CN2408983Y

CN2408983Y - Mandrel

Info

Publication number: CN2408983Y
Application number: CN 00213566
Authority: CN
Inventors: 王旭午; 杨为国
Original assignee: Yantai Lubao Steel Pipe Co Ltd
Current assignee: Yantai Lubao Steel Pipe Co Ltd
Priority date: 2000-02-18
Filing date: 2000-02-18
Publication date: 2000-12-06
Anticipated expiration: 2010-02-18

Abstract

The utility model discloses a mandrel, which is used for rolling steel pipes. The utility model is composed of a mandrel body 1 and the mandrel head 2 and is characterized in that the back part of the mandrel body 1 is provided with a part 3 with gradually reduced diameter; the back part of the steel pipe needed to cut is within the normal range. The utility model can avoid phenomena of the rolling, crushing, cutting, etc. of the back of the thin-wall steel tube and have the advantages of improving the high work efficiency, reducing the abrasion of deformed tool, improving the finished rate of the rolling steel pipes, and improving the productivity of the rolling steel pipes.

Description

A kind of plug

The utility model relates to used plug in the plug milling train, more particularly, is a kind of plug that can prevent the grating of steel pipe afterbody.

In steel pipe's production, plug is a very important warp tool in the plug milling train.Fig. 1 is the structural representation of existing plug, and it is made up of barred body 1 and caput 2, and characteristics are the diameter uniformity of barred body 1.But the rolling thin-wall pipe of this plug (meets outer diameter of steel pipes D _h/ thickness of steel pipe S _h〉=30 and thickness of steel pipe S _hThe steel pipe of one of two conditions of≤6mm) time, (referring to that the steel tube surface metal is wrinkling happens frequently often to cause the folding that rolls of steel pipe afterbody, become folding), grating, cut flag and (refer to that steel pipe afterbody metal enters the gap of roll and guider, steel pipe be directed to device cut become the flag shape) etc., cause the quite long steel pipe of steel pipe afterbody to become waste product, make resection length exceed normal crop length, cause the decline of steel pipe lumber recovery.The steel pipe afterbody of grating enters the gap of roller gap or guider (as godet or guide plate), just caused destruction, cuts flag when serious, cause steel pipe rolling interruption accident, needed to stop production and handle, both wasted the time, increase cost consumption again, also reduced production efficiency.The main cause of cause the afterbody of rolling thin-wall steel pipe to roll folding, grating, cutting flag is: the rolled steel tube afterbody, be that to belong to steel pipe free-ended rolling, the steel pipe tail end has expansion trend, i.e. transversely deforming increases, and belongs to the range of instability of rolling deformation, be easy to produce rolling folding, grating, cutting phenomenons such as flag of steel pipe tail end, when rolling thick walled steel tube, the probability that produces this phenomenon is not a lot, and this is because the relative wall thickness reducing amount during rolling thick walled steel tube is less, the steel pipe thickness of pipe wall, its bending resistance is big.And the relative wall thickness reducing amount during the rolling thin-wall pipe is bigger, the steel pipe bending resistance is little, add supplied materials thin-walled hollow billet afterbody and have inclined to one side wall, broken phenomenon (see in appearance and often be full horse-hof shape) more, when rolling afterbody, cause the steel pipe rolling instability, steel pipe afterbody fecund is given birth to ply rolling, during ply rolling, the resistance of deformation of steel pipe is big especially, causes the heavy wear of rolling folding, grating, cutting flag and warp tool of steel pipe afterbody.

The purpose of this utility model is, provides to prevent effectively that altogether steel pipe afterbody, particularly thin-wall steel tube afterbody from folding, grating occurring rolling, cutting phenomenon such as flag, reduces the wearing and tearing of warp tool, the plug of boosting productivity.

The purpose of this utility model reaches by the following technical programs: this plug is made up of barred body 1 and caput 2, and its special character is the position 3 that the afterbody of barred body 1 has a diameter to diminish.The position that this diameter diminishes can be at the end of barred body 1 afterbody, also can be at the non-end of barred body 1 afterbody, and it is the working face of rolled steel tube afterbody.Its working face shape can be set as required, as round table-like, thin neck shape etc.

The minimum diameter at position 3 makes the steel pipe afterbody outer diameter D that rolls out _WhWith its wall thickness S _WhRatio less than 30 or steel pipe afterbody wall thickness S _Wh〉=6mm.This guarantees that more effectively the afterbody of rolled steel tube does not occur rolling folding, grating, cuts phenomenons such as flag.

Position 3 is positioned at the stage casing of barred body 1 afterbody, and this position links to each other with barred body rounding off section 4 between the position.At this moment rounding off section 4 is two sections.

The total length of position 3 and rounding off section 4 is 0.3-1.5 times of rolling deformation section length.

If position 3 is positioned at the end of barred body 1 afterbody, then rounding off section 4 has only one section.Its total length also meet be rolling deformation district effective length 0.3-1.5 doubly.

Because the afterbody of the utility model plug attenuates; when making steel pipe rolling; its afterbody wall thickness thickens (as position 3 2mm that attenuates; then the afterbody wall thickness thickens 1mm); wall thickness reducing amount reduces (relative deformation's minimizing); thereby effectively prevented the steel pipe afterbody grating, roll folding and cut the flag phenomenon, reduced the wearing and tearing of warp tool (roll and steering tool etc.) and shut down number of times, improved operating efficiency.Because of having prevented that the steel pipe afterbody from rolling folding, grating, cutting the flag phenomenon, reduced crop loss, lumber recovery can improve more than 2%; Reduced the grating of invar pipe afterbody, cut the downtime 95% that flag causes; Reduced charge for loss of working time, mould takes about 10%.

The explanation of accompanying drawing drawing:

A kind of structural representation of Fig. 1-existing plug;

The structural representation of an embodiment of Fig. 2-the utility model;

Fig. 3-contain two-roller skew-rolling machine deformation principle schematic diagram of plug shown in Figure 2;

Fig. 4-second kind of structural representation of the present utility model;

Fig. 5-the third structural representation of the present utility model.

Provide embodiment of the present utility model below in conjunction with accompanying drawing, be used for further specifying technical solution.

Embodiment is with reference to figure 2, Fig. 3.In Fig. 3, the label of roll is 5, and the label of hollow billet is 6, and the total length of deformed area mn is 500mm.Plug length overall L=4000mm, the total length t=280mm of position 3 and rounding off section 4 wherein, the value of the two is 280/500=0.56.The length y=200mm at position 3, the thinnest position diameter d=134mm.When utilizing this mandrel rolling steel pipe, can be 168mm with outer diameter D M, wall thickness S _mFor the steel pipe rolling of 7.5mm becomes outer diameter D _hBe 168mm, wall thickness S _hBe 4.5mm, and the afterbody outer diameter D _WhBe 168mm, wall thickness S _WhSteel pipe for 6.5mm.At this moment, the D of steel pipe afterbody _Wh/ S _Wh=25.85, this is worth less than 30.

In like manner, the mandrel structure that can also provide according to Fig. 4, Fig. 5, rolled steel tube forms other embodiment.

Claims

1, a kind of plug, it is made up of barred body (1) and caput (2), it is characterized in that, at the position (3) that the afterbody of described barred body (1) has a diameter to diminish.

2, a kind of plug according to claim 1 is characterized in that, the minimum diameter of described position (3) makes the steel pipe that rolls out meet the outer diameter D of afterbody _WhWith its wall thickness S _WhRatio less than 30 and steel pipe afterbody wall thickness S _WhOne of two conditions of 〉=6mm.

3, a kind of plug according to claim 1 and 2 is characterized in that, described position (3) are positioned at the stage casing of afterbody, and this position links to each other with barred body rounding off section (4) between the position.

4, a kind of plug according to claim 3 is characterized in that, the total length of described position (3) and rounding off section (4) is 0.3-1.5 a times of rolling deformation section length.