JPS6144607B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to mechanization of weld bead cutting work on the inner surface of a steel pipe in the Uφ steel pipe manufacturing process.

(Prior art) In general, in the Uφ steel pipe manufacturing process, the inner weld bead at both ends of the pipe is cut and removed as shown in Figure 1 in order to ensure the sealability of the hydraulic tester after seam welding and to process the pipe end bevel. In this case, it is necessary to meet the conditions that the uncut bead height is 0.5 mm or less and that cutting of the base material is not allowed in order to ensure the wall thickness of the steel pipe.

A conventional internal weld bead cutting device for steel pipes, as shown in Fig. 2, is equipped with a grinding wheel 2 at the tip of a boom 1, a grinding wheel setting angle adjustment mechanism 3, and a height adjustment mechanism 3 in the vertical direction, as described in Japanese Utility Model Application Publication No. 55-66754. There is an apparatus for cutting an inner weld bead of a welded rectangular tube, which is characterized by having a mechanism 4 and a grinding head 7 equipped with a guide roller 6 that contacts the inner surface of a workpiece 5.

However, the conventional device shown in Fig. 2 is intended for removing the inner weld bead of a rectangular cylindrical pipe, and is applied to cutting the inner weld bead of a steel pipe with a circular cross section (hereinafter simply referred to as a steel pipe). In this case, there are the following problems.

(Problems with the prior art) In order to apply the conventional device to cutting the inner weld bead of a steel pipe, it is first necessary to deal with changes in the steel pipe diameter, but the conventional device is equipped with a grindstone setting angle setting mechanism 3. Therefore, it is possible to respond to changes in the inner diameter of the steel pipe by changing this angle as described later.

However, in the actual welded part of the Uφ steel pipe, the base metal on the left and right sides of the seam part of the steel pipe 8 is at an angle of α, as shown in Figure 3a.
As shown in figure b, there is an offset in which the base material on the left and right sides of the seam has a step of height a, and as shown in figure c, the bead at the end of the pipe extends in the longitudinal horizontal direction of the steel pipe. There are shape deviations from a straight, perfectly round steel pipe, such as a bend in the pipe axis direction of the bead part that is inclined at an angle β relative to the pipe, and in reality, a combination of these exists.

Although conventional equipment can be applied to perfectly round steel pipes, it does not have a shape deviation detection mechanism such as the above-mentioned peaking, offset, and bending in the pipe axial direction, nor a mechanism to set cutting conditions based on the detected values. When the device was applied to steel pipes with shape deviations, there was a risk that the uncut bead height would exceed the allowable value or the base material would be cut. For this reason, the inner bead cutting work of steel pipes has traditionally been carried out manually using a hand grinder. However, hand grinder work involves many factors that worsen the working environment, such as noise, dust, and vibration, so there was an urgent need to improve these issues.

(Objective of the Invention) The present invention aims to improve the range of allowable uncut bead height even when there are shape deviations such as peaking, offset, and bending in the axial direction of the pipe in the welded part of the steel pipe that cause these problems. The present invention provides an apparatus for cutting an inner weld bead at a seam portion of a Uφ steel pipe, which is characterized in that the work environment is improved and the number of personnel is rationalized by automatically cutting the inner weld bead within the seam section of a Uφ steel pipe.

(Summary and Structure of the Invention) The present invention provides a boom movable in the longitudinal direction, lateral direction, and vertical direction of the tube axis of a steel pipe, and a milling cutter and a copying roll are provided at the tip thereof, and the inclination angle of the milling cutter rotating shaft with respect to the boom and the copying roll are adjusted. This is a device for measuring shape deviations from straightness and perfect round steel pipes, such as peaking, offset, and bending in the pipe axis direction of steel pipe welds, in cutting equipment equipped with a mechanism that can arbitrarily set the amount of vertical displacement with respect to the boom. established,
Setting a milling cutter inclination angle, a milling cutter lateral movement amount, and a copying roll vertical movement amount according to the measured shape deviation amount, and moving the boom in the pipe axis direction while making the copying roll follow the surface of the steel pipe. This is a steel pipe inner surface weld bead cutting device that mills a steel pipe inner surface weld bead so that it falls within a predetermined bead height range.

The configuration of the apparatus of the present invention will be described below based on examples.

FIG. 4 is a front view showing an embodiment of the present invention, and FIG. 5 is a side view.

The apparatus of the present invention is comprised of a bead cutting device main body that cuts the inner weld bead of a steel pipe with an inclined milling cutter, a shape measuring device that measures the shape of the steel pipe near the weld, and a steel pipe fixing device that fixes the steel pipe during cutting.

Bead cutting device The bead cutting device consists of a boom equipped with an inclined milling cutter and a copying roll, and a 3-axis positioning device for the boom, and a steel pipe 8 placed horizontally.
installed at the end of the pipe.

A cutter head 11 includes a milling cutter 12 and a hydraulic motor 13 for driving the milling cutter, and is rotatably attached to the boom 10 via a shaft 14. The inclination angle of the cutter head with respect to the boom is set by an electric motor 17. Reference numeral 19 denotes a copying roll, which is attached to the boom 10 so as to be movable in the vertical direction, and the amount of movement thereof is set by an electric motor 21. The boom 10 includes a hydraulic cylinder 24,
It is slidably attached to the side surface of the moving block 23 via a hydraulic lowering device consisting of a fork end 25 and fulcrum shafts 26 and 27. The moving block 23 includes a screw guide 30, a screw shaft 31, and a screw shaft drive motor 3.
2. It is slidably attached to the upper surface of the moving block 29 via a lateral positioning mechanism consisting of a bearing 33. Furthermore, the moving block 29 is slidably attached to the upper surface of the fixed bed 34 via a tube axis longitudinal positioning mechanism consisting of a screw guide 35, a screw shaft 36, a screw shaft drive motor 37, and a bearing 38. .

Shape Measuring Device The shape measuring device consists of a vertical displacement meter 43 installed below the steel pipe and an elevating device for it. Displacement meter 4
3 is two rows of steel pipes in the longitudinal direction on the lifting frame 42;
There are four installed horizontally in each row. The elevating frame 42 is attached to the base frame 39 via an elevating hydraulic cylinder 40 and a guide post 41. The displacement meter 43 measures the distance from the reference position to the outer surface of the steel pipe by the displacement of the measuring element 44, and calculates the peaking angle offset amount and the bending angle in the pipe axis direction from the measurement results.

Note that a mechanism may be adopted in which the interval between the four displacement meters arranged in the horizontal direction can be changed according to the weld bead width. Further, a larger number of displacement meters may be installed.

Steel Pipe Fixing Device The steel pipe fixing device is installed at the end of the pipe, and has a mechanism in which pawls 48 and 49 clamp and fix the steel pipe under the action of a hydraulic cylinder 46.

(Operation of the Invention) The apparatus of the present invention operates with the steel pipe being conveyed in advance to a predetermined reference position and aligned so that the weld bead portion is at the lowest position on the circumference of the cross section of the steel pipe. The operation of this device in this state consists of fixing the steel pipe, measuring the shape near the weld bead, setting cutting conditions based on the results, and actually cutting the inner weld bead. These series of operations will be explained below.

Steel pipe fixation As shown in FIG.
It is fixed by being clamped by the lowering of the pawl 49 and the raising of the pawl 49, and has the effect of keeping the position of the steel pipe constant during cutting, as well as absorbing and attenuating the vibration of the steel pipe, thereby reducing cutting noise.

Shape measurement When the steel pipe is fixed at a predetermined position as described above, the displacement gauge 43 is raised to a predetermined position by the action of the hydraulic cylinder 40, and the tip of the probe 44 contacts the outer surface of the steel pipe and is pushed down to the level of the contact position. Displaced according to. Figures 6a and 6b are enlarged schematic diagrams of the bead portion in this state, and Figures 6c and d are principle diagrams showing the positional relationship of Figures 6a and 6b, respectively.

In Fig. 6c and d, the longitudinal horizontal direction of the steel pipe axis is Y.
If we take an X-Y-Z coordinate system with the horizontal direction as the X-axis and the vertical direction including the weld bead as the Z-axis, the displacement meter 4
3-1, 43-2, 43-3 and 43-4 are the same
Located in the XZ plane, and displacement gauges 43-2 and 43
-5 are located in the same YZ plane, and the contact points between the tip of the probe of these displacement meters and the outer surface of the steel pipe are respectively
Display as P ₁ , P ₂ , P ₃ , P ₄ , P ₅ . The four displacement gauges in the first row of the tube end are arranged at sufficiently narrow intervals compared to the diameter of the steel tube, and the weld bead has peaking, so in this area, the outer surface of the steel tube in the lateral direction is almost directly Can be approximated. Therefore, as shown in Fig. 6c, the peaking angle α can be evaluated by the angle formed by the straight lines P ₁ and P 2 on the X-Z plane and the direct lines P _{3 and} P ₄ , and the offset amount a can be estimated from the angle formed by the straight lines P 1 and P ₂ on the X-Z plane. , P ₂ and the straight lines P ₃ and P ₄ . Also, direct P ₁ , P ₂ and straight lines P ₃ , P ₄
The distance _x0 between the intersection with the Z-axis and the Z-axis is the amount of lateral movement of the milling cutter when dealing with offset, which will be described later.

Next, in Fig. 6b, displacement meters 43-2, 43
Since the interval of -5 is sufficiently small compared to the total length of the steel pipe, the outer surface of the welded part of the steel pipe can be almost directly approximated, and the bending angle β in the pipe axial direction at the pipe end is Y- as shown in Figure d.
It can be evaluated by the slope of straight lines P ₂ and P ₅ in the Z′ plane.

In the above process, by measuring the distance of the outer surface of the steel pipe from the reference position below the steel pipe weld, we can determine the shape deviation of the steel pipe, namely the peaking angle α shown in Figure 3a, the offset amount a shown in Figure 3b, and the peak angle α shown in Figure 3b. The bending angle β in the tube axis direction shown in FIG. 3c can be detected.

Cutting Condition Setting Next, the operation of setting cutting conditions using various quantities obtained by shape measurement will be explained.

Figure 7 shows the input conditions for determining cutting conditions: steel pipe inner diameter Di, peaking angle α, offset amount a,
FIG. 2 is a system diagram showing the relationship between bead bending angle β, milling cutter inclination angle Q ₀ , milling cutter lateral movement amount x ₀ , and copying roll position Z ₀ which are control variables for setting cutting conditions.

Setting of the milling cutter inclination angle Q ₀ FIG. 8 is an explanatory diagram showing the relationship between the milling cutter inclination angle and the steel pipe diameter. The tilt type milling cutter takes advantage of the fact that by tilting the axis of milling rotation with respect to the steel pipe, a cutting diameter that is approximately the same as the inner diameter of the steel pipe can be obtained within the narrow range of the bead width. This is handled by a set of milling cutters, and as shown in FIG. 8, the larger the tube diameter, the smaller the milling cutter inclination angle. Therefore, when the steel pipe is a perfect circle, the uncut bead height h will be approximately 0 if the milling cutter inclination angle is selected to obtain a cutting diameter approximately equal to the inner diameter of the steel pipe, as shown in FIG. 9a. However, when the inner diameter of the steel pipe is the same and there is peaking near the weld, if cutting is performed with the same milling cutter inclination angle as when there is no peaking, the uncut bead height h will increase as shown in Figure 9b. Not within the allowable range. Therefore, as shown in Fig. 9c, the milling cutter inclination angle Q ₀ is adjusted according to the peaking angle α with a predetermined correction.
By setting , and performing cutting by moving the milling cutter vertically by a predetermined amount, it is possible to keep the uncut bead height h within an allowable range even under conditions where peaking exists.

Setting the amount of lateral movement of the milling cutter Next, when there is an offset in the welded part, as shown in Figure 10a, under the condition that the amount of lateral movement of the milling cutter x = 0, the uncut bead height h falls within the allowable range. However, as shown in Figure b, by moving the milling cutter laterally to the lower side of the inner surface of the steel pipe by a predetermined amount x ₀ according to the offset amount, and also moving it a predetermined amount in the vertical direction, the uncut bead height h can be reduced. It is possible to keep it within the permissible range. Note that when dealing with the above offset, the base material below the bead on the side with the higher offset step will be cut to some extent, but the outer surface of this part is covered with an outer bead and the required wall thickness is guaranteed, so this part is cut. cutting is acceptable.

Setting the copying roll position Z ₀ Furthermore, if there is a level fluctuation in the vertical direction due to bending in the pipe axis direction at the end of the steel pipe, if the milling cutter is moved only in the longitudinal horizontal direction of the steel pipe axis and cutting is performed, the uncut bead height is not within the allowable range, but as shown in Figure 11, after setting the milling cutter inclination angle, the required vertical distance between the milling cutter tip and the copying roll tip is determined according to the steel pipe bending angle β.
Determine Z ₁ , take into account the amount of vertical movement of the milling cutter to correspond to the peaking and offset mentioned above, and set the copying roll position Z ₀ using a predetermined calculation to keep the positional relationship between the milling cutter and the copying roll constant. By maintaining this, it becomes possible to perform cutting so that the uncut bead height falls within the allowable range.

Function of the cutting device Next, the function of the cutting device will be explained. The operation of the cutting device is determined by setting the cutting conditions determined in the above process,
This operation consists of cutting down the bead boundary part of the length ' shown in FIG. 1 and cutting the inner weld bead of a predetermined length. FIG. 12 is an explanatory diagram showing a series of these operations.

While the cutting device is waiting at a predetermined position, the steel pipe whose inner and outer surfaces have been welded is transported, and when placed at a predetermined position, it is fixed by steel pipe fixing devices 46 to 49.

In this state, as shown in Fig. 12a, the shape near the weld bead is measured, and at the same time, the boom 10 is advanced into the pipe by the action of the pipe axial positioning mechanisms 35 to 38, and is moved to a predetermined length of the bead to be cut. Stop in position. In this position, as shown in FIG. 12b, the cutter head 11 is tilted by a predetermined angle Q ₀ by the action of the inclination angle setting mechanisms 15 to 17, and laterally by a predetermined amount x ₀ by the action of the lateral positioning mechanisms 30 to 33. Moving. On the other hand, the copying roll 19 is set to a position Z = Z 0 + △Z _{0 having a value obtained by adding a value △Z 0 corresponding} to the bead height to a predetermined set value Z 0 by the action of the copying roll position setting mechanisms ₂₀ and ₂₁ . .

Next, as shown in FIG.
The milling cutter 9 descends to a position where it contacts the inner surface of the steel pipe, and at this position the milling cutter 12 starts rotating.

Bead cutting by this device is performed using a hydraulic cylinder 24 with respect to a milling cutter 12, as shown in FIG. 12e.
A predetermined amount of reduction is applied by the copying roll 19.
This is done by retreating the milling cutter 12 toward the bead while keeping the depth of cut constant by keeping the positional relationship between the milling cutter and the inner surface of the steel pipe constant, but it is necessary to cut down the bead cutting boundary part diagonally. Yes, as shown in Fig. 12d, the copying roll position is changed from the initial setting position Z = Z ₀ + △Z ₀ to the predetermined setting position Z = Z ₀ in synchronization with the retreat of the milling cutter to change the depth of cut. The bead cutting start portion is cut down into a predetermined shape. When the cutting of the boundary part is completed, the copying roll 19 is held at the set position Z=Z ₀ as described above, and the milling cutter 12 moves back to cut a predetermined length of the inner weld bead, resulting in the state shown in FIG. 1. is obtained.

(Effects of the Invention) As explained above, the device of the present invention, which has put the present invention into practice, can cut the inner weld bead within the allowable uncut bead height range even for copper pipes with peaking, offset, and bending in the tube axis direction. This is an internal weld bead cutting device characterized by the following features, and the present invention can provide the remarkable effects described below.

(b) By adopting milling, the noise level is reduced by approximately 20% compared to conventional hand grinder grinding, and the working environment is greatly improved as the airborne dust generated by grinder grinding is greatly reduced.

(b) Since conventional manual work has been mechanized, the workload on workers is reduced, and the number of workers assigned per shift is reduced from 2 to 1 operator of this cutting equipment, resulting in rationalization of personnel.

As described above, the apparatus of the present invention exhibits excellent effects in terms of product quality and workability.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the state after cutting the internal weld bead, Fig. 2 is an explanatory diagram of the structure of a conventional internal weld bead cutting device, and Fig. 3 a, b, and c are explanatory diagrams of the shape deviation of the welded part of the steel pipe. , FIG. 4 is a front view of the inner weld bead cutting device of the present invention, FIG. 5 is a side view of the inner weld bead cutting device of the present invention, and FIG. 6 is a, b,
c and d are explanatory diagrams of the operation of the shape measuring device near the weld bead, Fig. 7 is a system diagram of the cutting condition setting operation, and Fig. 8 is a, b, c, and d are the principles of the inclined milling cutter. Explanatory diagrams, Figures 9a, b, and c are explanatory diagrams of cutting condition setting operations when cutting an inner weld bead of a steel pipe with peaking, and Figures 10a, b
11 is an explanatory diagram of the cutting condition setting operation when cutting an inner weld bead of a steel pipe having an offset.
The figure is an explanatory diagram of the cutting condition setting operation when cutting the inner weld bead of a steel pipe having a bend in the pipe axis direction. FIG. 3 is an explanatory diagram of the operation of the device. 1... Boom, 2... Grinding wheel, 3... Grinding wheel setting angle adjustment mechanism, 4... Vertical height adjustment mechanism, 5...
Workpiece (square tube), 6... Guide roller, 7... Grinding head, 8... Steel pipe, 9... Inner weld bead, 9'
...Outer surface welding bead, 10...Boom, 11...Cut head, 12...Milling cutter, 13...Milling cutter drive hydraulic motor, 14...Cut head rotation axis, 15...Worm wheel, 16...Worm gear, 17...Electric motor, 18...Copying roll guide ,1
9... Copying roll, 20... Screw shaft, 2
DESCRIPTION OF SYMBOLS 1... Electric motor, 22... Balance weight, 23... Moving block, 24... Hydraulic cylinder, 25... Fork end, 26... Fulcrum shaft, 27... Fulcrum shaft, 28...
Balance weight, 29...Moving block, 30...
Screw Guide, 31... Screw Shaft,
32...Electric motor, 33...Bearing, 34...Fixed bed,
35... Screw guide, 36... Screw shaft, 37... Electric motor, 38... Bearing, 39... Base frame, 40... Hydraulic cylinder, 41... Guide post, 42... Lifting frame, 43... Displacement meter, 44
... Measuring element, 45... Base frame, 46... Hydraulic cylinder, 47... Steel pipe fixing device frame, 48... Inner pawl, 49... Outer pawl.

Claims (1)

[Claims] 1. At the tip of the boom, which can position the steel pipe in three directions: the axial direction, the lateral direction, and the vertical direction, there is a milling cutter, a mechanism for setting the inclination angle of the milling cutter to the boom, and a mechanism for setting the vertical displacement amount of the copying roll and the copying roll relative to the boom. At the same time, peaking in the weld bead of the steel pipe, offset, bending in the pipe axis direction, deviation from a straight and perfectly round steel pipe are detected, and the amount of lateral movement of the milling cutter in the pipe axis direction is calculated for the detected offset amount. The milling cutter inclination angle is calculated for the amount of peaking, and the copying roll vertical movement amount is calculated for the bending in the tube axis direction. Based on the calculation results, the milling cutter position, milling cutter inclination angle, and copying roll position are corrected at the same time. A steel pipe inner weld bead cutting device characterized by being equipped with a shape deviation measuring device.