JPS5855526A - Method and apparatus for atmospheric heat treatment - Google Patents

Abstract

PURPOSE:To heat-treat steel pieces with excellent productivity without the formation of scale, by continually carrying out the atmospheric heat treatment of the steel pieces by heating them in atmospheric gas, spraying cooling water to them and throwing them into a cooling water cell. CONSTITUTION:Workpieces W treated by radiation of heat are successively continually charged in an induction-heating oven 1 through its lower part and heated at a quenching temperature. The workpieces W lifted up and withdrawn from the heating oven 1 are introduced into an atmospheric chamber 3 and carried to a position below a chamber 22 by a carrying means 5. The chamber 22 is lowered to surround the workpiece W, while cooling water is forcedly poured through a pipe 214 into a liquid-supply case 21 at the lower part. The cooling water is sprayed through spray holes 231 provided in a cooling ring 23 at the side wall of the chamber 22 to directly cool the workpiece W. Thereafter, the chamber 22 is lifted up, and then the workpiece W is thrown into a cooling water cell 6 by the carrying means. Since the treatment from heating to cooling is carried out in atmospheric gas, the heat-treatment such as quenching can be continually performed with excellent productivity without the formation of oxide scale.

Description

[Detailed description of the invention] The present invention relates to a novel atmospheric heat treatment method and apparatus for materials.

When a member is subjected to atmospheric heat treatment, a conventional method and apparatus shown in FIG. 1 are used.

That is, the cylinder t with its upper end surface as a gap and its lower end surface as an open surface is inserted up to a predetermined lower part into a water tank P filled with cooling liquid, and the cylinder is placed between the upper closed end surface and the surface of the cooling liquid. An induction heating coil C is placed in the space of the tank P, and the space is filled with a non-oxidizing or inert gas to form an atmosphere chamber Ac.
An apparatus is used which is equipped with a member loading table S that moves up and down in the cooling liquid and the above-mentioned atmosphere chamber Ac as shown by the arrow by means of an elevating device E attached to the bottom outer wall of the apparatus. When heat treating a member W, the member W is placed with the member mounting table S lowered into the cooling liquid, and then the member mounting table S is raised and positioned within the heating coil C in the atmosphere chamber Ac. Thereafter, the heating coil C is energized to heat the member W to a predetermined temperature. The heated member W is cooled in the cooling liquid by lowering the member mounting table S, and after cooling is completed, the heated member W is drawn out from the cooling liquid to the outside of the water tank P. Although this method achieves the purpose of atmospheric heat treatment in that it places members that are easily heated to high temperatures and oxidized in an atmosphere, it unfortunately has the drawback of extremely low production efficiency. In other words, since heating and cooling are all performed on one component mounting table, the heating coil is in a non-operating state during cooling, and also during the rising and falling time between the cooling liquid of the component mounting table and the atmosphere chamber. It is also in a non-operational state. Moreover, the loading and unloading of the components onto and from the component mounting table must be carried out in a cooling liquid, resulting in a lack of workability.

The present invention is intended to eliminate the above-mentioned drawbacks of conventional atmospheric heat treatment, and provides an atmospheric heat treatment method and apparatus with extremely high productivity.

The gist of the first invention of the present application is that (1) a member is heated to a predetermined temperature while passing through an induction heating furnace by stepwise feeding and is intermittently discharged from an outlet, (2) after cooling at least from the time of high temperature rise. While maintaining a non-oxidizing or inert atmosphere until the low temperature of (3) cooling liquid injection at a fixed position,
The present invention is an atmospheric heat treatment method in which the cooling liquid is sequentially updated by the injected cooling liquid, and the cooling liquid is individually rapidly cooled by using two cooling means.

Further, the gist of the second invention of the present application is an apparatus K for carrying out the first invention, comprising: (1) a vertical induction heating furnace into which members are intermittently introduced from an entry side that opens downward; And (2
) a cooling station that cools the parts heated in the induction heating furnace; (3) an outlet opening above the induction heating furnace, a cooling station, and a cooling water tank into which the parts cooled in the cooling station are put; (4) an atmosphere gas supply device that circulates and supplies atmospheric gas to the atmosphere chamber; and (5) a heating member that is intermittently discharged from the outlet side of the induction heating furnace to a cooling station. This is an atmospheric heat treatment device consisting of a transport device that can be transported and that can transport the components cooled in the cooling station to a cooling water tank, and the top lid of the cooling station (2) above is on the same plane as the transport path and serves as a cooling positioning lid. a liquid supply case embedded in the conveyance path; ■ a vertically movable cylindrical chamber that is placed above the cooling position and has an open lower end face and a cooling liquid injection hole near the upper closed end face; It consists of a cooling ring having a cooling liquid injection hole on the inner circumferential wall, which is attached to a predetermined position in the inner part of the lower end of the chamber, and the chamber is displaced downward each time the member reaches the cooling position. The fixed cooling position is set so that it can be covered watertight, and the cooling liquid is also set so that it can be supplied from the liquid supply case to the inside of the cooling ring. The reason is that the parts to be processed are kept in the atmosphere when the temperature is high, when they are transported at high temperatures, and when they are rapidly cooled.

The present invention will be explained using an embodiment shown in FIG.

The heating device for heating the member W is a vertical induction heating furnace 1, which is attached to the induction heating furnace 1 just below the entrance side that opens downward, and the member W is pushed up and inserted into the induction heating furnace 1. For example, the cylinder 11 and the rod 1 of the cylinder 11
A push-up device 10 equipped with an end plate 13 fixed to the tip of the index tray 14 on which the member W is placed is used to lift the member W fed from the right side of the figure on the index tray 14 by a pushing device such as a cylinder 16 at predetermined time intervals. It is designed to be supplied separately. 15 is a member W supplied into the induction heating furnace 1.
It goes without saying that these are stoppers that prevent the pins from falling, and that they can only rotate upward from the illustrated position about the pin 151 as the center of rotation. Therefore, member W
is successively pushed upward in a pedestrian manner by the subsequent member W)C supplied from the lower entry side of the induction heating furnace 1 at predetermined time intervals, and is heated to a predetermined temperature while passing through the induction heating furnace 1. Therefore, it is intermittently discharged from the upper exit side.

Incidentally, the time interval at which the heated member W is intermittently discharged from the exit side of the induction heating furnace 1 is determined by the cooling time required to cool the member W at the cooling station, which will be described later, and the time required to transport the member to the cooling station. The induction heating furnace 1 is designed by taking into account the shape, heating conditions, and material of the member W, i.e., the furnace length, the length of the furnace It is necessary to make a design based on the power input to the heating coil, frequency, and other factors.

A cooling station 2 is provided at a position separated from the outlet of the induction heating furnace 1 by a predetermined distance. The cooling station 2 includes a liquid supply case 21 buried in the conveyance path of the member W that is on the same horizontal plane as the outlet of the induction heating furnace 1, and a chamber 22 provided above the liquid supply case 21. and a cooling ring 23 attached to a predetermined position on the inner peripheral wall of the chamber 22.

The above-mentioned components of the cooling station 2 will be explained in further detail.

The liquid supply case 21 is, for example, a circular box having a predetermined capacity, and is buried so that the surface of the upper lid 211 is on the same level as the above-mentioned conveyance path, and the liquid supply case 21 has a container on the surface that surrounds a predetermined area in the center. A groove 212 is carved, and the groove 21
The central portion surrounded by 2 is a cooling fixed position 213. The liquid supply case 21 includes one or more coolant supply pipes 2.
14 is connected, and coolant flows in from a coolant supply source (not shown). Coolant supply cooler 2210 body cavity and groove 212
A plurality of through holes communicate with each other, forming a distribution path 215 in which the cooling liquid flowing into the body cavity can be distributed and ejected in the direction of the groove 212. Note that 216 is a drain pipe, and by operating a solenoid valve 217, the coolant in the body cavity can be drained.

The chamber 22 is formed into a cylindrical shape having a predetermined volume with an open upper end face and an open lower end face, and has an inner diameter that is approximately the same as the outer circumference of a groove 212 carved in the upper lid 211 of the liquid supply case 21. One end of the tube is open near the upper end face, and the other end is bent downward to open onto a cooling water tank to be described later, forming a cooling liquid supply source 221. chamber 2
A hem portion 222 is formed on the entire outer circumference of the lower end surface of the hem portion 222, and a sealing material 223 of, for example, an O-ring is formed in a large groove for fitting the bag 7, which is carved over the entire circumference of the lower surface of the hem portion 222. It is fitted.

Further, on the upper closed end surface of the chamber 22, the tip of a rod 225 of a lifting device, for example, a cylinder 224, etc., which is arranged outside the atmosphere chamber to be described later, penetrates through the ceiling of the atmosphere chamber and is fixed. There is. Therefore, by driving the cylinder 224 and retracting the p-rad 225, the chamber 22 is displaced upward, and the lower end surface of the chamber 22 and the cooling fixed position 2 on the conveyance path are moved upward.
13 and move the rod 225 forward to displace the chamber 22 downward, press the hem 222 of the chamber 22 onto the upper lid 211 around the outer periphery of the groove 212, and seal the water with the sealing material 223. Possible to retain.

A cooling ring 23 is attached to the lower inner periphery 11 of the chamber 22 in a hanging state so that its lower part is below the lower end surface of the chamber 22. A large number of coolant injection holes 231 are provided in the inner circumferential wall of the cooling ring 23, and furthermore, the ring-shaped lower end surface is formed, for example, into an open surface. Therefore, if the length and ring width of the part hanging down from the lower end of the chamber 22 are set to be the same as the depth of the groove 212 surrounding the cooling fixed position 213, and the width is set to be slightly to small, the above-mentioned chamber When the cooling liquid 22 is displaced downward, the hanging portion is fitted into the groove 212, and the ejection from the cooling liquid distribution path 215 that occurs when the cooling liquid flows into the liquid supply case 21 described above is not received into the cooling ring body cavity. , can be injected from the coolant injection hole 231.

Reference numeral 3 denotes an atmosphere chamber surrounded by side walls and a ceiling so as to cover the area from the outlet side of the induction heating furnace 1 through the cooling stage 2 to a predetermined cooling liquid level 61 of a cooling tank 6 provided on the left side in the figure. The shape of the atmosphere chamber 3 does not need to be specified in particular and may be designed so that the atmosphere gas can be used efficiently, but in this embodiment, a small atmosphere chamber 311 that covers the outlet side of the induction heating furnace 1 is used. - A large atmosphere chamber 312 that covers the cooling station 2 and the liquid level of the cooling tank 6, and a section connecting the two chambers are divided into upper and lower parts by a partition ceiling wall 315, and the lower part is divided into a transport tunnel 313, and the upper part is divided into an atmospheric gas extraction tunnel 314. It is being

A non-oxidizing gas such as nitrogen or an inert gas such as argon is supplied into the atmosphere chamber 3 by an atmospheric gas supply device consisting of a pipe system shown as 4. The atmospheric gas supply device 4 includes, for example, a pump P, a heat exchanger Ex, an atmospheric gas replenishment tank T, and the like, and includes a large atmosphere chamber 3.
The gas supplied to the small atmosphere chamber 311 passes through the transport tunnel 313 and is drawn out from there through the atmosphere gas extraction tunnel 314 to the outside of the atmosphere chamber 3 . During this time, the atmospheric gas whose temperature has increased by the heating member W is transferred to the heat exchanger E.
It is cooled by x, sent to the large atmosphere chamber 312 again, and circulated.

A conveyance device 5 made of, for example, a cylinder is provided outside the right side wall of the small atmosphere chamber 311 in the figure, and the rod 51 of the conveyance device 5 penetrates the side wall and enters the atmosphere chamber 3. When moving backward, its tip is on the right side wall of the small atmosphere chamber 311 as shown in the figure, and when moving forward, it crosses the small atmosphere chamber 311, passes through the conveyance tunnel 313, and reaches the first stage forward position where its tip reaches the cooling fixed position 213. , the specifications are set so that it is possible to take the second stage forward position which further crosses the cooling fixed position 213 from the side wall edge and reaches the right edge of the cooling water tank 6 on the left side.

Inside the cooling water tank 6, for example, there is an endless chain belt having four tin sockets T1/71, one of which is provided near the bottom of the tank and the other outside of the tank, and a plurality of claws 72 extending between both sprockets T1/71. 73 is provided, and is set to be rotatable in the direction of the arrow.

The process of heat-treating the member W using the embodiment apparatus having the above configuration will be explained. The rod 12 of the pushing up device 10 is moved back to wait for the arrival of the member W sent by the index tray 14, the rod 51 of the conveyance device 5 is also moved back, and the rod 225 of the lifting device 224 is moved back to wait for the arrival of the member W sent by the index tray 14. As the upward displacement is performed, an opening is established between the lower end surface and the cooling fixed position 213. Further, after starting the circulation of the atmospheric gas into the atmosphere chamber 3, the supply of electricity to the induction heating furnace 1 is started. In this state, the supply of the members W to the index tray 14 is started.

The members W that are sent along the index tray 14 in the direction of the arrow and reach the left end are sequentially pushed up and inserted into the induction heating furnace 1 by the push-up device 10 which operates at predetermined time intervals, and the subsequent members W are inserted. It is pushed up step by step until it reaches the vicinity of the exit side. During this time, heating progresses and the temperature rises to a high temperature. Since the exit side opens into the atmosphere chamber, the atmospheric gas also enters the induction heating furnace 1, and the member W that has reached a high temperature is in the atmospheric gas. The member W heated to a predetermined temperature is pushed up by the following member W and is intermittently discharged from the exit side at predetermined time intervals. At this point, the transport device 5 is driven to advance the rod 51 to the first stage forward position and then immediately return it to the original position. Member W heated by the forward motion of the rod 51
passes through the transport tunnel 313 on the transport path to the cooling fixed position 2.
It is conveyed by push-feeding up to 13. When the member W reaches the cooling position 213, the elevating device 224 is driven to displace the chamber 22 downward and the member W is housed in the chamber 22. Next, a coolant supply source (not shown) is driven to cause the coolant to flow into the liquid supply case 21 via the coolant supply pipe 214. The coolant immediately fills the liquid supply case 21 with a predetermined capacity, flows into the body cavity of the cooling ring 23 via the plurality of distribution channels 215, and is then injected from the coolant injection holes 231 to fill the cooling ring 23. The heating member W placed surrounded by the inner peripheral wall is directly cooled. Since the chamber 22 is set to have a predetermined volume and the lower end surface skirt 222 is set to be watertight with the upper lid 212, the injected coolant immediately fills the body cavity of the chamber 22 and flows into the overflow pipe 221. It overflows to the outside of the chamber 22 and flows into the cooling water tank 6. Since the flow of the coolant into the liquid supply case 21 continues for a predetermined period of time, the members W in the chamber 22 are cooled by two cooling means: one is directly hit by the injected coolant, and the other is in the coolant that is sequentially updated by the injected coolant. Cooling progresses rapidly, and treatments such as rapid cooling and quenching are performed.

When the cooling of the member W is completed, the drive of the cooling liquid supply source is stopped, and the injection of the cooling liquid from the injection hole 231 is stopped. Then, the solenoid valve 217 is operated to open at least the chamber 22.
After draining the coolant remaining in the chamber from the drain pipe 216, the lifting device 224 is driven to displace the chamber 22 upward, and then the conveying device 5 is driven to move the rod 51.
is advanced to the second stage forward position and immediately returned to the backward position.

The member W is brought to the cooling fixed position 21 by the operation of the rod 51.
3 and is then transported by force and dropped into the cooling liquid in the cooling water tank 6. Since the member W is transported and cooled in the atmospheric chamber from the high-temperature heating state to the completion of cooling, there is no risk of oxidation and formation of scale.

After the rod 51 returns to the backward position from the second stage forward position, the subsequent member W maintains the element for a predetermined time from the outlet side of the induction heating furnace 1 as described above. The heated member W is conveyed to the cooling station 2 through the same process as described above, and after being cooled there, it is thrown into the cooling water tank 6, and this process is sequentially repeated. The heat-treated member W placed into the cooling water tank 6 is transported out of the cooling water tank 6 by the transport device 7 and transported to the next process.

In the above embodiment, the member W is transported by the forward movement of the rod 51 in the transport device 5 to the first and second stage forward positions. If only the above operation is performed, and the unloading from the second-stage cooling station is carried out by penetrating the side wall of a manipulator provided outside the left side wall of the atmosphere chamber 3 and grasping it with an arm that moves forward and backward. , it is possible to shorten the ejection time of the member W by the time required for the rod 51 to move back and forth between the atmosphere chamber 311 and the transport tunnel 315 by moving it to the second stage forward position, and furthermore, the member W can be cooled. For example, in the case of quenching, the cooling at station 2 is limited to the quenching time necessary for the member W to complete martensitic transformation, and the subsequent cooling is performed in the cooling water tank 6, thereby reducing the temperature of the member W. The discharge interval can be further shortened, and the device can be operated more efficiently.

In addition, the lower entry side of the induction heating furnace 1 is located in a water tank 8 as shown in FIG.
Therefore, if the member W is carried into the induction heating furnace 1 in the water tank 8, the inside of the induction heating furnace 1 is completely filled with atmospheric gas, and a more complete atmospheric heat treatment can be performed. It becomes possible.

By carrying out the present invention, (1) the object of atmospheric heat treatment can be fully achieved since the member remains in the atmospheric gas during the entire period from the time of heating up to the end of cooling; In comparison, high efficiency, high speed, and high productivity are demonstrated in the following points.

■In the conventional method, the heating coil is not in operation during cooling and transportation, but in the present invention, heating and cooling of the component are performed separately, so the induction heating furnace is in operation during the above time and the subsequent component is not being operated. It is heating up and there is no time loss.

■In the conventional method, the no-load state is repeated even if the heating coil is turned on and off or continues to be energized, but with the method of the present invention, the heating coil is always in operation and the same load state is maintained, so the service life of the heating power supply system is shortened. It is significantly longer than before.

■ Cooling is achieved by a combination of two methods: the injected coolant inside the chamber and the coolant that is sequentially updated by the injected coolant, so the rapid cooling effect is noticeable and the cooling time can be shortened.
Even so, there is almost no loss of coolant.

(2) Cooling in the cooling water tank can be added to the cooling in the chamber, so the cooling time can be further shortened.

It is highly practical and has great effects.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional front view of a conventional atmospheric heat treatment apparatus, FIG. 2 is a cross-sectional front view of an apparatus according to an embodiment of the present invention, and FIG. 3 is a cross-sectional front view of another embodiment of the present invention. 1-9 Conduction heating furnace 2... Cooling station 21...
Liquid supply case 211...Top lid 213...Cooling fixed position 22...Channeau (-2212...Cooling liquid injection hole
23... Cooling ring 231... Coolant injection hole 3.
... Atmosphere chamber 4 ... Atmosphere gas supply device 5 ... Conveyance device 6 ... Cooling water tank L ... Conveyance path W ... Component patent applicant Den Kobayashi, patent attorney for Koshuha Netoren Co., Ltd. (21) Rod 1 figure

Claims (1)

[Claims] 1.) A member that is heated to a predetermined temperature while passing through an induction heating furnace by sidewalk feeding and is intermittently discharged from an outlet,
A non-oxidizing or inert atmosphere is maintained at least from the time of high temperature rise to the low temperature after cooling. An atmospheric heat treatment method characterized by quenching separately by using two cooling means in combination. 2.) A vertical induction heating furnace into which parts are intermittently introduced from an entry side that opens downward, a cooling station that cools the parts heated in the induction heating furnace, and a cooling station that opens above the induction heating furnace. an atmosphere chamber that covers a predetermined liquid surface of the cooling water tank into which the components cooled by the cooling station and the cooling station are fed; an atmosphere gas supply device that circulates and supplies atmospheric gas to the atmosphere chamber; and the induction heating furnace. a conveying device capable of conveying a heating member intermittently discharged from the outlet side of the cooling station to a cooling station, and a conveying device capable of conveying a member cooled at the cooling station to a cooling water tank, and the cooling station is connected to the cooling station whose upper lid is the same as the conveying path. a liquid supply case buried in the conveyance path so as to be on a flat surface and in a fixed position for cooling;
A vertically movable cylindrical chamber is disposed above the fixed cooling position and has an open lower end face and a coolant injection hole near the upper closed end face, and a cylindrical chamber is installed at a predetermined position inside the lower end of the chamber. and a cooling ring having a cooling liquid injection hole on the inner circumferential wall, and each time the member reaches the cooling position, the chamber is set to be able to move downward to cover the cooling position in a watertight manner, and An atmospheric heat treatment device that is set so that a cooling liquid can be supplied from a liquid supply case into a cooling ring, and that a member heated and heated in an induction heating furnace is in an atmosphere during high temperature, high temperature transfer, and rapid cooling. , 3. ) The atmospheric heat treatment apparatus according to claim 2, wherein the inlet side of the induction heating furnace is opened into water.