JPS6142442A - Method and apparatus for monitoring steel tube upsetter - Google Patents

Abstract

PURPOSE:To enable to monitor accurately whether upsetting is being made normally or not in forming an upset part at the end of a steel tube by measuring load applied to an upset punch and displacement. CONSTITUTION:The end part 1B of a steel tube 1 is heated to about 1250 deg.C and inserted to a die 18, and the body 1A of the steel tube 1 is held firmly by a clamping jaw 17. Then a fly-wheel 12 is rotated, and the rotation torque is transmitted to a punch holder 15 through a crank shaft 11, a connecting rod 13 and a oil pressure cushion device 14 and receprocation of 1 cycle is made in about 6sec. Consequently, an upset punch 16 set to the punch holder 15 forms upset at the heated end 1B of the steel tube. This course of upser forming process is detected from the load spplied to the upset punch 16 and deformation, and quality of upsetting is judged from the pattern. Thus, monitoring of upsetting work is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method and apparatus for monitoring a steel pipe upsetter.

[Background technology] Upsetters use upset punches and dies to increase the thickness of the pipe end using an upset punch and die, in order to ensure joint strength at the threaded part of the pipe end of oil country tubular goods. It forms a set part. Figure 2 shows an example in which an outer surface upset portion 2A is formed on the tube end after the tube end of a steel pipe 1 is heated to about 1,250°C, an example in which an inner surface upset portion 2B is formed, and an example in which an inner surface upset portion is formed on the tube end. It is sectional drawing which shows each example which formed 2C.

Conventionally, in the operation of the upsetter described in (-), after the shapes of the upset punch and die are determined based on the thickening schedule of the steel pipe, continuous operation similar to that of a press machine is performed. That is, the operation of a conventional upsetter is, for example, as described in Kobe Steel Co., Ltd., Vol. 31, No. 1.
After setting the mechanical operation of the upset to the optimum condition, continuous operation is simply performed on the assumption that the condition will be maintained.

[Object of the Invention] The present invention measures the load value applied to the upset/punch during upset and the displacement of the upset punch,
The purpose is to monitor whether the upset has been executed normally.

[Structure of the Invention] A first aspect of the present invention is a method for monitoring steel pipe upsets in which an upset portion is formed by heating the end of a steel pipe. and determine the amount of cushioning, peak load value, and load pattern for the upset displacement. Standard cushion amount for upset displacement,
Compare the reference peak load value, reference load, <turn, and (
A) An abnormality in the relief valve setting pressure of the hydraulic cushion device for absorbing dimensional fluctuations in the master pipe, (B) Occurrence of slippage of the steel pipe during upset, and (C) Abnormality in the dimensions of the master pipe. It is designed to judge whether it is good or bad.

A second aspect of the present invention is a steel pipe upset monitoring device that forms an upset portion by heating the tube end of a steel pipe, and includes a load measuring means for measuring an upset load value applied to an upset punch, and an upset portion. Determine the displacement measurement means for measuring the displacement of the punch, the cushion amount, peak load value, and load pattern of the upset displacement, and adjust the determined cushion amount, peak load value, and load pattern of the upset displacement in an appropriate manner. Compare with the standard cushion amount, standard peak load value, and standard load pattern of the upset displacement predetermined for the set, and check whether (A) there is an abnormality in the relief valve setting pressure of the hydraulic cushion device for absorbing dimensional fluctuations of the original pipe, (B) ) Diagnose occurrence of steel pipe slip during upset, (C) dimensional abnormality of original pipe,
and determining means for determining whether the upset is good or bad.

[Detailed Description of the Invention] FIG. 1 is a perspective view schematically showing the entire upsetter 10 to which the present invention is applied. The upsetter IO is integrated with the crankshaft 11 and the main shaft of the crankshaft 11, and is connected to a flywheel 12. A connecting rod 13 connected at one end to the crank bin of the crankshaft 11, a punch holder 15 connected to the other end of the connecting rod 13 via a hydraulic cushion device 14, and an upset punch installed in the punch holder 15. 16° steel pipe 1
The clamp jaw 17 and the die 18 grip and hold the body portion IA of the machine, and the hydraulic cushion device 19 supports the clamp jaw 17 and the die 18.

That is, the steel pipe l whose pipe end IB is heated to about 1,250°C
is transversely fed to the upsetter 10, the tube end IB is stopped at a predetermined position relative to the clamp jaw 17 and the die 18, and the heated tube end IB of the steel tube I is inserted into the die 18, which is the non-heated part. When the body IIA is firmly gripped by the clamp jaws 17, a clutch interposed between a motor (not shown) and the flywheel 12 is connected, and the flywheel 12 starts rotating. The rotational torque of the flywheel 12 is transmitted to the punch holder 15 via the crankshaft 11, the connecting rod 13, and the hydraulic cushion device 114, and the punch holder 15 performs one cycle of reciprocating motion in about 6 seconds. Upsetting of the steel pipe 1 is performed near the top dead center of the reciprocating movement of the punch holder 15, and is completed within 0.8 seconds after the upset punch 16 contacts the pipe end IB of the steel pipe 1. Although the upset punch 16 enters into the pipe end IB of the steel pipe I inserted into the die 18, it does not reach into the body portion IA gripped by the clamp jaw 17.

The steel pipe 1 that has been upset with the die 18 in the -L section of the upsetting center 10 may complete the upset with that L shot, or may be subjected to a second upset with the die 18 at the bottom. . The former [l heat l shot]
The latter is called [1 hit 2 shots],
l If an extremely thick whitening process is required where the upset cannot be completed even with 2 heats and 2 shots, it is necessary to reheat the steel pipe 1 and perform a third 7-upset, which is called [2 heats and 3 shots]. be.

Here, the upsetter 10 is capable of absorbing the impact acting on the punch holder 15, upset punch 16, clamp jaw 17, and die 18 during the upseller by a hydraulic cushion device 14.19. Hydraulic cushion device for punch holder 15 and upset punch 16
il14 plays a particularly important role in upset operation-1. In other words, variations in the wall thickness and uneven thickness of the steel pipe l,
Due to errors in tool settings such as the upset punch 16 and the die 18, when the steel pipe 1 is upset, the die 18 may be underfilled, or conversely, the die 18 may be overfilled and burrs may come out from the die 18. In extreme cases, damage may occur to the upsetter 10. Therefore, when the hydraulic pressure of the hydraulic cushion device 14 reaches a certain pressure value, the relief valve 20 is opened to relieve the hydraulic fluid of the hydraulic cushion device 14, thereby making it possible to suppress the upset punch 16 from moving further. There is.

FIG. 3 shows the deformation process of the steel pipe 1 by the upsetter 10. The steel pipe 1 receives a compressive force from the upset punch 16 and initially buckles, bringing the outer surface of the steel pipe 1 into contact with the inner wall surface of the die 18 .

After this, the steel pipe l is cut with the upset punch 16 and the die 1.
8, thickening deformation occurs in a state where it is restrained between 8 and 8, thereby increasing the contact length between the upset punch 16 and the die 18. At this stage, if the metal flow in the thickness direction of the material of the steel pipe l is large, wrinkles will not be formed on the inner and outer surfaces of the upset part 2, but if the progress of buckling deformation is large,
As shown in the figure, wrinkles remain on the inner and outer surfaces of the upset portion 2.

Therefore, the inventor of the present invention has developed the process of deformation of a steel pipe as described in ``2'' by an upsetter IO.

This is detected based on the load value applied to the upset punch 16 and the amount of deformation of the upset punch 16, and the quality of the upset can be determined by patterning them.

FIG. 5 is a perspective view showing a load measuring means for measuring the load value applied to the upset punch 16. Reference numeral 21 denotes a load cell as a load measuring means that can directly measure the load value applied to the upset punch I6. The load cell 21 is mounted on the back surface of the punch holder 15 and measures the load value applied to the upset punch 16 during upsetting while being interposed between the punch holder 15 and the hydraulic cushion device 14. possible. The load cells 21 are of a desk type and have a mechanical strength of 4007 ON, and since there is an unbalanced load on the upset punch 16, one load cell is placed behind each axis of the lower upset punch 16, so the total Two pieces are supposed to be used. The punch holder 15 moves back and forth about 700 m during upset, and avoids the harsh environment caused by splashing of cooling water and hot lubricant during hot processing, and also secures wiring space for the signal output cable 22 of the load cell 21. Although there are difficulties in selecting the signal output cable 22, connecting method, strengthening the seal, and hydraulic cushion device 1.
By providing a groove for taking out the cable on the 4 side, the load cell 21 can be easily attached to the punch holder 1 without impairing the ease of maintenance and inspection.
5 can be installed.

It is also conceivable to use a load measuring means that can indirectly measure the load value applied to the upset punch 16 by measuring the back pressure of the hydraulic cushion device 14 with a strain gauge type high-speed response pressure gauge. In this case, since the back pressure of the hydraulic cushion device 14 passes through the cushion cylinder and the hydraulic piping,
Subtle load changes such as buckling of the steel pipe 1 cannot be observed, and the back pressure of the hydraulic cushion device 14 cannot be observed after the relief valve 20 is activated. Therefore, the inventors of the present invention decided to use the load cell 21, which is mounted on the punch holder 15 located closer to the upset punch 16 than the hydraulic cushion device 14 and which is heated at 15° C., as the load measuring means as described above.

FIG. 6 is a perspective view showing the linear scale 23 as a displacement measuring means for measuring the amount of displacement of the upset punch 16. In other words, non-contact measurement is preferable as a means of measuring displacement, but considering that the wiring space is narrow and the device is installed in an atmosphere containing water droplets and oil smoke due to hot working, the measurement accuracy must be ± A 0.1 layer magnetic linear scale 23 was selected. 24 is a scale body, 25 is a magnetic tape, 26 is a carrier, 27 is a carrier head, and 28 is a signal extraction cable. Note that 29 is a connecting arm fixed to the hydraulic cushion device 14, and 30 is a bottle fixed to the carrier 26. By engaging the connecting arm 29 and the bottle 30, the displacement of the upset punch 16 is transferred to the carrier 26. It can be transmitted to

However, during proper upset, load cell 2
The upset load value measured by 1 and the displacement amount of the upset punch 16 measured by the linear scale 23 can be specified for each dimension of the steel pipe 1. Therefore, as for the upset load value and the displacement amount, when the patterns at the time of proper upset and the patterns at the time of improper upset were compared, FIGS. 6 to 8 were obtained. Figure 6 shows the relationship between the relief valve pressure of the hydraulic cushion device and the upset load value and displacement amount, Figure 7 shows the relationship between steel pipe slippage and the upset load value and displacement amount, and Figure 8 shows the relationship between the relief valve pressure of the hydraulic cushion device and the upset load value and displacement amount. It shows the relationship between the dimensional fluctuation of the upset master tube, the amount of upset displacement, and the amount of cushion.

That is, in FIG. 6, in order to eliminate the influence of the outer shape and wall thickness of the original tube at the time of upset, an electric resistance welded tube is used as the original tube.
This is the result of investigating the relationship between the relief valve pressure setting of the hydraulic cushion device, the upset load value, and the amount of displacement.

That is, in this investigation, the relief valve pressure was set to 0.2k.
This was done by changing the load value and displacement pattern, as well as the peak load value and cushioning amount, by performing an upset by changing the pressure in every g/cm''. Figure 6 (A) shows the relief valve pressure 0.8kg/cm'', and Figure 6 (B) shows that the relief valve pressure is 0.8kg/cm.
This is the result of tn'. In this case, the upset specifications are:
Steel pipe APIN-80, outer diameter 2.378 inches (80,3
■■), wall thickness 4.83mm, heating temperature 1,250℃, clamp jaw grip pressure 180kg/cm
'is. FIG. 9 is a diagram showing the results of the above investigation.

According to this FIG. 9, it is recognized that the relief valve pressure setting value and the peak load value are in a completely proportional relationship. For example, if the steel pipe has an outer diameter of 2.378 inches (80.3
), if the wall thickness is 4.83 mm, the cushion amount is 30
Even if the amount of friction is normal at 10m5, the peak load value is 807ON and the load pattern is abnormal.
It becomes possible to determine that the upset result is abnormal.

FIG. 7 is a diagram showing the relationship between the slippage of the steel pipe, the seven-tube set load value, and the amount of displacement. If the grip of the steel pipe is not synchronized with the most forward end of the crankshaft during an upset, the grip force will decrease and the steel pipe will not be able to resist the upset force and will slip. When a steel pipe slips, the surface of the steel pipe is scratched by the clamp jaws, so the length of the scratch was defined as the slip length. Figure 7 (
A) is the result for a normal upset, Figure 7(B)
is the result for an abnormal upset. When the original tube slips, the cushion amount is 20 mm or less, the peak load value is 80 tons or less, the load pattern is abnormal, and all diagnostic items are abnormal. In addition, 7 in this case
The specifications of the tube set are steel pipe APIJ-55. Outer diameter 2-7
/8 inch (73,0■■), wall thickness 5.51cm, relief valve pressure 1.2kg/ctn', clamp jaw grip pressure 182kg/cm'', as shown in Figure 7 (A
The heating temperature of the steel pipe in ) is 1.220°C, the heating temperature of the steel pipe in Figure 7 CB) is 1.2H°C, and the slip length is 30 mm.

FIG. 8 is a diagram showing the relationship between the dimensional variation of the original tube, the amount of upset displacement, and the amount of cushion.

FIG. 8 shows that even if the cushion amount is diagnosed as abnormal, if the peak load value and load pattern are normal, the cushion amount varies depending on the dimensions of the original tube. That is,
It is shown that when the cushion amount is 40 sodium bicarbonate or more, creases occur in the thickened portion of the tube end, and when it is less than 20 sodium bicarbonate, wrinkles occur.

Since the average wall thickness of the original tube and the amount of cushioning have a linear relationship as shown in FIG. 10, diagnosis can be easily made. In addition, the upset specifications in this case are steel pipe APIJ-55
, outer diameter No. 2 7/8 inches (73,0+*m), wall thickness 5.81 m, relief valve pressure 1, 2 kg/crn
', clamp jaw grip pressure 182 kg/cr
It is n'. Also, the average wall thickness of the steel pipe in Fig. 8(A) is 5.
75■■, the heating temperature is 1,240°C. Also, the 8th
The average wall thickness of the steel pipe in Figure (B) is 5.50 mm, and the heating temperature is 1
．． The temperature is 280°C.

The diagnostic criteria for each diagnostic item of the cushion amount of the upset displacement, the peak load value, and the load pattern will be explained below.

The amount of cushioning is diagnosed as follows. The amount of movement of the upset punch when there is no load is 350S i n (i
*Δt) ......(1) Here, 350 m is the radius of rotation of the crank, i is the sampling number, and Δt is the sampling time. Xi is the linear scale value when the upset is actually performed.
Then, the elapsed time Yi of the cushion amount is Y[=35O5in (isΔt)−X i・−・(2
) is defined. The maximum value of Yi above is taken as the cushion amount. If the upset is performed normally, 20mm≦Yi≦40■■ ・・・・・・(
3). Therefore, the upset abnormality is IY
i-301>10mm ・・・・・・(4)
Diagnosis is possible by

Diagnose the peak load value using the following formula. That is, the upset load value is sampled every sampling time Δt. Since this sample value L+ is written into a high-speed digital memory, it is possible to easily determine the maximum value Limax of Li.

For example, if the steel pipe has an outer diameter of 2.3/8 inches and a wall thickness of 4.83 mm, Li max is 80 TON.
If it is below, it is a completely abnormal upset.

If Limax is 857ON or higher, it can be diagnosed that the upset is normal.

The load pattern is determined in the following manner.
The pattern in Figure (A) is defined by a broken line approximate curve, and this pattern is designated as Φ. Since the sampled load is Li, the difference between the reference load/<turn and the sampled load value is determined. The following diagnostic logic can be defined by taking the ratio of this difference and the reference load pattern for each sampling and setting the squared value as α. This α is from 0% to 10%
If so, it can be diagnosed that the load pattern is normal.

The diagnostic criteria for each of the above diagnostic items is that the outer diameter of the steel pipe is 203 mm.
/8 inches and a wall thickness of 4.83 mm, the results are as shown in Table 1.

FIG. 11 is a control circuit diagram of a monitoring device using a load cell 21 and a linear scale 23.

After the measured values of the two load cells 21 are added, they are amplified in an amplifier 31, and transmitted through a high-speed A/D converter 32 to a digital storage 33 using a large-capacity IC memory, where they are read. . Furthermore, the measured values of the linear scale 23 are also stored in the digital storage 33 and read therein.

The sample value read into the digital memory 33 is
It is transmitted to the microcomputer 34. 35 is a setting device, and in this setting device 35, diagnostic criteria for each diagnostic item similar to those shown in Table 1 are set for each size of the steel pipe. The set value of the setter 35 is also transmitted to the microcomputer 34.

Therefore, the microcomputer 34 determines the traction amount, peak load value, and load pattern of the upset displacement based on the upset load value and the displacement amount of the upset punch, and determines the traction amount, peak load value, and load pattern of the amplifier set displacement determined. The value and load pattern are compared with the reference traction amount, reference peak load value, and reference load pattern set in the setting device 35, and (A) abnormality in the relief valve setting pressure of the hydraulic cushion device for absorbing dimensional fluctuations of the original pipe is detected. , (B) Occurrence of slip in the steel pipe during upset, and (C) Diagnosis of dimensional abnormality of the original pipe. microcomputer 3
The determination result of No. 4 is displayed on the display 36. Furthermore, when the upset occurs abnormally, the alarm device 37 issues an acoustic or audio alarm.

[Effects of the Invention] As described below, according to the steel pipe upset monitoring method and device according to the present invention, the load value applied to the upset punch and the amount of displacement of the upset punch are measured during upsetting, and the It becomes possible to monitor whether the set has been executed normally.

[Brief explanation of drawings]

FIG. 1 is a perspective view schematically showing the entire upsetter to which the present invention is applied, FIG. 2 is a sectional view showing the shape of the upset part, and FIG. 3 is a diagram showing the process of deformation of a steel pipe due to upset. Fig. 4 is a perspective view showing an example of the load measuring means, Fig. 5 is a perspective view showing an example of the displacement measuring means, and Figs. 6 (A) and (B) show the relief valve pressure and upset. Diagram showing the relationship between load value and displacement amount, Figure 7 (A
) and (B) are diagrams showing the relationship between steel pipe slippage, upset load value, and displacement amount, and Figures 8 (A) and (B) are diagrams showing the relationship between the dimensional variation of the original pipe, upset position, and cushion amount. Figure 9 is a diagram showing the relationship between peak load value and relief valve pressure. Figure 10 is a diagram showing the relationship between cushion width and average wall thickness of the original tube. Figure 11 is a diagram showing the relationship between the cushion width and the average wall thickness of the original tube. FIG. 2 is a control circuit diagram showing an example of a monitoring device. DESCRIPTION OF SYMBOLS 1...Steel pipe, 2...Upset part, 10...Upsetter, 16...Upset punch, 18...
- Dice, 21...Load cell, 23...Linear scale, 33...Digital storage device, 34...Microcomputer, 35...Setting device, 36...Display device.

Claims (2)

[Claims] (1) In a method for monitoring a steel pipe upsetter that forms an upset portion by heating the end of a steel pipe, the upset load value applied to the upset punch and the amount of displacement of the upset punch are measured, and the upset displacement is measured. Determine the cushion amount, peak load value, and load pattern, and use the determined cushion amount, peak load value, and load pattern for the upset displacement as the standard cushion amount and standard for the upset displacement predetermined for proper upset. Compare the peak load value with the standard load pattern to determine whether (A) abnormality in the relief valve setting pressure of the hydraulic cushion device for absorbing dimensional fluctuations of the original pipe, (B) occurrence of slipping of the steel pipe during upset, (C) original pipe. A method for monitoring a steel pipe upsetter, the method comprising: diagnosing each dimensional abnormality of the steel pipe upsetter, and determining whether the upset is good or bad. (2) In a monitoring device for a steel pipe upsetter that forms an upset portion by heating the end of a steel pipe, there is a load measuring means that measures the upset load value applied to the upset punch and measures the amount of displacement of the upset punch. determine the amount of cushioning, peak load value, and load pattern for the upset displacement; Compare with the standard cushion amount, standard peak load value, and standard load pattern of the upset displacement, (A) abnormality in the relief valve setting pressure of the hydraulic cushion device for absorbing dimensional fluctuations of the original pipe, (B)
Occurrence of slip in steel pipe during upset, (C)
1. A monitoring device for a steel pipe upsetter, comprising: a determining means for diagnosing each dimensional abnormality of the original pipe and determining whether the upset is good or bad.