CN1775465A - Method and equipment for manufacturing high-alloy seamless steel pipe - Google Patents
Method and equipment for manufacturing high-alloy seamless steel pipe Download PDFInfo
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- CN1775465A CN1775465A CN 200510016388 CN200510016388A CN1775465A CN 1775465 A CN1775465 A CN 1775465A CN 200510016388 CN200510016388 CN 200510016388 CN 200510016388 A CN200510016388 A CN 200510016388A CN 1775465 A CN1775465 A CN 1775465A
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Abstract
The method for manufacturing high-alloy seamless steel tube includes the following main procedures: procedure for manufacturing tube blank by using continuous casting process; procedure for cooling tube blank; procedure for heating cooled tube blank to piercing temperature; procedure for piercing rolling the heated tube blank according to strain speed of 1/190-1/300 (1/sec.) to manufacture hollow tube blank; procedure for extension rolling steel tube; procedure for making recrystallization treatment; procedure for making normalizing treatment and procedure for making tempering treatment and straightening treatment.
Description
Technical field
The manufacturing equipment that the present invention relates to a kind of high-alloy seamless steel pipe manufacture method and implement this method.More particularly, relate to a kind of can make at low cost with good productivity by that simplify and manufacturing process serialization and manufacturing equipment have good intensity, the method for the high-alloy seamless steel pipe of performances such as toughness, corrosion-resistant and high temperature and the manufacturing equipment that is used to implement this method.
Background technology
Generally, aspect purposes such as pipe, adopt seamless steel pipe at boiler tube, petroleum cracking tube, oil well pipe, heat exchanger more.As its material, mainly be to be object with carbon steel, the low-alloy steel that contains alloying components such as Cr, Mo, high Cr stainless steel etc.In the manufacturing of these seamless steel pipes, often use Mannesmann's core rod type slitless tube mill mode.Make for the high-alloy seamless steel pipe that adopts Mannesmann's core rod type slitless tube mill mode,, product requirement is had high-performance, so general manufacturing process is very complicated owing to need carry out harsh processing in the drilling/rolling operation.
Fig. 1 illustrates an example of the manufacturing process of Mannesmann's core rod type slitless tube mill mode.Multiple working procedure is arranged between from the steel ingot to the product, advance multiple processing and heating, cooling repeatedly for machined material.Dotted line is depicted as the circuit change of following processing such as inter process transports, stacks for the moment among Fig. 1, in the manufacturing process of Mannesmann's core rod type slitless tube mill mode, repeatedly carries out the circuit change.Therefore, make high-alloy seamless steel pipe and need have H.D a plurality of equipment and lot of energy.Therefore, the manufacturing cost height is its intrinsic problem.
In order to reduce manufacturing cost, need to improve productivity, reduce cost of equipment, reduce operating cost.Particularly, making the product with the performance that is better than the existing product quality when simplifying manufacturing process and manufacturing equipment, is that high-alloy seamless steel pipe is made problem to be solved.In order to solve these problems, to the manufacturing development of high-alloy seamless steel pipe diversified technology.Particularly in rolling and finish rolling stage of the extension of in-process shown in Figure 1 and the heat treatment stages that the steel pipe of product has pre-determined characteristics after making as finish rolling, multiple scheme has been proposed.
For make the operation that the cross section is the pipe of circle from steel ingot, propose to omit split rolling method or forging process by continuous casting manufactured round tube base, be the pipe of circle promptly by continuous casting manufactured transverse shape, roll extending after this pipe perforation.But this method cracks in the perforation material easily in the heating of pipe blank condition that is used for drilling/rolling and the condition of carrying out drilling/rolling with Mannesmann piercing mill.
From the viewpoint of operation serialization, disclose in the Japanese iron and steel magazine a kind of will as the mandrel mill of continuous elongating mill with take off the direct-connected manufacturing equipment of pipe sizing mill as finishing mill.But this equipment only is in order to ensure hardening heat continuous elongating mill directly to be connected with finishing mill.Therefore, because the condition of high temperature after finish rolling is quenched, so crystal grain produces thickization, existence is as the problem of the toughness decline of the steel pipe of product.
Heat treatment step for the steel pipe that is used to make after the finish rolling has the desired pre-determined characteristics of product also has multiple motion.High-alloy seamless steel pipe requires to have high reliability and high-performance.Therefore, as shown in Figure 1, usually, carry out with the offline mode that can carry out strict control by the quenching of decision product quality and the heat treatment that temper is formed.Therefore, quenching unit and the tempering furnace that separates with the tubulation circuit is set.It is a big obstacle that the manufacture method that comprises such processed offline is saved the simplification of manufacturing equipment and energy.
For this reason, in recent years in the manufacturing of high-alloy seamless steel pipe, attempting adopting that the heat that utilizes the processed material after the finish rolling to possess carries out press quenching is so-called direct quenching method.Adopt the direct quenching method, just do not need the quenching unit of off-line, and owing to can simplify manufacturing process, so can also reduce cost significantly.For example, there is the expert to propose a kind ofly in high-alloy seamless steel pipe manufacturing process, after finish rolling, immediately steel pipe to be forced the direct quenching method cooled off.Yet, in fact, can not get the quality that is equal to the product that obtains of quenching by existing off-line by the product of this a kind of direct quenching manufactured.That is to say, and compare, thereby exist because thick toughness of crystal grain and the bad problem of corrosion resistance by the product of existing method manufacturing.
For the grain size of refinement steel, proposed online processed material to be processed heat treated technology.For example, the disclosed operation that in the middle of roughing (extending rolling) and finish rolling, increases cooling and heating again of SUMITOMO CHEMICAL company, in the treatment process that increases cooling and heating again after the finish rolling, in the operation of rolling, (extends between rolling and the finish rolling) and rolling back (finish rolling) is cooled off for twice with the operation that heats again etc.Above-mentioned these processing methods all are to cool off and heating again at presence, are characterized in from austenite to ferritic phase transformation and ferrite carries out more than 2 times altogether repeatedly to austenitic reverse phase transformation.
Said method is for all needing to force to be cooled to the temperature province that phase transformation begins or finishes as the steel pipe of processed material, and need be heated to the temperature province that the reverse phase transformation proceeded finishes again.Therefore, in said method, exist owing to the consumption energy high problems of construction cost that make the energy cost height and make manufacturing equipment owing to the manufacturing equipment complexity more.In addition, for the mechanical performance by the high-alloy seamless steel pipe of direct normalizing manufactured, the deviation of metal structure and mechanical strength etc. is big.This is owing to length direction or manufacturing between-lot normalizing temperature inequality at steel pipe cause.Therefore, there is the problem that is difficult to the uniform steel pipe of a large amount of workmanships of good productivity.Like this, said method is compared with the method for being quenched by existing off-line, not only do not seeing superiority aspect cost of equipment and the operating cost, and properties of product is also poor.
On the other hand, in the manufacture method of high-alloy seamless steel pipe, when with each operation off-line ground separate configurations, because the processing speed difference of inter process, so need deposit the space of machined materials such as steel billet.For example, use the stacking place of steel billet and the place of the steel pipe before the temporary transient keeping heat treatment owing to need be used for keeping as drilling/rolling, so must guarantee big space.In addition, also need transport the device of pipe, need the auxiliary many conveyers such as equipment that transport such as crane, truck at each inter process.
Fig. 2 illustrates an example of the manufacturing process of Diesel's retained mandrel tandem rolling tubular type slitless tube mill mode.When Diesel's Mannesmann piercing mill is bored a hole heated pipe, constitute a ring seal pass by two roll, two active godets and servo-actuated tops that are positioned at the centre that are in tilted layout with respect to roll line.Under the effect of roll, godet and servo-actuated top, pipe can produce torsional deflection, longitudinal shear distortion and tube wall plastic bending, makes the drilling/rolling operation of high alloy pipe become harsh, causes on the high alloy hollow bloom surfaces externally and internally and the inner defective etc. that produces.
Diesel's retained mandrel tandem rolling tubular type slitless tube mill mode is compared with Mannesmann core rod type slitless tube mill, and the former has reduced manufacturing cost effectively, has improved productivity.But the top of its roll pass and the peripheral speed difference between the sideshake make flow of metal inhomogeneous, cause roll Pass to cross the defective that is full of or owes to be full of easily, resistance of deformation obviously increases, inhomogeneous deformation very easily appears in the thin hollow forging of rolling high-alloy steel, cracks, defectives such as folding, absciss layer.
As mentioned above, for existing method, can not satisfy by the requirement of the manufacturing process of simplifying and manufacturing equipment with the good high-alloy seamless steel pipe of high productivity and cheap manufacturing cost manufacturing property.
Summary of the invention
The present invention makes in order to address the above problem, its purpose is to provide a kind of manufacturing equipment of making the method for high pressure alloy seamless steel pipe and implementing this control method, this method can have good productivity and the high pressure alloy seamless steel pipe that is better than the performance of existing product with low manufacturing cost manufacturing by manufacturing process and the manufacturing equipment of simplifying.
Another object of the present invention is to provide a kind of manufacturing equipment of making the method for high-alloy seamless steel pipe and being used to implement this manufacture method, this method can have good productivity and the high-alloy seamless steel pipe that is better than the performance of existing product with low manufacturing cost manufacturing by manufacturing process and the manufacturing equipment of simplifying.
For achieving the above object, the technical solution used in the present invention provides a kind of high-alloy seamless steel pipe manufacture method, and this method comprises continuous successively following operation;
1. be the operation of the pipe of circle by continuous casting manufactured transverse shape;
2. above-mentioned pipe is cooled to operation in 200～300 ℃ the temperature range under the Ar1 transformation temperature;
The above-mentioned pipe that 3. will cool off is heated to the heating process that can carry out piercing temperature;
The pipe that 4. will be heated to the temperature that can bore a hole carries out the operation of drilling/rolling, manufacturing hollow bloom with the rate of straining of 1/190～1/300 (1/ second);
5. by with the direct continuous elongating mill of configuration of punch with being connected, when the mean strain speed of being scheduled to processing and finishing temperature hollow bloom is extended rolling manufacturing hollow forging;
6. above-mentioned hollow forging is carried out tension force and decide the operation that tube reducing is made steel pipe;
7. in the temperature range between Ar1 transformation temperature and Ar3 transformation temperature, steel pipe is carried out again the operation of crystallization treatment;
8. the Ar3 transformation temperature to it in the temperature between 200 ℃, steel pipe is carried out the operation of normalized treatment;
9. above-mentioned steel pipe is carried out the operation of temper;
10. the operation that above-mentioned steel pipe is aligned.
A kind of high-alloy seamless steel pipe manufacturing equipment that is used to implement the described method of claim 1 also is provided.
Effect of the present invention is according to high-alloy seamless steel pipe manufacture method of the present invention and manufacturing equipment, can make the high-alloy seamless steel pipe that productivity is good and have the performance that is better than existing product with low manufacturing cost, so the present invention is very valuable for the manufacturing of industrial high-alloy seamless steel pipe.
Description of drawings
Fig. 1 is an embodiment process flow chart of existing seamless steel pipe manufacturing process;
Fig. 2 is the flow chart of existing high-alloy seamless steel pipe manufacturing process;
Fig. 3 is the figure of high-alloy seamless steel pipe of the present invention manufacturing process;
Fig. 4 is the block diagram of high-alloy seamless steel pipe manufacturing equipment configuration of the present invention.
Among the figure:
A, conticaster b, rotary heating furnace c, cone-type piercer machine
D, continuous rolling-tube unit e, tension force size-reducing mill f, normalized treatment device
G, tempering furnace h, straightener j, heating furnace
The specific embodiment
The present invention is described in detail to reach embodiment in conjunction with the accompanying drawings.
As Fig. 3 manufacturing process of the present invention is shown.Basic fundamental thought of the present invention is embodied in the following technology:
1. steel billet manufactures the pipe of transverse shape for circle by continuous casting process.By this method, can be omitted in needed cogging in pipe ingot or the occasion of square continuous casting steel billet, rolling or forging process as blank.
2. before the heating of carrying out for drilling/rolling, the pipe of casting once had been cooled to 200～300 ℃ temperature under the Ar1 transformation temperature.By this cooling, add next time and to pine for making effectively grain refinement.By crystal grain thinning, even can prevent also that in harsh drilling/rolling being perforated material cracks.
3. after pipe is cooled to the Ar1 phase point temperature, be heated the temperature that to carry out drilling/rolling.Begin to heat pipe by temperature high as far as possible below the Ar1 transformation temperature, the heat that is contained in the time of can making full use of casting.Energy needed in the time of can saving in the heating furnace heating significantly by this processing.In addition, and steel ingot or square continuous casting material are compared as the method for blank, can be dwindled site of storage significantly.
4. in the drilling/rolling, adopt diagonal rolling conical drilling/rolling method.When this drilling/rolling, by selecting suitable rate of straining, its speed is 1/190～1/300 (1/ second), can prevent that being perforated material cracks.
5. the continuous extension behind drilling/rolling rolling in, with the closely configuration on the same line of both milling train.By this configuration, can suppress to be rolled the temperature decline of material, and can accumulate machining deformation effectively.By this method, in the crystallization treatment again of next process, can make the remarkable refinement of crystal grain.
6. after continuous extension is rolling, more than the Ar3 transformation temperature, directly hollow forging is carried out tension force and decide reducing and rolling.The temperature that makes hollow forging reduces resistance of deformation more than the Ar3 transformation temperature, guarantee the accurate external diameter of steel pipe, and saves the energy of heating again.
7. during this, the steel pipe as processed material is carried out crystallization treatment again up to normalized treatment.By the slow air cooling during transporting at this, its temperature is carried out crystallization treatment again between Ar1 transformation temperature and Ar3 transformation temperature.Machining deformation accumulation by processed material in the last operation can make grain refinement effectively.
8. for the steel pipe of suitably adjusting crystal grain diameter, be not cool to room temperature always, but below the Ar1 transformation temperature 200 ℃ heat immediately, then, carry out normalized treatment from the temperature more than the Ar3 transformation temperature.
9. then carry out tempering by the tempering furnace that is located on the same line.
10. steel pipe is aligned.
By a succession of processing 6.～10., compare with existing product, can improve performances such as intensity and toughness.
The present invention will realize above-mentioned basic fundamental thought exactly.
Fig. 4 is the configuration mode figure that is used to implement the manufacturing equipment of the inventive method.Describe content of the present invention with reference to Fig. 3 and the Fig. 4 shown in preceding in detail at each procedure below.
Operation is the manufacturing of pipe 1.
Make by conticaster for circular pipe in the cross section, and this conticaster has molten steel injection portion transverse shape and is circular casting mold.The internal diameter of casting mold is selected according to the external diameter of pipe, and the external diameter of this pipe is determined according to the external diameter of the steel pipe that will make.Under this condition, cast pipe continuously with predetermined outer diameter and length.
Symbol l among Fig. 4 is a conticaster, and the casting mold of this conticaster a is circular in the transverse shape of molten steel injection portion, and this conticaster has the structure that can change casting mold according to the external diameter of the pipe of casting.Cast the figure base that has corresponding to the diameter of pipe-making method continuously by this conticaster a.And, after pipe casting station, also be provided with cutter sweep, pipe is cut into predetermined length in the basic end of solidifying of pipe central part or after finishing fully.In addition, for cast sturcture of improving pipe etc., conticaster also can have pipe is applied the roller frame of slightly depressing processing.In this occasion, roller is erected at before or after the cutter sweep of pipe.
The operation 2. grain refinement of pipe is handled (cooling)
Fluid origin pipe once had been cooled to temperature more than the following room temperature of Ar1 transformation temperature.Its reason is in order to obtain to bear the hot-workability of the harsh processing in the perforation process, and this perforation process is undertaken by diagonal rolling conical punch c.In order to improve the hot-workability of pipe, need carry out grain refinement to the metallographic structure of pipe.In the present invention,, be used to carry out the heating of pipe perforation subsequently, make the metallographic structure grain refinement by the temperature below the Ar1 transformation temperature that once pipe was cooled to phase transformation finishing temperature from austenite to ferritic phase.In order to make in the next process heating of pipe blank institute energy requirement the least possible, the chilling temperature of this moment be preferably below the Ar1 transformation temperature, near the temperature of Ar1 transformation temperature.But, even the lower limit of chilling temperature is also no problem more than room temperature.In order to cool off pipe, the pipe temperature can be set between the heating of pipe blank stove of conticaster and back operation drop to the following required separation distance of Ar1 transformation temperature or be provided with pipe is forced the device that cools off.
At the device of this operation shown in Figure 4, illustrate by the example that transports passage 2 and constitute that laterally transports form by pipe grain refinement processing.As mentioned above, time of stopping in when grain refinement is handled of pipe was determined by the time that makes casting pipe temperature be reduced to the following temperature of Ar1 transformation temperature.In this example, realize grain refinement with the air cooling mode, therefore, grain refinement is handled essence and is constituted by transporting passage 2.The length of transporting passage 2 is to make casting pipe temperature be reduced to the following required distance of Ar1 transformation temperature.When generations such as Facility Layout restrictions make can not be provided with as described above apart from the time, can solve the method that pipe cools off by compulsory cooling device is set in the way of transporting passage 2.
Operation is the heating of pipe 3.
In this operation, in rotary heating furnace b, pipe is fully heated and soaking, it is reached can be the temperature that cone-type piercer machine c carries out drilling/rolling with the perforation milling train at next process.Best heating-up temperature is according to the difference of material and difference, and it will carry out the characteristics such as high temperature ductility, elevated temperature strength of the material of drilling/rolling and determine by consideration.Heating-up temperature is usually in 1220～1270 ℃ scope.The heating of pipe blank stove adopts rotary heating furnace b.Pipe is sent into rotary heating furnace b by charger and is placed on the furnace bottom, rotates with furnace bottom, in rotation process, is installed in the burner heating of stove side wall and furnace roof, and behind rotation one circle, the pipe that will be heated by discharging machine takes out.Owing to can improve the efficiency of heating surface of steel billet by the pack completeness of packing into that improves steel billet among the rotary heating furnace b, so preferably make pipe length long as much as possible.The length of pipe when therefore, making it be adapted to drilling/rolling.
Operation is drilling/rolling 4.
In the present invention, the pipe that is in as-cast condition that does not carry out hot rolling is carried out drilling/rolling, make hollow bloom with cone-type piercer machine c.Because drilling/rolling is very harsh processing, very easily produces defective so be perforated material in perforation procedure.As countermeasure, be by the metallographic structure of refinement pipe and rate of straining be limited under the condition below 1/190 (1/ second) perforation and suppress defective and take place in occasion of the present invention.Therefore, in the present invention, it is necessary condition that the rate of straining during with drilling/rolling is located at below 1/190 (1/ second).
Here, rate of straining is the speed by the following formula definition.
In the formula:
S
0Be the cross-sectional area of processed material before processing;
S
1Be the cross-sectional area of processed material after processing;
T is the processing required time, chronomere: second.
For the material of hot-workability difference, be preferably under the high as far as possible temperature and bore a hole.For this reason, the front that belt heating furnace abuts against punch 5 is provided with, and the temperature that reduces pipe descends.
Rate of straining is not particularly limited its lower limit as long as below 1/190 (1/ second).But when rate of straining during less than 1/300 (1/ second), the life-span of instruments such as the plug of cone-type piercer machine c, guide block significantly shortens, so preferably be located at more than 1/300 (1/ second).
So long as the tapered roller perforation milling train of engaging in internal strife, adopt which type of type can as the cone-type piercer machine c of perforation milling train.Wherein, for the present invention, the chiasma type diagonal rolling conical roller perforation milling train that can carry out thin-walled perforation and the perforation of high pipe expanding rate is particularly suitable.Its reason is such, owing to can bore a hole into the hollow bloom of the big multiple size of diameter from a kind of round billet of external diameter, is easy to the unified size of concentrating required steel billet.
The temperature of hollow bloom is different with material, perforation condition etc. when finishing the drilling/rolling operation, is typically about 1230～1260 ℃.
5. operation extends rolling
The passage 7 that transports that transports form by straight line is transported to hollow bloom on the entrance side roller-way of the continuous rolling-tube unit d (retained mandrel formula seamless pipe rolls stool) that is located at its rear portion.Here, at first plug is inserted in this pipe, the rear end of plug is used restraint by the mandrel stem retainer and protects.Subsequently by continuous rolling-tube unit d more than the mean strain speed 1/380 (1/ second), extend rollingly under the condition of 900～1100 ℃ of degree of finish more than 2%, finishing temperature, roll into the hollow forging of preliminary dimension.
Continuous rolling-tube unit d is suitable for adopting the continuous elongating mill of being made up of a plurality of frames.Because the temperature of hollow bloom reduces,, continuous extension processing processes so comparing under lower temperature with the drilling/rolling operation of front.One of the present invention is characterised in that the processing that utilizes under this lower temperature processes heat treatment, can further be processed by continuous rolling-tube unit d immediately before the processing strain that is produced by the perforation milling train is replied.Can make the steel pipe recrystal grain refinement effectively that takes place later by the processing of satisfying this condition, this operation is important operation for purposes of the invention.
That is even in the occasion with same road secondary program tubulation, when cone-type piercer machine c heating furnace and continuous rolling-tube unit d partition distance separate configurations, the crystal grain diameter after the crystallization is grown up again.In order to obtain steel pipe as having of the target of the present invention quality better than existing product, make as described above cone-type piercer machine c and continuous rolling-tube unit d close, in series the configuration be indispensable.
In this operation, must be more than 1/600 (1/ second) by the mean strain speed of above-mentioned (a) formula definition.In the occasion of mean strain speed less than 1/600 (1/ second), between each passage, take place again through crystalline substance, thus can not accumulation strain.Under such condition, in the operation of back, just can not obtain the effect of abundant refinement recrystal grain.In addition, the degree of finish in this operation must be more than 2%.This be because, after dependent variable is converted into degree of finish (section slip), do not reach 2% occasion, crystallization is difficult for carrying out again, thereby can not get the grain refining effect as target.
In addition, extend the finishing temperature of the hollow forging after rolling continuously in 900～1100 ℃ scope.This is because in the time of in this temperature range, the grain refining effect of crystallization generation is very big more thereafter.Therefore, determining in this operation that mean strain speed is that degree of finish is more than 3% more than 1/400 (1/ second), is 1030～1080 ℃ in the finishing temperature of elongating mill continuously.
Necessity that the upper limit of mean strain speed and degree of finish is not determined especially.But, when mean strain speed surpasses 1/370 (1/ second), obviously reduce as the life-span of the instruments such as core handful of continuous rolling-tube unit d, so preferably fix on below 1/370 (1/ second).In addition, the becoming significantly of defective when degree of finish surpasses 25% is so preferably fix on below 25%.
As the retained mandrel formula seamless-tube rolling mill of the used continuous rolling-tube unit d of the present invention so long as following such one type then can use any form, the retained mandrel formula seamless-tube rolling mill of the type has plug restraint device (plug supporter), and this plug restraint device can retrain the rear end as the plug of inner face setting means, and plug is recycled by turning back to the milling train inlet side in the hole type roll row.Wherein, the retained mandrel formula seamless-tube rolling mill that preferably adopts above-mentioned plug restraint device to have a kind of like this function, promptly can be in the extension of hollow bloom be rolling with the translational speed of the speed control plug of the rolling translational speed that is independent of pipe.
6. operation decides the finish rolling of tube reducing milling train
In finish rolling, adopt the tension force size-reducing mill e that forms by a plurality of frames.Because the temperature of blank reduces, process to compare under lower temperature and process with the rolling processing of continuous extension of front so decide tube reducing.One of the present invention is characterised in that the processing that utilizes under this temperature processes heat treatment, and this operation is important operation for purposes of the invention.In occasion of the present invention, as the retained mandrel formula seamless-tube rolling mill of continuous rolling-tube unit d and not partition distance configuration of tension force size-reducing mill e as finishing mill, but with direct-connected form configuration, specifically, these 2 milling trains are to be slightly larger than interval and the in series configuration on same straight line by the length of the rolling hollow forging of continuous elongating mill.By this configuration, can before replying, the strain that is produced by continuous rolling-tube unit d further process by tension force size-reducing mill e immediately.Can make the hollow forging recrystal grain refinement effectively that takes place later by the processing of satisfying this condition.
Even in the occasion with same road secondary program tubulation, when continuous rolling-tube unit d and tension force size-reducing mill e partition distance separate configurations, the temperature of hollow forging reduces, and the crystal grain diameter after the crystallization is grown up again, and work hardening seriously occurs.In order to obtain steel pipe as having of the target of the present invention quality better than existing product, make as described above that continuous rolling-tube unit d and tension force size-reducing mill e are close, in series configuration is indispensable, it connects the length that the length of transporting passage 9 between the two is greater than described hollow forging.Continuous rolling-tube unit d and tension force size-reducing mill e
In addition, as the tension force size-reducing mill e of finish rolling the finishing temperature of the steel pipe after rolling in 870～900 ℃ scope.This is because in the time of in this temperature range, the grain refining effect of crystallization generation is very big more thereafter.And the elastic modelling quantity of material reduces, and Poisson's ratio raises, and yield limit reduces, and it is easier to be out of shape, and work hardening and residual stress are reduced.
Operation is crystallization treatment more 7.
In the present invention, after tension force size-reducing mill e is rolling, steel pipe is carried out crystallization treatment again in the temperature more than the Ar3 transformation temperature before the normalizing.In this operation, the mutual combination of the rolling and rolling processing strain that produces of tension force size-reducing mill e and the slow cooling method of this operation produces crystallization again, realization grain refinement effectively by the continuous extension in the operation in front.This operation is the distinctive processing of the present invention, is very effectively to process facture for improving the quality of products.Crystallization treatment is by what be located at as the tension force size-reducing mill e outlet side of finishing mill again, the conveyer of steel pipe slow cooling is located at transports on the passage 11, and the temperature that makes the steel pipe slow cooling is between 500～600 ℃.
After the rolling end of a period of tension force size-reducing mill e the steel pipe slow cooling is scheduled to the method for normalizing temperature to the temperature below the Ar1 transformation temperature.In this operation, owing to need before normalizing begins, making the remelt junction bundle make grain refinement, so cooling velocity is good a bit slowly.Cooling velocity forms coarse grain or mixes the grain tissue when air cooling is above, the toughness of steel is descended.Therefore, cooling velocity is the cooling velocity that comprises air cooling.Cooling velocity is preferably in below 1.5 ℃/second.
In this operation, for the slow cooling steel pipe, for example for fear of chilling, can adopt exporting to the method that passage 13 covers etc. of transporting between the normalizing device portal from tension force size-reducing mill e as finishing mill, the cover that is used to cover can adopt heat-insulating materials such as mineral wool make liner or with the plate of minute surface with reflected radiation heat as liner.Blank temperature when being easy to guarantee normalizing with the slow cooling method can be saved the energy of normalizing operation.
Operation is normalizing 8.
After the crystallization treatment, steel pipe is sent to heating furnace j again, adopts the method for stove heating to be easy to make the temperature homogenisation of steel pipe, have the advantage that reduces the product deviation significantly at length direction and manufacturing between-lot by transporting passage 13.After the heat treated, will in stove, be heated to steel pipe more than the Ar3 transformation temperature and be sent to the normalizing light and handle furnace apparatus f by transporting passage 15.Handle among the furnace apparatus f at light, the steel pipe that is in the above temperature of Ar3 transformation temperature is protected normalized treatment, prevent that the surface of steel pipe from producing oxide layer.
In order to make steel pipe have enough intensity and toughness, normalizing need be from the temperature chilling more than the Ar3 transformation temperature.In addition, even thick-walled pipe also need cool off with enough fast speed.Therefore, light is handled furnace apparatus f employing and is had the device of the interior outside of cooling pipe simultaneously, and the protector that prevents the steel tube surface oxidation.
Operation is tempering 9.
Be transplanted on the tempering furnace g on the line that is configured in after light is handled furnace apparatus f by passage 17 through the steel pipe that normalized treatment is crossed contiguously.That is, light processing furnace apparatus f and tempering furnace g are connected in series by passage 17.In tempering furnace g by steel pipe being heated to predetermined temperature, soaking, carrying out the air cooling temper.
Because tempering is the important process process of decision final products performance, thus need determine best temperature corresponding to target capabilities, and in the soaking fully of this temperature.The deviation of temperature is to the maximum ± and 10 ℃, be preferably ± 5 ℃.By such processing, can with yield strength and draw the deviation of Zhong Qiangdu be suppressed at target strength ± scope of 50N/mm2 in.
10. operation aligns
After the temper, the passage 19 that transports that transports form by straight line is transported to steel pipe on the entrance side roller-way of the straightener h that is located at temper device rear portion, under the condition of normal temperature, steel pipe is aligned processing by straightener h subsequently, form high-alloy seamless steel pipe as product.
Embodiment:
Manufacture method of the present invention is confirmed by following 2 tests.
Test 1
Investigated the relation between the crackle that produces in rate of straining when pipe carried out drilling/rolling and the perforation back hollow bloom.Test is that the casting mold of 200mm is made with pipe by molten steel being injected internal diameter, and this molten steel has the chemical composition B that is equivalent to the chemical composition A of T5 and is equivalent to T91 shown in the following table 1.Molten steel solidification takes out steel billet after finishing immediately from casting mold.Each steel billet is all cooled off the temperature below the Ar1 transformation temperature shown in the following table 1 (for steel A is 500 ℃, is 600 ℃ for steel B).After this, kept 1 hour more than the Ar3 phase point temperature by heating furnace.Subsequently, the cone-type piercer milling train by experiment usefulness carries out drifting test, the making hollow bloom.At the generation of the hollow bloom that obtains investigation crackle, measure maximum crack depth.
The table 1 test chemical composition (weight %) of steel billet
| Steel Si S N 0. 03～0. | Chemical analysis (weight %) Mn | Transformation temperature (℃) C P | |||||||||||||
| Cr 8 ～ 9. 5 | Mo 0. 85 ～ 1. | Ni ≤ 0. 4 | V 0. 18 ～ 0. | Al 0. 00 5~ 0. | Nb 0. 06 ～ 0. | Cu ≤0 .2 0 | Ar 1 760 | Ar 3 870 | A | 0. 08 ～ 0. 12 | 0. 2 ～ 0. 5 | 0. 3 ～ 0. 6 | ≤ 0. 02 | ≤ 0. 01 | |
| 07 - | 4. 0 | 05 0. 45 | ≤ 0. | 25 - | 04 0. 00 | 1 - | ≤0 .2 | 831 | 914 | B | 0. 09 ～ | 02 5 ～ | 0. 35 ～ | ≤ 0. 02 | ≤ 0. 01 |
| 0. 15 | 0. 5 | 0. 60 | 5 | 6. 0 | 0. 60 | 0. 04 |
The measurement result of the maximum crackle generation degree of depth of table 2 hollow bloom
| Steel | Rate of straining (1/ second) | |||||||
| 1/ 30 | 1/ 70 | 1/ 110 | 1/ 150 | 1/ 190 | 1/ 210 | 1/ 250 | ||
| Maximum crack depth (mm) | A | 0 | 0 | 0 | 0 | 0 | 0.2 | 0.8 |
| B | 0 | 0 | 0 | 0 | 0 | 0.3 | 1.1 | |
Shown in the table 2 is the measurement result of the maximum crackle generation degree of depth of hollow bloom.
As shown in Table 2, for steel A and steel B, when the rate of straining of drilling/rolling in 1/190 (1/ second) and when following, all do not crack in both hollow blooms.In contrast, when rate of straining surpasses 1/210 (1/ second), produced crackle.
Therefore, can confirm that the temperature that the steel billet after will casting once had been cooled to below the Ar1 transformation temperature is heated to the occasion that the temperature that can carry out drilling/rolling is carried out drilling/rolling then, the rate of straining during drilling/rolling must be located at below 1/190 (1/ second).
Test 2
The external diameter of testing used steel billet is identical with test 1 used steel billet with chemical composition.Solidify and from casting mold, take out steel billet immediately after the end, be cooled to the temperature below the Ar1 transformation temperature.Then in heating furnace in Ar
3Transformation temperature is above to be kept 1 hour.Afterwards, under Fig. 7 and condition shown in Figure 8, simulate drilling/rolling, extension is rolling, stretch reducing is rolling, normalizing, tempering and aligning processing.
See Table 3 and table 4 shown in, test No.1～18 be example of the present invention, testing No.19～24 is comparative example, the part of creating conditions of this comparative example is outside scope of the present invention.Test No.25 and test No.26 are the conventional example of making the occasion of steel pipe according to existing operation shown in Figure 1.For conventional example, the rate of straining that the punch of steel billet adds man-hour is little bigger than scope of the present invention, and extends rolling not continuous enforcement of processing simulation of deciding tube reducing with tension force continuously.In addition, decide reducing and rolling from tension force and be cooled to normal temperature to the test material normalizing.Example of the present invention, comparative example are all tested as object with steel A and two kinds of tests of steel B material.Cooling velocity shown in the table 4 will be for testing under the occasion of material from the finishing temperature slow cooling to the above temperature of Ar31 transformation temperature after drilling/rolling and tension force are decided tube reducing and rolled carrying out under table 3 condition
Cooling velocity.Steel A and steel B are being carried out same rolling processing and heat treated occasion, the intensity of the test material of steel A and steel B is different, can not compare yield strength, ballistic work etc., and set different normalizings and temperature, so as can be under different conditions the intensity of comparative test material.
The mechanical strength and the ballistic work of material have been investigated at the test material after the processing.
Result of the test is shown in Table 5.
At first, be benchmark with test No.25, the No.26 of conventional example, compare with example of the present invention.For temperature is 690～820 ℃ steel A, and test No.1～9 of example of the present invention are compared with the test No.25 of conventional example, and crystal grain diameter is little, is obtaining the performance better than conventional example aspect mechanical strength and the ballistic work.In addition, be that 690～810 ℃ steel B adopts for temperature, relatively the test No.26 of test No.10～18 of example of the present invention and conventional example can obtain the result same with the occasion of steel A.
The comparative example of test No.19～24 of making under the condition outside the scope of the invention is compared with example of the present invention, and crystal grain diameter is big, the poor performance of mechanical strength and ballistic work.Its reason is, compares with example of the present invention, and the effect of crystal grain thinning is not little by processing and crystallization again for it, and heat treating regime is unreasonable.
Can confirm that by above result of the test by the high-alloy seamless steel pipe that the inventive method is made, its mechanical performance, performance such as shock-resistant all wait and be better than the high-alloy seamless steel pipe made with existing method.
The comparative example of test No.19～24 of making under the condition outside the scope of the invention is compared with example of the present invention, and crystal grain diameter is big, the poor performance of mechanical strength and ballistic work.Its reason is, compares with example of the present invention, and the effect of crystal grain thinning is not little by processing and crystallization again for it, and heat treating regime is unreasonable.
Can confirm that by above result of the test by the high-alloy seamless steel pipe that the inventive method is made, its mechanical performance, performance such as shock-resistant all wait and be better than the high-alloy seamless steel pipe made with existing method.
According to the present invention, can make high-alloy seamless steel pipe with the continuous a succession of production line from the pipe to the product and under stable creating conditions by manufacturing process and the manufacturing equipment of simplifying.Therefore, the high-alloy seamless steel pipe by manufacture method of the present invention and manufacturing equipment manufacturing of the present invention can have the performance that is better than existing product.In addition, owing to can reduce the construction cost and the operating cost of manufacturing equipment, so can reduce the manufacturing cost of high-alloy seamless steel pipe.In addition, can also make high-alloy seamless steel pipe in large quantities with superior productivity.Like this, high-alloy seamless steel pipe manufacture method of the present invention and manufacturing equipment are fit closely for payable high-alloy seamless steel pipe manufacturing.
Table 3 is rolling for test 2 middle punches, the rolling and finish rolling data of extension
| Table 2 test No | The temperature of packing into of heating of pipe blank stove (℃) | Punch processing | The processing of retained mandrel tandem mill | Remarks | ||||
| Degree of finish (%) | Rate of straining (1/ second) | Degree of finish (%) | Rate of straining (1/ second) | Finishing temperature (℃) | ||||
| 1 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1030 | Example of the present invention |
| 2 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1035 | |
| 3 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1040 | |
| 4 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1045 | |
| 5 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1050 | |
| 6 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1060 | |
| 7 | A | 500 | 35 | 1/180 | 3 | 1/450 | 1070 | |
| 8 | A | 450 | 35 | 1/180 | 3 | 1/450 | 1080 | |
| 9 | A | 300 | 35 | 1/180 | 3 | 1/450 | 1090 | |
| 10 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1080 | |
| 11 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1090 | |
| 12 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1100 | |
| 13 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1105 | |
| 14 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1110 | |
| 15 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1115 | |
| 16 | B | 600 | 35 | 1/180 | 3 | 1/450 | 1120 | |
| 17 | B | 450 | 35 | 1/180 | 3 | 1/450 | 1130 | |
| 18 | B | 300 | 35 | 1/180 | 3 | 1/450 | 1140 | |
| 19 | B | 500 | 35 | 1/180 | 3 | 1/450 | 1010 | Comparative example |
| 20 | B | 500 | 35 | 1/180 | 3 | 1/450 | 1100 | |
| 21 | B | 500 | 35 | 1/180 | 3 | 1/450 | 1150 | |
| 22 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1050 | |
| 23 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1180 | |
| 24 | A | 600 | 35 | 1/180 | 3 | 1/450 | 1250 | |
| 25 | B | Room temperature | 35 | 1/180 | 3 | 1/400 | 1050 | Conventional example |
| 26 | B | 35 | 1/180 | 3 | 1/400 | 1100 |
Table 4 is the normalized conditions and the tempered condition of test 2
| Test No | Normalizing temperature (℃) | Chilling temperature (℃/second) | Temperature (℃) |
| 1 | 920 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 2 | 920 | ℃/second 1.5 (cooling of bright normalizing stove) | 800 |
| 3 | 930 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 4 | 930 | ℃/second 1.5 (cooling of bright normalizing stove) | 800 |
| 5 | 940 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 6 | 940 | ℃/second 1.5 (cooling of bright normalizing stove) | 800 |
| 7 | 950 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 8 | 960 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 9 | 970 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 10 | 1040 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 11 | 1040 | ℃/second 1.5 (cooling of bright normalizing stove) | 800 |
| 12 | 1040 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 13 | 1050 | ℃/second 1.5 (cooling of bright normalizing stove) | 800 |
| 14 | 1050 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 15 | 1050 | ℃/second 1.5 (cooling of bright normalizing stove) | 800 |
| 16 | 1060 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 17 | 1060 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
| 18 | 1060 | ℃/second 1.5 (cooling of bright normalizing stove) | 700 |
The test material that table 5 obtains for test 2 is investigated the intensity and the ballistic work data of material
| Test No | Yield strength (MPa) | Hot strength (MPa) | Elongation after fracture (%) | Ballistic work (J) | Remarks |
| 1 | 550 | 670 | 20.0 | 266 | This test example |
| 2 | 425 | 565 | 21.5 | 266 | |
| 3 | 550 | 670 | 18.5 | 274 | |
| 4 | 425 | 580 | 28.5 | 218 | |
| 5 | 550 | 670 | 18.5 | 275 | |
| 6 | 410 | 555 | 24.5 | 249 | |
| 7 | 550 | 665 | 18.5 | 282 | |
| 8 | 545 | 670 | 20.5 | 279 | |
| 9 | 540 | 655 | 14.0 | 284 | |
| 10 | 720 | 995 | 18.0 | 367 | |
| 11 | 605 | 840 | 19.5 | 368 | |
| 12 | 720 | 995 | 17.5 | 379 | |
| 13 | 620 | 860 | 26.0 | 302 | |
| 14 | 720 | 995 | 17.0 | 380 | |
| 15 | 595 | 825 | 22.5 | 345 | |
| 16 | 715 | 990 | 16.5 | 390 | |
| 17 | 720 | 995 | 18.5 | 386 | |
| 18 | 705 | 975 | 13.5 | 393 | |
| 19 | 420 | 535 | 27.5 | 218 | Comparative example |
| 20 | 385 | 510 | 29.0 | 182 | |
| 21 | 360 | 475 | 30.5 | 175 |
| 22 | 580 | 775 | 21.5 | 289 | |
| 23 | 520 | 630 | 23.5 | 261 | |
| 24 | 495 | 595 | 24.5 | 256 | |
| 25 | 315 | 440 | 28.5 | 167 | Conventional example |
| 26 | 375 | 515 | 20.5 | 230 |
Claims (10)
1, a kind of high-alloy seamless steel pipe manufacture method is characterized in that: this method comprise continuous successively 1. following～10. operation;
1. be the operation of the pipe of circle by continuous casting manufactured transverse shape;
2. above-mentioned pipe is cooled to below the Ar1 transformation temperature operation in 200～300 ℃ the temperature range;
The above-mentioned pipe that 3. will cool off is heated to the heating process that can carry out piercing temperature;
The pipe that 4. will be heated to the temperature that can bore a hole carries out the operation of drilling/rolling, manufacturing hollow bloom with the rate of straining of 1/190～1/300 (1/ second);
5. by with the direct continuous elongating mill of configuration of punch with being connected, when the mean strain speed of being scheduled to processing and finishing temperature hollow bloom is extended rolling manufacturing hollow forging;
6. above-mentioned hollow forging is carried out tension force and decide the operation that tube reducing is made steel pipe;
7. in the temperature range between Ar1 transformation temperature and Ar3 transformation temperature, steel pipe is carried out again the operation of crystallization treatment;
8. in the Ar3 transformation temperature to 200 ℃ temperature range more than the transformation temperature, steel pipe is carried out the operation of normalized treatment;
9. above-mentioned steel pipe is carried out the operation of temper;
10. the operation that above-mentioned steel pipe is aligned.
2, high-alloy seamless steel pipe manufacture method according to claim 1, it is characterized in that: implement described tension force and decide operation that tube reducing handles 6. the time, be directly to carry out deciding tube reducing manufacturing processing at the steel pipe that 5. described operation is handled, do not need the reheating furnace heat treated.
3, the manufacture method of the golden seamless steel pipe of height according to claim 1, it is characterized in that: the operation of implementing described crystallization treatment again is 7. the time, and being the steel pipe that will 6. make in described operation is cooled to Temperature Treatment between Ar1 transformation temperature and the Ar3 transformation temperature with the cooling velocity of air cooling.
4, high-alloy seamless steel pipe manufacture method according to claim 1, it is characterized in that: 8. the operation of implementing described normalized treatment is with in described operation 7. the time, handled steel pipe is heated to the Ar3 transformation temperature again and in the temperature between 200 ℃, carries out normalized treatment with bright normalizing furnace to the transformation temperature.
5, high-alloy seamless steel pipe manufacture method according to claim 1 is characterized in that: the operation of implementing described temper is 9. the time, is that the steel pipe that will 8. handle in described operation is heated to temperature after the Ar1 transformation temperature again and carries out air cooling and handle.
6, a kind of high-alloy seamless steel pipe manufacturing equipment that is used to implement the described method of claim 1, it is characterized in that: the device of following (a)～(h) is configuration continuously successively, promptly, this device comprise be used to make transverse shape for the conticaster (a) of circular pipe by transporting the pipe rotary heating furnace (b) that passage (2) connects the steel billet that is used to heat casting, connect the diagonal rolling conical perforation milling train (c) that is used for the pipe drilling/rolling after the heating is become hollow bloom by passage (5), be connected with and be used for hollow bloom is extended rolling retained mandrel formula continuous rolling-tube unit (d) by transporting passage (7), be connected with the hollow forging that is used for after heating again by passage (9) and carry out the tension force size-reducing mill (e) that tension force is decided the tube reducing processing, be connected with heating furnace (j) by transporting passage (11), be connected with the bright normalizing treating apparatus (f) that is used for the steel pipe after the finish rolling is carried out online normalized treatment successively continuously by transporting passage again, be used for the steel pipe after the normalizing is carried out the tempering furnace (g) of online temper, be used for the finish rolling steel pipe after the heat treatment is processed into the finishing straightener (h) of prespecified geometric.
7, high-alloy seamless steel pipe manufacturing equipment according to claim 6, it is characterized in that: the length of transporting passage (2) between the pipe rotary heating furnace (b) of the conticaster (a) of pipe and steel billet has the distance that makes steel billet temperature pipe is encased in the pipe rotary heating furnace in the scope of Ar1 transformation temperature and room temperature.
8, high-alloy seamless steel pipe manufacturing equipment according to claim 6 is characterized in that: the passage (2) that transports between the pipe rotary heating furnace (b) of the conticaster (a) of pipe and steel billet is to have the pipe temperature to be forced be cooled to the cooling device of Ar1 transformation temperature to the temperature province more than the room temperature.
9, high-alloy seamless steel pipe manufacturing equipment according to claim 6, it is characterized in that: the length of transporting passage 9 between continuous rolling-tube unit d and tension force size-reducing mill e is greater than the length of described hollow forging, the temperature of hollow forging is remained on the Ar3 transformation temperature and be transported to the inlet of tension force size-reducing mill.
10, according to claim 6 or 7 described high-alloy seamless steel pipe manufacturing equipments, it is characterized in that: between tension force size-reducing mill (e) and bright normalizing treating apparatus (f), be provided with the tube quality checkout gear.
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| CN104131232A (en) * | 2014-07-25 | 2014-11-05 | 宝山钢铁股份有限公司 | Seawater corrosion-resistant steel pipe and manufacturing method |
| CN104438334A (en) * | 2014-09-19 | 2015-03-25 | 衡阳华菱钢管有限公司 | Medium-caliber 9Ni low-temperature seamless steel tube and production method |
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