of the workpiece W (diffuser).

Next, the high-frequency heating is stopped, the degree of vacuum is lowered, and the cooling coil 16 and the fan 17 are activated to cool and circulate the gas in the furnace, so that the workpiece W is cooled and coarsened by high-temperature heating. Crystal grains are refined (gas cooling).

Next, the inside of the induction hardening furnace 2 and the transfer chamber 3 are supplied with a gas supply device.
At the same time, while the bottom of the cover 9 is curtain-sealed, the opening 5 is opened while the cover 9 is filled with nitrogen gas, and the cart 7 is jacked up and pressed against the bottom of the furnace. , the workpiece W is carried out from the plasma carburizing furnace 1 by the reverse procedure of carrying into the furnace, placed in the cover 9 on the trolley 7, and covered with the lid 8, and the trolley 7 is jagged down to be transferred to the induction hardening furnace. 2, the workpiece W is placed in the induction hardening furnace 2 at the center of the induction hardening furnace 2 surrounded by the high-frequency coil 19 using the support wall 18. , and close the opening 5, and then operate the vacuum suction device to reduce the pressure inside the induction hardening furnace 2 and increase the degree of vacuum, so that the degree of vacuum is approximately 5 x 10-2x.
-3 Torr, while maintaining this degree of vacuum, apply an AC voltage to the high frequency coil 19 to heat the workpiece W to 750 to 850°C for 5 minutes by high frequency heating, and then burn off oil, water, etc. When the liquid is sprayed onto the workpiece W using a liquid injection spray device, the hardening process of the workpiece W is completed. On the other hand, near the end of high-frequency heating, the pressure inside the furnace is returned to atmospheric pressure, the post-processing opening 5 is opened, and the processed product W' is transported out of the high-frequency hardening furnace 2 in the reverse order of the transport procedure into the furnace. and sent out to a carry-out conveyor 11 by a cart 7. At this time, the cover 9 is removed together with the upper lid 8.

By the way, the above work is performed when carburizing and quenching are performed sequentially, such as when there is one plasma carburizing furnace 1 and one induction quenching furnace 2, but when there are multiple plasma carburizing furnaces 1 and multiple induction quenching furnaces 2. In some cases, the workpiece W after carburization is carried into the induction hardening furnace 2, and the hardening process may be performed in parallel with the carburization of other workpieces W.

In such a case, the power required for the above work is 400 KW for the carburizing period of plasma carburizing in the plasma carburizing furnace 1 and 200 KW for the diffuser, whereas the power required for the above work is 400 KW for the heating and holding in the induction hardening furnace 2, and the power required for the diffusion Since electric power can be passed to the induction hardening furnace 2 during the 230 minutes of heating, the induction hardening process is started on the diffuser while performing plasma carburizing treatment due to the independent structure of each furnace, and during gas cooling, or Only during gas cooling, image processing can be performed in parallel using the same high-frequency generating power source.

(Effects of the Invention) As described above, in the present invention, plasma carburizing and induction hardening can be performed independently of each other, so parallel processing of carburizing and quenching is possible, and the advantages of plasma carburizing (high speed and uniformity of processing) can be realized. Together with effective utilization, it is possible to significantly improve processing quality and efficiency, and it is also possible to share the high frequency generation power source, thereby reducing equipment costs and saving energy.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the present invention, FIG. 2 is a carburizing and quenching operation cycle diagram, and FIG. 3 is a schematic diagram showing a conventional example. 1. Plasma carburizing furnace, 2. Induction quenching furnace, 3. Transfer chamber, 4. Lid, 5. Opening, 6. Lifting ram, 7.
・Dolly, 8, 9... Sealed door, 10.11 ・Transport conveyor, 12.18... Frame, 13... Anode, 14.19
...High frequency coil, 15.. DC power supply, 16.. Cooling coil, 17.. Fan, 20.. Support stand.

Claims (1)

[Claims] 1. A carburizing and quenching treatment apparatus, characterized in that a plasma carburizing furnace and an induction quenching furnace are arranged independently in parallel, and a high-frequency coil for diffusion heating is provided in the plasma carburizing furnace.