JP4348403B1 - Internal bead cutting device for ERW steel pipe - Google Patents

Abstract

An inner surface bead cutting device for an electric resistance steel pipe capable of cutting an inner surface bead of an electric resistance steel pipe without causing an inner surface stepping failure.
SOLUTION: Sputtering 3 flying from a welding point is applied to an outer periphery of an internal mandrel 6 inserted into a steel pipe near the welding point in order to cut an inner bead 5 generated in the manufacturing process of the electric resistance welded steel pipe. A sputter guide 14 for guiding downstream of the lower roller 8 of 6 was provided. It is preferable to provide a scraper 15 that guides the spatter dropped into the steel pipe to a position where the lower roller 8 does not step on. As a result, the inner surface where the lower roller 8 steps the spatter is prevented from being poorly stepped. The scraper may have a plate shape or a resin block.
[Selection] Figure 1

Description

  The present invention relates to an improvement in an inner surface bead cutting device for an electric resistance welded steel pipe used for cutting an inner surface bead generated in the manufacturing process of the electric resistance welded steel pipe.

  An electric resistance steel pipe is manufactured by a method in which a steel strip is gradually bent in the width direction by a large number of forming rolls to form a tubular shape, and between the end faces thereof is continuously pressure welded. For this reason, a weld bead is generated in the weld seam portion, but not only the appearance is bad as it is, but also various problems are generated in terms of the function of the steel pipe. Although the outer surface bead formed on the outer surface of the steel pipe can be easily removed by the cutting tool, the cutting of the inner surface bead formed on the inner surface of the steel pipe is not easy.

  Therefore, conventionally, a method has been developed in which an internal mandrel with a cutting tool protruding at the tip is inserted into the steel pipe near the weld point to cut the inner bead. Since this internal cutting mandrel needs to press the cutting tool against the inner surface of the steel pipe, it is provided with wheels or rollers as shown in Patent Document 1, for example, to receive a reaction force.

  The internal cutting mandrel is supported inside the steel pipe by a shaft extending from the unwelded side of the steel pipe, and cuts the inner surface bead immediately after welding. For this reason, the arrangement is usually in the order of welding points, cutting tools, and rollers from the unwelded side of the steel pipe toward the downstream direction (the pipe making direction).

  For this reason, it is unavoidable that spatter generated on the inner surface side of the steel pipe at the welding point scatters in the vicinity of the welding point and the steel pipe moves to the downstream side and the spatter of the internal mandrel is stepped on the spatter. Sputters that have been stepped on in this way cannot be separated from the inner surface of the steel pipe even if inner surface blowing or the like is performed, resulting in a defect called inner surface stepping failure. In particular, in cylinder pipes and oil well pipes that require smooth inner surfaces, this inner surface treading failure is regarded as important, so manual rework is required, increasing intermediate inventory, delaying delivery times, increasing costs for reworking, etc. It was causing many problems.

JP-A-6-134613

  Accordingly, an object of the present invention is to provide an inner surface bead cutting device for an electric resistance welded steel pipe capable of cutting the inner surface bead of the electric resistance welded pipe without causing an inner surface stepping failure.

  The present invention made to solve the above-mentioned problems is based on the welding point on the outer periphery of the internal mandrel inserted into the steel pipe near the welding point in order to cut the inner surface bead generated in the manufacturing process of the ERW steel pipe. A sputter guide that guides the sputters that come in to the downstream side of the lower roller of the internal mandrel is provided.

  In the inner surface bead cutting device for an electric resistance welded steel pipe according to the present invention, as shown in claim 2, it is preferable that the internal cutting mandrel has a cutting tool protruding on the upper surface. According to a third aspect of the present invention, it is preferable to provide a high-pressure water blower for blowing spatter generated at the welding point downstream from the welding point of the internal mandrel. Further, as shown in claim 4, it is preferable that the sputter guide is provided in a plurality of upper and lower stages, and as shown in claim 5, the sputter guide is preferably made of a flexible heat-resistant material. Furthermore, as shown in claim 6, it is preferable that the sputter guide has a width that the tip of the sputter guide contacts the inner wall surface of the steel pipe, and as shown in claim 7, it is upstream of the lower roller of the internal mandrel. It is preferable to provide a scraper on the side that guides the spatter dropped into the steel pipe to a position where the lower roller does not step on.

  Further, as shown in claim 8, the scraper may be made of a resin block and attached to the upstream side of the lower roller so as to be swingable in the vertical direction. In this case, as shown in claim 9, it is preferable that the scraper is pressed against the front surface of the lower roller by a spring and is pressed downward on the inner surface of the steel pipe following the rotation of the lower roller. As shown in Item 10, it is preferable that the scraper is provided with a groove for blowing out spatter that has entered the lower surface of the scraper by air pressure.

  According to the first aspect of the present invention, the sputter guide is provided on the outer periphery of the internal cutting mandrel, and the sputter flying from the welding point is guided downstream of the lower roller of the internal cutting mandrel. For this reason, the spatter is not stepped on the inner surface of the steel pipe by the lower roller of the internal mandrel.

  According to the invention of claim 2, since the internal cutting mandrel has a cutting tool protruding on the upper surface thereof, the cutting waste is also guided downstream of the lower roller by the sputter guide, and the inner surface can be further smoothed. There is.

  According to the invention of claim 3, since the high-pressure water blowing device for blowing the spatter generated at the welding point upstream from the welding point of the internal mandrel is provided downstream, the spatter can be blown away in the direction of the sputter guide. .

  According to the fourth aspect of the present invention, since the sputter guides are provided in the upper and lower stages, the spatter flying from the welding point can be more reliably captured and guided downstream from the lower roller.

  According to the invention of claim 5, since the patch guide is made of a flexible heat-resistant material, it can be used as it is because the tip is curved even when the inner diameter of the steel pipe to be manufactured is changed. It is possible to manufacture ERW steel pipes having various inner diameters using a cutting mandrel.

  According to the invention of claim 6, since the tip of the sputter guide can be brought into contact with the inner wall surface of the steel pipe, the spatter does not enter the upstream side of the lower roller from the outside of the sputter guide, and the inner surface is more reliably stepped on. Defects can be prevented.

  According to the seventh aspect of the present invention, even when the spatter falls to the upstream side of the lower roller of the internal mandrel, the scraper can guide the lower roller to a position where it cannot be stepped, so that the inner surface is more reliably stepped. Can be prevented.

  According to invention of Claim 8, since the scraper was made from the resin block, it can endure long-term use. Further, since it is attached so as to be swingable in the vertical direction, when it hits the intermediate bead, it can be retracted upward and is not damaged.

  According to the invention of claim 9, since the downward pressure is applied to the scraper following the rotation of the lower roller, the scraper can always be pressed against the inner surface of the pipe, and it is possible to cope with the wear of the scraper. .

  According to the invention of claim 10, since the spatter that has entered the lower surface of the scraper can be blown out by air pressure, the spatter that has entered the lower surface of the scraper is not stepped on with a roller.

It is sectional drawing of the longitudinal direction of the steel pipe which shows the 1st Embodiment of this invention. It is sectional drawing of a perpendicular direction with respect to FIG. It is a bottom view which shows the shape of the scraper of 1st Embodiment. It is sectional drawing of the longitudinal direction of the steel pipe which shows 2nd Embodiment. It is a front view which shows the scraper of 2nd Embodiment. FIG. 6 is a bottom view of FIG. 5. It is operation | movement explanatory drawing of a scraper. It is operation | movement explanatory drawing of a scraper.

Preferred embodiments of the present invention are shown below.
FIG. 1 is a longitudinal sectional view of a steel pipe showing an embodiment of the present invention, and FIG. 2 is a sectional view perpendicular to FIG. 1 is a steel pipe, and as is well known, a steel strip is gradually bent in the width direction by a large number of forming rolls to form a tubular shape, and its end faces are continuously pressure welded while being pressed by a squeeze roll 2. A sewn steel pipe is manufactured. In FIG. 1, the lower end part of the squeeze roll 2 is a welding point. Since the steel pipe 1 continuously travels to the right side of FIG. 1, in this specification, the left side is referred to as the upstream side and the right side is referred to as the downstream side.

  As described above, spatter 3 is generated at the welding point, and the outer bead 4 and the inner bead 5 are formed along the weld line. Although the outer bead 4 can be easily cut from the outside of the steel pipe 1, the inner bead 5 is formed inside the steel pipe 1, and therefore, the internal mandrel 6 as shown in FIG. The inner surface bead 5 is cut and removed by a cutting tool 7 inserted and held at a fixed position.

  At this time, since the internal mandrel 6 receives a downward reaction force from the inner surface of the steel pipe, a pair of lower rollers 8 are provided on the lower side. Since the lower roller 8 is pressed against the inner lower surface of the steel pipe 1 by this reaction force, if the spatter 3 falls on the upstream side of the lower roller 8, an inner surface treading defect occurs. The internal cutting mandrel 6 is also provided with upper rollers 9 and 9 at the upper front and rear positions, so that vertical positioning is possible.

  In this embodiment, the internal mandrel 6 has a cylindrical shape and is held at a fixed position by an arm 10 extending to an unwelded portion of the steel pipe 1. A high-pressure water blowing means 11 is provided upstream of the welding point of the internal machining mandrel 6, and high-pressure water is blown from the nozzles 12 and 13 toward the welding point, and the sputter 3 generated at the welding point is downstream. Blowing to the side.

  A sputter guide 14 is provided on the outer periphery of the internal cutting mandrel 6 to guide the sputter 3 flying from the welding point to the downstream side of the lower roller 8 of the internal cutting mandrel 6. As shown in the figure, the sputter guide 14 is preferably provided in a plurality of upper and lower stages.

  The sputter guide 14 is a bowl-shaped member made of a flexible heat-resistant material such as Teflon (registered trademark), and has a width at which the tip contacts the inner wall surface of the steel pipe 1 as shown in FIG. It is preferable that The reason why heat resistance is required is to avoid damage due to high-temperature spatter 3. The reason why flexibility is required is that even if the inner diameter of the manufactured steel pipe 1 changes, it can be used without being replaced. Because.

  The upstream tip of the sputter guide 14 is located near the upstream end surface of the internal mandrel 6 to reliably receive the sputter 3 generated at the welding point and blown off with high-pressure water. The entire sputter guide 14 is inclined so that the downstream side is lower, and the tip on the downstream side reaches the downstream side of the lower roller 8.

  For this reason, it is possible to avoid that the sputter 3 falls to the upstream side of the lower roller 8 and is stepped on by the lower roller 8. In order to ensure this effect, it is preferable that the tip of the sputter guide 14 is in contact with the inner wall surface of the steel pipe 1 so that no gap is generated.

  In addition, a plate-shaped scraper 15 made of an elastic body is attached to the upstream side of the lower roller 8, and even if the spatter 3 falls to the upstream side of the lower roller 8, the spatter 3 is moved by the scraper 15, It is preferable to escape to the downstream side through the middle part of the two lower rollers 8. For this purpose, the scraper 15 is formed in a pair of L-shapes as shown in FIG. 3, and the sputter 3 is guided to the center of the two lower rollers 8 so that the stepping by the lower rollers 8 can be avoided. It is preferable to keep it.

  In the first embodiment described above, the plate-shaped scraper 15 is used, but in the second embodiment shown in FIG. 4 and subsequent figures, a scraper 20 made of a resin block is used. The scraper 20 is made of a hard resin such as 6 nylon, and has a bottom shape as shown in FIG. The scraper 20 is provided with bolt through holes on the left and right, and is attached to the upstream side of the bearing 23 of the lower roller 8 by two bolts 22 on the left and right through the bolt through holes. In this embodiment, the lower roller 8 is single. A spring 21 is provided between the head of the bolt 22 and the scraper 20, and the scraper 20 is always ejected in the direction of the lower roller 8. Further, a gap is provided between the bolt through hole and the shaft portion of the bolt 22. For this reason, the scraper 20 can swing in the vertical direction while being springed by the spring 21.

  Further, as shown in FIG. 7, a concave surface 28 on an arc that contacts the lower roller 8 is formed on the back side of the scraper 20. The concave surface 21 comes into contact with the front surface of the lower roller 8 by the pressing force Fs by the spring 21. For this reason, the scraper 20 is pressed downward by the frictional force following the rotation of the lower roller 8 and is always in contact with the inner surface of the steel pipe 1. Therefore, even when the lower surface of the scraper 20 is worn, the scraper 20 can always be brought into stable contact with the inner surface of the steel pipe 1.

  The intermediate bead 24 is present on the inner surface of the steel pipe 1, but when the lower roller 8 rides on the intermediate bead 24, the scraper 20 can be swung upward and retracted as shown in FIG. . Further, the upper surface of the scraper 20 is springed downward by a leaf spring 25 (FIG. 5) extending from the bearing 23 to the upstream side so as to return to the original position again after retraction.

  As shown in FIGS. 5 and 6, the scraper 20 has an air inlet 26 and two ring-shaped grooves 27, 27 that communicate with the air inlet 26 and blow out the sputter 3 that has entered the lower surface of the scraper 20. It is provided. As a result, the spatter 3 that has entered the lower surface of the scraper 20 is reliably blown out to the left and right through the groove 27, so that it does not step on the lower roller 8 and cause an inner surface pressing failure.

  Since the inner surface bead cutting device of the present invention is configured as described above, the inner surface bead 5 can be cut by the cutting tool 7 of the internal cutting mandrel 6 and, of course, the sputter 3 generated from the welding point is spouted by the sputter guide 14. In this way, it is possible to prevent the inner surface stepping failure by guiding it further downstream. Even when the sputter 3 falls to the upstream side of the lower roller 8, the lower roller 8 can be moved to a position where the lower roller 8 cannot be stepped on by the scraper 15 or the scraper 20. The effect of the present invention is great, and according to the results of the applicant company, the occurrence rate of internal treading defects is almost zero before and after the implementation of the present invention, which greatly contributes to improvement of productivity, improvement of steel pipe quality, and cost reduction. I was able to.

DESCRIPTION OF SYMBOLS 1 Steel pipe 2 Squeeze roll 3 Spatter 4 Outer surface bead 5 Inner surface bead 6 Internal cutting mandrel 7 Bit 8 Lower roller 9 Upper roller 10 Arm 11 High pressure water blow means 12 Nozzle 13 Nozzle 14 Sputter guide 15 Scraper 20 Scraper 21 Spring 22 Bolt 23 Bearing 24 Relay bead 25 Leaf spring 26 Air inlet 27 Groove

Claims (10)

  Spatter flying from the welding point on the outer periphery of the internal cutting mandrel inserted inside the steel pipe near the welding point to cut the inner bead generated in the ERW steel pipe manufacturing process, downstream of the lower roller of the internal cutting mandrel An inner surface bead cutting device for an electric resistance welded steel pipe, characterized in that a sputter guide for guiding is protruded.   2. The inner surface bead cutting device for an electric resistance welded steel pipe according to claim 1, wherein the internal cutting mandrel has a cutting tool protruding on the upper surface.   2. The inner surface bead cutting device for an electric-resistance-welded steel pipe according to claim 1, further comprising a high-pressure water blow device for blowing spatter generated at the welding point downstream from the welding point of the internal mandrel.   2. The inner surface bead cutting device for an electric resistance welded steel pipe according to claim 1, wherein the sputter guide is provided in a plurality of upper and lower stages.   The inner surface bead cutting device for an electric resistance welded steel pipe according to claim 1, wherein the sputter guide is made of a flexible heat-resistant material.   2. The inner surface bead cutting device for an electric-resistance-welded steel pipe according to claim 1, wherein the sputter guide has a width at which a tip thereof is in contact with an inner wall surface of the steel pipe.   2. A bead cutting device for an inner surface of an ERW steel pipe according to claim 1, wherein a scraper is provided upstream of the lower roller of the internal cutting mandrel to guide the spatter dropped into the steel tube to a position where the lower roller does not step on the inner roller. .   8. The inner surface bead cutting device for an electric-resistance-welded steel pipe according to claim 7, wherein the scraper is made of a resin block and is attached to the upstream side of the lower roller so as to be swingable in the vertical direction.   9. The inner surface bead cutting of an electric-resistance-welded steel pipe according to claim 8, wherein the scraper is pressed against the front surface of the lower roller by a spring and is pressed downward on the inner surface of the steel pipe following the rotation of the lower roller. apparatus.   9. The inner surface bead cutting device for an electric-resistance-welded steel pipe according to claim 8, wherein the scraper is provided with a groove for blowing out spatter that has entered the lower surface of the scraper by air pressure.

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