KR940011290B1 - Grinding method of rolling roll - Google Patents

Abstract

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Description

Step grinding method of rolling roll

1 is a diagram illustrating a step grinding method of a rolling roll according to an embodiment of the present invention.

2 is a diagram illustrating a situation of rolling roll grinding by online.

3 is a side view showing a grinding mechanism.

4 is an explanatory diagram of the wear state of the rolling roll.

5 is a diagram illustrating the situation of step grinding.

6 to 9 are explanatory views of the grinding surface after the step grinding.

10 is an explanatory diagram of the grinding surface after grinding step difference in the left step part.

11 is an explanatory diagram of a grinding surface after grinding of the step of the right step.

FIG. 12 is an explanatory diagram showing the distribution of the grinding direction and grinding ability of a cup-shaped bottom stone.

* Explanation of symbols for main parts of the drawings

1: rolling roll 1a, 1a ': stepped portion

1b: Mail order part 3, 3 ': Low stone

The present invention relates to a step grinding method of a rolling roll which enables reuse by grinding a roll worn during rolling.

The surface of the rolling roll for rolling the rolled material such as steel is necessarily worn. In that case, the surface of the rolled roll 1 is in the same range as the width l of the rolled material S, that is, the plate part ( 1b) is worn out, and both of the non-walled parts 1a and 1a 'of the plate part 1b are not worn. In order to remove the step between the plate part 1b and the non-plate part 1a (width l ₁ ) caused by abrasion, and to recover the surface damage of the rolling roll 1 due to abrasion, to maintain a smooth roll surface at all times during rolling What is called on-line roll grinding which grinds the rolling roll 1 is performed.

2 shows an example of on-line roll grinding, in which six cup bottoms 3 are installed in a case 4 while maintaining a constant interval p, and the whole case 4 is installed by a moving device not shown. Is moved in the transverse direction of the rolling roll 1, and grinding is performed over the full width of the rolling roll 1. 3 shows the grinding mechanism of the grinding device, and the cup-shaped bottom stone 3 is pressed by the hydraulic cylinder 5 provided in the case 4 to press the roll 1 to be ground to a predetermined pressure for grinding.

The case 4 is supported by a screw jack 6 and the screw jack 6 is operated by a motor 7 to serve to arbitrarily adjust the height of the bottom 3. On-line roll grinding includes step grinding to grind the stepped portion of the non-plate part and full-face grinding to grind the full width of the rolling roll 1 including the stepped portion 1a.

In fact, as in the fourth diagram, the stepped portion 1a, which is a non-plate part, is ground to a level almost the same as that of the plate part 1b, like a dotted line. Grind and finish. 5 shows the situation of the step grinding. The stone slabs 3 and 3 'are pressed against the rolling roll 1 which rotates without driving, and the front part is inclined to be ground while being driven continuously about the axes 3x and 3x'. In the figure, β ₁ and β ₂ are the setting values of the positions for turning ON (grinding execution) and OFF (grinding stop) of the stones (3, 3 '). That is, the contact length between the grinding surface of the bottom stones 3 and 3 'and the stepped portion 1a of the rolling roll 1 The grinding is switched on or off depending on whether is greater than or less than the set value β ₁ or β ₂ .

Specifically, in the left bottom stone 3 for β ₁ , grinding is ON, In case of <β ₁ , change to grinding OFF.

In the same way, on the right bottom 3 ' for β ₂ , grinding is ON, In case of <β ₂ , change to grinding OFF.

In this set value β ₁ , β ₂ , the grinding ability Vg (grinding amount per rotation of the rolling roll 1: μm / rev) of the low stone (3. 3 ') is the low stone (3, 3'). It is set as follows based on the data obtained experimentally as being equal throughout the contact width with the high rolling roll 1, and the like.

β ₁ = β ₂ ≒ 0.6w

However, w is the contact width of the low stone rolling roll.

6 to 9 show the difference in roll shape after grinding when the set values β ₁ and β ₂ are set to different values.

Here, grinding amount (DELTA) R (micrometer) of the step part c point can be represented by the following formula.

ΔR = Vg · tg

However, n is rotation speed (rev / sec) of the rolling roll 1, and tg is grinding time (sec) of c point.

The grinding ability Vg becomes large when the pressure line pressure rho (kg / mm) of the low stones 3 and 3 'is high.

ρ = Q / l / d

However, Q is the pressing force (kg) per one stone, ld is the contact length (mm) of the stone and the rolling roll.

6 shows the case of β = w. Since Δtg = 0 or ρ does not change at the step c, the grinding shape is insufficient.

7 shows the case of β 0.8 W. When grinding with the same pressure buoyancy force (Q), ρ = Q / β becomes higher than ρ = Q / W at the time of normal grinding, and Vg becomes large, but grinding time (Δtg = Δw / Vo ≒ 0.2w / Vo) It becomes short, and the grinding amount is still insufficient.

8 shows the case of β ≒ 0.6w. The increase in Vg due to the increase in the pressure line pressure and the grinding time (Δtg ≒ 0.4w / Vo) are balanced to obtain a good grinding shape.

9 shows the case of β ≒ 0.4w. The increase in Vg and the grinding time (Δtg ≒ 0.6w / Vo) due to the increase in pressure line pressure are too long, resulting in excessive grinding.

Therefore, it can be seen that the best grinding shape is obtained in the case of β ≒ 0.6w. The principle of the cup-like stone 3 is to grind by the relative sliding speed Vg of the stone 3 and the rolling roll 1, as shown in FIG. Moreover, since the direction of this relative sliding speed Vs differs in each point of the contact line of the bottom stone 3 and the rolling roll 1, it is a big characteristic that the outstanding grinding | polishing ability is obtained by the direction of a grinding trace crossing.

However, it can be seen that the direction of the relative sliding speed Vs is larger in the outer direction than the inner side of the bottom stone 3. For this reason, the outer side portion of the bottom stone 3, in which the directions of the grinding traces intersect well, is higher than the inner side.

Although the cup-like bottom stone 3 differs in grinding ability from inside and outside, it grinds conventionally as (beta) ₁ = (beta) ₂ 20.6w without considering this difference.

Therefore, as shown in FIG. 10, when the grinding power Vg is appropriate at a point in time at the point c of the left stepped portion 1a (β ₁ ≒ 0.6w), grinding is performed inside the low stone 3 having low grinding power. Therefore, the grinding amount tends to be insufficient. In addition, as shown in FIG. 11, at the point c 'of the right stepped portion 1a', when the grinding ability Vg is appropriate at a certain point (β ₂ ≒ w), grinding is performed outside of the high stone 3 having high grinding ability. Therefore, the grinding amount tends to be excessive. As a result, a problem arises that the left stepped portion 1a has a k-shaped grinding shape, while the right stepped portion 1a 'has a k-shaped grinding shape.

In order to solve the above problems, the step grinding method of the rolling roll according to the present invention is a rolling roll grinding for grinding the step between the plate part of the rolled material and the non-plate part on both sides of the rolled roll by pressing the cup-shaped stone on the rolling roll during continuous rolling. In the method, when grinding one direction step part and the other direction step part, it is characterized by making a difference in the grinding width of a low stone.

Specifically, in the left stepped portion where the grinding amount is insufficient as the set value β when the grinding ability is equal, the set value β _{1 is made} to be a little smaller, and the grinding time is elongated at the step c point to eliminate the insufficient grinding amount.

In addition, in the right step portion where the grinding amount becomes excessive, the set value β ₂ is slightly increased to shorten the grinding time at the step c 'point, thereby eliminating the excessive grinding amount.

That is, the grinding time is adjusted by changing the low stone grinding width in the case of grinding the stepped portion in the other direction than when grinding one stepped portion. Thus, a roll grinding surface for maintaining a smooth shape of left and right symmetry is obtained.

Referring to the first embodiment of the present invention in more detail as follows.

1 is an explanatory diagram of a rolling roll grinding method according to an embodiment of the present invention. In addition, the same parts as those shown in FIGS. 2 to 5 will be omitted by the same reference numerals. In addition, since the structure, operation | work, and grinding sequence of the roll twisting apparatus which are the objects of this embodiment are also the same as that of the prior art, overlapping description is omitted.

FIG. 1 shows a situation in which the both sides of the worn plate portion 1b and the non-weared rolled portion 1 of the unrolled rolling roll 1, that is, the step portions 1a and 1a ', are completely ground using the bottom stones 3. In this case, the distance between the outer end a of the bottom stone 3 and the inner end c of the stepped portion 1a Or the distance between the inner end b 'of the bottom stone 3' and the inner end c 'of the stepped portion 1a'. Is for the predetermined set values β ₁ , β ₂ β ₁ , When β ₂ is reached, grinding is performed. At this time, in the conventional set value β, the set value β ₁ is reduced by lowering the low stone 3 (the low stone inclined in the direction away from the point c of the stepped portion 1a when the grinding is turned off). The grinding time is eliminated by lengthening the grinding time at the step c point.

On the other hand, in the right side stone 3 '(the stone inclined in the direction away from the step portion c' point when grinding is turned off), the set value β ₂ is made larger than the conventional set value to solve the excessive grinding, as described above. .

That is the grinding is carried out by a β <β _2. In this way, by changing β ₁ and β ₂ appropriately in consideration of grinding conditions, grinding surface conditions, etc., it is possible to perform step grinding to smooth the roll grinding surface and maintain the symmetrical roll shape as shown in the figure. Thereafter, as shown in the two-dot chain line, the entire width of the rolling roll 1 is ground and the roll grinding is completed.

The rolling roll grinding method of the present invention differs from the low stone width when grinding one stepped portion and the low stone grinding surface width when grinding the other stepped portion, so that the difference is appropriately changed for grinding. The lack of grinding and the excessive grinding caused by the difference in the viability are eliminated. As a result, the step grinding is performed to keep the roll grinding surface smooth and to maintain the left and right symmetrical roll shapes.

Claims (1)

In the rolling roll grinding method in which a cup-shaped low stone is pressed against a rolling roll during continuous rolling to grind the stepped portion between the plate portion of the rolled material and the non-plate portion on both sides of the rolled roll, when grinding one step portion. And grinding step of grinding roll, characterized in that the difference in grinding width of the low stone when grinding the other step.