JPH09141332A - Method for detecting abnormal lubrication of mandrel for rolling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new method for detecting abnormal lubrication, by which the occurrence of abnormal lubrication in a tube is detected at the time of the cold rolling of the metallic tube such as cold pilger rolling. SOLUTION: In the rolling of a tube, by which a metallic tube is rolled by inserting a mandrel into the inside of the metallic tube, a vibration sensor 10 is mounted on a mechanical part coming into contact with a mandrel rod 7 supporting a mandrel 2. When the amplitude of the vibration of a certain frequency band detected by the vibration sensor 10 has increased, it is judged that lubrication between the mandrel 2 and a tube 6 to be rolled is not normal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting the occurrence of abnormal lubrication in a pipe during cold metal pipe rolling such as cold Pilger rolling.

[0002]

2. Description of the Related Art A conventional method for detecting the occurrence of abnormal lubrication in a pipe during cold metal pipe rolling will be described below with reference to the drawings. In FIG. 1, cold pilger rolling is performed by inserting the mandrel 2 supported by a mandrel rod 7 into the inside of the pipe 6 to be rolled and moving the Gulliver roll 1 back and forth. Mandrel 2 and rolled tube 6 during rolling
The lubricating oil discharged from the lubricating oil supply device 3 is sent into the mandrel rod 7 by the oil supply arm 8 and is a tip end portion of the mandrel rod, which is a blowout hole near the joint with the mandrel 2. It is done by blowing out from 9.

A part of the lubricating oil supplied by the above-described lubricating oil supply method moves in the rolling pipe 6 in the rolling direction as a lubricating film between the mandrel 2 and the rolling pipe 6 during rolling.
Further, a part of the material flows under the inner surface of the unrolled portion of the rolled pipe 6, moves to the rear of the rolling, and flows out from the rear end of the rolled pipe 6. Conventionally, the quality of lubrication between the mandrel 2 and the rolled pipe 6 during rolling has been determined by visually confirming the presence or absence of lubricating oil flowing out from the rear of the rolled pipe 6 described above by an operator. According to this method of determining the lubrication state, when the lubricating oil is flowing out from the rear of the rolled pipe 6, a sufficient amount of lubricating oil is ejected from the blowing hole 9 at the tip of the mandrel rod 7, This is based on the empirical rule that no abnormalities such as scratches occur on the inner surface of the pipe that is formed.

[0004]

By the way, in the above-described method for determining the lubrication state, it is difficult to perform constant monitoring because it is monitored by an operator who performs other tasks at the same time, and the rolling mill is automatically operated. It is an obstacle to doing. When abnormality occurs in the lubrication between the mandrel 2 and the rolled pipe 6 during rolling, the inner surface of the rolling pipe 6 is damaged. Further, if this abnormal lubrication continues for a long time, seizure occurs between the pipe 6 to be rolled and the mandrel 2, resulting in a great loss in production. Therefore, it is important for the operator to monitor the lubrication state in order to improve both quality and productivity.

In the method for detecting abnormal lubrication of the mandrel for rolling according to the present invention, the quality of the lubrication state is judged by the vibration generated from the lubrication surface, and the vibration is detected by the machine part in contact with the mandrel rod. Characterize.

[0006]

According to the present invention, a mandrel is placed inside a metal tube, and in the tube rolling for rolling the metal tube, a vibration sensor is attached to a mechanical portion in contact with a mandrel rod supporting the mandrel, and the vibration sensor detects the vibration. A method for detecting abnormal lubrication of a rolling mandrel, which determines that the lubrication between the mandrel and the pipe to be rolled is not normal when the amplitude of vibration in a certain frequency range increases. Further, specifically, it is a method for detecting a lubrication abnormality of a rolling mandrel in which a vibration sensor for detecting a lubrication abnormality is installed in a mandrel clamp portion that clamps the vicinity of a rear end portion of a mandrel rod that supports the mandrel. Further, it is a method for detecting abnormal lubrication of a rolling mandrel, in which a vibration sensor for detecting abnormal lubrication is placed on an oil supply arm that is in contact with a rear end of a mandrel rod that supports the mandrel and that supplies lubricating oil into the mandrel rod.

[0007]

When the lubrication between the pipe to be rolled and the mandrel during rolling is normally performed, the average amplitude of vibration generated by friction between the pipe to be rolled and the mandrel is small, but the pipe to be rolled and the mandrel during rolling are small. If the lubrication during the period is not normally performed, the average amplitude of this vibration increases as the friction coefficient of the lubricated surface increases. The present invention utilizes the above-mentioned relationship between vibration and lubrication for monitoring the lubrication state.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a lubrication abnormality detecting method for a mandrel for rolling according to the present invention will be described below with reference to the drawings. In FIG. 1, which is an explanatory view of an embodiment, the mandrel rod 7 is repeated according to the repeated rotation of the rolled pipe 6 in the circumferential direction while the rear end of the mandrel rod 7 is clamped by a mandrel clamp portion 5 which is a chuck device. It is rotated and rolled. A vibration sensor 10 such as a piezoelectric element type vibration sensor is attached to the mandrel clamp portion 5.

This vibration sensor 10 is attached to a chuck holder 11 to which a chuck 12 is attached, as shown in an enlarged view of the rear end portion of the mandrel rod 7 in FIG. 1, and the vibration of the mandrel 2 is It can be detected through the rod 7 and the chuck 12.

The vibration signal obtained by the vibration sensor 10 is input to the monitoring system 4 which is set to output an abnormal signal when the average amplitude of vibration during a certain period of time exceeds a certain value. To be done. The abnormal signal output from the monitoring system 4 is input to a rolling mill body control system (not shown) to immediately stop the rolling mill body.

The vibration generated between the rolled pipe material 6 and the mandrel 2 is in close contact with the mandrel rod 7, and the mandrel 2 is the most mechanical part in close contact with the mandrel rod 7.
The vibration between the material to be rolled 6 and the mandrel 2 can be more accurately detected by attaching the vibration sensor 10 to the chuck holder 11 close to the.

When the pipe 6 to be rolled and the mandrel 2 are normally lubricated during rolling, the average amplitude of vibration generated by the friction between the pipe 6 to be rolled and the mandrel 2 is small. When the lubrication between the pipe 6 to be rolled and the mandrel 2 is not normally performed, the average of the amplitude of this vibration increases as the friction coefficient of the lubricated surface increases. In this embodiment, such a relationship between vibration and lubrication is used for monitoring the lubrication state.

The vibration generated between the rolled pipe material 6 and the mandrel 2 is transmitted to the mandrel rod 7, but the mandrel clamp portion 5 is in close contact with the mandrel rod 7, and the chuck holder 11 in close contact with the mandrel rod 7 is The mechanical vibration can be detected more accurately.

Next, another embodiment will be described with reference to FIG. In the above example, the vibration sensor is provided in the chuck holder, but in this example, it is provided in the oil supply holder. That is, the mandrel clamp portion 5 as a chuck device clamps the rear end of the mandrel rod 7 and repeatedly rotates the mandrel rod 7 in accordance with the repeated rotation of the rolled pipe 6 in the circumferential direction to perform rolling. Supply of lubricating oil between the mandrel 2 and the rolled pipe 6 during rolling is
The lubricating oil discharged from the lubricating oil supply device 3 is supplied to the oil supply arm 8
Is sent to the inside of the mandrel rod 7 and is blown out from the blow-out hole 9 which is the tip of the mandrel rod and near the joint with the mandrel 2. A vibration sensor 10 is attached to a refueling arm 8 which is in contact with a rear end of a mandrel rod 7 which supports the mandrel 2 and which supplies lubricating oil into the mandrel rod 7, so that the vibration between the material 6 to be rolled and the mandrel 2 is prevented. It is detected via the rod 7 and the refueling arm 8.

[0015]

As described above, according to the method for detecting abnormal lubrication of the mandrel for rolling according to the present invention, the lubricating state between the pipe to be rolled and the mandrel during rolling is kept constant with vibration detected by the vibration sensor. When the average time amplitude is equal to or greater than a certain value, it is regarded as an abnormal signal and is input to the monitoring system 4 for monitoring. Therefore, it becomes possible to constantly monitor the lubrication state, and it is possible to automate it.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a method for detecting abnormal lubrication of a mandrel for rolling according to an embodiment,

FIG. 2 is an explanatory diagram showing a method for detecting abnormal lubrication of a rolling mandrel according to another embodiment.

3 is a perspective view of a vibration sensor installation unit of FIG. 1. FIG.

[Explanation of symbols]

 1 Gulliver Roll 2 Mandrel 3 Lubricating Oil Supply Device 4 Monitoring System 5 Mandrel Clamp Section 6 Atsueen Tube Material 7 Mandrel Rod 8 Lubrication Arm 9 Blowout Hole 10 Vibration Sensor 11 Chuck Holder 12 Chuck

Claims (3)

[Claims] 1. In pipe rolling in which a mandrel is placed inside a metal pipe to roll the metal pipe, a vibration sensor is attached to a machine portion in contact with a mandrel rod supporting the mandrel, and the vibration amplitude in a certain frequency range detected by the vibration sensor. The method for detecting abnormal lubrication of a mandrel for rolling is characterized by determining that the lubrication between the mandrel and the pipe to be rolled is not normal when the number of times increases. 2. A vibration sensor for detecting a lubrication abnormality is installed in a mandrel clamp portion that clamps near a rear end portion of a mandrel rod that supports the mandrel.
A method for detecting abnormal lubrication of a mandrel for rolling according to the description. 3. The mandrel for rolling according to claim 1, wherein a vibration sensor for detecting abnormal lubrication is installed on an oil supply arm which is in contact with a rear end of a mandrel rod supporting the mandrel and supplies lubricating oil into the mandrel rod. Lubrication abnormality detection method.