JPS60130411A - Rolling method of bar material - Google Patents

Abstract

PURPOSE:To improve the dimensional accuracy of a product such as bar or wire rod by comparing a measured drooping quantity of loop with its target value and controlling the number of revolutions of a rolling roll so as to eliminate the deviation between both values. CONSTITUTION:An arithmetic control unit 13 indexes the Young's modulus table of a memory unit 14 in accordance with an information, which specifies an interstand condition, outputted from a setting board 12, and decides also the target value delta0 of a loop-drooping quantity corresponding to a target axial force by consulting other inputted data, to output it to a comparator unit 15. The unit 15 compares the target value delta0 with a measured value delta outputted from a drooping quantity detector 10, to input its deviation epsilon to the unit 13. The unit 13 outputs a control signal Cu or Cd so as to make the deviation epsilon zero in accordance with the epsilon. Though the signal Cu is primarily given to rolling rolls 1 on the upstream side, the successive control for all the rolling rolls on the upstream side is successively preformed after the control of rolls 1. The same is performed in regard to the signal Cd.

Description

[Detailed description of the invention]

[Industrial Application Field 1] The present invention relates to a method for rolling a strip in which the strip is inserted into a plurality of rolling stands and continuously stretched, and in particular, it relates to a method for rolling a strip in which the strip is continuously stretched by being inserted into a plurality of rolling stands. Regarding the method. [Background 1] As a strip of appropriate length, such as a billet, heated in a heating furnace is sequentially passed through a rough rolling train, an intermediate rolling train, and a finishing rolling train, the cross-sectional area is reduced and the speed gradually increases. A steel bar of a predetermined size and shape. In recent years, there has been a strong desire for a rolling method that can achieve high dimensional accuracy over the entire length so that rolled wire rod products can be directly cold forged. The dimensional deviation within a single rod or wire rod product depends on the mutual force relationship that the rolling stands exert on the strip, that is, the tension or compression force (hereinafter collectively referred to as "shaft") on the strip between the stands. Therefore, conventionally, a method has been adopted in which the axial force between the stands is set from zero to a small constant force at the level of operability, and this is controlled. For example, S N T C (Su
miLom. Axial force control is performed by a direct method such as the axial force control method (No. 5 ion control), or by an indirect method such as the so-called constant torque arm method. However, each of these methods involves a complex control process based solely on large-scale computer processing, and these methods also require the use of shafts between short-span stands in one rolling train. It is only a control of the force, and there is no example of direct control of the axial force between rolling rows, which have relatively long spans such as those where loops are formed. From the perspective of precise control, the only option is to make the control flow in the computer more precise or to increase the precision of the sensors and actuators. Ikekata has a problem that cannot be avoided. [Objective of the Invention 1] Therefore, the main object of the present invention is to provide a novel rolling method in which the axial force can be easily controlled. The purpose of the plate is to

(2) To provide a method for rolling a strip material that primarily (basically) contributes to the overall control accuracy using L'L measures. [Summary of the invention 1] The present invention focuses on a loop of strip material, which was conventionally only recognized as a buff 7, between stands with relatively long spans, including between rolling rows, and calculates the amount of suspension of this loop. This method was developed to control the axial force between the stands to the set axial force by adjusting the axial force for one month by controlling the amount of suspension of the loop. When forming and rolling, the target axial force between the rolling stands including those between the rolling stands where the axial force is controlled is determined in advance based on the steel type, cross-sectional shape and average temperature of the material to be rolled. While setting the target value of the suspension amount of the loop, the actual measurement value is compared with the target value of the suspension amount of the loop, which is set in advance by obtaining the actual value of the suspension amount of the loop in the actual rolling operation. The basic feature is that the number of rotations of the rolling rolls of the upstream or downstream rolling stands including either one of the rolling stands mentioned above is controlled so as to eliminate the deviation between the two. There is. DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below with reference to detailed descriptions thereof and embodiments illustrated in the accompanying drawings. [Example 1] First, between the stands of a rolling train or between the rows of a rolling train (
One method for determining the target hanging amount of the loop at a set axial force (hereinafter referred to as "between stands") will be explained. An explanatory diagram based on modeling between stands is shown in Fig. 1. 1
2 is a rolling roll on the upstream side, 2 is a rolling roll on the downstream side having a rotational axis perpendicular to the rotational axis of rolling roll 1, and the strip-shaped rolled material 3 is rolled from left to right in the figure based on the pass line 4. proceed. An exit roller 5 for the guy Y is arranged near the exit of the rolling roll 1 so as to be in contact with the pass line 4, and an exit roller 5 for the guy Y is arranged near the entrance of the rolling roller 2 so as to be in contact with the pass line 4.
An inlet roller 6 is disposed on the same side. rolling roll 1,
The positional relationship between the rollers 2 and the rollers 5 and 6 is symmetrical with respect to the center of the two stands, that is, the imaginary line 7. Then, for the material to be rolled 3, the rolling roll 1.
2 or left and right fixed ends, exit roller 5 and large roller 6
each forms a free end that provides displacement, and the rolled material 3
forms a symmetrical loop 8 with the exit and entrance rollers 5° and 6 open. Therefore, the basic formula for dividing the loop 8 into minute elements and calculating the deflection of the elastic ring beam for each element is as follows: (M: bending moment), E: Young's modulus. By sequentially solving I: second moment of area (I5': displacement from the pass line, x: position in the rolling direction), the amount of suspension of the loop 8 can be determined. Since E and I are unique values for the loop material, it is important to calculate the moment h1 at each element under the given boundary conditions. FIG. 2 shows an explanatory diagram showing M in each element. In the figure, PN is the reaction force at the fulcrum, and MN is the moment around the fulcrum. TN is the tension collar hi is the position in the rolling direction up to the i element. lyi represents the amount of suspension of the path line 4 at the I element, and if the self-weight up to the i-element is Wi, and the moment due to the self-weight up to the i-element is Mu+i, the moment Mi on the right side of one element is Mi = 'PN・lxi -T-Kyou・lyi+MN+W
It is expressed as i・hi Mu+i (2). Figure 3 shows the flowchart for calculating the hanging amount of loop 8.
゜The unknown quantities to be found are the length of the loop (reaction force at the fixed end and reaction force at the free end) and moment at the fixed end).
. It is. If these values can be determined, the displacement of each element can be determined by sequentially solving equations (1). The true solution matches the displacement given at the free end, and also satisfies the condition that the gradient of the loop is zero at the center of the stand since the stands are symmetrical. This multi-point boundary problem was solved using the scissor-shoot calculation method. In addition, 511111 rivers] were adopted as the limit per element. As shown in FIG. 4, the value of the bending rate E required for calculation is given by temperature and steel type from data measured by a static load simple tensile test that has already been published. The data in Figure 4 is from "Tetsu to Hagane J, vo.
1.49 (1963), (13). This is equivalent to the data published in 28-33. - As an example, between the rolling rows where the loop 8 is likely to be formed, using the above analysis method, the axial force (K, g/111an
2) Amount of pull-up from the loop pass line (related)
Figure 5 shows the relationship between . The graph in Fig. 5 shows that the inter-row distance (I-) is 14 m, the distance between the output [second] roller 5 and the large roller 6 is 6+++, and the cross-sectional shape and dimensions of the rolled material forming the loop 8 are ≠5010111 and φ601111+1. Young's modulus E (K g/m+++2) for each of the two types is 6000 and 80.
(These are the calculation results for 10,10,000 and It is understood that the tension side is more sensitive than the compression side.Also, qualitatively, as predicted by equation (1), the smaller the moment of inertia of the area, the more sensitive the tension side is. , the smaller the Young's modulus, the greater the amount of suspension, and this is quantitatively demonstrated by the graph in Figure 5.In this way, the correspondence between the axial force and the amount of suspension according to the parameters was quantified. In the example shown in Figure 5, the amount of suspension is several tens of l1lI1 depending on the axial force.
It varies from 1 to several hundred 11II11. Under these conditions where loops are likely to form (especially between rows),
At least the axial force between the stands can be controlled by calculating the deviation from the suspension amount for the set axial force between the stands forming the loop and adjusting the speed, that is, controlling the number of rotations of the rolling rolls, to eliminate it. As a result, this has a positive effect on the dimensional accuracy of the finished product. FIG. 6 shows an outline of the control system according to the embodiment. 10 is a suspension amount detector for detecting the suspension amount of the loop 8; 11
1 is a computer as an electronic calculation control means; 12 is a parameter setting board for manually setting parameters; the computer 11 includes at least a calculation control section 13;
, a data storage section 14 , and a data comparison section 15 . The data storage unit 14 stores the steel type of the material to be rolled 3, a table of Young's modulus specified by the average temperature, various parameters regarding the material to be rolled 3, and a loop suspension amount uniquely determined for a given target axial force. Target value tables as well as other tables or individual data are stored. From the setting panel 12, information specifying the distance between the stands, that is, parameters such as the distance between the rolling rolls 1 and 2, the distance between the rollers 5 and 6, the steel type of the rolled material 3, cross-sectional shape, average temperature, target axial force, etc. parameter group 1]. Arithmetic control unit 1
3 indexes the Young's modulus table in the storage unit 14 in accordance with this and also refers to the pond input data to determine the target value δ of the loop suspension amount corresponding to the target axial force. is determined and output to the comparison section 15. In the comparison section 15, the target value δ. and the actual measurement value δ from the suspension amount detector 10, and input the deviation ε to the calculation control unit 13. The calculation control unit 13 outputs the control signal CLI or the control signal Cd according to this deviation ε so that the deviation ε becomes zero. The control signal Cu is then applied to the upstream rolling roll 1, but following the control of the rolling roll 1, the entire rolling roll on the first upstream side is sequentially controlled. The same applies to the control signal Cd. However, in order to simplify the control, the control signals CLI, Cd
It is preferable to use either one of the following. FIG. 7 shows a 70-diagram of processing according to the embodiment. Note that here, the deviation is 1δ in the judgment step. −δ1
is a predetermined tolerance ε. We are checking whether it is within the range of . If it is within the allowable range, rolling of one strip continues as it is; if it is outside the range, then the rotation speed of the rolling roll group on either the upstream or downstream side is successively controlled. That's what I do. Also, the variable parameters are not changed within 10 rounds, but if the loft changes, the settings of the variable parameters are adjusted from the setting board according to the lot conditions. The control according to the above embodiment is performed between stands with relatively long spans forming the rolling loop, preferably between the rolling rows (at most two locations in the case of rough, intermediate, and finishing). Even in one rolling row, the rolling process may be performed between stands having a relatively large span and forming a loop (in the past, the axial force is not controlled). This control may be performed at multiple locations between rows and between stands within the rolling row. The control according to the embodiment is used in combination with the direct method or indirect method of axial force control described above, but since the control itself is a simple process, there is no possibility of interference with the direct method or indirect method of controlling the axial force. few. Therefore, it is possible to perform a two-step control in which relatively coarse control is performed using this method and precise control is performed using the conventional method. Therefore, while it is economically and technically disadvantageous to try to improve control accuracy in one control process, it is not disadvantageous to add a simple means with less interference. This contributes to improving the overall control accuracy without any problems, and this makes it possible to obtain products with greater dimensional accuracy than at present. The above embodiment is based on a down loop that utilizes the action of gravity, but the same applies to an up loop in which an 11-loop is formed in the anti-gravity direction. It is also possible to control the axial force based on the correlation with the amount of displacement. [Effect 1] According to the present invention, which is based on the knowledge that the amount of suspension of the loop corresponds to the axial force, as described above, the target axial force can be achieved and lightened by simple means such as controlling the amount of suspension of the loop. This can greatly contribute to improving the dimensional accuracy of rod and wire products.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram based on modeling between stands according to the principle of the present invention, Fig. 2 is an explanatory diagram based on an illustration of the analysis method, and Fig. 3
The figure shows a specific flow diagram of the analysis method, Figure 4 is a graph giving Young's modulus, Figure 5 is a graph showing the correspondence between axial force and suspension amount as an example, and Figure 6 is an example of the present invention. FIG. 7 is a flowchart for explaining one method of the embodiment. 1.2... Roll of rolling stand, 3... Rolled material, =12- 4... Pass line, 5, 6... Roller, 8... Loop or loop phase, 10... Suspended wind detector, 11.
... Computer, 12 ... Parameter setting board, 13
. . . Arithmetic control section, 14 . . . Storage section, 15 . . . Comparison section. Patent Applicant Kobe Steel Co., Ltd. Representative Patent Attorney (2 persons) Figure 1 JP-A-130411 (5) Figure 3 Water-shaped cross section, yag umbrella stand)? I @ distance, cooler's ifLIi'4 site - 91 give group t14i Ma's 7- non-MO assumes troubled Ma's reach Pot Negation T8 Lan't #nt 汀 Vinegar pan's strawberry each fpf, +=-7...2 positions, Ka slope, path length 1 stitch B Nose 6 - Regular free end 7.4-E square Mo carving Otsu included To mackerel barley arrangement NQ 1 2nd UJLLl/6N, OIX+ 4., l//-4 wards (ul/D90) Xl and a half, //'-^ size

Claims (2)

[Claims] (1) When rolling is performed by forming a loop in the material to be rolled between rolling stands, the target axial force between the rolling stands including the rolling stands where the axial force is controlled is set to the steel type of the material to be rolled. The target value of the suspension amount of the loop is calculated in advance based on the cross-sectional shape and average temperature, and the target value of the suspension amount is preset by obtaining the actual value of the suspension amount of the loop during actual rolling operation. and the above-mentioned actual measurement value, and the number of rotations of the rolling rolls of the upstream or downstream rolling stand including either one of the rolling stands is controlled so as to eliminate the deviation between the two. Method of rolling strips. (2) The method for rolling a strip according to claim (1), wherein the rolling stands are stands belonging to different rolling rows.