JPS58215209A - Mandrel device of planetary type skew rolling mill for producing seamless steel pipe - Google Patents

Abstract

PURPOSE:To extend considerably the life of a mandrel by moving the mandrel inserted into a rough pipe together with the rough pipe until the rolling work is finished thereby preventing the mandrel from receiving local overheating by rolling. CONSTITUTION:A rough pipe A which is formed to a hollow pipe is conveyed forward to the inlet side of the guide tube 2 of a planetary type skew rolling mill B and the mandrel 3 mounted at the forward end of a mandrel bar 6 is inserted loosely and supported in the pipe A. A carriage 5 is moved in this state on a supporting device 4 and the mandrel 3 is advanced by the bar 6 to feed the pipe A into the tube 2. The pipe A is subjected to a rolling reduction by three circular conical rolls and the mandrel 3 continues to advance and moves together with the pipe A until the operation is completed. The pipe A which is completed of the reduction and elongation is moved to the next stage. The life of the mandrel 3 is extended considerably without receiving local heating.

Description

[Detailed Description of the Invention] The present invention relates to a mandrel device for supporting a rough tube by reducing or stretching the rough tube by planetary inclined roll rolling vA during the manufacturing process of a jointed rounded tube. A stone. As one of this type of rolling equipment, JP-A-1@5B-78965
There is a method described in the above publication, which describes that when the rough tube (A) is reduced in diameter by planetary inclined roll rolling IIA (B) K,
The mandrel (3) penetrates through the rough pipe 0) and supports it.
The structure is such that the rolling operation of the rough tube (A) is carried out with the tip of the mandrel (3) fixed at the conical roll (1) position of the rolling mill. is constantly in contact with the heated high-temperature rough tube (71) during the rolling operation,
Since it receives the rolling edge of the conical roll (1), it is locally overheated and is prone to seizure. For this reason, the lifespan of mandrel hemorrhoids is extremely short.

Moreover, replacing the mandrels becomes a bottleneck for operations, and 4. expensive mandrels must always be kept in reserve, which increases running costs. In addition, when it is not possible to select an appropriate mandrel material that meets the severe conditions mentioned above, it is difficult to use a planetary inclined roll with extremely high diameter reduction capacity. 4.

The mandrel that penetrates the inside of the Japanese tube and supports it is moved together with the rough tube until the rolling operation is completed, and the position on the mandrel that receives the rolling blade of one conical roll and comes into contact with the hot rough tube is determined. The purpose is to prevent local overheating by moving the mandrel without fixing it, and to significantly extend the life of the mandrel.

Embodiments of the present invention will be described below based on the drawings.

@ In Figures 1, 2, and 8, (1) is a planetary inclined roll rolling mill ψ configured to perform drawing by rotating and revolving around the rolled material (rough pipe) (A). ) of 8
(2) is a guide tube located in front of the conical roll (1), and the heat-treated rough tube (A) passes through the mandrel (7).
3) The stone is fed into this guide tube (2) while being supported by the stone.

Also, the mandrel (3) is the conical roll (1) of the Ii tube (A).
), the VC structure is such that it is moved together with the rough tube <A) even during the rolling process.

That is, in order to movably support the mandrel (3) along the central axis of the guide tube (2), a support device (4) is disposed along an extension of the axis in front of the entrance to the dormitory tube, and this support The mandrel bar (6) is moved over the device (4) using the carriage (5) which is freely disposed.
) is provided protruding toward the inlet of the guide tube (2), and the mandrel (3) is connected to the end of this mandrel bar (6) #AI.
Connect K exchangeable VC, and 8 of mandrel (3)
For example, the rack (7) is attached to the carriage (6).
Attach this rack (7) to the seven mesh vinyl:.

5' pinion (8) is placed on the support device (4) and the pinion (6
) DC motor σ connected via rζ transmission mechanism (0)
OK, control the rotation speed of the pinion (8).

In addition, in order to reliably support the mandrel (3) at the axial center Vi of the guiding groove (2), the carriage CB) or the rack (7) is firmly held so as to be movable along the support device (4). In addition, the length of the mandrel (3) should be slightly longer than the rough pipe to be rolled, but the stroke of rank (7) should be at least as long as the length of the mandrel (8) and the mandrel bar (
It is necessary to make the total length of 6) longer. Next, the mode of operation of the above embodiment will be explained.

A round bar material heated by heated PVc is formed into a hollow rough tube by an inclined rolling mill or a perforation press, and is conveyed to the front of the inlet side of the guide tube (2) of the inclined roll rolling mill, and inside the rough tube (A). With the mandrel (8) loosely inserted and supported, the mandrel (3) is advanced and the rough tube (4) is fed into the guide tube (2). Then, the coarse tube GA) is brought into contact with the conical roll (1) VC for the purpose of diameter reduction work, and until the work is completed, the mandrel (3
) continues to move forward together with the coarse tube (, A). In addition, there are eight cases of the mandrel movement speed in the rolling operation as shown below. That is, the rolling speed on the entry side of the conical roll (1) of (, ):II tube Buddha) is increased. (b
) Follow the rolling speed of the rough tube (A) on the entrance side to the conical roll (1), and do not apply VC pushing force to the rough tube (A). (C); Conical roll (1
), and apply a pushing force to the rough tube cA). By the way, the present invention can be implemented in any of the cases (a) to (C) above, but (
b) is the most common, and in the case of (,), the coarse tube c
A) Adjustment of the pushing force applied by K The exit speed can be made faster than IMK, and the rolling conditions can be stabilized. The coarse tube (A) thus reduced in diameter and drawn by the inclined roll rolling mill is then passed through another rolling mill to be finished into a seamless tube as a final product.

As explained above, according to the present invention, when reducing the diameter of a rough tube using a planetary inclined roll mill, I! The mandrel is supported by a mandrel that penetrates the inside of the pipe, and the mandrel is moved together with the rough pipe even during the rolling operation using the conical rolls in the first feed, so the rolling blade action area of the conical rolls relative to the mandrel always moves and only one location is localized. Compared to the conventional device that fixes the mandrel in a predetermined position, the life of the mandrel can be greatly extended, and stable use over a long period of time can be achieved. Benefits of seamless pipes! ! 1. By making it possible to control the speed of the mandrel, it is possible to obtain an appropriate mandrel movement speed for various rolling conditions, contributing to the stabilization of paper conditions, etc. play.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram showing an embodiment of the great invention. 2 is a partially enlarged explanatory view of FIG. 1, and FIG. 8 is a detailed view of the rolled end portion of the mandrel in FIG. 1.

Claims (2)

[Claims] (1) A mandrel device that supports the bile duct when the rough pipe is reduced to l diameter using a planetary inclined roll rolling machine in the process of manufacturing seamless pipes, and the mandrel penetrates the inside of the m%F. Vl is supported and fed into the guide tube of the inclined roll rolling machine, and also with the rough tube when rolling the rough tube with conical rolls! - A mandrel device for a planetary type inclined roll rolling mill for manufacturing rayless tubes, characterized in that it is configured to be movable and controllable in speed. (2) The mandrel is connected to the tip of the mandrel par.
2. A mandrel device as claimed in claim 1, wherein the mandrel pars are exchangeably connected and the mandrel per is moved via a support and sliding drive to a carriage which is movable on the support device.