JPH04285133A - Conveying roll for continuous strip heat treatment equipment and its control method - Google Patents

Abstract

PURPOSE:To provide the conveying roll and control method surely preventing a strip from slip walk thereof in the continuous strip heat treatment equipment. CONSTITUTION:To a part in contact with strip in the conveying roll for conveying the strip in a heat treatment furnace, surface machining is executed so as to become 2-6mum center line average roughness (Ra) and >=150 number in terms of the frequency of a distance repeating between a crest of >=0.5mum and a valley of >=0.5mum, respectively higher and lower than the central line of the roughness carve per one inch (PPI: peak per inch), and by controlling with PPI or Ra and PPI, the desired friction force between the conveying roll and the strip can be obtd. and exchanging time can easily be decided.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a conveyor roll for conveying a strip in a heat treatment furnace in a continuous strip heat treatment facility for continuously subjecting a strip such as a steel strip to heat treatment such as annealing. It concerns management methods.

0002

2. Description of the Related Art Conventionally, strip continuous heat treatment equipment has been available in which a strip is continuously passed through a heat treatment furnace with conveyor rolls in order to perform heat treatment on the strip.

[0003] As an example of such heat treatment equipment, a continuous annealing treatment equipment for steel strips has a heating furnace, a soaking furnace, a primary cooling furnace, an overaging furnace, and a secondary cooling furnace as heat treatment furnaces. The steel strip is continuously transported by transport rolls (hearth rolls) provided inside each furnace and between each furnace.

[0004] In the above-mentioned conveyance roll, it is necessary to manage the frictional force between the conveyance roll and the strip in order to prevent slips and meandering walks of the strip and to reliably convey the strip. However, since the frictional force cannot be directly controlled, the surface roughness of the part that contacts the strip is controlled to be within a predetermined range.For example, in Japanese Patent Publication No. 54-7244, A conveying roll is disclosed in which unevenness is formed so that the roughness (Ra) is 0.2 μm to 5.0 μm.

[0005]

[Problem to be Solved by the Invention] However, the center line average roughness can be determined by determining the roughness curve of the object to be measured, setting the center line to 0, folding back the negative side part, and using this folded curve and the center line. Since it is the value obtained by dividing the area of the enclosed part by the measured length, for example, if the unevenness has large ridges and the number of ridges per unit length is small, the centerline average roughness value will actually be large. However, it is considered that the desired frictional force cannot be obtained because the surface is relatively smooth. This becomes a problem when surface treatment is applied to the strip contacting portion of the conveying roll.

[0006] Furthermore, the center line average roughness of the conveyance roll decreases over time after the roll has been used to a certain extent, making it difficult to manage the conveyance roll in order to determine when it is time to replace it. .

In view of the problems of the prior art, the main object of the present invention is to provide a conveyor roll and its management method that can reliably prevent strip slipping and walking in continuous strip heat treatment equipment. It is in.

[0008]

[Means for Solving the Problems] According to the present invention, the above-mentioned object is achieved by continuously conveying a strip with a conveyor roll in a heat treatment furnace composed of one or more furnaces. A conveyance roll of a strip continuous heat treatment equipment for performing desired heat treatment, and a portion of the conveyance roll that the strip can come into contact with has a center line average roughness (Ra) of 2 μm to 6 μm, and a roughness curve The number of pairs of peaks of 0.5 μm or more and valleys of 0.5 μm or more from the center line per inch (PPI: peak per inch)
A conveyor roll for continuous strip heat treatment equipment, characterized in that the surface of the strip has been treated so that the A method of managing a conveyance roll for continuous strip heat treatment equipment for conveying and subjecting the strip to a desired heat treatment, wherein the surface roughness of a portion of the conveyance roll that the strip can come into contact with is determined by the center line of the roughness curve. Number per inch (PPI) of pairs of peaks of 0.5 μm or more and valleys of 0.5 μm or more from or centerline average roughness (Ra) and 0.5 μm from the centerline of the roughness curve
This is achieved by providing a method for managing conveyor rolls for continuous strip heat treatment equipment, which is characterized by managing the number per inch (PPI) of pairs of peaks of m or more and valleys of 0.5 μm or more.

[0009]

[Function] In this way, the surface roughness of the conveyor roll can be adjusted so that the center line average roughness is 0.5 μm or more from the center line of the roughness curve.
．． Number of valley pairs of 5 μm or more per inch (hereinafter referred to as P
It is abbreviated as PI. ) and the size of the peak (hereinafter abbreviated as Ra), it is possible to obtain a desired frictional force between the conveyance roll and the strip. In addition, if the surface roughness of the conveyance roll is managed using PPI or PPI and Ra, it can be managed almost in the same way as directly managing the frictional force.

0010

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below based on specific embodiments shown in the accompanying drawings.

FIG. 1 shows a schematic configuration of continuous strip annealing equipment to which the present invention is applied. A strip 2 is continuously supplied to this equipment from a payoff reel 1 installed at the line entrance, and the tip of the next strip is overlapped and welded by a welding connection device 3 to the end of the previous strip.
Next, it is cleaned by a cleaning device 4, the supply amount is adjusted by an inlet looper device 5, and then sent into a furnace for heat treatment. The strip 2 is heat-treated according to a predetermined heat cycle after passing through a heating furnace 6, a soaking furnace 7, a primary cooling furnace 8, an overaging furnace 9, and a secondary cooling furnace 10. After that, it is sent to the skin pass mill 12. This skin pass mill 12
After skin-pass rolling, the strip 2 is divided or defective parts are removed by an inspection and finishing device 13, and the processed strip 2 is wound onto a tension reel 14. A large number of hearth rolls 15 are provided in each furnace for applying appropriate tension to the strip 2 and causing it to run continuously.

FIG. 2 is a schematic front view of only the hearth roll 15. This hearth roll 15 has a generally cylindrical shape with a reduced diameter at both ends, and a surface portion 15a with which the strip 2 can come into contact has a Ra
is 2 μm to 6 μm, and PPI is 150 to 200
It has been processed to be within the range of

FIG. 3 shows a hearth roll 15 according to the present invention.
Fig. 3 shows changes in PPI and Ra of the surface portion 15a over time. Here, point P is the point at which slip occurs between the steel strip 2 and the hearth roll 15.

As is clear from the graph in FIG.
After 5a is smoothed out, the change over time becomes smaller and it is difficult to judge the above point P.However, since PPI gradually decreases with a relatively large slope from the initial stage to point P, PPI In other words, the time to replace the hearth roll 15 can be easily determined.

In reality, (1) when PPI becomes 50 or less, (2) Ra or PPI becomes the initial value (Ra: 2 μ
The hearth roll 15 is replaced when either of the following conditions is satisfied:

[0016]

Effects of the Invention As is clear from the above explanation, according to the conveyance roll of continuous strip heat treatment equipment and its management method according to the present invention, by setting the surface roughness of the conveyance roll by PPI and Ra, A desired frictional force can be obtained between the strip and the strip, and slip or walk of the strip can be reliably prevented. In addition, if the surface roughness of the conveyor roll is managed using PPI or PPI and Ra, it can be managed in the same way as directly controlling the frictional force, so it is possible to accurately judge when to replace the conveyor roll, and the strip change due to changes over time can be controlled. Slips and walks can also be reliably prevented.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a continuous steel strip annealing facility to which the present invention is applied.

FIG. 2 is a schematic front view of a hearth roll to which the present invention is applied.

[Figure 3] PPI on the surface of the hearth roll to which the present invention is applied
and is a graph showing changes in Ra over time.

[Explanation of symbols]

1 Payoff reel 2 Strip 3 Welding connection device 4 Cleaning device 5 Input side looper device 6 Heating furnace 7 Soaking furnace 8 Primary cooling furnace 9 Overaging furnace 10 Secondary cooling furnace 11 Output side looper device 12 Skin pass mill 13 Inspection and finishing equipment 14 Tension reel 15 Hearth roll 15a Surface part

Claims (2)

[Claims] [Claim 1] A conveyor roll of a continuous strip heat treatment equipment for continuously conveying a strip with a conveyor roll in a heat treatment furnace composed of one or more furnaces and subjecting the strip to a desired heat treatment. The portion of the conveying roll that the strip can contact has a center line average roughness (Ra) of 2 μm to 6 μm, and a peak of 0.5 μm or more from the center line of the roughness curve and a peak of 0.5 μm from the center line of the roughness curve. A conveyor roll for continuous strip heat treatment equipment, characterized in that the surface is processed so that the number of the above pairs of valleys per inch (PPI: peak per inch) is 150 or more. 2. A conveyor roll for continuous strip heat treatment equipment for continuously conveying a strip with a conveyor roll in a heat treatment furnace composed of one or more furnaces and subjecting the strip to desired heat treatment. A method of controlling the surface roughness of a portion of the conveying roll that the strip can come into contact with per inch of a pair of peaks of 0.5 μm or more and valleys of 0.5 μm or more from the center line of the roughness curve. number (PP
I), or the center line average roughness (Ra) and the number per inch (PPI) of pairs of peaks of 0.5 μm or more and valleys of 0.5 μm or more from the center line of the roughness curve. A method for managing conveyor rolls for continuous strip heat treatment equipment.