JP2006077281A - Heat treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat treatment apparatus for heat-treating a steel bar, which spends a constant and extremely short period of time between works of extracting the steel bar from a heating furnace and charging it into a cooling pond, so as to obtain an expected heat treatment effect. <P>SOLUTION: This heat treatment apparatus comprises: a heating furnace having a furnace body with a necessary length for heating the steel bar; a cooling pond which is placed on an extended line of a doorway of the heating furnace, is filled with a coolant, and has a length necessary for cooling a heated steel material; a tray for entering into and leaving from the inside of the heating furnace, in a state of mounting a material to be heat-treated thereon; a pair of chains that run in parallel to each other and a driving means therefor, which are placed on the cooling pond, charges the tray into the heating furnace and extracts it from the heating furnace; and a pair of elevating devices which are placed on both ends of the cooling pond, support the extracted tray and the heated steel material mounted thereon, charge them into the coolant and raise them therefrom. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a heat treatment apparatus having a heating furnace and a cooling bath for performing heat treatment such as quenching on a rod-shaped steel material. In the present invention, the term “rod-shaped steel material” is used to include round bars, square bars, odd-shaped cross-section bars and small-diameter molds of steel and various alloys having a certain length.

In order to heat-treat steel that is not as long as wire rods, such as steel bars and small-diameter steels, but to a certain extent, it has so far been placed in a heating furnace having the required length and held at a predetermined temperature for a predetermined time. Then, it took the procedure of taking it out and putting it into a cooling tank filled with a cooling liquid. As an apparatus for performing this heat treatment, there is a heating furnace provided with a muffle made of a refractory metal. In this heating furnace, a U-shaped tray having a length corresponding to the length is used for handling the material to be heat-treated. Therefore, cooling has been performed by extracting the entire tray from the heating furnace, lifting it with a crane, and immersing it in the cooling liquid of the cooling tank.

Lifting and handling high-temperature steel with a crane is dangerous and environmentally unfriendly, so remote control and some degree of automation have been undertaken, which has had some effect. However, the biggest problem of this work is that it takes time to put the steel material extracted from the heating furnace into the coolant, and the time is considerably varied. Since thin steel bars and die steels are rapidly reduced in temperature during handling, if the time required for handling varies, the effect of cooling also varies, which is not preferable for quality control.

An object of the present invention is an apparatus for solving such a problem and performing heat treatment of steel bars, in which the time from extraction from a heating furnace to introduction into a cooling bath is constant, and the time is extremely short. Thus, an object of the present invention is to provide a heat treatment apparatus that can achieve the desired effect of heat treatment.

The heat treatment apparatus of the present invention that achieves the above object is a heating furnace having a furnace body having a length necessary for heating a rod-shaped steel material, and an heated wire on an extension line on the entrance / exit side of the heating furnace. A cooling tank filled with a coolant of the length necessary to cool the furnace, put the material to be heat-treated into the heating furnace, put out the tray from the heating furnace, and insert this tray into the heating furnace In addition, to support a pair of parallel running chains for extraction from the furnace and their drive means, and the extracted tray and the heated steel on it, put it into the coolant and pull it up from there And a pair of lifting devices provided at both ends of the cooling tank.

If the heat treatment apparatus of the present invention is used, the process of extracting the heated steel bar from the heating furnace and putting it into the cooling liquid in the cooling tank can be performed almost automatically without using a crane, Since the required time in the meantime is extremely short and constant, the effect of the heat treatment can always be obtained to the highest degree. As a result, the variation in product quality becomes extremely small, and quality control of the heat-treated product can be ideally performed. Of course, the safety of the process is enhanced and the working environment is improved.

A specific example of the heat treatment apparatus of the present invention will be described with reference to the drawings. The overall arrangement of this apparatus is as shown in FIG. 1 (plan view) and FIG. 2 (side view), and the internal structure of the heating furnace is shown in FIG. 3 (vertical vertical sectional view) and FIG. 4 (vertical in the muffle). As seen in the cross-sectional view. The heating furnace (1) has a heat-resistant metal muffle (13) penetrating through the furnace body (11) lined with a refractory (12), and the inner bottom surface of the muffle has a smooth surface. A refractory metal pad (14) is laid to assist sliding of the tray (2). This pad can also be made of CC composite material or graphite. The refractory bricks (15) spaced below the muffle support the weight of the tray and bar. The rear end of the muffle protrudes from the furnace body, and an anti-slip mechanism consisting of a telescope structure (16) and a weight (17) is provided to increase the muffle length as the temperature rises. It is configured so that it is kept at a fixed position and does not interfere with tray entry and exit.

On the cooling tank (5) side, a pair of chains (3, 3) run in parallel for loading and extracting the tray. As shown in FIGS. 5A and 5B, a connecting tool (4) that interlocks and separates the tray (2) by rotation of the L-shaped claw (41) is fixed to the chain. Each chain is driven by a sprocket (31) at both ends, and reciprocates in a direction toward the heating furnace and a direction away from it. The steel bar (M) to be heat-treated is placed on the tray (2) drawn from the heating furnace (1), and the chain is driven toward the heating furnace in a state where the coupling tool (4) is not coupled to the tray. Then, the coupler pushes the tray toward the heating furnace and inserts it into the furnace. When the steel bar is heated, open the lid of the furnace and place the connector (4) in contact with the tray (2), rotate the L-shaped claw (41) to engage the end of the tray, and connect Combine the tool and the tray so that the tray can be linked to the chain. FIG. 5 shows a state in which the tray is coupled with an L-shaped nail.

In this state, when the pair of chains (3, 3) is driven in a direction away from the heating furnace (1), the tray (2) on which the heated steel bar (M) is placed is extracted from the heating furnace. At this time, the tray lifting device (7) is at the upper limit position, and the extracted tray is placed on the I-shaped steel (6) of the lifting device, and slides on the I-shaped steel surface as the chain moves, Move over the cooling bath. When the tray on which the steel bar is placed has completely left the heating furnace and has come to the top of the cooling tank (5), the steel bar is placed in the lower limit position by operating the elevating device. It is immersed in and rapidly cooled.

The internal structure of the cooling tank (5) is as shown in FIG. 6 (vertical sectional view), and the tray elevating device (7) is located at both ends of the I-shaped steel (6) having a length corresponding to the length of the tray. This is a structure that is supported by a U-shaped tray support tool (71) that is opened and lowered and raised and lowered. The details of the tray lifting device (7) are as shown in FIG. 7 showing one of the pair of tray supports. The upper end of the tray support (71) is supported by a free other end of a lever (8) whose one end (81) is fixed by a shaft and the other end (82) is rotatable. By moving up and down by the expansion and contraction of 9), the I-shaped steel (6) is moved up and down while maintaining its level, and the tray (2) placed thereon is moved up and down. In FIG. 7, the upper limit position of the tray support (71) is indicated by a solid line, and the lower limit position is indicated by a broken line.

A heat treatment apparatus having the structure shown in each drawing and having a heating furnace and a cooling bath for heat treating a steel bar having a maximum length of 3 m was constructed. The muffle of the heating furnace has an inner size of 170 mm x 100 mm, and the drive speed of the chain is as follows:
When loading tray Low speed: 5 m / min. Medium speed: 10 m / min.
During tray extraction Medium speed: 10 m / min. High speed: 30 m / min.
The stroke of the lifting device is 38.5 cm.

Using this heat treatment apparatus, two round steel bars having a diameter of 50 mm were collectively heated to 1000 ° C. and then quenched with water. The time required from the start of tray extraction to the completion of charging into the cooling water was 55 seconds. In the conventional method of manually extracting the tray, hanging it with a crane and throwing it into the cooling water, the required time is about 20 times compared to the time required for 75 ± 15 seconds from the start of the extraction to the completion of the addition. The seconds were shortened, and the benefit of virtually no time variation was obtained.

The top view which shows the whole structure of the heat processing apparatus of this invention. The side view of the heat processing apparatus of FIG. The vertical longitudinal cross-sectional view which shows the internal structure of the heating furnace part in the heat processing apparatus of this invention (The heat generating body is abbreviate | omitted). FIG. 4 is a vertical enlarged cross-sectional view in the II direction of FIG. 3 showing a muffle and a tray. The top view (A) and sectional drawing (B) which show the structure of the connector part in the heat processing apparatus of this invention. The vertical cross-sectional view which shows the inside of the cooling tank in the heat processing apparatus of this invention, and the structure of a tray raising / lowering apparatus. The side view which shows the detail and operation | movement of a tray raising / lowering apparatus.

Explanation of symbols

1 Heating Furnace 11 Furnace 12 Refractory 13 Muffle 14 Pad
DESCRIPTION OF SYMBOLS 15 Refractory brick 16 Telescope structure 17 Weight 2 Tray 3 Chain 31 Sprocket 4 Connecting tool 41 L-shaped claw 5 Cooling tank 6 I-type steel 7 Tray lifting device 71 Tray support 8 Lever 81 One end of lever 82 Other end of lever
9 Air cylinder M Steel bar L Coolant

Claims (4)

A heating furnace having a furnace body having a length necessary for heating the rod-shaped steel material, and an extension line on the inlet / outlet side of the heating furnace, and a cooling liquid having a length necessary for cooling the heated steel material. A filled cooling bath, a tray for putting the material to be heat-treated into and into the heating furnace, a tray for taking out from the heating furnace, a pair running in parallel for loading the tray into the heating furnace and extracting from the heating furnace A pair of trays provided at both ends of the cooling tank to support the chain and its driving means, and the extracted tray and the heated steel material thereon, put into the cooling liquid, and lift from there Heat treatment equipment composed of equipment. The heating furnace has a heat-resistant metal muffle that penetrates the furnace body, a pad that assists sliding of the tray is arranged on the inner bottom surface of the muffle, and a telescope structure, a weight, and a rear end of the muffle projecting from the furnace body The heat processing apparatus of Claim 1 provided with the slip prevention mechanism which consists of these. A pair of parallel running chains for loading and unloading the tray has splices at one end of the chain, with a coupling that connects and separates the chain from the tray by the rotation of the L-shaped pawl. The heat treatment apparatus according to claim 1, wherein the heat treatment apparatus reciprocates. A pair of tray lifting and lowering devices support both ends of the I-shaped steel having a length corresponding to the length of the tray with a U-shaped tray support that is opened upward. 2. The heat treatment apparatus according to claim 1, wherein the tray is moved up and down by supporting the free end of a lever which is fixed and rotatable at the other end and moving the free end of the lever up and down by expansion and contraction of an air cylinder.

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