CN1044205C - Full-floating plug continuously rolling process - Google Patents

Abstract

The present invention discloses a full-floating core rod continuous rolling technology which comprises: the roll pass, the rolling speed and the roll gap preliminary adjustment quantity parameters of each machine frame, which are designed according to the normal rolling following the principle that in the process of continuous rolling, the flow per second of the metal of each machine frame is equal, are used as basic technology parameters, the basic technology parameters are adjusted, so that the principal strain machine frame realizes rolling by thrust force in the rolling process, and except the principal strain machine frame, a machine frame close to an outlet realizes tension rolling. In the technology, equipment does not need to be reformed, and rings can be effectively controlled; the ring value is controlled to be within 8%, and the product success ratio is greatly increased.

Description

Full-floating plug continuously rolling process

The present invention relates to a kind of full-floating plug continuously rolling process, belong to the hot continuous rolling tube side method in Metal Forming field.

Full-floating plug continuously rolling process of the prior art, the general pair rolling scheme of following each frame metal mass flow equal principle design in the tandem rolling that all adopts, see " steel pipe theory of plastic deformation " first volume that metallurgical industry publishing house publishes, the control of the roll pass design of its every rolling mill, mill speed and roll gap pre-adjustment amount, follow at each frame metal mass flow of stable state rolling sequence and equate, the operation of rolling had not only had tension force but also had not had the principle of thrust.But because of the limited length of pipe, the unstable state of nipping and dishing out is rolling to account for the over half of the operation of rolling.The variation of stage plug speed owing to nip and dish out causes that the metal mass flow of each frame changes, and it is rolling to have formed thrust, makes that the head and tail wall thickness and the diameter of pipe increases behind the tandem rolling, produces so-called " ring " phenomenon.When ring＞10%, causing behind stretch reducing pipe end to cut to decrease increases, and greatly reduces the lumber recovery of product.Conventional ring control measure are the suitable speed that reduces some frame of the stage of nipping and dish out at pipe, but the control effect is undesirable.At present to produce the effective measures of ring be that hydraulic pressure is depressed the application on continuous rolling-tube unit to the control full-floating plug, but the investment of scrap build is quite big.

The purpose of this invention is to provide a kind of full-floating plug continuously rolling process, this technology need not be transformed equipment, can effectively control the generation of ring, improves the lumber recovery of product.

The object of the present invention is achieved like this: to follow in the continuous rolling process, the pair rolling of each frame metal mass flow equal principle is designed, it is the basic process parameter that the roll of each frame rolls type, mill speed and roll gap pre-adjustment amount parameter, it is adjusted, make the operation of rolling realize that in main transformer shape frame thrust is rolling, frame near outlet beyond main transformer shape frame realizes tension-rolling, and concrete method of adjustment is as follows:

(1) be the benchmark frame with frame second from the bottom, this frame adopts roll pass, mill speed and the roll gap pre-adjustment amount of pair rolling;

(2) the frame frame does not adopt the roll pass and the roll gap pre-adjustment amount of pair rolling, and mill speed reduces 0.2%-1% than pair rolling speed;

(3) the roll gap pre-adjustment amount of each frame employing pair rolling of approaching outlet beyond the main transformer shape frame, export to Way in by rolled piece, the roll pass of each frame, on pair rolling roll pass basis, increase the pass width by frame, recruitment is for increasing progressively 2%-3% by frame, each frame mill speed reduces by frame than pair rolling speed, and the reduction amount is the 0.5%-3% that successively decreases by frame;

(4) first frames adopt the roll pass of pair rolling, and mill speed improves 1%-6% than pair rolling speed, and roll gap pre-adjustment amount reduces (5%-10%) P than the roll gap pre-adjustment amount of pair rolling ₀/ K;

(5) other each main transformer shape frame, its roll pass is on pair rolling roll pass basis, the pass width increases 5%-10%, enter the mouth to Way out by rolled piece, the mill speed of each frame reduces by frame than pair rolling speed, its reduction amount is the 0-5% that successively decreases by frame, and the roll gap pre-adjustment amount of each frame reduces (5%-20%) P than the roll gap pre-adjustment amount of pair rolling ₀/ K;

P wherein ₀Be the roll-force of place frame pair rolling, K is the stiffness coefficient of place frame.

Adopt process of the present invention, after adjusting according to roll pass, mill speed and the roll gap pre-adjustment amount of each designed frame of pair rolling, between main transformer shape frame, realized that thrust is rolling, make the stable state rolling sequence cause that because of thrust is rolling pipe degree of filling in pass increases, wall thickness increases, caliber increases, and nip and relative the reducing of this phenomenon of the stage of dishing out, also promptly increase the wall thickness at tandem rolling pipe middle part, and reduced pipe wall thickness end to end relatively.This effect is just opposite with the phenomenon that the full-floating plug continuously rolling process generation increases end to end, and the result of both stacks is under control the ring of full-floating plug tandem rolling pipe.And the frame near outlet has realized tension-rolling beyond main transformer shape frame, to eliminate because of adopting the rolling pipe wall thickness that causes of thrust to increase and the caliber increase between main transformer shape frame, the caliber of the tandem rolling pipe that assurance is obtained is the same with the pipe that conventional full-floating plug tandem rolling is obtained with wall thickness.Because of these frames are non-main transformer shape frame, lengthening coefficient is little, thereby little to the pipe influence of wall thickness, and the ring increase that causes and main transformer shape frame thrust is rolling, and that the ring decrease is compared is much smaller.

The mill speed of last rolling mill is reduced 0.2%-1% than the mill speed of pair rolling, and it is rolling to form microthrust between rolling mill second from the bottom and last rolling mill, makes the degree of filling increase of pipe in roll pass, produces the gap between pipe and the plug.

The advantage that the present invention is compared with prior art had is: need not equipment is transformed, can effectively control the generation of ring phenomenon, the ring value can be controlled in 8%, improved the lumber recovery of product greatly.There is the gap between pipe and the plug behind the tandem rolling, helps taking off rod, reduce the generation of resolving excellent phenomenon.

Be that example describes in detail embodiments of the invention with eight frame full-floating plug tandem rolling pipes below.

On 140 units, eight frame Tandem Tube Rolling Mill with Full Floating Mandrel, be the pipe material of 177 * 11.75 millimeters of Φ with raw material, production specification is 152.5 * 4.0 millimeters pipes of Φ.According to process of the present invention, adjust as follows to 8 frames according to the designed roll pass of the pair rolling of prior art, mill speed, roll gap pre-adjustment amount respectively:

The roll pass of the 8th frame and roll gap pre-adjustment amount are constant, and mill speed reduces by 0.5%;

The roll pass of the 7th frame, mill speed, roll gap pre-adjustment amount are all constant;

The 6th frame, roll gap pre-adjustment amount is constant, and the roll pass width increases by 2%, and mill speed reduces by 2%;

The 5th frame, roll gap pre-adjustment amount is constant, and the roll pass width increases by 4%, and mill speed reduces by 4%;

The 4th frame, the roll pass width increases by 8%, and mill speed reduces by 7%, and roll gap pre-adjustment amount reduces 8%P ₀/ K;

The 3rd frame, the roll pass width increases by 10%, and mill speed reduces by 4%, and roll gap pre-adjustment amount reduces 20%P ₀/ K;

The 2nd frame, the roll pass width increases by 10%, and mill speed is constant, and roll gap pre-adjustment amount reduces 15%P ₀/ K;

The 1st frame, roll pass is constant, and mill speed improves 4%, and roll gap pre-adjustment amount reduces 5%P ₀/ K;

After adjusting, between 1-2 frame, 2-3 frame, these main transformer shape frames of 3-4 frame, realized that thrust is rolling, controlled ring effectively.Between 4-5 frame, 5-6 frame, 6-7 frame, realized tension-rolling, constant with the dimensions that guarantees its finished product tubing.Between the 7-8 frame of rolling outlet, realized that microthrust is rolling, made between pipe and plug and produce the gap.

Rolling the back assay shows: the pipe sizing of producing meets the specification of 152.5 * 4.0 millimeters of Φ.The average thick of pipe middle part is S _In=4.06 millimeters, head thickest Smax ₁=4.28 millimeters, afterbody thickest Smax ₂=4.34 millimeters,

All less than 8%.

Claims (1)

1. full-floating plug continuously rolling process, it is characterized in that: designed with the pair rolling of following each frame metal mass flow equal principle in the continuous rolling process, the roll pass of each frame, mill speed and roll gap pre-adjustment amount parameter are the basic process parameter, it is adjusted, make the operation of rolling realize that in main transformer shape frame thrust is rolling, frame near outlet beyond main transformer shape frame realizes tension-rolling, and concrete method of adjustment is as follows:

(1) be the benchmark frame with frame second from the bottom, this frame adopts roll pass, mill speed and the roll gap pre-adjustment amount of pair rolling;

(2) the frame frame does not adopt the roll pass and the roll gap pre-adjustment amount of pair rolling, and mill speed reduces 0.2%-1% than pair rolling speed;

(3) the roll gap pre-adjustment amount of each frame employing pair rolling of approaching outlet beyond the main transformer shape frame, export to Way in by rolled piece, the roll pass of each frame, on pair rolling roll pass basis, increase the pass width by frame, recruitment is for increasing progressively 2%-3% by frame, each frame mill speed reduces by frame than pair rolling speed, and the reduction amount is the 0.5%-3% that successively decreases by frame;

(4) first frames adopt the roll pass of pair rolling, and mill speed improves 1%-6% than pair rolling speed, and roll gap pre-adjustment amount reduces (5%-10%) P than the roll gap pre-adjustment amount of pair rolling ₀/ K;

(5) other each main transformer shape frame, its roll pass is on pair rolling roll pass basis, the pass width increases 5%-10%, enter the mouth to Way out by rolled piece, the mill speed of each frame reduces by frame than pair rolling speed, its reduction amount is the 0-5% that successively decreases by frame, and the roll gap pre-adjustment amount of each frame reduces (5%-20%) P than the roll gap pre-adjustment amount of pair rolling ₀/ K;

P wherein ₀Be the roll-force of place frame pair rolling, K is the stiffness coefficient of place frame.