JPS6244984Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a large number of hearth rolls disposed on the hearth of a heat treatment furnace for heat treating objects to be treated such as thick plates, thin plates, and slabs.

BACKGROUND TECHNOLOGY When heat-treating a workpiece 9 such as a thick plate, thin plate, or slab, a heat treatment furnace 8 having a large number of hearth rolls 7...7 disposed on the hearth is often used, as shown in FIG. ing. That is, the object to be processed 9 is normally fed into a heat treatment furnace 8 which is uniformly maintained at a predetermined ambient temperature for each zone, and is supported by each hearth roll 7 while being given a forward driving force. According to
passed through the heat treatment furnace 8 at a predetermined speed,
A predetermined heat treatment is performed.

The hearth roll 7 has a high temperature atmosphere in the furnace (approximately 1200 to 1300
℃), so heat-resistant steel is used as the body material, and the structure is such that cooling water flows inside the body so that the specified strength is not lost.
Due to the powerful cooling effect of cooling water, it is necessary to cool and maintain the temperature at a constant level.

Problems that the invention aims to solve Hearth rolls are cooled down to the surface of the body due to the strong cooling effect of internal water cooling, which reduces the heating efficiency of the workpiece, and the heat inside the furnace is transferred to the outside of the furnace by the cooling water. It is inevitable that a large amount of heat will be lost due to being taken out. The heat loss generally amounts to 10 to 15% of the amount of heat input into the furnace.

In addition, the roll body uses a thick-walled cylinder made of expensive heat-resistant steel to maintain a certain level of strength, and when the body reaches the end of its useful life,
The cost is extremely high because the entire body must be replaced.

The present invention provides an improved internal water-cooled hearth roll to solve the above problems.

Means for solving the problem The hearth roll of the present invention has a roll shell of 12
, roll ends 2, 2 fitted to both ends of the roll shell 12, and a heat-resistant steel sleeve 11 fitted coaxially to the roll shell 12, and a refrigerant flow path 6 inside the roll shell 12. In the internally cooled hearth roll in which the sleeve 11 is fitted into the roll shell 12 via a protrusion formed on its inner surface or the outer surface of the roll shell 12, the sleeve 11 and the roll are connected to each other. A gap 13 is formed between the sleeve 11 and the sleeve 12, and cut grooves 14 having a substantially U-shape in a direction substantially aligned with the roll axis direction are formed at multiple locations in the circumferential direction at both ends of the sleeve 11. A sleeve locking pin 4 implanted in the roll shaft engages with each of the notched grooves 14, and the groove surface of the notched groove 14 and the pin 4 that engages in the groove engage with each other. A feature is that a gap is provided between them as an expansion allowance for the sleeve 11 in the axial direction.

Function The hearth roll of the present invention has a double structure in which a refrigerant such as cooling water is circulated inside the roll shell 12, and the sleeve 11 is fitted on the outside of the roll shell with a gap 13 interposed therebetween. The voids 13 serve as a heat insulating layer, and therefore, even under the strong cooling action of the cooling water required to maintain roll strength, defects in the sleeve 11 that cause heat loss in the furnace and a reduction in heating efficiency of the workpiece are avoided. Necessary cooling is avoided.

Sleeve 11 fitted into roll shell 12
, a substantially U-shaped notch groove 14 formed at both ends thereof, and a pin 4 implanted in the roll shaft 2.
Since the sleeve 11 can be attached by engaging with the sleeve 11, the structure is simpler than attachment methods such as welding or bottle tightening, and the work of attaching and detaching the sleeve 11 is easier.
It is also possible to use ceramic sleeves that cannot be attached by welding.

Further, since the sleeve 11, which is attached by the engagement relationship between the approximately U-shaped notch groove 14 at both ends and the pin 4 as described above, is a free end that is not subject to thermal expansion and contraction, both ends thereof are free ends. The difference in thermal expansion between the roll shell 12, which is in direct contact with the refrigerant, and the sleeve 11, which is separated by the gap 13, is smoothly absorbed, and therefore the sleeve 11 is prevented from deforming (bulging, bending, etc.) and cracking. It is also possible to use a sleeve made of ceramic, which is a preventive and brittle material.

Note that the roll shell 12, which is directly cooled by the refrigerant in the body with a double structure of the roll shell 12 and the sleeve 11, may be made of ordinary steel or stainless steel. Therefore, the heat-resistant steel sleeve 11 does not need to be a thick cylindrical body as in the case of a conventional single-layer structure, but may be a thin and lightweight cylindrical body.

Embodiments Hereinafter, the present invention will be specifically explained based on drawings showing embodiments thereof.

FIG. 1 is a partially sectional front view showing an example of the hearth roll of the present invention. In the figure, 1 is a substantially cylindrical body, and both ends of the body 1 are provided with a multi-stage structure extending outward. The maximum diameter portions 21, 21 of the shafts 2, 2, which are reduced in diameter and have a multistage cylindrical shape, are fitted internally, respectively. In addition, in the center of the shafts 2, 2, a through hole 22,
22 are bored respectively, and cooling water is supplied from a cooling water supply source (not shown) to the inside of the body 1 of the hearth roll through one of the through holes 22, and after flowing through the inside thereof, the cooling water is supplied to the inside of the body 1 of the hearth roll from a cooling water supply source (not shown). It is now being discharged from the

Now, the body 1 is made of a heat-resistant material such as heat-resistant steel or ceramic, and the sleeve 11 is the outer layer of the body 1, and the sleeve 11 is made of a high-strength material such as ordinary steel or stainless steel, and the inner layer of the body 1 is made of a high-strength material such as ordinary steel or stainless steel. Naru Roll Ciel 12
Although it has a two-layer structure, the inner diameter of the sleeve 11 is slightly larger than the outer diameter of the roll shell 12, and when the two are combined, a slight gap 13 is formed between them. It is becoming more and more like this. Note that annular protrusions 12a...12a whose maximum diameter is comparable to the inner diameter of the sleeve 11 are formed at multiple locations on the outer periphery of the roll shell 12, and the sleeve 11 is rotated from the inner diameter side by the annular protrusions 12a...12a. Since it will be supported, sleeve 1
1 and the roll shell 12 are arranged coaxially.

Note that the protrusions 12a for forming the gap 13 between the roll shell 12 and the sleeve 11 may be formed on the inner surface of the sleeve 11, and these protrusions are not necessarily continuous in the circumferential direction. There is no need to be continuous, and they may be discontinuous in the circumferential direction at regular intervals.

Further, both end surfaces of the roll shell 12 are fixed by fillet circumferential welding 3 to the outer peripheral surfaces of the maximum diameter portions 21, 21 of the shafts 2, 2.

Further, on each of the left and right ends of the sleeve 11, cut grooves 14 having a substantially U-shape and oriented substantially in the same direction as the roll axis are formed at a plurality of locations in the circumferential direction. On the other hand, the roll shaft 4 has a pin 4 corresponding to the notch groove 14 of the sleeve.
will be planted. Each pin 4 engages with each notch groove 14 of the sleeve 11 externally mounted on the roll shell 12 and serves as a stopper to prevent the sleeve 11 from shifting or coming off in the axial direction and rotating in the circumferential direction.
The substantially U-shaped notch groove 14 is designed to prevent the innermost part of the substantially U-shaped notch groove 14 from coming into contact with the pins 4...4 even when the sleeve 11 thermally expands and reaches its maximum length. is formed. That is, the sleeve 11 is attached to the shaft 2 and the roll shell 12 with a margin (gap) commensurate with the thermal expansion allowance in the axial direction.

Also, inside the body 1, between the two shafts 2, both ends are open, and the central part has walls 5c, 5.
A water cooling pipe 5 closed by c is arranged. At both ends of the water cooling pipe 5, round holes 5a are provided at multiple locations on the circumference.
Further, on the outer peripheral surface of the central part, a spiral blade 5 whose maximum diameter is comparable to the inner diameter of the roll shell 12 is provided.
b is attached. The cooling water supplied from one of the through holes 22 is supplied from the inside of the water cooling pipe 5 to the outside of the water cooling pipe 5 through one of the round holes 5a...5a, and is divided by the blades 5b. After turning around the spiral gap 6, the other round hole 5a...
The water returns to the inside of the water cooling pipe 5 through the pipe 5a, and is then discharged through the other through hole 22. In this way, cooling water is constantly supplied to Roll Ciel 1.
The roll shell 12 is supplied so as to be in contact with the inside of the roll shell 12, and the roll shell 12 is cooled. Note that since the cooling water swirls and flows through the gap 6, the flow rate is increased and the cooling effect of the roll shell 12 is improved.

FIG. 2 is a graph showing the estimated temperature distribution in the radial direction of the hearth roll of the present invention and its vicinity, with the horizontal axis representing temperature and the vertical axis representing the position of the hearth roll in the radial direction. In addition, position A on the vertical axis corresponds to the inner peripheral surface of the roll shell 12, position B corresponds to the outer peripheral surface of the roll shell 12, and position C corresponds to the inner peripheral surface of the sleeve 11. , position D is sleeve 11
The positions corresponding to the outer circumferential surface of are shown respectively. Therefore, the part below position A is part of the gap 6 inside the roll shell 12 through which cooling water flows, and the part between positions B and C is between the roll shell 12 and sleeve 11. The portions of the void 13 formed in the above position D correspond to the portions outside the sleeve 11 that are filled with the furnace atmosphere.

As is clear from these results, by using the hearth roll of the present invention, the roll shell 12 can be sufficiently water-cooled, while the sleeve 11 can be maintained at a temperature comparable to the furnace atmosphere temperature. I understand that.

In addition, in the above explanation, cooling water is used to cool the body 1 of the hearth roll from the inner diameter side, but it goes without saying that a cooling medium other than cooling water, such as cooling air, may be used. Nor.

Moreover, the structure of the hearth roll of the present invention can of course be applied to a conveying roll for conveying a workpiece outside a heat treatment furnace.

Effects of the Invention The hearth roll of the present invention has a double structure in which the body is composed of a roll shell that is directly cooled by a refrigerant and a sleeve that is fitted into this through a gap as a heat insulating layer. There is less heat loss in the furnace due to the flow of refrigerant, and the heating efficiency of the object to be processed is improved.

The sleeve is fixed by the engagement relationship between the approximately U-shaped notch grooves at both ends and the pin attached to the roll shaft, so compared to fixing structures such as welding or bottle tightening, the sleeve is installed and has a long service life. It is easy to remove later, and the attachment/detachment work can be done easily and in a short time.

Furthermore, since both the left and right ends of the sleeve are free ends against thermal expansion and contraction, the sleeve is exposed to the high-temperature atmosphere inside the furnace, while the roll shell is directly cooled by the refrigerant. In this case, the difference in thermal expansion between the sleeve and the roll shell is smoothly absorbed and relaxed, so that the sleeve is not deformed or damaged due to thermal stress.

As mentioned above, the body has a double structure consisting of a roll shell and a sleeve, and since the roll shell is sufficiently cooled by the refrigerant, it is only necessary to apply heat-resistant steel to the sleeve. material costs are reduced. In addition, the sleeve is not welded or bottle-tightened, but is fixed in a state where thermal expansion and contraction are free by the engagement relationship between the notch groove and the pin, so the sleeve material is made of brittle materials that cannot be welded. It is now possible to apply ceramics, which have high heat resistance and high abrasion resistance, and it is also possible to further improve and stabilize the service life of hearth rolls.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional front view showing an example of the hearth roll of the present invention, Fig. 2 is a graph showing the estimated temperature distribution in the radial direction of the hearth roll of the present invention and its vicinity, and Fig. 3 is a graph showing the estimated temperature distribution in the radial direction of the hearth roll of the present invention. FIG. 2 is a vertical cross-sectional view schematically showing a heat treatment furnace. DESCRIPTION OF SYMBOLS 1... Body of hearth roll, 11... Sleeve, 12... Roll shell, 12a... Annular projection, 13... Gap, 14... Approximately U-shaped notch groove, 2
...Shaft, 4...Pin, 5...Water cooling pipe,
6...Spiral gap (a gap through which the cooling medium flows).

Claims (1)

[Claims for Utility Model Registration] A roll shell 12, roll shafts 2, 2 fitted to both ends of the roll shell 12, and a heat-resistant steel sleeve 11 fitted coaxially to the roll shell 12, In an internally cooled hearth roll in which a refrigerant flow path 6 is formed inside the roll shell 12, the sleeve 11 is fitted into the roll shell 12 via a protrusion formed on its inner surface or the outer surface of the roll shell 12. As a result, a gap 13 is defined between the sleeve 11 and the roll shell 12, and a gap 13 is formed between the sleeve 11 and the roll shell 12, and a gap 13 is formed at both ends of the sleeve 11 at multiple locations in the circumferential direction in a direction that substantially coincides with the roll axis direction. A notch groove 14 having a substantially U-shape is formed, and a sleeve locking pin 4 implanted in the roll shaft engages with each of the notch grooves 14, and the groove surface of the notch groove 14 and , a hearth roll characterized in that a gap is provided between the sleeve 11 and the pin 4 that engages in the groove as an allowance for thermal expansion in the axial direction of the sleeve 11.