CN107626766A - Rolling manufacturing method of special-shaped seamless steel tube - Google Patents

Abstract

The invention relates to a rolling manufacturing method of a special-shaped seamless steel pipe, which directly utilizes cold rolling to realize the manufacture of a special-shaped seamless steel pipe, and specifically includes the following process steps: raw material→roller straightening→flaw detection→pretreatment of cold rolling→cold Rolling→heat treatment→straightening→marking→warehousing; hot rolling is performed first to obtain special-shaped seamless steel pipe blanks that are cold-rolled at room temperature, and then cold rolling is used to realize the manufacture of special-shaped seamless steel pipes, specifically including the following processes Steps: raw material→heating→hot rolling→annealing→roller straightening→flaw detection→cold rolling pretreatment→cold rolling→heat treatment→straightening→marking→warehousing. The advantage is that the special-shaped seamless steel pipe can be manufactured without being restricted by raw materials. The combination of hot rolling and cold rolling or cold rolling alone by using rolling tools and mandrel molds has the advantages of easy implementation and high yield. At the same time, it can be flexibly combined and installed according to needs, and the accuracy of installation can be controlled.

Description

A rolling manufacturing method of special-shaped seamless steel pipe

technical field

The invention belongs to the technical field of manufacturing seamless steel pipe products, and in particular relates to a rolling manufacturing method of special-shaped seamless steel pipes.

Background technique

Special-shaped steel pipe is a general term for steel pipes with cross-sectional shapes other than round pipes. With the rapid development of various industries such as construction, manufacturing, aerospace, marine engineering, petrochemical, electric power, highways, high-speed railways, mining machinery, construction machinery, etc., special-shaped steel pipes are economical cross-section profiles that can meet different stress conditions. , attracting more and more attention. Special-shaped steel pipes can better adapt to the particularity of use conditions, save metal and improve labor productivity in parts manufacturing. Special-shaped steel pipes generally have a large moment of inertia and section modulus, and have a large resistance to bending and torsion, which can greatly reduce the structural weight and save steel. There are various types of cross-sections of special-shaped steel pipes: oval, outer square and inner circle, hexagonal, square, octagonal, semicircular, unequal hexagonal, melon seed, etc., and so on.

The traditional main methods for manufacturing special-shaped seamless steel pipes include cold drawing, electric welding, extrusion, hot rolling, etc. Among them, the cold drawing method has been widely used:

One of the traditional main methods of manufacturing special-shaped seamless steel pipes is the "cold drawing method" production process, and its production process includes: tube blank→heating→heading→annealing→pickling→lubrication→cold drawing→heat treatment→straightening→flaw detection→ Mark → Inventory. The limitation of this method lies in the strict requirements on the specifications of raw materials (blank tubes for cold drawing), and one cold drawing die can only be adapted to the production of special-shaped seamless steel pipe products with a narrow range. When the production specifications change, it is necessary to replace the cold drawing die , the production specification change is inflexible and it takes a long time to change the production specification.

Patent application number: 201210332169.8, which discloses a method for manufacturing special-shaped seamless steel pipes, which adopts the method of combining hot extrusion and cold drawing. This method has no substantial difference from the cold drawing process. The key point is to try to There is a margin of variation in the amount of extrusion deformation so that a certain cold drawing die can accept tube blanks of different diameters, but the blank received by the cold drawing die --- the production process of the raw tube blank has not changed. In other words, the patent uses the investment in the production line equipment of the hot extrusion process to replace the large number of cold-drawn mold specifications - the economic value of this method is debatable, not to mention the investment in deep and long hole drilling and drilling equipment is not small .

The above-mentioned patent also discloses a solution: the method of processing welded or seamless steel pipes into special-shaped steel pipes by using roll-type cold-bending to push and deform steel pipes. This patent also provides a large initial development investment. When the design is unreasonable, it is necessary to redesign the processing roll, which will cause a waste of resources such as manpower and material resources, and increase the production cost.

Contents of the invention

In order to overcome the deficiencies of the prior art, the purpose of the present invention is to provide a special-shaped seamless steel pipe roll that will not cause the problem of redesigning and processing the roll when defects are found in the debugging process, economical, safe, low cost, and short construction period. The pressing manufacturing method adopts the combination of hot rolling and cold rolling, or uses cold rolling alone to produce special-shaped seamless steel pipes to achieve surface finishing, which can obtain high surface roughness precision, and at the same time improve the surface quality of the inner and outer surfaces of steel pipes. Hardness, wear resistance and fatigue strength, which can ultimately improve the surface quality of the part.

To achieve the above object, the present invention is achieved through the following technical solutions:

A rolling manufacturing method of a special-shaped seamless steel pipe, which directly utilizes cold rolling to realize the manufacture of a special-shaped seamless steel pipe, specifically includes the following process steps:

Raw materials→roller straightening→flaw detection→cold rolling pretreatment→cold rolling→heat treatment→straightening→marking→storage;

Hot rolling is performed first to obtain special-shaped seamless steel pipe blanks that are cold-rolled at room temperature, and then cold rolling is used to realize the manufacture of special-shaped seamless steel pipes, which specifically includes the following process steps:

Raw materials→heating→hot rolling→annealing→roller straightening→flaw detection→cold rolling pretreatment→cold rolling→heat treatment→straightening→marking→warehousing.

The hot rolling is: when the raw material is heated to 1160-1300°C, under the extrusion of the rolling tool, at the same time, a mandrel mold is set in the inner hole of the raw material, and the relative position of the rolling tool and the mandrel mold is kept fixed No change, that is, no radial movement, no axial movement; the mandrel mold is a layered structure, used for radial contraction and expansion, and the radial stroke of expansion and contraction can ensure that after rolling processing, the core After the diameter of the rod mold is reduced, the surface of the inner hole of the finished special-shaped seamless pipe can not be scratched, and the principle is smooth extraction. The rolling tool is used to cooperate with the outer surface of the raw material and the mandrel mold in the inner hole for rolling forming.

The cold rolling is: using the plastic deformation of metal at normal temperature, so that the raw material is squeezed by the rolling tool, and at the same time, the mandrel mold is set in the inner hole of the raw material, and the rolling tool and the mandrel mold are kept in relative position. Fixed, that is, no radial movement, no axial movement; the mandrel mold is a layered structure, used for radial contraction and expansion, and the radial stroke of expansion and contraction can ensure that after rolling processing, After the mandrel is reduced in diameter, the surface of the inner hole of the finished special-shaped seamless pipe can not be scratched, and the principle is smooth extraction. The rolling tool is used to roll and form the outer surface of the raw material and the mandrel in the inner hole.

The rolling tool includes rollers, which are arranged axially along the mandrel mold, and the feed rate of rolling processing S=0.035-0.1mm; the size tolerance of raw materials before and after rolling is reduced by 10-15% according to the diameter calculation; The pressing speed is controlled at 35-40m/min.

The rollers are arranged in one to three rows along the axial direction of the mandrel mold.

The roller is a ball, a cylindrical roller or a conical roller, and the R of the ball is 3-5 mm.

The size of the mandrel mold used in hot rolling is smaller than the size of the mandrel mold used in cold rolling.

The shape of the wall of the mandrel mold matches the shape of the inner hole of the raw material.

By controlling the shape of the mandrel mold used in the inner hole of the cold-rolled seamless pipe, the ratio of the cross-sectional area of the cold-rolled blank pipe to the special-shaped seamless steel pipe is controlled at 1.01-1.045.

The raw materials are finished seamless steel pipes, semi-finished seamless pipes, blanks for seamless pipes, welded steel pipes or blank pipes.

Compared with prior art, the beneficial effect of the present invention is:

The process route is optimized, and the manufacture of special-shaped seamless steel pipes is realized without restriction of raw materials. The combination of hot rolling and cold rolling or cold rolling alone by using rolling tools and mandrel molds has the advantages of easy implementation and high yield. At the same time, it can be flexibly combined and installed according to needs, and the accuracy of installation can be controlled. A variety of products are used as raw materials, which greatly reduces the construction cost of the production line. If the general-purpose seamless steel pipe is inconvenient to be used as a raw material for some special-shaped products, the rolling process itself can also roll the steel plate and then weld it into a seamless steel pipe as a raw material, ensuring the continuous operation of rolling .

Description of drawings

Figure 1 is a flow chart of the combination of hot rolling and cold rolling.

Fig. 2 is a finished cross-sectional view of the special-shaped seamless steel pipe of the first embodiment.

Fig. 3 is a schematic cross-sectional view of a special-shaped seamless steel pipe formed by balls in Embodiment 1.

Fig. 4 is a schematic structural diagram of the manufacturing process of the special-shaped seamless steel pipe formed by using balls or rollers in the first embodiment.

Fig. 5 is a schematic diagram showing that the balls or rollers are arranged in sequence along the axial direction according to the feed rate when the special-shaped seamless steel pipe of the first embodiment is formed by balls or rollers.

Fig. 6 is a diagram of the working state of the mandrel mold of the first embodiment.

In the figure: 1-special-shaped seamless steel pipe 2-roller 3-connecting shaft 4-support frame 5-axis 6-slide 7-travel block 8-sector plate 9-wedge 10-hydraulic cylinder 11-mandrel.

detailed description

The present invention will be described in detail below in conjunction with the accompanying drawings, but it should be pointed out that the implementation of the present invention is not limited to the following embodiments.

See Fig. 1-Fig. 6, a rolling manufacturing method of special-shaped seamless steel pipes, which directly uses cold rolling to realize the manufacture of special-shaped seamless steel pipes, specifically including the following process steps:

Raw materials→roller straightening→flaw detection→cold rolling pretreatment→cold rolling→heat treatment→straightening→marking→storage;

Hot rolling is performed first to obtain special-shaped seamless steel pipe blanks that are cold-rolled at room temperature, and then cold rolling is used to realize the manufacture of special-shaped seamless steel pipes, which specifically includes the following process steps:

Raw materials→heating→hot rolling→annealing→roller straightening→flaw detection→cold rolling pretreatment→cold rolling→heat treatment→straightening→marking→warehousing.

Among them, the raw materials are finished seamless steel pipes, semi-finished seamless pipes, seamless pipe blanks, welded steel pipes or blank pipe blanks. Only when the cross-sectional shape is special, and it is necessary to provide the initial raw pipe billet that meets the processing requirements of the special cross-section, the non-finished seamless steel pipe or welded steel pipe, or the semi-finished seamless steel pipe——the raw pipe billet is used as the raw material.

The hot rolling step is: when the raw material is heated to 1160-1300°C, under the extrusion of the rolling tool, at the same time, a mandrel mold is set in the inner hole of the raw material, and the relative position of the rolling tool and the mandrel mold is kept fixed. Change, that is, no radial movement, no axial movement; the mandrel mold is a layered structure, used for radial contraction and expansion, and the radial stroke of expansion and contraction can ensure that the mandrel can After shrinking, the inner hole surface of the finished special-shaped seamless pipe can not be scratched, and the principle is smooth extraction. The rolling tool is used for rolling forming on the outer surface of the raw material and the mandrel mold in the inner hole.

Annealing treatment refers to heating the material to a temperature higher than Ac1 and Ac3 (the specific temperature depends on the material, and the standard of the parameter range is given by the raw material composition design research department), heat preservation, and then slowly cooling to obtain a stable state. , Improve the plasticity of steel to facilitate cold rolling processing.

The flaw detection step is to carry out flaw detection treatment on the blank pipe for cold rolling forming, and the cold rolling forming step only performs cold rolling forming on the blank pipe for cold rolling forming that passes the flaw detection. Setting flaw detection steps can improve the product qualification rate.

The pretreatment step of cold rolling includes: after the flaw detection step and before the cold rolling forming step, pickling, heading, phosphating, saponification, and baking drying are performed on the annealed raw material. Setting the pre-processing step of cold rolling can reduce the wear of the mandrel mold and the rolling tool (roller 2) and further improve the qualified rate of the product.

The cold rolling step is: use the plastic deformation of the metal at room temperature to make the raw material under the extrusion of the rolling tool, and at the same time, set the mandrel mold in the inner hole of the raw material, and keep the relative position of the rolling tool and the mandrel mold fixed No change, that is, no radial movement, no axial movement; the mandrel mold is a layered structure, used for radial contraction and expansion, and the radial stroke of expansion and contraction can ensure that after rolling processing, the core After the diameter of the rod mold is reduced, the surface of the inner hole of the finished special-shaped seamless pipe can not be scratched, and the principle is smooth extraction. The rolling tool is used to cooperate with the outer surface of the raw material and the mandrel mold in the inner hole for rolling forming.

Among them, the size of the mandrel mold used in the hot rolling is smaller than the size of the mandrel mold used in the cold rolling, and the size mainly refers to the outer diameter of the mandrel mold.

The rolling tool includes a roller 2, which is arranged along the axial direction of the mandrel mold. The larger the diameter of the roller 2, the larger the surface area of the roller contacting the workpiece, and the plastic deformation is insufficient; when the diameter of the roller 2 and the radius of the arc (that is, the radius of the ball) If it is too small, it will leave indentations on the processing surface. Practice shows that the working diameter of the three rollers 2 is D=11~14mm, the ball R=3~5mm, which is the best size, and the feed rate for rolling processing is S=0.035~ 0.1mm (0.1-0.3mm/r in production, that is, the radial feed of roller 2); the size tolerance of raw materials before and after rolling is reduced by 10-15% according to the diameter; the rolling processing speed is controlled at 35-40m/min. The roller 2 is a ball, a cylindrical roller or a conical roller, preferably a ball or a roller 2, and using the ball as a deformation member can reduce the cost of the entire rolling tool. Moreover, the ball has high precision, high hardness, and a small contact surface with the workpiece. With a small rolling force and a small interference, a high pressure and a small roughness can be obtained. Moreover, the ball has a long service life, is not easy to wear, is cheap, and is easy to replace. The rollers 2 are arranged in 1 to 3 rows along the axial direction of the mandrel mold, and Fig. 3 shows 3 rows.

The wall shape of the mandrel mold matches the shape of the inner hole of the raw material. By controlling the shape of the mandrel mold used in the inner hole of the cold-rolled seamless pipe, the ratio of the cross-sectional area of the cold-rolled blank pipe to the special-shaped seamless steel pipe 1 is controlled at 1.01 to 1.045; if the ratio is too large, the cold-rolled During the pressing process, the shape of the special-shaped seamless steel pipe 1 is not easy to control, and uneven deformation is likely to occur.

The heat treatment is at least one of annealing, normalizing, tempering, quenching, tempering, chemical heat treatment or solution treatment. This heat treatment step is to further meet the quality requirements of different products.

The straightening step is to use arc-shaped anvil to straighten the special-shaped seamless steel pipe after cold rolling. The curvature and cross section of the steel pipe 1 meet the technical requirements.

In addition to the above-mentioned raw materials, with the rapid development of science and technology, the source of raw materials can also be raw materials provided by 3D printing technology. (On August 2, 2015, it was learned from the 705th Research Institute of China Shipbuilding Industry Corporation: Direct metal laser sintering technology is the jewel in the crown of 3D printing technology. Because this technology is directly deposited by laser melting metal powder, the density of structural parts can reach 99% % or more, close to the forged material body. At present, this technology is mainly used in the world to manufacture high-stress components and complex components that cannot be processed by traditional techniques, and the formation of irregular components. It can reach 90% to 95% of the highest strength of the same brand metal %, has the characteristics of high precision and few molding restrictions, and is widely used in high-end precision parts manufacturing and other fields).

Embodiment one

The present invention will be further elaborated below in conjunction with a specific embodiment of a three-lobed seamless steel pipe, but the present invention is not limited thereto. Other special-shaped seamless steel pipes 1: such as outer square inner circle, hexagonal, square, octagonal Shaped, semicircular, unequal hexagonal, melon-shaped special-shaped steel pipes, etc., only need to change the shape of the corresponding hot rolling die and cold rolling die.

Utilize above-mentioned manufacturing method, produce special-shaped seamless steel pipe 1 shown in Fig. 1, specifically adopt following steps to manufacture:

In addition to the above-mentioned raw materials, the source of raw materials can also be special-shaped seamless pipes formed by welding and forming plate-shaped raw materials after rolling.

Hot rolling, the mandrel mold used has a margin for cold rolling, that is, the raw material tube is heated to 1200°C, and then the inner hole is used with a mandrel mold, and the outer ball or rolling wheel is used to extrude the raw material tube , to determine the outer diameter of the raw material for cold rolling, to obtain the raw material for cold rolling (the number of rollers 2 in the axial direction can also be 1, 2...5, etc., the rollers 2 are in the same The number along the circumferential direction (radial direction) on the axial position can also be 1, 2...5, etc., and the shape of the roller 2 can be in various styles, which is determined by the shape of the product);

The pressing form of each roller 2 can be divided into screw mechanical pressing and hydraulic pressing, and electric driving pressing, electro-hydraulic hybrid driving pressing, etc. can also be used. The cost of mechanical pressing is low, and the operation of hydraulic pressing is convenient (controlled by PLC). The transmission mode is a universal joint, and the adjustment range can be large. In order to facilitate the replacement of the rolling wheel, the outer frame and the bottom plate are mostly connected by reversible hinges.

When the pressing form adopts hydraulic pressing, the rolling wheels arranged in the circumferential direction (radial direction) on the same axial position, if the rolling wheels are evenly distributed along the radial direction, the pressing force hydraulic cylinder can move them The hydraulic oil pipeline is connected into an integral connecting ring, which can realize the simultaneous pressure and automatic centering of the rolling wheels evenly distributed in the radial direction; the processed special-shaped seamless tube or tube blank is evenly stressed, and the centering accuracy is high.

As shown in Figure 4, the rolling tool (both hot rolling and cold rolling adopt this structure) includes support frame 4, shaft 5, slideway 6, stroke stopper 7, connecting shaft 3, roller 2, support frame 4 and shaft 5 is fixedly connected, the support frame 4 is slidingly connected with the slideway 6, the support frame 4 is provided with a connecting shaft 3, and the rollers 2 are radially evenly distributed around the connecting shaft 3, and the connecting shaft 3 drives the roller 2 to rotate around the connecting shaft 3, and the connecting shaft The position of 3 is limited by the travel block 7; the support frame 4 is driven by the shaft 5 to advance along the slideway 6 to the outer wall of the raw material. On the slideway 6, on the depressing driving piston rod of the axle 5, a guide key or a guide slider can be set as required, and a position-adjustable stroke stopper 7 can also be set on it or at other suitable positions.

During hot rolling, a mandrel mold is set in the inner hole of the raw material, and the relative position of the rolling tool and the mandrel mold remains fixed (circumferential and axial serial movement is not allowed), and the mandrel mold is Layered, capable of radial contraction and expansion (the radial stroke of expansion and contraction can ensure that after rolling processing, the mandrel mold can be pulled out smoothly without scratching the surface of the inner hole of the finished special-shaped seamless pipe after the diameter is reduced. Designed for the principle), the rolling tool cooperates with the mandrel mold in the inner hole on the outer surface of the raw material - rolling forming.

The mandrel mold has a great influence on the finished product, and the precision can be determined according to the product requirements. If the mandrel mold can be used to produce products with low precision but can meet the user's requirements, the mandrel mold can be used. ; However, if the user is concerned about product accuracy, and the higher cost is acceptable, 3D printing technology can be used to provide a mandrel mold with a small outer diameter and many layers.

See Fig. 4 and Fig. 6, the mandrel mold includes a three-layer structure of a mandrel 11, a wedge 9, and a fan-shaped plate 8 from the inside to the outside, and the wedge 9 and the fan-shaped plate 8 have a three-lobed structure in the radial direction (the number of petals Depends on the number of grooves to be processed, which is the same as the number of grooves to be processed), the outer contour of the wedge 9 along the axis is serrated, the inner contour of the fan-shaped plate 8 matches the outer contour of the wedge 9 along the axis, and the fan-shaped plate The shape of the outer arc of 8 matches the shape of the inner hole wall of the raw material to be processed by rolling; when working, the hydraulic system (hydraulic cylinder 10) drives the wedge 9 to move in the axial direction, so that the inner diameter of the wedge 9 moves along the mandrel 11 , the outer diameter drives the fan-shaped plate 8 to perform a radial movement of contraction and expansion, and Fig. 6 is a schematic diagram of diameter expansion.

Hot rolling can also produce special-shaped seamless steel pipes with spiral grooves that are very difficult (or even impossible) to produce by cold drawing process. Extrude the spiral groove, and this relative position maintains a reliable spiral movement (the realization of the spiral movement is a mature technology, which will not be described in detail here).

Then annealing treatment, roller straightening and flaw detection treatment are carried out sequentially, and the cold rolling waste pipes which pass the flaw detection are sequentially subjected to cold rolling pretreatments such as pickling, heading, phosphating, saponification, and baking drying.

The cold rolling forming treatment after the pretreatment of cold rolling is to use the plastic deformation of the metal at room temperature, so that the processed raw material is squeezed by the rolling tool, and the mandrel mold undergoes radial contraction and expansion inside the raw material. After that, the rolling tool cooperates with the mandrel mold in the inner hole on the outer surface of the raw material - rolling forming.

The number of rollers 2 arranged in the axial direction of the rolling tool is set to 3 rows. When the ball diameter D=12mm and R=4mm, the rolling feed rate S=0.065mm. The dimensional tolerance before and after rolling can be calculated according to the diameter. Shrunk by 10-15%, and the rolling speed is controlled at 37m/min.

Cold rolling forming is a material-saving, energy-saving and efficient metal forming new process and new technology. In the cold rolling forming process, there is only bending deformation, and the thickness of the deformed material remains unchanged during the forming process, except for a slight local thinning at the bending angle of the billet. This processing method is especially suitable for the processing of high-precision products with long and vertical shapes and large batches. Many parts with thin wall, light weight, high rigidity and complex cross-sectional shape can be rolled out.

According to the actual situation, the heat treatment process can also be omitted.

Process characteristics of cold rolling forming:

1) High production efficiency, suitable for mass production

2) The length of processed products is basically unlimited;

3) The product has high precision and good consistency;

4) The surface quality of the product is good;

5) Other auxiliary processing procedures, such as online punching, embossing, welding, riveting, etc., can be integrated on the roll forming production line;

6) Compared with the stamping process, it can save about 20% to 30% of materials;

7) Suitable for forming high-strength steel;

8) The investment in equipment is low, and it is convenient to replace the product after changing the mold;

9) The cross-section can be so complex that stamping is irreplaceable.

There are many ways to clamp the ball, for example, it can be realized by taking the support frame 4 of the used bearing and slightly modifying it, so this embodiment is only for reference.

See Figure 4, if the use of balls cannot meet the needs of manufacturing, the method of roller 2 can also be used. The outer circle of roller 2 is in the shape of a ring, and the overall shape of roller 2 is a disc shape; roller 2 rotates on the connection ( Bearing not shown), the connecting shaft 3 is fixed on the support frame 4, the support frame 4 is connected with the hydraulic cylinder through the shaft 5, the shaft 5 slides in the slideway 6, and the position of the stroke stopper 7 is adjustable.

See Fig. 5, roller 2 can be a plurality of passes (shown in Fig. 5 is 5 passes) in the axial direction of the processed special-shaped seamless pipe for hot rolling. For the roller 2, the pressing stroke can be allocated according to the regulations of the process regulations, and the source of the process parameters can be the existing design data, or it can be inferred based on field experiments and analogies. Roller 2 is in the axial direction of the processed special-shaped seamless pipe. For cold rolling, it is better to use 1 pass, and it should not be more than 3 passes at most. The pressing stroke of each roller 2 can be in accordance with the regulations of the process regulations. For distribution, the source of process parameters can be existing design data, or based on field experiments and analogy inferences, etc.

Claims (10)

1. a kind of rolling manufacture method of special-shaped seamless steel pipe, it is characterised in that directly realize special-shaped seamless steel using cold rolling The manufacture of pipe, specifically include following processing step：

Raw material → roll straightening → flaw detection → cold rolling pre-treatment → cold rolling → heat treatment → aligning → mark → storage；

Heat rolling is first carried out to obtain the special-shaped seamless steel tube blank of progress cold rolling under normal temperature, is then realized using cold rolling different The manufacture of type seamless steel pipe, specifically include following processing step：

Raw material → heating → hot rolling → annealing → roll straightening → flaw detection → cold rolling pre-treatment → cold rolling → heat treatment → Aligning → mark → storage.

A kind of 2. rolling manufacture method of special-shaped seamless steel pipe according to claim 1, it is characterised in that the heat rolling For：Raw material is when being heated to 1160~1300 DEG C, under the extruding of rolling tools, meanwhile, plug mold is set in raw material endoporus, Rolling tools position relative with plug mold keeps immobilizing, i.e., without radial-play, without axial float；Plug mold is layering knot Structure,, can not after plug mold undergauge after the radial stroke of harmomegathus is can ensure that rolling and processing radial contraction and swell Scratch finished product special-shaped seamless pipe bore area, it is principle smoothly to extract out, and rolling tools are used in raw material outer surface and endoporus Plug mold, which coordinates, carries out roll forming.

A kind of 3. rolling manufacture method of special-shaped seamless steel pipe according to claim 1, it is characterised in that the cold rolling For：At normal temperatures utilize metal plastic deformation so that raw material under the extruding of rolling tools, meanwhile, set in raw material endoporus Plug mold, rolling tools position relative with plug mold keeps immobilizing, i.e., without radial-play, without axial float；Plug tire Tool is hierarchy, radial contraction and swell, after the radial stroke of harmomegathus is can ensure that rolling and processing, and plug mold After undergauge can not scratch finished product special-shaped seamless pipe bore area, it be principle smoothly to extract out, and rolling tools are in raw material outer surface Coordinate with the plug mold in endoporus and carry out roll forming.

4. the rolling manufacture method of a kind of special-shaped seamless steel pipe according to Claims 2 or 3, it is characterised in that described Rolling tools include roller, and roller is axially arranged along plug mold, amount of feeding S=0.035~0.1mm of rolling and processing；Rolling Front and rear raw materials size tolerance is calculated by diameter reduces 10~15%；Rolling and processing speed control is in 35~40m/min.

A kind of 5. rolling manufacture method of special-shaped seamless steel pipe according to claim 4, it is characterised in that described roller Along the row of axially arranged 1 row of plug mold~3.

A kind of 6. rolling manufacture method of special-shaped seamless steel pipe according to claim 4, it is characterised in that described roller For ball, cylindrical rollers or conical roller, described ball R=3~5mm.

7. the rolling manufacture method of a kind of special-shaped seamless steel pipe according to claim 3, it is characterised in that heat rolling uses Plug mold size be less than with cold rolling used by plug mold size.

A kind of 8. rolling manufacture method of special-shaped seamless steel pipe according to Claims 2 or 3, it is characterised in that the core The wall shape and the shape of raw material endoporus of rod mold match.

9. the rolling manufacture method of a kind of special-shaped seamless steel pipe according to claim 1, it is characterised in that cold by controlling The shape of the plug mold used in seamless pipe orifice is rolled by cold rolling hollow forging and the cross-sectional area of the special-shaped seamless steel pipe The ratio between control 1.01~1.045.

A kind of 10. rolling manufacture method of special-shaped seamless steel pipe according to claim 1, it is characterised in that the raw material For finished product seamless steel pipe, seamless pipe semi-finished product, seamless pipe blank, welded still pipe or waste pipe.