JPH08352Y2 - Roller hearth type heat treatment furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a configuration of a hearth roll in a roller hearth type heat treatment furnace.

[Conventional technology]

In order to uniformly heat the round bar-shaped object to be heated in the roller hearth type heat treatment furnace, a large number of hearth rolls with guide grooves formed on the outer periphery are set by inclining at a constant angle in the horizontal plane with respect to the conveying direction, There is already known a heat treatment furnace in which the object to be heated is supported in the guide groove so that the object to be heated can be conveyed while rotating in the furnace.

[Problems of conventional technology]

By the way, in the hearth roll provided with the guide groove for the object to be heated as described above, since the thermal expansion due to the temperature of each heat treatment zone is not uniform, the guide groove of each hearth roll should be aligned in the furnace length direction. I was having a hard time because of this. In other words, if the guide grooves of each hearth roll are not aligned on the straight line in the furnace length direction after thermal expansion of each hearth roll, the round bar-shaped object to be heated cannot be well supported and there is a risk of falling defects or bending. Therefore, each hearth roll must determine the dimension at normal temperature in consideration of the heating temperature of the heat treatment zone to be set. For this reason, each hearth roll must be manufactured with slightly different guide groove dimensions at room temperature, depending on the setting position in the heat treatment furnace.However, such dimension adjustment is not possible with the conventional hearth roll structure. Since it is extremely difficult, it was a factor that increased the production cost.

[Means for solving the problem]

The present invention is intended to solve the above-mentioned problems of the prior art. A large number of hearth rolls each having a guide groove formed on the outer periphery thereof are provided in respective heat treatment zones such as a preheating zone, a heating / soaking zone, and the like in the conveying direction. In a heat treatment furnace that is set to be tilted in a constant angle horizontal plane, and a round bar-shaped object to be heated is supported in the guide groove to convey the object while rotating in the furnace, each hearth roll is Several hollow shell-shaped heat-resistant cast steel drums, which are integrally formed with inward ribs on the inner surface and both end edges, are joined to each other so that they are axially continuous to the outer periphery of the roll body, Each hearth roll is attached to the roll body by welding the rib of the drum unit to the fixed ring and the rib of the other drum unit to the slide ring, and adjusting the cutting amount of the end face of each drum unit to attach it to the roll body. heat Position of the guide grooves after thermal expansion in the physical zone is that configured to be in a straight line in the furnace length direction.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a horizontal cross section of the hearth rolls provided at intervals of about 400 mm in the preheating zone and the heating / soaking zone of this heat treatment furnace. These hearth rolls are set to be inclined by 20 degrees in the horizontal plane with respect to the transport direction of the object to be heated as shown in the figure. Reference numerals 2a and 2b denote side walls of the heat treatment furnace, and both ends of the cylindrical roll body 1 penetrate the side walls 2a and 2b. Support shafts 3a and 3b are fixed to both ends of the roll body 1, and the support shafts 3a and 3b are rotatably supported outside the furnace by bearings 4a and 4b. Reference numeral 5 is a sealing material for preventing gas leakage from the through holes of the side walls 2a and 2b. Reference numeral 6 denotes a rotary shaft which is supported by bearings 7 and which is rotatably driven by a sprocket 8. The rotary shaft 6 and the tip of the support shaft 3b are connected by a universal joint 9. The roll body 1 has a water cooling structure in which a water supply pipe for passing cooling water is provided as needed in a heat treatment zone in which the hearth roll is set.

On the outer circumference of the roll body 1, drum units 10a and 10b as shown in FIGS. 2 and 3 are provided adjacent to each other so as to be axially continuous. The drum unit 10a is manufactured for both ends, and the inward ribs 11 and 1 are formed on the inner surface.
1 is integrally formed, and inward ribs 12 and 12 are integrally formed at both end edges, which is made of heat-resistant cast steel in a hollow shell shape, and two guide grooves 13 and 13 are formed on the outer periphery. Also, drum unit 10b
Is a hollow shell made of heat-resistant cast steel manufactured for the middle part.Inward ribs 11, 11, 11 are integrally formed on the inner surface, and inward ribs 12, 12 are integrally formed on both edges, and the outer periphery is formed. 3-way guide groove 1
3,13,13 are formed. In addition, 14,14,14 is the rib 1 at the edge
It is a pin insertion hole opened in 2. This drum alone 10a, 1
When mounting 0b on the outer circumference of the roll body 1, the drum unit 10b is placed in the center and the drum units 10a are arranged adjacent to each other on both sides, and the ribs 12 at both edges are pinned to the pin insertion holes 14.
Connect by inserting 15. And the roll body 1
Fix the fixing ring 16 to the outer periphery near one end of the by welding,
The rib 12 at the other end of the drum unit 10a is welded and fixed to the fixing ring 16. A slide ring 17 is fixed to the rib 12 of the other drum unit 10a by welding, and a cylindrical stopper 18 is externally fitted to the outer periphery of the roll body 1 so as to be slidable in the axial direction. To fix.

In this roller hearth type heat treatment furnace, however, when the drum units 10a and 10b are joined by the pin 15, the end faces (joint faces) of the drum units 10a and 10b are cut and the length is adjusted by adjusting the cutting amount. Perform each heat treatment zone. That is, the hearth rolls set in each zone of the heat treatment furnace such as the preheating zone and the heating / soaking zone have different heating temperatures and different amounts of thermal expansion. In the present invention, the cutting amount of the end surface of each drum unit is adjusted so that it is aligned in a straight line. The drum units 10a and 10b are manufactured by casting a large number of those having a constant shape and a constant length, and the end faces are cut according to the set position of this hearth roll to adjust the dimensions. These drums made of heat-resistant cast steel are formed into a hollow shell shape by the inward ribs 11 and 12, and the roll body 1
Since the contact area with the surface is small, the amount of heat transferred to the roll body 1 is relatively small even if the drum unit is exposed to high heat in the furnace and becomes high temperature, and the roll body 1 can be protected from heating and cooled. Heat loss through water is also minimized.

[Effect of device]

As described above, the roller hearth type heat treatment furnace of the present invention adjusts the cutting amount of the end surface of several heat-resistant cast steel drums that are provided adjacent to each other so as to be continuous in the axial direction on the outer circumference of the roll body, thereby adjusting each hearth Since the position of the guide groove after thermal expansion of the roll is aligned on the straight line in the furnace length direction, fine dimension adjustment according to the heating temperature of each heat treatment zone can be easily performed, and the guide groove position error can be prevented. This is useful because it is possible to prevent the occurrence of flaws and the bending of the heat-exposed material, which is the underlying cause.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a horizontal sectional view of a hearth roll, and FIGS. 2 and 3 are perspective views of a drum unit. 1 ... Roll body, 2a, 2b ... Side wall, 3a, 3b ... Support shaft, 4
a, 4b …… Bearing, 10a, 10b …… Drum alone, 11,12 …… Rib, 13 …… Guide groove, 14 …… Pin insertion hole, 15 …… Pin, 16
...... Fixed ring, 17 …… Slide ring.

Claims (1)

[Scope of utility model registration request] 1. A large number of hearth rolls each having a guide groove formed on the outer periphery thereof are set in respective heat treatment zones such as a preheating zone, a heating / uniform heating zone, and the like in a horizontal plane inclined at a constant angle with respect to the conveying direction. In a heat treatment furnace in which a rod-shaped object to be heated is supported in the guide groove and conveyed while rotating in the furnace, each hearth roll has an inward rib integrally formed on the inner side surface and both end edges. A number of hollow shell-shaped heat-resistant cast-steel drums formed on the outer surface of the roll body are joined together so that they are axially continuous, and the ribs of one drum are welded to the fixing ring. , The ribs of the other drum unit are welded to the slide ring, and the amount of cutting of the end face of each drum unit is adjusted and attached to the roll body, so that each hearth roll is positioned in the guide groove after thermal expansion in each heat treatment zone. Roller hearth-type heat treatment furnace, characterized by being configured so as to be on a straight line in the furnace length direction.