JPS6188906A - Grinding method of roll - Google Patents

Abstract

PURPOSE:To improve the accuracy of grinding by computing the distribution of the amount of roll wear in the body-length direction based on a rolling record, to obtain a roll profile as well as to compute the necessary amount of grinding based on the difference between the computed profile and a prescribed one. CONSTITUTION:A traverse bed 4 is installed below a roll 1, and a whetstone bed 4a is slidably fitted to the bed 4. Respective profiles and rolling conditions of an initial target of roll 1 and respective computing equations, etc. are previously set in an arithmetic and a control unit 10. Next, the profile of roll 1 is computed from the distribution of roll wear in the direction of roll-body length based on the inputted information of rolling conditions. The scheduled amount of grinding is obtained by computing the difference between the set target value of unit 10 and the computed profile, to grind the roll 1 by moving the whetstone 6. Further, the actual amount of grinding at respective positions in the body-length direction is computed, to control a driving motor 13 and a hydraulic unit 8. In this way, the grinding accuracy is improved.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a method of grinding a roll worn by rolling into a predetermined profile. The present invention relates to a method of calculating the profile based on rolling conditions, the length of the material to be rolled, etc. without actually measuring the profile, and grinding the roll to a predetermined profile based on the calculated value.

[Prior art]

Recently, energy conservation has been promoted in steel factories, and one of the ways to do so is to charge continuously cast slabs into the heating section while still at high temperature, or directly without charging them to the heating furnace, for example, in a hot strip mill. A direct pressure technology has been developed in which the material is rolled using a rolling mill or the like.

Although direct pressure technology can improve thermal efficiency, there are limits to the size of slabs that can be continuously cast or the size of slabs that can be extracted from a heating furnace depending on the rolling schedule of the mill. To explain this in detail, the part of the rolling roll that comes into contact with the slab or the rolled steel material is worn out as it is rolled, and this wear causes the contact part of the roll, that is, the middle part in the lengthwise direction of the roll, to become smaller in diameter. Since steps are formed in the longitudinal direction, it is not possible to roll slabs wider than this, and for this reason, there is a so-called narrow-down constraint in the rolling method, in which strips with narrower widths are sequentially rolled.
Supplied to improve thermal efficiency (e.g. iv+
This is because it is not possible to roll any of the slabs of i.

Rolling 1 knoll is replaced with a roll of a predetermined profile after rolling a narrow-width roll according to a narrow-down rolling schedule, or when rolling a wide roll after a narrow roll due to a change in the rolling schedule. It is ground back to the desired profile.

Roll grinding is generally performed by removing the roll from the stand, but a method has been developed in which the roll is ground without removing the roll from the stand in order to improve work efficiency and productivity. This method involves placing a grinding tool such as a grinder or whetstone around the roll and pressing it against the roll to move it in the lengthwise direction of the roll, or placing a grinding tool along the entire length of the roll in the lengthwise direction of the roll and moving it in the lengthwise direction of the roll. The required metal is ground by pressing it against the metal.

[Problem that the invention seeks to solve]

The accuracy required for grinding the roll is from several μm to more than ten μm, and for this purpose, it is necessary to measure the wear amount of the roll with high precision before grinding, and to perform the grinding with high precision based on the measurement 11k.

Measurements are performed by moving a highly sensitive measuring device, such as a differential transformer, along the length of the roll, but the environment around the mill stand is very high and humid.

fH shock vibration 5 Due to dust etc., the measuring instrument was moved in the longitudinal direction 3
The accuracy of the IIJ device is easily lost (therefore, when using this 1 Jtl constant, it is difficult to expect stable measurement over a long period of time).

[Means for solving problems]

The present invention has been made to solve such problems, and it calculates the distribution of wear amount of worn rolls in the trunk length direction and the profile determined by this without using measuring instruments, moving devices, etc. It is an object of the present invention to provide a roll grinding method that makes it possible to obtain a predetermined profile by grinding a roll.

Such a roll grinding method according to the present invention is a method for grinding a roll worn by rolling into a predetermined profile.
The profile of the roll is determined by calculating the distribution of roll wear in the length direction of the roll based on the rolling conditions and the rolling history including the length and width of the material to be rolled, and the grinding required corresponding to the difference between this profile and a predetermined profile is calculated. (2) is calculated, and the roll is ground based on this calculated value.

〔Example〕

The present invention will be specifically explained below based on the drawings.

FIG. 1 is a schematic partial side view of a mill stand showing an implementation state of the present invention, and FIG. 2 is a front view of the same. In the figure, reference numeral 1 indicates a lower rolling roll attached to the mill stand.

When the roll 1 is not in use, it has an initial crown with a radius longer by about 0.2 vm at the center in the lengthwise direction of the roll than at the ends, and when used, a heat crown is formed, and the center part in the lengthwise direction of the roll has a longer radius than the ends. Parts that directly contribute to rolling wear out.

A pulse generator 2 is attached to the roll 1, and the pulse generator 2 outputs a signal related to the speed of one revolution of the roll 1, and the output signal is given to the arithmetic and control unit 10.

A load cell 9 is installed on the stand that pivotally supports the roll 1, and this detects the rolling ratio of 6:1, and the roasting signal is manually input to the arithmetic and control unit 10.

A traverse pedestal 4 is installed below the roll 1 in the lengthwise direction of its body.It is slightly longer than the roll 1 and has a horizontal trapezoidal cross section.A traverse pedestal 4 is installed below the roll 1, and a grindstone base 4a for moving the grindstone can be slid on this. It is fitted.

A cylinder 5 for pressing the whetstone is attached to the whetstone base 4a with its rod 5a facing upward, and a whetstone bracket 7 is attached to the tip of the rod 5a so as to be rotatable around an axis parallel to the roll 1. The grindstone 6 is fixed to this.

The rod 5a of the cylinder 5 can be moved forward and backward by a hydraulic device 8, and by this movement, the grindstone 6 can be pressed against or separated from the roll 1, and the force for controlling and pressing is determined by a signal set in the arithmetic and control device 10. It is controlled by a hydraulic device 8 installed at a position slightly apart from the roll l based on the following.

In addition, the pressing force is measured by the oil pressure gauge of the hydraulic device 8,
The constant signal is given to the arithmetic and control unit 10.

The whetstone base 4a is capable of reciprocating in the longitudinal direction of the traverse frame 4, and its movement is controlled by chains 12 whose ends are attached to both horizontal edges of the whetstone base 4a.
The drive sprocket 15 is arranged so that the distance between the axes is slightly longer than the length of the traverse frame 4. The drive motor 13 to which the drive sprocket 15 is attached rotates forward and backward at a predetermined number of rotations by rotating the sprocket 16 by 4J times, and the width of the movement is a pitch corresponding to the width of the grindstone 6.

A pulse generator 14 (not shown in FIG. 2) is attached to the drive motor 13, and the pulse generator 14 calculates a signal related to the amount of movement of the grindstone base 4a, that is, the roll grinding position of the grindstone 6, as a feedback signal. Output to the control device 10.

A heat insulating plate 11 is placed below the retraction limit of the rod 5a.
a, and the heat insulating plate 11 is provided by inserting the rod 5.
The rod 5a is inserted in the lengthwise direction of the roll body passing through the position where the rod 5a is inserted.
is opened so that it can be moved. The insulation Fj,ll
is cylinder 5. Traverse mount 4. Drive motor 13. It covers the pulse generator 14 and the like to provide some protection from the bad environment inside the stand during rolling or from dust during grinding.

The arithmetic and control unit 10 controls the rotation amount of the roll 1 based on the input signals from the pulse generator 2 and the rotor 2, and the circumferential speed of the roll 1 based on the input signal from the pulse generator 2 and the initial diameter of the roll, which will be described later. The rolling load is measured based on the input signal from the load cell 9.
When the signal from the pulse generator 2 exceeds a predetermined check value, it is determined that the rolled material (not shown) is caught in the roll l, and based on the input period of the signal, the circumferential speed signal of the roll 1 from the pulse generator 2, etc. Measure the length of the rolled material after rolling. Note that the arithmetic and control unit 10 is installed away from the mill stand so that it is not affected by the adverse environment around the stand.

In addition, the arithmetic and control device O includes the initial stage of the roll 1, each target profile, the initial diameter of the roll 1, the material of the material to be rolled which is the rolling condition, whether or not to use rolling oil and its type, and various calculation formulas to be explained later. are set, and the arithmetic and control unit 10 inputs these setting information, the rolling history of the length and one width of the rolled material after rolling, and the information measured by a thermometer (not shown) installed on the roll entrance side. Calculations are performed based on manual information on rolling conditions such as the temperature T of the rolled material and the rolling load to calculate the roll wear amount distribution in the trunk length direction and the profile of the roll l. Further, when a command signal for roll grinding is input from a higher-level arithmetic and control device (not shown), the arithmetic and control device 10 inputs and sets a predetermined roll profile target value necessary for the material to be rolled thereafter, or obtains it from information on a group of materials to be rolled. , calculate the difference between the target value and the roll profile at the time of calculation, calculate the planned grinding amount of the roll 1 at the distribution position in the roll body length direction, and drive the drive motor 13 based on the planned grinding amount. The grindstone 6 on the grindstone base 4a is moved in the length direction of the roll every predetermined dimension, and the cylinder 5 is pressed against the roll 1 by the hydraulic device 8 to grind the roll l, and the rotation amount of the roll 1 is 1 rotation speed.

The amount of grinding is calculated based on each input information of the pressing force of the grindstone 6, the amount of grinding at the distribution position in the body length direction is determined, and it is determined whether the predetermined amount of grinding has been achieved, and if the grinding amount is insufficient, the amount of grinding is determined. The hydraulic device 8° drive motor 13 is controlled until the profile is achieved.

Next, the f5 calculation; l++ control contents of the method of the present invention will be explained based on the flowchart shown in FIG. In order to calculate the amount of grinding required, it is necessary to calculate the amount of wear from the crown profile of the roll immediately after it is mounted on the stand or in the initial stage after grinding, and this is first calculated as shown in Figure 3+a+.

The amount of wear is correlated with the length of the rolled material after rolling, the material, whether or not rolling oil is used, its type, the temperature T of the rolled material, and the rolling load Pr, and the distribution of the amount of roll wear in the length direction of the rolled material It varies depending on the width of the roll 1 or the contact position relationship between the rolled material and the roll 1.

Therefore, the wear amount Cafkl at position X in the roll body length direction
is expressed by the following equation (1), which is a multiple regression model, and 'l
'A calculation control device 10 is set in advance.

Ca(xl=Σδa −L (ao +a, +a2
・Pr+,,13-'r+a4 ・'r2)
・=(11 However, L: Length a of each rolled material after rolling
o: Coefficient al determined based on the material of the material to be rolled: Coefficient a2 determined based on whether or not rolling oil is used and its type; Coefficient a3 determined based on rolling load. a4:
The coefficient δa in the above equation (1), which corrects the amount of wear that changes depending on the temperature T of the rolled material, is calculated by δa=O1 L closer to the center from the position where the ends of the rolled material in the width direction contact. In the area up to this point, the corners of the width ends of the rolled material widen during rolling, and the amount of wear there becomes larger than that of the flat central part, so δa = 1 + ε (0 < ε), and in other areas, δa =1.

The arithmetic and control unit IO determines the length L of the rolled material after rolling based on the signal based on the amount of rotation from the pulse generator 2 as input information and the biting information of the rolled material from the load cell 9, and determines the length L of the material to be rolled after rolling. A signal regarding δa based on the length of the material to be rolled and the width dimension of the material to be rolled after rolling inputted from the upper-level arithmetic and control unit, and a coefficient a□ which is also determined based on the material of the material to be rolled.

Coefficient d determined based on whether rolling oil is used and its type
1, further set coefficient a2. a3. Based on a4 and the input signal rolling load Pr+rolled material temperature T, the amount of wear after each rolling is determined for each area equally divided in the lengthwise direction of the roll, for example, for each width of the grinding wheel 6, and this is cumulatively calculated. and wear (
Calculate iCa(xi.

Then, the arithmetic and control device 10 calculates the crown profile by subtracting the calculated wear amount from the roll initial crown profile set in advance, and stores the calculated value. In addition, in calculating this crown profile, when only compensating for the amount of wear in the center of the roll 1 in the lengthwise direction, there is no need to take into account the heat assorted crown. When changing the heat crown conditions, the amount of heat crown must be calculated without being corrected.

For example, when grinding to correct the amount of heat crown,
The amount of thermal expansion Ch (Xl) at the position X in the longitudinal direction of the roll body is calculated using the following equation (2) regarding thermal expansion, which is set in advance in the arithmetic and control device 10.

CI+ fX)=K ・(Th (xi T
o ) -+21 However, K: Coefficient Th related to the amount of thermal expansion (xl: Temperature To at position ix in the body length direction of the roll
: Th(Xl) on the right side of the product temperature equation is the following (
3) Can be calculated in real time based on the formula, d
Thfil = dQfX)/V-f)
-(31 However, dThfxl: r per unit time: 2
- Amount of temperature change d (Hx): Change in heat input per unit time ρ:
Specific heat V of the roll Roll weight per unit length in the roll body length direction dQ(Xl on the right side of equation (3) can be calculated from the following equation (41).

dQfxl=δ・b,・Wdt+δ・b2・(T−
Th (Xl) dtb3・(Th (xi Tc
) dt = [41 However, W: Processing heat per unit length in the width direction of the rolled material TC: Room temperature or roll cooling water temperature b1: Coefficient dependent on processing heat b2: Heat transfer from the rolled material to the rolls Coefficient b3 related to roll cooling: Coefficient δ related to roll cooling by roll cooling water: 1 at the position where the rolled material contacts the roll. A constant that takes 0 at a position where there is no contact.Therefore, by substituting dQ(xi obtained from equation (4) into equation (3) and calculating dTb(xi), Ch(Xl
is found.

Note that three-dimensional heat conduction in the roll body length direction and radial direction is not taken into consideration in formula (2) and +31, but the heat transfer equation is not used because it poses no practical problem.

The thus obtained Ch(Xl) is subtracted from Ca(x), and each time the obtained value is subtracted from the roll initial crown profile, a crown profile is obtained and stored.

Then, the arithmetic and control device 10 calculates the planned grinding amount by performing calculations necessary for grinding based on a command signal for grinding the rolls after the completion of rolling a predetermined number of rolls, which is a human signal from the host arithmetic and control device. Grinding cylinder 5. Controls the drive motor 13.

Next, the calculation and control details of the planned grinding hole are shown in Figure 3(b).
The explanation will be based on. First, the arithmetic and control unit 10 is the upper/ii
Imports information on the material to be rolled from the i-calculation control device,
Calculate and set the accuracy of the target crown profile during roll grinding. Note that this setting may be performed by setting an accuracy value determined in advance by the operator.

Then, the arithmetic and control unit IO retrieves the stored current value data of the crown profile, subtracts this crown profile from a predetermined crown profile (target), and calculates the required amount of grinding.

Next, the grinding conditions such as the cumulative amount of roll rotation, the grinding wheel pressing force, and the circumferential speed of the roll, which are the amount required for grinding, are determined. The grinding conditions are selected based on the relationship between the amount of grinding, the cumulative amount of roll rotation, the grindstone pressing force, and the circumferential speed of the roll, as shown in FIGS. 5 and 6.

FIG. 5 is a graph showing the relationship between the amount of grinding and the cumulative amount of roll rotation when the grindstone pressing force is varied in three levels, with the horizontal axis representing the cumulative amount of roll rotation and the vertical axis representing the grinding amount. In the figure, O and M1 indicate the results when the grindstone pressing force was large, medium, and small, respectively. Note that the pressing force uses the component of cylinder pressure directed toward the center of the roll, and the diagram is organized based on this component. As can be understood from this figure, the cumulative amount of roll rotation is large regardless of the pushing force (if this is the case, the area in contact with the grinding wheel increases, so the amount of grinding increases, and this increase is due to the large pressing force of the grinding wheel). On the other hand, if the pressing force is small, it becomes small, and there is a substantially linear relationship between the cumulative amount of roll rotation and the amount of grinding, which varies depending on the pressing force of the grindstone.

Figure 6, like Figure 5, shows the amount of grinding and the amount of roll rotation KAEI when the roll circumferential speed is varied in three levels, with the horizontal axis representing the cumulative amount of roll rotation and the vertical axis representing the amount of grinding. It is a graph showing the relationship between O in the figure.

Marks 1 and 2 show the results when the roll circumferential speed was high, medium, and low, respectively. As can be understood from this figure, when the roll rotation cumulative amount is the same, the amount of culm grinding is increased when the roll circumferential speed is small, and conversely, the larger the roll circumferential speed is, the smaller the grinding amount is. It is presumed that this is because a water film is generated as the rotation becomes higher and the grinding efficiency decreases. Therefore, there is a substantially linear relationship between the roll rotation cumulative amount and the grinding amount, the range of which varies depending on the roll circumferential speed.

From the relationship based on FIGS. 5 and 6, the m constant amount Cg(X) of roll grinding by the grindstone is: CgfXl=δg −c・ΣN−P−r M −
(5) However, N: Roll rotation amount P: Grindstone pressing force C: Can be expressed as a coefficient. δg in the above formula (5) is δg = 1.0 in the portion where the roll contacts the grindstone, and δg = 0 in the portion where the roll does not contact. In addition, f (Vl is a correction term for the influence of the water film formation, and is set to a value based on the roll circumferential speed ■ as shown in Fig. 7. Therefore, Cg The amount, grindstone pressing force, and roll circumferential speed can be determined.

Grinding amount Cg (to) at position X obtained in this way
The grindstone base 4a is moved in the length direction of the body by the width of the grindstone 6, and the rod 5a of the cylinder 5 is adjusted to move forward or backward. At this time, information regarding the pressing force from the hydraulic device 8 inputted during grinding at the X pitch, the pulse generator 14
Grinding wheel position information from.

Calculate the theoretical actual grinding force based on the rotation amount information from the pulse generator 2 and the information regarding the roll circumferential speed,
Determine whether or not the planned amount has been ground by calculating the difference from the planned amount of grinding obtained earlier. When the planned amount has been ground, move the grindstone to the next X, and judge the grinding amount at that point in the same way as before. However, when the planned amount is ground, the next position X is ground, and the entire width is ground.

In addition, iii + ac! Amount of wear Ca (xl is based on the length L of the rolled material Ca (xl=Σδ"'L' (ao "al
) - (61).The reason for this is that the mill used in the experiment was a hot strip mill with a small number of types of rolled materials, and the wear amount was calculated using data on the amount of wear on finishing work rolls and equation (1). Perform multiple regression analysis of
As a result, the amount of wear Ca for the rolling load Pr and the temperature T of the rolled material is
This is because the effect on () was extremely small.

Figure 8 shows the average of each wear amount where position X is the center point of the roll and the midpoint between the roll end and the center, and the wear amount Ca
This is a graph showing the relationship between (x) (vertical axis) and the total length of rolled material (horizontal axis), and as can be understood from this figure, the wear amount can also be calculated by the above equation (6).

Furthermore, in the above embodiment, the grindstone base is sequentially moved in the lengthwise direction of the grindstone in pinches equal to the width of the grindstone, but the present invention is not limited to this movement method. , or the grindstone may be moved continuously. When moving in this manner, the unevenness on the surface of the grindstone is evened out, making the roll surface smoother, and the grindstone is self-dressing.

Further, in the above embodiment, the grinding wheel is moved in the longitudinal direction of the roll, but the present invention is not limited to this, and the present invention is applicable to other methods, such as a tow bar type in which the grinder is moved in the longitudinal direction of the roll. Of course, it is also applicable to a fixed type in which a plurality of grindstones are arranged over the entire length of the roll body.

When the present invention is applied to the traverse type, the amount of grinding may be affected by water film formation based on the roll circumferential speed, so it is preferable to take the roll circumferential speed into consideration when calculating the actual grinding amount. .

Further, in the above embodiment, the length L of the rolled material after rolling is calculated based on the biting information from the load cell 9 and the roll rotation amount from the pulse generator 2, but the present invention is not limited to this. The length of the rolled material before rolling is determined based on the weight, width, thickness dimension, and specific gravity of the rolled material in rolling AiJ or by a TV camera, etc., and this value and the thickness reduction rate 1
The length of the material to be rolled may be determined based on the width reduction ratio, or it may be determined directly using a TV camera or the like.

〔effect〕

The effects of the present invention will be explained below. Usually 14 pieces of board material
Body length 16 where rolls are replaced after rolling 5 rolls
50tm, roll crown amount 0.2 tar1
The profile of the pair roll [see Figure 9 (a)] is set to 30.
Measured according to the present invention for each main rolling, and 60 rolls 12
Grind the roll after the 0th rolling, and after each grinding and 130
The actual roll feel was measured.

FIG. 9 is a graph showing the results of the profile measurement, and α in the figure indicates that the actual width is a little wider than the nominal width and the increase in roll wear width due to center deviation of the plate material. When there are 30 mills, a concave portion with a width corresponding to the minimum width to maximum width (nominal width) of 1200 to 1380 m of the rolled material is formed (b), and then the width of the rolled material is 1200 = 1250 +
+n was replaced with rolling, and 60 rows were rolled with 2 rolls as shown in (c).
A stepped recess is formed.

When this was ground for about 10 minutes according to the present invention, it became smooth as shown in (d). After that, the width is further increased to 1
Rolling a narrower material of 050 to 1100 mm, 9
Measure the profile of the 0-piece mouth (e), and narrower the width of 900 mm.
A material to be rolled of ~1050 m was rolled and the roll feel of the 120th roll was measured (to). After that, it was ground for 15 minutes to obtain a smooth state as shown in Figure 1.The 121st row was slightly wider, 1200 to 1250 mm.The rolled material was rolled for 10 rows, that is, the 130th row, and the profile was measured. blood). As can be understood from this figure, the unevenness of each roll surface after grinding is 10 to 15 μm, and 1
Some unevenness was printed on the surface of the plate material that was rolled at the transition to the 21st roll, and only a few so-called high stubs, ridge breaks, etc. were formed.

As described in detail below, the present invention can measure the wear amount and profile of a roll by calculation, so there is no need for precise measuring instruments or moving devices, and therefore a stable and highly accurate profile can be obtained over a long period of time. Furthermore, since the grinding conditions are determined based on the profile and the amount of grinding is checked by calculating the grinding results, it is possible to perform accurate grinding, which is an excellent effect.

[Brief explanation of the drawing]

Fig. 1 is a schematic partial side view of a mill stand showing the implementation state of the present invention, Fig. 2 is a front view of the same, Fig. 3 is a flowchart showing the calculation control contents of the method of the present invention, and Fig. 4 is I7 wear amount. Fig. 5 is a graph showing the relationship between grinding wheel pressing force, roll rotation cumulative amount, and grinding m;
Figure 7 is a graph showing the relationship between roll circumferential speed, roll rotation cumulative amount, and grinding amount, Figure 7 is a graph showing the relationship between roll peripheral speed and correction term fM, and Figure 8 is a graph based on the length of the rolled material. Graph showing the validity of the formula for calculating wear 1cafxl, No. 9
The figure is a detailed explanatory diagram of the present invention. ■...Roll 2...Pulse generator 9...
・Load cell 10... Arithmetic control device 14... Pulse generator patent Applicant Sumitomo Metal Industries Co., Ltd. Agent Patent attorney Noboru Kono Figure 4 Roll Ii] w-1 volume →
Roll times VT, military horizontal amount - 51st
Fig. 6 Roll station running speed T Note 7 Fig. 7 It embroidery LfflJε material length 8 Fig.

Claims (1)

[Claims] 1. In a method of grinding a roll worn by rolling into a predetermined profile, the roll profile is determined by calculating the roll wear amount distribution in the trunk length direction based on the rolling conditions and the rolling history including the length and width of the material to be rolled. A roll grinding method characterized in that the required grinding amount corresponding to the difference between the profile and a predetermined profile is calculated, and the roll is ground based on this calculated value.