CN109530442A - The production method of minor diameter seamless steel tube - Google Patents

Abstract

The present invention provides a kind of production method of minor diameter seamless steel tube comprising following steps: operating open circles pipe progress tube reducing to obtain the hollow billet with predetermined diameter, the hollow billet is handled to obtain minor diameter seamless steel tube finished product by tandem rolling.The present invention is not required to the continuous casting circular tube blank that will be relatively large in diameter with bar mill, after rolling becomes the pole of small diameter, could be used to produce minor diameter hot rolled seamless steel tube on limiting mandrel tandem rolling pipe machine.

Description

The production method of minor diameter seamless steel tube

Technical field

The invention belongs to seamless steel tube production field more particularly to a kind of production methods of minor diameter seamless steel tube.

Background technique

China's minor diameter seamless steel tube is taken mostly uses the hot rolled seamless steel tube of major diameter as blank, through cold rolling (pulling out) side Formula production, although the good product quality produced with this technique, at high cost, recovery rate is low.Also need before cold rolling (pulling out) into Environment is polluted in row surface treatment (mainly pickling).

If pipe diameter is big, bring waste pipe diameter big.The hollow forging of major diameter uses big sizing reduction on stretch-reducing mill When tube reducing, it will cause thickness of steel pipe unevenness, interior side and surface quality defect, when serious, will lead to steel pipe and scrap.Also, steel pipe Wall unevenness end to end is serious, and it is very big to cut damage.In general, there is stringent limit to the waste pipe diameter for entering stretch reducing machine progress tube reducing System, single chassis reducing rate commonly use 6.5% single chassis reducing rate within 6-12%.It is necessary to use the lesser pipe of diameter Base.

Baosteel Φ 140mm floating core rod continuous rolling-tube unit is obtained using the pipe of Φ 175mm using hollow ingot reducing process The hollow billet of Φ 141mm, Φ 179mm and tri- kinds of specifications of Φ 184mm, and through subsequent Tandem Tube Rolling Mill with Full Floating Mandrel, stretch reducing machine Rolling deformation after, the fished pipe of 21.3-153.7mm of Φ can be produced.

For the MPM tube rolling mill of small dimension, the continuous rolling-tube unit of the rack number of use than full-floating plug It is few, it is also different to take off bar mode.Currently, in order to produce the hot rolled seamless steel tube of minor diameter in MPM tube rolling mill, by Unit deformability limitation and product quality requirement, cannot directly use the continuous casting circular tube blank of major diameter as the feelings of blank Under condition, the minor diameter pipe that diameter meets technique requirement have to be rolled into.So, production chain is extended, is increased Cost and metal consumption, also, it is also easy to surface quality defect occur after continuous casting circular tube blank rolling, influence tube quality.

Therefore, needing one kind can either produce on conticaster, and can be directly in small dimension limiting mandrel tandem rolling pipe machine It is used in group, diameter >=Φ 150mm continuous casting circular tube blank is come the method that produces minor diameter hot rolled seamless steel tube.

Summary of the invention

It is an object of the present invention to provide a kind of production methods of minor diameter seamless steel tube, and provide behind at least and will say Bright advantage.

It is a further object to provide a kind of production method of minor diameter seamless steel tube, being not required to will with bar mill The continuous casting circular tube blank being relatively large in diameter could be used for limiting mandrel tandem rolling pipe machine after rolling becomes the pole of small diameter Produce minor diameter hot rolled seamless steel tube.

Technical scheme is as follows:

The production method of minor diameter seamless steel tube comprising following steps:

It operates open circles pipe progress tube reducing to obtain the hollow billet with predetermined diameter, the hollow billet is handled to obtain by tandem rolling Minor diameter seamless steel tube finished product.

Preferably, in the production method of the minor diameter seamless steel tube,

Continuous casting circular tube blank is heated to temperature to be 1280 ± 20 DEG C and keep the temperature the continuous casting circular tube blank for heating its austenitizing；

The open circles pipe is made by perforation processing in the continuous casting circular tube blank of heating.

Preferably, in the production method of the minor diameter seamless steel tube, the enlarging rate of the open circles pipe is less than 20%。

Preferably, in the production method of the minor diameter seamless steel tube,

The tube reducing operation carries out on the sizing mill of 8-10 rack.

Preferably, in the production method of the minor diameter seamless steel tube,

Total reducing rate of the tube reducing operation is greater than 30%；

Single chassis maximum reducing rate is 4%.

Preferably, in the production method of the minor diameter seamless steel tube,

The tandem rolling processing includes reheating, tube rolling, de- stick and stretch reducing；

The hollow billet is sensed to be heated to 1270 DEG C, and hollow billet is rolled into famine through 5 rack limiting mandrel tandem rolling pipe machines and rod stripping machine Pipe, most rolls into minor diameter seamless steel tube finished product through stretch-reducing mill afterwards.

The present invention is include at least the following beneficial effects:

Present invention solves the technical problem that be the continuous casting circular tube blank for being not required to be relatively large in diameter with bar mill, by rolling become compared with After the pole of minor diameter, it could be used to produce minor diameter hot rolled seamless steel tube on limiting mandrel tandem rolling pipe machine.This method include according to Secondary progress heating of pipe blank, hollow bloom sizing, induction heating (not needing sometimes), retained mandrel Continuous Seamless Tube Mill, takes off pipe perforation Stick, hollow forging heating (not needing sometimes), stretch reducing, cooling, cutting, aligning, flaw detection and finishing, inspection (change) are tested, are packed.

Method of the invention is to be incited somebody to action using after the perforation of continuous casting circular tube blank perforated machine using the sizing mill of 8-10 racks Perforated hollow base carries out tube reducing (maximum gauge sizing reduction is up to 30% or more), obtains being able to satisfy in small dimension retained mandrel tandem rolling Hollow billet diameter (< Φ 150mm) required for minor diameter hot rolled seamless steel tube is produced on pipe unit, because of the hollow bloom after perforation In sizing, there are 80-150 DEG C of temperature drops, using the method for induction heating, carry out mending temperature to the hollow bloom after sizing, make It meets temperature requirement when Continuous Seamless Tube Mill.

The method of the present invention proposes small dimension (Φ 140mm or less) MPM tube rolling mill and directly uses diameter >=Φ The production technology of the continuous casting circular tube blank production minor diameter hot rolled seamless steel tube of 150mm.It simplifies because conticaster is difficult to produce < Φ The continuous casting circular tube blank of 150mm, can only be casting continuously to form >=diameter of Φ 150mm after using heating, split rolling method is at small-sized bar And then the process flow for small dimension MPM tube rolling mill production minor diameter hot rolled seamless steel tube, energy can be saved Source reduces cost, has broad application prospects.

Further advantage, target and feature of the invention will be partially reflected by the following instructions, and part will also be by this The research and practice of invention and be understood by the person skilled in the art.

Specific embodiment

Below with reference to the present invention is described in further detail, to enable those skilled in the art's refer to the instruction text energy It is enough to implement accordingly.

It should be appreciated that such as " having ", "comprising" and " comprising " term used herein do not allot one or more The presence or addition of a other elements or combinations thereof.

The present invention provides a kind of production method of minor diameter seamless steel tube comprising following steps:

Continuous casting circular tube blank is heated to temperature to be 1280 ± 20 DEG C and keep the temperature the continuous casting circular tube blank for heating its austenitizing, It is required that the heating temperature of pipe is uniform, no heating defect, for different steel grades, heating temperature is made the appropriate adjustments；

The continuous casting circular tube blank of heating is handled by perforation, open circles pipe is made, moderate control enlarging rate, generally less than 20%, it avoids hollow bloom outer diameter too big and increases the sizing reduction that open circles pipe passes through base reducing mill；

Tube reducing is carried out to the open circles pipe to operate to obtain the hollow billet with predetermined diameter, and the hollow billet is handled by tandem rolling Obtain minor diameter seamless steel tube finished product.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention, at the perforation Reason is isometrical perforation or micro- extension diameter perforation.According to the tube reducing for reducing hollow bloom when tandem rolling to the requirement of capillary outer diameter and as far as possible Amount, general enlarging rate control are not to be exceeded 20% within 10%.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention, the open circles The enlarging rate of pipe is less than 20%.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention

Total reducing rate of the tube reducing operation is greater than 30%；

Single chassis maximum reducing rate is 4%.

When determining single chassis reducing rate and total reducing rate, there is such as internal wrinkles, interior side, rolls in the hollow billet after preventing sizing The mass defects such as folding.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention,

The tube reducing operation carries out on the sizing mill of 8-10 rack, according to trimmed size and milling train, winding arbor extraction press and stretch reducing machine Sizing reduction selection reducing mill rack number, single chassis sizing reduction and total sizing reduction obtain meeting hollow billet as defined in pass schedule straight Diameter.

After hollow circular-tube pipe tube reducing, temperature can reduce by 80-150 DEG C, and according to product specification and steel grade situation, selection is The no method for needing to take induction heating carries out it to mend temperature, requirement when meeting Continuous Seamless Tube Mill, to hollow billet temperature.It is specific next It says: when with carbon steel rolling medium thickness pipe, not needing to mend temperature, rolled alloy steel, when thin-wall steel tube needs to mend temperature.Whether need Mend it is mild mend temperature number completed with entire rolling deformation in the austenite structure of steel as principle.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention, single chassis tube reducing The distribution of rate is pressed along the descending distribution of rolling direction, and the single chassis reducing rate of the last one rack is minimum.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention, the continuous casting circle Diameter >=150mm of pipe.

In one embodiment of the production method of the minor diameter seamless steel tube provided by the invention,

The tandem rolling processing includes reheating, tube rolling, de- stick and stretch reducing；

The hollow billet is sensed to be heated to 1270 DEG C, and hollow billet is rolled into famine through 5 rack limiting mandrel tandem rolling pipe machines and winding arbor extraction press Pipe, most rolls into minor diameter seamless steel tube finished product through stretch-reducing mill afterwards.

Induction heating, depending on the temperature of its steel grade, steel pipe specification and hollow billet.Guarantee that steel pipe is best in plasticity, deformation It is completed in the maximum austenite structure of ability；

De- stick, hollow forging heating, stretch reducing, cooling, cutting, aligning, flaw detection, finishing, inspection (change) processes and the existing limit such as test Dynamic plug continuously rolling process is identical.

Application example

1. using the carbon steel seamless steel pipe of the continuous casting circular tube blank production Φ 21mm of Φ 150mm on certain MPM tube rolling mill

Continuous casting circular tube blank diameter of phi 150mm, is heated to 1280 ± 10 DEG C, on the cross-rolling punch by filled circles pipe pierced billet at Φ The hollow bloom of 160mm obtains the hollow billet of Φ 120mm after 10 rack sizing mill sizings.Hollow billet is sensed to be heated to 1270 DEG C Hollow billet, is rolled into Φ through 5 rack limiting mandrel tandem rolling pipe machines and rod stripping machine by left and right (such as temperature can not be heated in this range) The hollow forging of 100mm or so most rolls into the fished pipe of Φ 21mm through 24-28 frame stretch-reducing mills afterwards.

2. the carbon steel of the continuous casting circular tube blank production Φ 21mm on certain MPM tube rolling mill using Φ 160mm is seamless Steel pipe

Continuous casting circular tube blank diameter of phi 160mm, is heated to 1280 ± 10 DEG C, on the cross-rolling punch by solid pipe billet pierced billet at Φ The hollow bloom of 170mm obtains the hollow billet of Φ 135mm after 10 rack sizing mill sizings.Hollow billet is sensed to be heated to 1270 DEG C Hollow billet, is rolled into Φ through 5 rack limiting mandrel tandem rolling pipe machines and rod stripping machine by left and right (such as temperature can not be heated in this range) The hollow forging of 110mm or so most rolls into the fished pipe of Φ 21mm through 24-28 frame stretch-reducing mills afterwards.

Although the embodiments of the present invention have been disclosed as above, but its is not only in the description and the implementation listed With it can be fully applied to various fields suitable for the present invention, for those skilled in the art, can be easily Realize other modification, therefore without departing from the general concept defined in the claims and the equivalent scope, the present invention is simultaneously unlimited In specific details.

Claims (5)

1. the production method of minor diameter seamless steel tube, which comprises the following steps:

It operates open circles pipe progress tube reducing to obtain the hollow billet with predetermined diameter, the hollow billet is handled to obtain by tandem rolling Minor diameter seamless steel tube finished product.

2. the production method of minor diameter seamless steel tube as described in claim 1, which is characterized in that the expansion of the open circles pipe Diameter rate is less than 20%.

3. the production method of minor diameter seamless steel tube as described in claim 1, which is characterized in that

Total reducing rate of the tube reducing operation is greater than 30%；

Single chassis maximum reducing rate is 4%.

4. the production method of minor diameter seamless steel tube as claimed in claim 3, which is characterized in that

The tube reducing operation carries out on the sizing mill of 8-10 rack.

5. the production method of minor diameter seamless steel tube as described in claim 1, which is characterized in that

The tandem rolling processing includes reheating, tube rolling, de- stick and stretch reducing；

The hollow billet is sensed to be heated to 1270 DEG C, and hollow billet is rolled into famine through 5 rack limiting mandrel tandem rolling pipe machines and rod stripping machine Pipe, most rolls into minor diameter seamless steel tube finished product through stretch-reducing mill afterwards.