JPS60184425A - Shape detecting method of pipe in roll type pipe reforming machine and roll position setting method - Google Patents

Abstract

PURPOSE:To detect a shape of a pipe, and to reform correctly the pipe by derivering a residual bend quantity by a variation of a difference of a load of each roll of the delivery of the pipe, and deriving a residual ellipse factor by a variation of a load of one roll. CONSTITUTION:In a roll type pipe reforming machine which has three pairs or more of a pair of rolls opposed to each other, offsets at least one pair of rolls against other rolls, crushes and moves a pipe by the rolls opposed to each other, and straightens the pipe, load cells 23, 27 are provided through supporting levers 22, 26 on each roll 21, 25, respectively, of a stand 13 positioned at the delivery of a pipe 10, and a load of each roll 21, 25 is detected, and inputted to an operator 33 through amplifiers 31, 32. Also, from a pulse oscillator 24 installed to the roll 21, a pulse signal is inputted to said operator 33 at every one rotation. In the operator 33, from this input signal, a variation quantity of a load difference of each roll 21, 25 and a variation quantity of a load of the roll 25 are calculated, also a residual bend quantity and a residual ellipse factor of the pipe are deived, and an offset quantity and a crush quantity are set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for detecting the shape of a tube and a method for setting the roll position of a roll bone straightening machine for straightening a tube such as a steel tube.

[Prior art]

Steel pipes manufactured by various pipe manufacturing methods need to be refined through various treatments in order to obtain predetermined quality.

The straightening process is one of such refinement processes, and its purpose is to remove bends in the pipe and make it straight. The bend straightening method includes three or more pairs of rolls facing each other, and at least one silk roll is arranged so that the pipe is bent with respect to the other rolls, The so-called L! rotates each roll and moves the tube while applying external pressure between each pair of opposing rolls to make the tube straight and perfectly round! - A straightening iE machine is commonly used.

Conventionally, the method of setting the position of each roll in this roll bone straightening machine has been difficult, partly because strain, stress, etc. during straightening of the tube have not been clarified experimentally or theoretically.
Workers visually judge the bending of the pipe based on past data.
The most common method was based on the experience of the worker. For this reason,
The quality of the pipe, such as straightening accuracy and yield strength, changes due to differences in the experience of workers, and since the desired quality cannot be obtained with one bend straightening, it is often necessary to straighten the pipe again, and the setting process takes a long time. There was the inconvenience that it required

〔the purpose〕

The present invention has been made in view of the above circumstances, and uses a roll straightening machine to correct the residual bending of the tube and the residual bending of the tube based on the fluctuation of the load applied to a set of rolls located on the exit side of the tube. To provide a method for detecting the shape of a tube in a roll osteotomy straightening machine that can accurately detect the bending of a tube by determining the ellipticity, and to determine the amount of offset based on the residual bending of the inserted tube. By determining the amount of crush based on the residual ellipticity of purpose.

〔principle〕

Next, the present invention will be explained in detail.

FIG. 1 is a schematic view showing the state of correction of a tube by a roll osteotomy correction machine, and FIG. 2 is an enlarged schematic cross-sectional view taken along line nn in FIG. 1. This roll bone straightening machine is of the so-called 2-2-2 type, in which three sets of stands each having one upper and lower drum-shaped roll facing each other with their axes tilted to each other are arranged side by side. The tube 10 is rotated and moved from the left side of the drawing to the right side as shown by the white arrow in FIG.

In contrast to each roll of the first stand 11 on the left side and the third stand 13 on the right side, each roll of the second stand 12 in the center is translated upward in order to bend the pipe 10, which is a so-called offset state. The amount of offset is δ. It is indicated by.

In addition, the gaps between the rolls of each stand II, 12.13 are set slightly smaller than the perfect circular outer diameter (product target outer diameter) of the tube 10 in order to apply external pressure to the tube 10, so that the tube 10 has a so-called crush Therefore, the tube 10 has a flat elliptical shape as shown in FIG. The amount of crush δC is expressed by the difference between the outer diameter of the perfect circle (the outer diameter of the perfect circle determined by the circumferential length of the tube 10) d and the distance between the rolls (therefore, the minor axis of the tube that has become a flat ellipse).

FIG. 3 is a schematic diagram showing the state of the load applied to the tube 10 from each roll. Due to the crash of each roll in the first stand 11, the tube 10 is
A crush load Pc1 of equal magnitude is applied in each direction above, and a crush load Pc21 of equal magnitude is applied to the second stand 2 and third stand 13 as well.
P c 3 is applied in the downward and upward directions by the upper and lower rolls.

Next, considering the load due to the offset of the second stand 12, that is, the offset load, in the second stand 12 where the rolls are offset, the offset load Po2 is applied upward from the lower roll, and the offset load Po2 is applied upward from the lower roll. In each third stand 11.13, the load 1i is loaded downward from the upper roll.
po1+PO3 come first.

Each offset load Po 1. Since Po 21 Po 3 is in equilibrium, Po 2 = Po 1 + Po
It becomes 3. Now, 2-2 with the second stand offset
-2 type, if a load meter is installed on each roll of the third stand 13 on the exit side of the pipe 10 and the load applied to each roll is measured, the offset load Po on the third stand 13
3 is expressed as the difference between the load on the upper roll (P03+PC3) and the load on the lower roll (Pc 3 ), and the crush load Pc3 is the load on the lower roll (Pc 3 ).
) is equal to In addition, in the type 1-2-2-1, which has one roll installed below the exit side of three sets of opposing rolls, a load meter can be installed on the smallest roll to reduce the residual amount. Information for bend detection can be obtained.

Next, the relationship between fluctuations in offset load PO and residual bending will be explained. STB 42 with outer diameter 60 mm and thickness 5 mm
The results of an experiment conducted on the relationship between the fluctuation of offset load Po per roll rotation and residual bending using steel pipes are summarized in the fourth section.
As shown in the figure. It can be seen from this graph that when the residual bending is large, the variation in the offset load Po becomes large.

Therefore, if the relationship between the fluctuation of the offset load Po and the residual bending is determined in advance, the offset load P per one rotation of the roll can be
.

By detecting fluctuations in the amount of bending in the pipe, the amount of bending occurring in the pipe can be determined.

Furthermore, the relationship between fluctuations in crush load Pc and ellipticity will be explained. STB with outer diameter 60mm and thickness 5II+l
42 steel pipe, crush load P per roll rotation
FIG. 5 shows the results of an experiment conducted regarding the relationship between the variation of c and the ellipticity. The variation in crush load Pc per rotation of the roll and the ellipticity are approximately proportional to each other. Therefore, if the relationship between the variation in the crush load Pc per rotation of the roll and the ellipticity is determined in advance, the ellipticity of the pipe can be determined by the variation in the crush load Pc.

Next, the relationship between the amount of offset, the amount of crush, and the residual curvature after correction will be explained. An experiment was conducted to investigate the relationship between the offset and residual bending of STB 42 steel pipe with an outer diameter of 60 mm and a thickness of 5 inches. That is, the residual curvature of the steel pipe was measured when the curvature of the steel pipe before straightening was set to 2 van/m, the amount of crush was kept constant, and the amount of offset was changed and the steel pipe was straightened. In this case, the residual bending that occurs for each offset amount is as shown in FIG. Further, FIG. 7 shows the results of straightening a steel pipe under similar conditions by keeping the amount of offset constant and varying the amount of crush. Curd correction can be achieved mainly by offset, and crush contributes to bend correction, but there is no clear tendency. As is clear from Fig. 6, if the offset amount is less than 1 (ln), the residual bending is inversely proportional to the offset amount, but if it exceeds 10 cranes, the residual bending tends to increase. , bend correction is most effective when the amount of offset is about 10 cranes.In this way, bend correction is most effective depending on the pipe dimensions, material, etc., and initial bend amount (bending amount before correction). If there is a target offset amount, and the relationship between the pipe size, material, etc. and the offset amount with respect to the initial bending amount and the residual bending is determined in advance, the most effective offset amount for bend correction can be easily determined.

Therefore, when determining the amount of offset, it is necessary to accumulate data in advance that shows the relationship between the amount of offset and the residual bend for the dimensions of the original pipe (pipe before straightening) and the amount of bend per piece of material, and use this. Bye.

Furthermore, the relationship between the amount of crush and the residual ellipticity after correction will be explained. Figure 8 shows the ellipticity of STB 42 steel pipe with an outer diameter of 6011 and a thickness of 5 fl before straightening at 3 to 4%.
It is a graph showing the relationship between the crush rate (the ratio δC/d of the crush amount δC and the outer diameter d) and the residual ellipticity when the offset amount is constant.

The crush rate δc/d and the residual ellipticity are approximately inversely proportional, and the higher the crush rate, the more effective the ellipse correction becomes, but the hardness of the steel pipe increases and the quality deteriorates. Therefore, if the relationship between the crush rate and residual ellipticity is determined in advance based on the pipe dimensions, material, etc. and initial ellipticity (ellipticity before correction), and the increase in hardness of the pipe is taken into consideration, it is possible to correct the flatness of the pipe. The most effective rush rate is determined and the amount of crash is determined. In determining the amount of crush in this way, data showing the relationship between the crush rate and the residual ellipticity with respect to the dimensions, materials, and ellipticity of the original tube may be accumulated in advance and used.

〔composition〕

The present invention has been made with attention to the above principle, and has three or more sets of rolls facing each other, at least one set of rolls is offset with respect to the other rolls, In a roll straightening machine that straightens a tube by moving the tube while crushing it with opposing rolls, the load applied to a set of rolls located on the exit side of the tube is detected, and the load applied to each of the opposing rolls is detected. The shape of the pipe is detected by determining the amount of residual bending in the pipe based on the variation in the difference in the applied load, and the residual ellipticity of the pipe based on the variation in the load applied to one roll. The amount of offset is determined based on the amount of bending, and the amount of crush is determined based on the determined residual ellipticity of the pipe.

〔Example〕

Next, examples of the method of the present invention will be described. Figure 9 shows
Output in the 2-2-2 roll type tube straightening machine used to carry out the method of the present invention? FIG. 3 is a schematic front view of the third stand 13 of R1. The support rod 22 of the upper roll 21 is provided with a load cell 23 that detects the upward load applied to the roll 21 due to the movement of the tube 10, and the roll 21 is equipped with a pulse that outputs a predetermined signal every rotation. Oscillator 24
is provided.

A load cell 27 is provided on the support rod 26 of the lower roll 25 to detect the downward load applied to the roll 25 due to the movement of the tube 1o.

The output of the load cell 23 provided on the support rod 22 of the upper roll 21 is given to an arithmetic unit 33 via an amplifier 31, and the output of the lower load cell 27 is given to an amplifier 32.
The data is sent to the arithmetic unit 33 via. Furthermore, the output of the pulse oscillator 24 provided on the roll 21 on the second side is also provided to the computing unit 33.

Based on the signal from the pulse oscillator 28, the calculator 33 calculates the difference between the maximum and minimum differences in the loads applied to each roll 21.25 per rotation of each roll, that is, the amount of variation in the difference in loads per rotation of each roll. It also calculates the amount of variation in the roll load per rotation of the lower roll 25, and calculates the difference between the preset offset load and the residual load based on the amount of variation in the difference in roll load per rotation of the roll. The residual bend in the pipe 10 is determined from the relationship with the bend, and the value is recorded in the residual bend recorder 34. Furthermore, based on the amount of load variation of the lower roll 21, that is, the amount of crash load variation, a preset crash value is determined. The ellipticity is calculated based on the relationship between the load variation amount and the ellipticity, and the value is recorded by the ellipticity recorder 35.

The shape of the tube 10 is determined from the values recorded by the recorders 34 and 35, and the amount of bending is used, for example, to protect measuring instruments in the non-destructive inspection process that is the next step after the straightening process using this tube straightening machine. In addition, when correcting and changing the offset amount and lash amount of the next pass in the roll bone straightening machine, the amount of bending is determined based on the relationship between the offset amount and the residual bending, which is predetermined for the tube. In addition to obtaining the offset amount based on the data shown, the ellipticity can be used to calculate the crush amount based on the relationship between the predetermined crush amount and the residual ellipticity corresponding to the pipe. .

In the above embodiment, the residual bending amount and residual ellipticity are calculated based on the amount of variation in the load applied to each roll 21 and 25, and the offset amount and crushing amount are determined from each residual bending amount and residual ellipticity, respectively. However, the method for setting each roll position may be such that the offset amount and crush amount are directly determined from the amount of variation in the load applied to each roll 2L25.

In addition, in the above-described embodiment, the requested amount of residual curvature and residual ellipticity are recorded respectively, but the computing unit 33 calculates the amount of offset and the amount of crush from the amount of residual curvature and residual ellipticity, respectively. , the roll position of the roll bone straightening machine 2 in the next pass culm may be automatically corrected and changed based on the calculated value, and in this case, the straightening process can be fully automated.

〔effect〕

The present invention calculates the amount of residual bending and residual ellipticity by changing the load applied to the rolls, so the bending state of the pipe can be determined by
It can be accurately captured, making it possible to improve accuracy in the correction process and prevent damage to equipment in the non-destructive inspection process. Since the offset amount and crush amount in the roll straightening machine are determined from the determined residual bending amount and residual ellipticity, the product quality in the straightening process is significantly improved, and the roll position setting time is significantly reduced. It has excellent effects such as being shortened to .

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing the tube straightening state in the roll bone straightening machine, Fig. 2 is an enlarged sectional view taken along the line ■-■ in Fig. 1,
Figure 3 is an explanatory diagram of the load applied to the tube during straightening, Figure 4
Figure 5 is a graph showing the relationship between offset load fluctuation amount and residual bending amount, Figure 5 is a graph showing the relationship between beam lash load fluctuation amount and residual ellipticity, and Figure 6 is a graph showing the relationship between offset amount and residual bending amount. Graph, FIG. 7 is a graph showing the relationship between crush amount and residual bending, FIG. 8 is a graph showing the relationship between crush rate and residual ellipticity, and FIG. 9 is a graph showing the relationship between the crush amount and residual ellipticity. It is a schematic diagram of the exit side stand of a straightening machine. 10...Tube II, 12.13...Stand 2+
, 25...Roll 23, 27...Load cell
24...Pulse oscillator time 1 person Sumitomo Metal Industries Co., Ltd. agent Patent attorney Noboru Kono 5 -1 Hani Go to number 1

Claims (1)

[Claims] 1. Three or more sets of oppositely facing rolls are installed, at least one set of rolls is offset from the other rolls, and the pipe is crashed by the oppositely facing rolls. In a roll straightening machine that straightens the tube by moving the tube while moving the tube, the load applied to a set of rolls located on the exit side of the tube is detected, and the residual amount of the tube is determined by the fluctuation of the difference in the load applied to each opposing roll. A method for detecting the shape of a tube in a roll bone straightening machine, characterized in that the amount of bending is determined and the residual ellipticity of the tube is determined by varying the load applied to one roll. 2. It has three or more sets of opposing rolls, at least one set of rolls is offset from the other rolls, and the pipe is moved while being crushed by the opposing rolls. In a roll straightening machine that straightens the tube, the load applied to one silk roll located on the exit side of the tube is detected, and the amount of residual bending of the tube is estimated by the fluctuation of the difference in the load applied to each opposing roll. , the amount of offset l- is determined based on the amount of residual bending, the residual ellipticity of the pipe is determined by variation of the load applied to one roll, and the amount of crush is determined based on the residual ellipticity. How to set the roll position of a bone straightening machine.