JPH0899184A - Mandel tool - Google Patents

Abstract

PURPOSE: To provide a mandrel for preventing the pressed flaw of spattering and the clogging of spatter. CONSTITUTION: This mandrel tool 11 is used at the time of manufacturing a pipe B from a band steel A with an induction welding. A tool holder 17 fitting a cutting tool 16 for inner surface bead is arranged in the series at the tip part of the mandrel 24 in the interval of >=150mm from the tip part of a core case 15 including an impedance core 14 for improving the heating efficiency of a work coil 12. A cooling water flow passage 21 for supplying the cooling water into a spouting hole 22 opened at the tip part of the core case 15 is extended to the tool holder 17 to form the cooling water from the spouting hole 23 opened near the cutting tool 16 for inner surface bead in the tool holder 17 as spoutable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mandrel tool equipped with an impeder core for enhancing heating efficiency by a work coil and a cutting tool for cutting an inner surface bead when manufacturing an electric resistance welded tube by high frequency welding, for example.

[0002]

2. Description of the Related Art An electric resistance welded pipe is manufactured by, for example, high frequency induction welding of both edges of a steel strip which is continuously formed into a circular shape by a forming roll group. At the time of manufacturing this electric resistance welded pipe, a mandrel supporting an impeder core that enhances the heating efficiency of welding is inserted into the inner surface of the electric resistance welded pipe.

By the way, the performance of the impeder core deteriorates when it is affected by heat. Therefore, in order to prevent the performance of the impeder core from deteriorating, a cooling water passage is provided in the mandrel 2 as shown in FIG. A structure for cooling the impeder core 3 provided at the tip thereof is adopted. Furthermore, when the jet port 5 of the cooling water flow path is provided at the tip of the core case 4 located near the welding point V and the spatter C sprayed from the jet port 5 and scattered on the inner surface of the pipe B is removed from the bite holder 6. At the same time, the bead cutting bite 7 attached to the bite holder 6 is being cooled.

[0004]

In the mandrel tool 1 having the above-mentioned structure, in order to remove the spatter C, cooling water must be sprayed near the welding point V. Further, in order to cool the bead cutting tool 7, there is a restriction that the cooling water must be sprayed from a position close to the bead cutting tool 7. Therefore, the bite holder 6 must be arranged in the vicinity of the welding point V where the spatter C is generated, and the spatter C easily falls to the bite holder 6.

Since the bead cutting tool 7 and the receiving rollers 8 and 9 are provided in the bite holder 6, the gap between the bite holder 6 and the inner surface of the pipe B is small, and the spatter C is received without flowing out of the pipe B. It is pressed by the rollers 8 and 9, and a spatter pressing flaw is generated on the inner surface of the pipe B or spatter is clogged.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a mandrel tool for preventing spatter pressing flaws and spatter clogging.

[0007]

In order to achieve the above-mentioned object, the mandrel tool of the first aspect of the present invention is a mandrel tool used when manufacturing an electric resistance welded pipe from a steel strip by induction welding. A tool holder with an internal bead cutting tool installed at a distance of 150 mm or more from the tip of the core case containing the impeder core that enhances the heating efficiency of the coil was arranged in series at the tip of the mandrel and opened at the tip of the core case. The cooling water flow path for supplying cooling water to the injection port is extended to the bite holder so that the cooling water can be ejected from the injection port opened near the inner bead cutting bite of the bite holder.

The mandrel tool of the second invention is
In the mandrel tool used when manufacturing electric resistance welded pipe from steel strip by induction welding, from the tip of the core case containing the impeder core that enhances the heating efficiency of the work coil,
A bite holder with an inner bead cutting bite attached at an interval of 0 mm or more is arranged in series at the tip of the mandrel, and the tip of the core case is extended to the vicinity of the bite holder, and the tip of the extended core case is extended. A cooling water flow passage is provided so that cooling water can be jetted from the opening toward the cutting bite, and further cooling water can be jetted from the outer circumference of the core case toward the welding point.

The present inventor manufactured electric resistance welded pipes using mandrel tools in which the distance from the welding point to the bite holder mounting portion was variously changed, and as a result of examining the occurrence rate of spatter pressing flaws, as shown in FIG. In addition, it was found that the distance between the bite holder mounting portion and the welding point should be 150 mm or more, and based on this knowledge, the distance between the inner bead cutting bite and the tip of the core case was 150 mm or more in the present invention.

[0010]

According to the mandrel tool of the first aspect of the present invention, the tool holder is provided with a tool holder having an inner bead cutting tool mounted at a distance of 150 mm or more from the tip of the core case containing the impeder core for enhancing the heating efficiency of the work coil. And the cooling water flow path that supplies cooling water to the injection port opened at the tip of the core case is extended to the bite holder, and the cooling water is supplied from the injection port opened near the inner bead cutting bite of the bite holder. Since it is formed so that it can be sprayed, the cooling water sprayed from the spray port formed at the tip of the core case removes spatter, and the cooling water sprayed from the spray port formed near the inner bead cutting tool is the inner bead cutting tool. To cool.

The mandrel tool of the second invention is
The tip of the core case is extended to the vicinity of the bite holder, and cooling water can be jetted from the tip end opening of the extended core case toward the cutting bite, and cooling water is further directed from the outer periphery of the core case to the welding point. Since a cooling water flow path that can be injected is attached, the cooling water injected from the tip opening of the core case cools the internal bead cutting tool, and the cooling water injected from the injection port formed immediately below the welding point removes spatter. To do.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a diagram showing a configuration of a mandrel tool of the present invention according to claim 1, and FIG. 2 is a diagram showing a configuration of a mandrel tool of the present invention according to claim 2.

In FIG. 1, reference numeral 12 denotes a work coil for heating a steel strip A continuously supplied while being formed into a circular shape. Squeeze rolls 13 are provided on both edges of the steel strip A heated by the work coil 12. The pipe B is manufactured by pressurizing and joining by.

Reference numeral 11 denotes a mandrel tool which is inserted into the inner surface of the pipe B when the pipe B is manufactured. A core case 15 having a work coil 12 and an impeder core 14 for heating the steel strip B is attached to the tip of a mandrel 24. At the tip of the case 15, a bite holder 17 to which an inner bead cutting bite 16 for further cutting the inner bead is attached is connected in series via a bar 18 having a length of 150 mm or more. In addition, 19 and 20 are receiving rollers provided in the bite holder 17.

By the way, a cooling water passage 21 for cooling the impeder core 14 is provided inside the core case 15, and an injection port 22 for injecting cooling water toward the spatter C is provided at the tip of the core case 15. Needless to say, the cooling water flow passage 21 is further extended to the bite holder 17 so that the cooling water can be jetted toward the inner bead cutting bite 16 and the lower receiving roller 20 in the bite holder 17. Cooling water can be jetted from the opened jet port 23 toward the inner bead cutting bite 16 and the receiving roller 20.

The mandrel tool 11 according to the first aspect of the present invention is constructed as described above, and in the state where the mandrel tool 11 is arranged, the steel strip A continuously formed into a circular shape by a forming roll group (not shown) is welded. Then pipe B
To manufacture. At this time, the spatter C is removed by the cooling water jetted from the jet port 22, the inner bead cutting bite 16 is cooled by the cooling water jetted from the jet port 23, and the spatter C is prevented from being caught in the receiving roller 20. ing.

The mandrel tool 31 of the second invention is also provided.
As shown in FIG. 2, the mandrel tool 1 of the first invention is shown.
1, instead of extending the cooling water flow path 21 to the bite holder 17, the tip of the core case 15 is extended to the bite holder 17, and from the extended tip opening 32 of the core case 15 toward the inner bead cutting bite 16. The cooling water is sprayed. In addition to this second
In the mandrel tool 31 of the present invention, the cooling water passage 33 is provided on the outer peripheral side of the cooling water passage 21 so as to inject the cooling water from the outer periphery of the core case 15 toward the welding point V. In addition, 34 is a tip injection port of the cooling water flow path 33.

When manufacturing the pipe B using the mandrel 31 of the second aspect of the present invention having the above-mentioned structure, a pump (not shown) is driven to inject cooling water from the tip opening 32 and the injection port 34 to sputter. C is removed, and the inner bead cutting tool 16 is cooled.

Using the mandrel tool of the present invention described above, 0.30w with an outer diameter of 31.8 mm and a wall thickness of 3.0 mm.
An electric resistance welded tube of t% C was manufactured, the occurrence of spatter pressing flaws was investigated, and Fig. 3 shows a comparison of the occurrence rate of spatter pressing flaws. From FIG. 3, it is clear that the present invention reduces spatter pressing defects.

[0020]

As described above, according to the mandrel tool of the present invention, the cooling water sprayed from the spray port formed at the tip of the core case removes spatters and the spray port formed near the inner bead cutting bite. The cooling water sprayed cools the inner bead cutting tool, and the cooling water sprayed from the tip opening formed at the tip of the core case that extends to the vicinity of the tool holder cools the inner bead cutting tool, and the area immediately below the welding point By removing the spatter by the cooling water sprayed from the spray port formed in 1, the spatter pressing flaws on the inner surface of the pipe and the clogging of the spatter are prevented, so that a high quality electric resistance welded pipe can be efficiently manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a mandrel tool of the present invention according to claim 1.

FIG. 2 is a diagram showing a configuration of a mandrel tool of the present invention according to claim 2;

FIG. 3 is a diagram showing a comparison of a generation rate of a pressing flaw due to sputtering in the present invention and a conventional mandrel tool.

FIG. 4 is a diagram showing a configuration of a conventional mandrel tool.

FIG. 5 is a diagram showing the relationship between the distance from the welding point to the bite holder mounting portion and the rate of occurrence of spatter pressing flaws.

[Explanation of Codes] 11 Mandrel Tool 12 Work Coil 14 Impeder Core 15 Core Case 16 Inner Bead Cutting Tool 17 Bit Holder 21 Cooling Water Flow Path 22 Injection Port 23 Injection Port 24 Mandrel 31 Mandrel Tool 32 Tip Opening 33 Cooling Water Flow Path 34 Injection Port A Steel strip B Pipe C Spatter V Welding point

Claims (2)

[Claims] 1. A mandrel tool used when manufacturing an electric resistance welded pipe from a steel strip by induction welding, with a space of 150 mm or more from the tip of a core case containing an impeder core that enhances the heating efficiency of a work coil. The bite holder with the bead cutting bit on the inner surface is arranged in series at the tip of the mandrel, and the cooling water flow path that supplies cooling water to the injection port opened at the tip of the core case is extended to the bite holder. A mandrel tool characterized in that cooling water can be injected from an injection port opened near the bead cutting tool. 2. A mandrel tool used when manufacturing an electric resistance welded pipe from a steel strip by induction welding, with a distance of 150 mm or more from a tip of a core case containing an impeder core for enhancing a heating efficiency of a work coil. A bite holder with an internal bead cutting bite is arranged in series at the tip of the mandrel, the tip of the core case is extended to near the bite holder, and cooling is performed from the tip opening of the extended core case toward the cutting bite. A mandrel tool which is provided with a cooling water flow path which is capable of spraying water and further spraying cooling water from the outer periphery of the core case toward the welding point.