JPH0683847B2 - On-line grinding method for rolling rolls - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an on-line grinding method for rolling rolls.

<Prior Art> Conventionally, in a hot rolling mill or the like, as the amount of rolling increases,
The surface of the roll (work roll) in contact with the rolled material may be locally worn, and the surface quality of the rolled product may be impaired due to roughening of the surface due to partially adhered foreign substances. Therefore, it is often necessary to replace with a spare roll, but the roll replacement work requires a great deal of time and labor, and in order to reduce production efficiency, the work roll is rotated in the state of being incorporated in the rolling stand, While pressing a grinding body such as the one on the roll surface, it reciprocates in the roll axial direction to remove rough skin,
Various so-called on-line roll grinding devices have been proposed which reduce the number of roll changes by grinding to a required roll profile. The outline of the on-line grinding machine to which the present invention is applied will be described below with reference to the schematic front view shown in FIG.

In the figure, 1 is a work roll, 2 is a plurality of grinding bodies arranged in the roll axial direction (a direction perpendicular to the paper surface), and at the tips of grinding body holders 4 individually housed in holder frames 3, respectively. By attaching the rear end of each holder 4 to a pressing device 5 composed of a hydraulic cylinder, and setting the hydraulic pressure supplied from the pipe 7 to each cylinder 5 to an arbitrary set pressure, each grindstone is set to a predetermined size. It can be pressed against the surface of the roll 1 by the pressing force.

The holder frame 3 is supported on a support beam 8 attached to a rolling mill housing (not shown), and can be moved parallel to the roll axis along a guide member 8a on the support beam 8 by a reciprocating mechanism 9 not shown in detail.

When the work roll 1 is ground by the grinding device having the above configuration, the grinding ability (grinding amount per roll revolution (μ)) and grinding ratio (grinding amount per grinding wheel wear volume (μ)) are first calculated. From the above, the hydraulic fluid pressure of the cylinder 5 is set so as to obtain an appropriate pressing force F, and while maintaining this state, the grindstone 2 is pressed against the surface of the roll 1 and reciprocated in the axial direction of the roll to obtain a desired profile. It can be ground.

However, the relationship between the pressing force F, the grinding ability and the grinding ratio is generally as shown in FIG.

That is, the grinding ability is low in the region A where the pressing force F is low and does not fluctuate much, but sharply increases in the region B where the pressing force F is high. On the other hand, the grinding ratio is high in area A,
Moreover, although it does not fluctuate so much, it sharply decreases in the region B. Therefore, the setting of the pressing force F during grinding is usually
The pressing force (for example, F _{1 in} FIG. 3) near the boundary between the two areas A and B, that is, near the inflection points m and n is used. However, as shown in FIG. 4, when the grinding force (μ / time) changes with time, when grinding is performed with the pressing force F in the area A, the grinding performance decreases with an increase in the grinding amount (μ), and finally the grinding is performed. It becomes impossible. This is because crushing and clogging occur on the grinding surface of the grindstone 2. On the other hand, in the case of the pressing force F in the region B, there is almost no change with time.

<Problems to be Solved by the Invention> That is, when grinding is performed with a constant set pressing force as in the prior art, the grinding ability is deteriorated due to crushing and clogging. However, there is a problem in that the grinding work requires a lot of time and labor. If the pressing force F is set to a value in a high region B as a countermeasure against this, the grinding ability can be maintained, but the life of the grindstone due to spillage of the grindstone shortens, which is uneconomical.

The present invention has been made in view of the current situation, while preventing a decrease in the grinding ability due to the grinding and clogging of the grinding wheel at the time of grinding, reduce the reduction of the grinding ratio due to spillage due to the grinding wheel itself, An object of the present invention is to provide a rational rolling roll online grinding method capable of extending the life of a grindstone by a stable grinding ability and a high grinding ratio.

<Means for Solving the Problems> In order to achieve the above-mentioned object, the structure of the present invention has a plurality of grinding bodies arranged in the roll axial direction, each of which is individually set on the roll surface with an arbitrary pressing force. In an on-line roll grinding apparatus for a rolling mill, which has a pressing mechanism capable of crimping and is configured to reciprocate the grinding body parallel to the roll axis direction, one pressing force is applied to a grinding ability curve and a grinding force against the pressing force. The pressing force is set to an arbitrary pressing force close to the pressing force at the substantially same inflection point on the ratio curve and lower than the pressing force, and the other pressing force is set to a region higher than the pressing force at the inflection point. Is set to an arbitrary pressing force, and the set pressing force is alternately switched at an arbitrary setting frequency to perform grinding.

<Operation> With the above configuration, since two types of set pressing forces are alternately switched to perform grinding, it is possible to continue stable grinding with an initial grinding capability and a grinding ratio.

<Example> An example of the present invention will be described below with reference to the drawings.

FIG. 1 is a mechanism conceptual diagram of a pressing force control mechanism for a grinding body according to an embodiment of the present invention. In the figure, 10a and 10b are hydraulic pressure control valves, 11 is a hydraulic pressure switching device (servo mechanism), and 12 is A timer is shown, and this pressing force control mechanism is attached to each pressing device 5 of each grindstone 2. Therefore, the pressure liquid supplied from the hydraulic pump (not shown) is set to two kinds of pressures of the low pressure P ₁ and the high pressure P _{2 by} the adjusting valves 10a and 10b, respectively, and the pressure is supplied via the servo mechanism 11. Are alternately switched and supplied to the pressing cylinder 5. This pressure switching is configured so that it can be automatically switched at an arbitrary set time interval via a timer 12 or the like.

Assuming that the pressing forces of the grindstone ₂ by the hydraulic fluid pressures P ₁ and P ₂ are F ₁ and F ₂ , respectively, the pressing force F ₁ is set as shown in FIG. Grinding is performed on the basis of this pressing force F ₁ as an arbitrary value within the low pressing force region A that approaches the inflection points m and n that rapidly change as F increases. On the other hand, the pressing force F ₂ is set to an arbitrary value within the high pressing force region B as shown in FIG. 3, but the crushing that occurs on the grinding surface of the grindstone 2 during grinding with the low pressing force F ₁ is performed. If the grinding ability is reduced due to clogging, select an appropriate pressing force that can cause spillage and regenerate the grindstone surface within a relatively short time.

The set pressing forces F ₁ and F ₂ can be determined in advance by experiments according to the properties of the grindstone used. That is, in the grinding ability curve and the grinding ratio curve in FIG. 3, generally, when the pressing force F of the grindstone 2 is increased during grinding, fine spillage occurs on the surface of the grindstone 2 with a predetermined pressing force. Then, since the surface roughness of the surface becomes large, the grinding ability is increased. When the spillage occurs, the abrasion of the grindstone 2 increases correspondingly, and the grinding ratio decreases. Thus, the inflection point m of the grinding ability curve for increasing the grinding ability
And the inflection point n of the grinding ratio curve at which the grinding ratio decreases are present at substantially the same set pressing force F ₁ . And this is the same even if the type of grindstone used changes.

On the other hand, during the grinding with the set pressing force F ₁ , the grinding ability decreases due to the occurrence of crushing and clogging.Therefore, when the grinding wheel surface needs to be regenerated, the pressing force set for each grinding wheel was set experimentally.
Since the required grinding amount (μ) at F ₁ can be obtained in advance, it can be easily determined by setting the required grinding time T ₁ from the rotation speed of the roll 1 at the time of grinding. Similarly, the setting of the shortest grinding time T ₂ required to regenerate the whetstone surface due to spillage can be easily set in advance by experiments corresponding to the set pressing force F ₂ .

Therefore, by inputting the set grinding times T ₁ and T ₂ to the tie 12, grinding can be performed while alternately and automatically switching the pressing forces F ₁ and F ₂ .

FIG. 2 shows an example of the switching control pattern of the set pressing forces F ₁ and F ₂ .

Since the method of the present invention has the above-mentioned configuration, when grinding is started with the pressing force F ₁ , the grinding wheel surface is crushed with an increase in the grinding amount (μ), clogging occurs, and the deterioration of the grinding ability reaches a predetermined limit. When it reaches, that is, after ₁ hour from T
Low hydraulic pressure P ₁ is switched to high hydraulic pressure P ₂ via 11 and high pressing force
While doing F ₂ for T ₂ hours only, after causing spillage to regenerate the grinding surface of the grindstone, switch to low pressing force F ₁ again,
It is possible to continue stable grinding with the initial grinding ability and grinding ratio.

<Effects of the Invention> As described above, according to the present invention, the reduction of the grinding ability and the grinding ratio can be remarkably reduced as compared with the conventional grinding method. That is, it is possible to maintain a stable grinding ability and a high grinding ratio at all times, and there is an advantage that the life of the grindstone can be extended.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a pressing force control mechanism of a grinding body according to an embodiment of the present invention, FIG. 2 is a principle diagram of an example of a control pattern of a set pressing force, and FIG. 3 is a grinding ability against pressing force. And a graph showing the relationship of the grinding ratio, and FIG. 4 is a graph showing the change over time in the grinding ability. In the figure, 1 is a roll, 2 is a grinding body, 5 is a pressing mechanism, 9 is a reciprocating mechanism, A is a low pressing force region, B is a high pressing force region, and F ₁ and F ₂ are set pressing forces. The forces, m and n, are inflection points.

Claims (1)

[Claims] 1. A pressing mechanism capable of individually crimping a plurality of grinding bodies arranged in the roll axis direction on a roll surface with an arbitrary set pressing force, and the grinding bodies are parallel to the roll axis direction. In an on-line roll grinding device of a rolling mill configured to be capable of reciprocating motion, one pressing force is close to the pressing force at substantially the same inflection point in the grinding ability curve and the grinding ratio curve with respect to the pressing force, and the pressing force. While setting to an arbitrary pressing force within a lower region, the other pressing force is set to an arbitrary pressing force within a region higher than the pressing force at the inflection point, and the set pressing force is set at an arbitrary setting frequency. An on-line grinding method for rolling rolls, which is characterized by alternately switching and grinding.