CN104028598B - A kind of bellows processing technology - Google Patents

Abstract

The invention discloses a corrugated pipe processing technology, which comprises the following steps: S1, forming a short thick-walled pipe blank into a long thin-walled pipe by using a powerful spinning forming process; S2, forming the long thin-walled pipe obtained in step S1 Heat treatment eliminates work hardening, and the condition of heat treatment is complete annealing; S3, the long thin-walled tube obtained in step S2 is necked and formed by a necking spinning process. The beneficial effects of the present invention are: the present invention not only completely eliminates the longitudinal welds of the tunnel pipe parts, but also can greatly reduce the circumferential welds of the product, has higher forming precision, and is convenient for product assembly; greatly improves the pass rate and processing of products Efficiency reduces the production cost of the product; in the spinning process, the grain is refined, the product quality is good, and the service life is greatly improved.

Description

A kind of corrugated pipe processing technology

technical field

The invention relates to the technical field of metal pipe processing, in particular to a bellows processing technology.

Background technique

The forming process of bellows includes hydroforming, roll forming and welding forming. Hydroforming is the most commonly used forming method for bellows. Using the liquid pressure in the tube blank, the tube blank is bulged in the confining ring until yielding occurs along the ring direction, and then the tube blank is compressed to the required length and small diameter. Bellows mostly use this method. The roll forming process is mainly used to process large corrugated pipes. It relies on the rolling forming of the forming wheel set in the tube blank. It can be formed by single wave rolling, and some devices can also form several corrugations at a time. The corrugated pipes formed by hydroforming and roll forming are all formed by expanding under internal pressure, and the deformation zone bears tensile stress, and the structure performance, stability and performance of internal pressure are poor. For bellows with excessive wave height or special waveform, the stamping welding process is often used. When the wave height exceeds the limit, the elongation of the material does not allow the overall forming process, or when the overall forming is extremely difficult due to the complex waveform, welding is often used. This type of bellows is not suitable for flexible sections of expansion joints because they cannot withstand internal pressure.

At present, the commonly used tunnel pipe is obtained by segmented forming and multi-section welding, that is, each sub-section is processed separately, and then many sub-sections are welded into one by welding technology. The specification requirements of the tunnel pipe are that the pipe diameter is greater than 250mm, the pipe wall thickness is 2.7-3.5mm, and the wave height is 10-15mm. Due to the large pipe diameter, thin pipe thickness, and high wave height, the current processing technology for each section is mostly "plate The traditional process method of "beading-rolling-welding" is to select a plate with a thickness of 2.7-3.5mm, press the wave on the plate, then roll the plate after pressing the wave, and weld the joint to obtain a small section. Finally, several subsections are welded to obtain the tunnel pipe 1, as shown in FIG. 1 . Since the thickness of the currently produced pipes with an outer diameter greater than 250mm is 15-25mm, therefore, it is currently the most economical and economical to select a plate with a thickness of 2.7-3.5mm and use "plate beading-rolling-welding" to manufacture tunnel pipes. effective means of processing.

The traditional manufacturing method of "plate beading-rolling-welding" mainly has the following process disadvantages: (1) The welding area 2 is prone to stress concentration, which reduces the fatigue strength of the product, and the weld area may be produced during long-term storage. Microcracks and expand, affecting the service life of the product; (2) A large number of longitudinal welds, circumferential welds, especially cross welds, making it difficult to guarantee the welding quality of the tunnel pipe. According to the design requirements, the welds of the product The quality must be 100% inspected, and the efficiency of weld inspection is low and the cost is high; (3) Due to the limitations of the process itself, the length of each section is relatively short, currently it is mainly within 1100mm, which makes the number of sections of the tunnel pipe more, The processing technology is complicated and the production efficiency is low; (4) The product deformation is large during the welding process, and the product forming accuracy and consistency are poor. Therefore, the products manufactured by the traditional process method not only have poor forming accuracy, low processing efficiency, and high production cost, but most importantly, the product quality and reliability are poor, which cannot meet the product design requirements.

Chinese patent 91106244.0 discloses a bellows processing method and equipment. The machine tool drives the tube blank to rotate, the spinning wheel feeds and spins along the radial direction, and at the same time, the double plasma torch heats the tube blank heating zone, and the axial pressure head moves along the tube Axial pressure is applied to the billet, and after a wave is formed, the spinning wheel moves a wave moment in the axial direction to carry out the next wave spinning. However, the processing object is a bellows with a small outer diameter D (60-110mm) and a large wall thickness δ (3.5-5mm). Therefore, it is not suitable for bellows with a diameter greater than 250mm and a wall thickness of 2.7-3.5mm. processing. Chinese patent 200810021178.9 discloses a copper corrugated pipe spiral corrugation forming equipment and its forming process. The copper pipe is a hard copper pipe. The forming equipment is provided with a roller device, and the roller device is provided with three rollers in the circumferential direction of the copper pipe. The uniformly distributed rollers roll the copper pipe; the three rollers are all deflected at the same angle to the vertical direction of the axis of the copper pipe, which is the helix angle of the helical corrugation of the copper pipe. However, the processing object is the bellows on the air-conditioning equipment. Since the outer diameter of the bellows on the air-conditioning equipment is small, it is also not suitable for processing bellows with a diameter greater than 250mm and a wall thickness of 2.7-3.5mm. Using the above-mentioned equipment to process corrugated pipes with a pipe diameter greater than 250mm and a pipe wall thickness of 2.7-3.5mm, there are deformation defects due to the large pipe diameter and thin wall thickness during the forming process, and the processing of the tunnel pipe cannot be completed.

Facing the current situation, researching a method for manufacturing tunnel pipe parts with good product forming quality, low production cost, simple and efficient has become a technical problem that technicians in this field urgently need to solve.

Contents of the invention

The object of the present invention is to overcome the disadvantages of the prior art and provide a bellows processing technology with simple process, good forming quality, high forming precision and high processing efficiency.

The purpose of the present invention is achieved by the following technical solutions: a bellows processing technology, which comprises the following steps:

S1. Using the powerful spinning forming process, the short thick-walled tube blank is formed into a long thin-walled tube;

S2. Carrying out heat treatment to the long thin-walled tube obtained in step S1 to eliminate work hardening, the condition of heat treatment is complete annealing;

S3. The long thin-walled tube obtained in step S2 is necked and formed by a necking spinning process.

The diameter of the long thin-walled pipe obtained in step S1 is greater than 250mm, and the wall thickness is 2.7-3.5mm.

The operation method of the powerful spinning forming process in step S1 is: install the short thick-walled tube blank on the mandrel of the spinning machine, the mandrel drives the short thick-walled tube to rotate, and the wheel A of the spinning machine rolls the short The thick-walled tube blank is fed axially, so that the short thick-walled tube blank is continuously thinned and attached to the mandrel to become the required long thin-walled tube.

The powerful spinning forming process includes 3 to 4 passes of spinning, the thinning rate of each pass is 25% to 40%, the axial feed rate is 1.5 to 3.0mm/r, and the core mold speed is 60r/min ~120r/min.

The powerful spinning forming process uses three rotary wheels A for spinning, and the three rotary wheels A are uniformly distributed along the circumference of the mandrel. The working angle of the rotary wheels A is 15° to 30°, and the withdrawal angle of the rotary wheels A is 25°. ～35°, the fillet radius of rotary wheel A is 0.4t ₀ ～1t ₀ , t ₀ is the original wall thickness of the short thick-walled tube blank.

The operation method of the necking spinning process in step S3 is: install the long thin-walled tube obtained in step S2 on the main shaft of the spinning machine, and apply an axial traction force to the tail end of the long thin-walled tube, driven by the main shaft The long thin-walled tube rotates, the spindle speed is 50r/min~100r/min, and it is formed by spinning with three rotary wheels B, which are evenly distributed along the circumference of the mandrel, and the three rotary wheels B of the spinning machine are synchronously along the diameter To feed, the radial feed speed is 0.5 ~ 5.0mm/s, spin the tube wall of the long thin-walled tube, after the waveform spinning on the rear side of the wheel B, start to make axial feed movement, the axial The feed rate is 1~2mm/r. When the trough of spinning reaches the predetermined length, the axial feeding is stopped, and the three rotary wheels B are retracted synchronously in the radial direction, and after feeding a waveform width in the axial direction, the spindle is stopped. The three rotary wheels B are fed radially again synchronously for the next cycle.

The axial traction force F=0.3σS˜0.7σS, wherein, σ is the yield strength of the long thin-walled pipe, and S is the cross-sectional area of the long thin-walled pipe.

The outer diameter of the rotary wheel B used in the necking spinning process is φ=0.5D～2D, D is the outer diameter of the trough of the finished bellows part, and the edge of the rotary wheel B is defined by the plane of the rotary axis of the rotary wheel B. The intercepted profile is composed of three sequentially connected circular arcs. The three sequentially connected circular arcs are arc B at the top and circular arc A and circular arc C symmetrically arranged on both sides of circular arc B. The radius R ₁ of arc B =1t～3t, t is the wall thickness of the long thin-walled tube, the radius R ₀ of arc A and arc C =1.0R～1.2R, R is the fillet radius of the corrugated top of the finished bellows .

The present invention has the following advantages:

Good product quality: the invention not only completely removes the longitudinal weld of the tunnel pipe parts, but also the length of the tunnel corrugated pipe processed by the spinning process is not limited by the process, which is far greater than the 1100mm that can only be achieved by the existing process. Greatly reduce the circumferential weld of the product. At the same time, the forming precision of the new process is higher, which is convenient for product assembly. Moreover, compared with the traditional process, the grains of the products formed by the new process are refined during the spinning process, the metallographic structure is uniform and compact, and the service life is greatly improved.

Increased yield: due to the cancellation of the longitudinal weld, this process can completely avoid the intersecting area of the longitudinal and circumferential welds on the product, the circumferential welds are greatly reduced and the automatic welding process can be used, which greatly reduces the welding difficulty and improves the production efficiency. Product pass rate.

Due to the reduction of the amount of weld seam welding, the workload of welding, weld seam inspection and grinding processes is correspondingly reduced, thereby improving the processing efficiency, and can save a lot of welding material costs and weld seam inspection costs, and reduce the production cost of the product.

Description of drawings

Fig. 1 is the structural representation of prior art processed product

Figure 2 is a schematic diagram of the processing structure of the present invention during powerful spinning

Fig. 3 is a schematic diagram of the right view structure of the present invention during powerful spinning

Fig. 4 is a structural schematic diagram of the rotary wheel A used in the powerful spinning forming of the present invention

Fig. 5 is a schematic diagram of the processing structure during necking spinning of the present invention

Fig. 6 is a right-view structural schematic diagram of the present invention during necking spinning

Fig. 7 is a schematic structural view of the rotary wheel B used in the necking spinning of the present invention

Figure 8 is a schematic diagram of a partially enlarged structure of the rotary wheel B

Fig. 9 is the structural representation of the finished product of the present invention

In the figure, 1-tunnel tube, 2-welding area, 3-mandrel, 4-roller A, 5-straight line A, 6-top arc, 7-straight line B, 8-spindle, 9-traction Motor, 10-rotary wheel B, 11-arc A, 12-arc B, 13-arc C.

detailed description

The present invention will be further described below in conjunction with accompanying drawing and embodiment, protection scope of the present invention is not limited to the following:

Example 1:

A corrugated pipe processing technology, it comprises the following steps:

S1. As shown in Figure 2 and Figure 3, the short thick-walled tube blank is formed into a long thin-walled tube by using a powerful spinning forming process; the material of the short thick-walled tube blank is 5A03 (LF3), and the heat treatment state of the pre-spin blank is O State, short thick-walled blank pipe length L=650mm, inner diameter d=264.6mm, wall thickness t ₀ =10mm, the wall thickness of the long thin-walled pipe obtained in the step S1 is 3mm, and the inner diameter of the trough of the finished bellows is d =247mm, outer diameter D=253mm, fillet radius R=13.2mm at the corrugated top of the finished bellows;

S2. Carry out heat treatment to the long and thin-walled tube obtained in step S1. The condition of heat treatment is complete annealing. After spinning, the preformed blank will be hardened. If the diameter reduction spinning is performed directly, the product is easy to break. Therefore, the preformed blank needs to be heat treated before the diameter reduction spinning to eliminate work hardening;

S3. As shown in FIG. 5 and FIG. 6, the long thin-walled tube obtained in step S2 is necked and formed by a necking spinning process.

As shown in Figure 2 and Figure 3, the operation method of the powerful spinning forming process in the step S1 is as follows: the short thick-walled tube blank is installed on the core mold 3 of the spinning machine, and the blank is pushed up with the tail jacking block. Close on the mandrel 3, the mandrel 3 drives the short thick-walled tube blank to rotate, and the rotary wheel A4 of the spinning machine rolls the short thick-walled tube blank and makes an axial feed movement, so that the short thick-walled tube blank is continuously thinned And lean against mandrel 3 and become required long thin-walled pipe.

According to the process conditions and the accuracy requirements of the workpiece size, the total thinning rate is 70%. The powerful spinning forming process in this embodiment includes 3 passes of spinning, the first pass thinning rate is 30%, and the feed rate is 1.6. mm/r; the thinning rate of the second pass is 30%, and the feed rate is 1.8mm/r; the thinning rate of the third pass is 39%, the feed rate is 1.5mm/r, and the speed of core mold 3 is 75r/r min.

As shown in Fig. 2 and Fig. 3, the described powerful spinning forming process adopts three rotary wheels A4 for spinning, and the three rotary wheels A4 are evenly distributed along the circumferential direction of the mandrel 3, and their radial forces can be balanced with each other, and the deformation zone is approximately Ring, the workpiece size, shape and surface quality are better. As shown in Figure 4, the working angle of the rotary wheel A4 is 20°, the exit angle of the rotary wheel A4 is 30°, the fillet radius of the rotary wheel A4 is 6mm, and _t0 is the original wall thickness of the short thick-walled tube blank, namely The edge of the rotary wheel A4 is cut from the plane of the axis of rotation of the rotary wheel A4. The included angle of the axis of rotation is 20°, the radius of the arc portion 6 at the top is 6mm, and the angle between the straight line portion B7 and the axis of rotation of the wheel is 30°.

As shown in Fig. 5 and Fig. 6, the operation method of the necking spinning process in the step S3 is as follows: one end of the long thin-walled tube obtained in the step S2 is installed on the main shaft 8 of the spinning machine, A traction motor 9 is installed on the other end of the wall pipe, and the traction motor 9 exerts an axial traction force on the tail end of the long thin-walled pipe. This axial traction force can greatly reduce the axial wrinkling tendency during the bellows forming process and improve The forming limit is driven by the main shaft 8 to rotate the long thin-walled tube. The rotating speed of the main shaft 8 is 60r/min. Three rotary wheels B10 are used for spinning forming. The wheel B10 feeds in the radial direction synchronously, and the radial feeding speed is 0.5~5.0mm/s, and spins the tube wall of the long thin-walled tube. Give the movement, the axial feed rate is 2mm/r, when the trough of the spinning reaches the predetermined length, stop the axial feed, and the three rotary wheels B10 will retreat in the radial direction synchronously, and then feed a wave width in the axial direction , the axial feed is stopped, and the three rotary wheels B10 are synchronously fed again in the radial direction, and the next cycle is performed, and finally the tunnel pipe 1 is obtained, as shown in FIG. 9 .

The said axial traction force F=7 tons.

As shown in Fig. 7 and Fig. 8, the outer diameter of the rotary wheel B10 used in the necking spinning process is φ=300mm, and the edge of the rotary wheel B10 is cut by the plane of the rotary axis of the rotary wheel B10. The circular arcs connected in sequence by the three sections are composed of the circular arc B12 at the top and the circular arc A11 and the circular arc C13 symmetrically arranged on both sides of the circular arc B12, and the radius R of the circular arc B12 is ₁ =6mm, and the radius R ₀ of arc A11 and arc C13 =16.2mm, the wheel can better form the corrugated shape and avoid instability in the wave peak area.

Example 2:

A corrugated pipe processing technology, it comprises the following steps:

S1. As shown in Figure 2 and Figure 3, the short thick-walled tube blank is formed into a long thin-walled tube by using a powerful spinning forming process; the material of the short thick-walled tube blank is 5A03 (LF3), and the heat treatment state of the pre-spin blank is O State, short thick-walled blank pipe length L=650mm, inner diameter d=264.6mm, wall thickness t ₀ =10mm, the wall thickness of the long thin-walled pipe obtained in the step S1 is 2.7mm, and the inner diameter of the trough of the finished bellows is d=244.6mm, outer diameter D=250mm, fillet radius R=16.2mm at the top of the finished corrugated pipe waveform;

S2. Heat-treat the long thin-walled tube obtained in step S1. The conditions for heat treatment are complete annealing, the heating temperature is 400°C, the temperature is kept for 60 minutes, and the furnace is cooled to 170°C to eliminate work hardening. After strong spinning, the preformed blank Hardening will occur. If the diameter reduction spinning is performed directly, the product is easy to break. Therefore, the preformed blank needs to be heat treated before the diameter reduction spinning to eliminate work hardening;

S3. As shown in FIG. 5 and FIG. 6, the long thin-walled tube obtained in step S2 is necked and formed by a necking spinning process.

As shown in Figure 2 and Figure 3, the operation method of the powerful spinning forming process in the step S1 is as follows: the short thick-walled tube blank is installed on the core mold 3 of the spinning machine, and the blank is pushed up with the tail jacking block. Close on the mandrel 3, the mandrel 3 drives the short thick-walled tube blank to rotate, and the rotary wheel A4 of the spinning machine rolls the short thick-walled tube blank and makes an axial feed movement, so that the short thick-walled tube blank is continuously thinned And lean against mandrel 3 and become required long thin-walled pipe.

According to the process conditions and the accuracy requirements of the workpiece size, the total thinning rate is 73%. The powerful spinning forming process in this embodiment includes four spinning passes, the first pass thinning rate is 30%, and the feed rate is 3mm /r, the mandrel 3 rotating speed is 100r/min; the second pass thinning rate is 30%, the feed rate is 3mm/r, the mandrel 3 rotating speed is 100r/min; the third pass thinning rate is 26.5%, and the The feed rate is 2.3mm/r, the core mold 3 speed is 100r/min; the fourth pass thinning rate is 25%, the feed rate is 1.34mm/r, and the core mold 3 speed is 75r/min.

As shown in Fig. 2 and Fig. 3, the described powerful spinning forming process adopts three rotary wheels A4 for spinning, and the three rotary wheels A4 are evenly distributed along the circumferential direction of the mandrel 3, and their radial forces can be balanced with each other, and the deformation zone is approximately Ring, the workpiece size, shape and surface quality are better. As shown in Figure 4, the working angle of the rotary wheel A4 is 15°, the withdrawal angle of the rotary wheel A4 is 25°, and the fillet radius of the rotary wheel A4 is 4mm, that is, the edge of the rotary wheel A4 is formed by the rotation axis of the rotary wheel A4 The outline cut from the plane of the center line is composed of three straight line parts A5, the top arc part 6 and the straight line part B7 which are connected in sequence. The radius of the arc portion 6 is 4 mm, and the included angle between the straight portion B7 and the axis of rotation of the rotary wheel A4 is 25°.

As shown in Fig. 5 and Fig. 6, the operation method of the necking spinning process in the step S3 is as follows: install one end of the long thin-walled tube obtained in the step S2 on the main shaft 8 of the spinning machine, A traction motor 9 is installed on the other end of the wall pipe, and the traction motor 9 exerts an axial traction force on the tail end of the long thin-walled pipe. This axial traction force can greatly reduce the axial wrinkling tendency during the bellows forming process and improve The forming limit is driven by the main shaft 8 to rotate the long thin-walled tube. The rotating speed of the main shaft 8 is 50r/min. Three rotary wheels B10 are used for spinning forming. The wheel B10 feeds synchronously in the radial direction, the radial feeding speed is 0.5-5.0mm/s, and spins the tube wall of the long thin-walled tube. Give the movement, the axial feed rate is 1.5mm/r, when the trough of the spinning reaches the predetermined length, stop the axial feed, and the three rotary wheels B10 will retreat in the radial direction synchronously, and then feed a waveform width in the axial direction Finally, the axial feeding is stopped, and the three rotary wheels B10 are synchronously fed again in the radial direction, and the next cycle is performed, and finally the tunnel pipe 1 is obtained, as shown in FIG. 9 .

The said axial traction force F=7 tons.

As shown in Figures 7 and 8, the outer diameter of the rotary wheel B10 used in the necking spinning process is φ=500mm, and the edge of the rotary wheel B10 is cut by the plane of the rotary axis of the rotary wheel B10. Three The circular arcs connected in sequence by the three sections are composed of the circular arc B12 at the top and the circular arc A11 and the circular arc C13 symmetrically arranged on both sides of the circular arc B12, and the radius R of the circular arc B12 is ₁ =8.1mm, the radius R ₀ of the arc A11 and the arc C13 =16.2mm, the rotary wheel can better form the corrugated shape and avoid the instability phenomenon in the peak area.

Example 3:

A corrugated pipe processing technology, it comprises the following steps:

S1. As shown in Figure 2 and Figure 3, the short thick-walled tube blank is formed into a long thin-walled tube by using a powerful spinning forming process; the material of the short thick-walled tube blank is 5A03 (LF3), and the heat treatment state of the pre-spin blank is O State, short thick-walled blank pipe length L=650mm, inner diameter d=264.6mm, wall thickness t ₀ =12mm, the wall thickness of the long thin-walled pipe obtained in the step S1 is 3.5mm, and the inner diameter of the trough of the finished bellows is d=246mm, outer diameter D=253mm, fillet radius R=13.2mm at the corrugated top of the finished bellows;

S2. Heat-treat the long thin-walled tube obtained in step S1. The heat treatment condition is complete annealing, the heating temperature is 390°C, the heat preservation is 70min, and the furnace is cooled to 180°C to eliminate work hardening. After strong spinning, the preformed blank Hardening will occur. If the diameter reduction spinning is performed directly, the product is easy to break. Therefore, the preformed blank needs to be heat treated before the diameter reduction spinning to eliminate work hardening;

S3. As shown in FIG. 5 and FIG. 6, the long thin-walled tube obtained in step S2 is necked and formed by a necking spinning process.

As shown in Figure 2 and Figure 3, the operation method of the powerful spinning forming process in the step S1 is as follows: the short thick-walled tube blank is installed on the core mold 3 of the spinning machine, and the blank is pushed up with the tail jacking block. Close on the mandrel 3, the mandrel 3 drives the short thick-walled tube blank to rotate, and the rotary wheel A4 of the spinning machine rolls the short thick-walled tube blank and makes an axial feed movement, so that the short thick-walled tube blank is continuously thinned And lean against mandrel 3 and become required long thin-walled pipe.

According to the process conditions and the accuracy requirements of the workpiece size, the total thinning rate is 68%. The powerful spinning forming process in this embodiment includes 3 passes of spinning, the first pass thinning rate is 40%, and the feed rate is 1.6. mm/r, core mold 3 speed is 120r/min; second pass thinning rate is 29%, feed rate is 1.8mm/r, core mold 3 speed is 100r/min; third pass thinning rate is 25% , the feed rate is 1.5mm/r, and the core mold 3 speed is 60r/min.

As shown in Fig. 2 and Fig. 3, the described powerful spinning forming process adopts three rotary wheels A4 for spinning, and the three rotary wheels A4 are evenly distributed along the circumferential direction of the mandrel 3, and their radial forces can be balanced with each other, and the deformation zone is approximately Ring, the workpiece size, shape and surface quality are better. As shown in Figure 4, the working angle of the rotary wheel A4 is 30°, the withdrawal angle of the rotary wheel A4 is 35°, the fillet radius of the rotary wheel A4 is 12mm, and _t0 is the original wall thickness of the short thick-walled tube blank, namely The edge of the rotary wheel A4 is cut from the plane of the axis of rotation of the rotary wheel A4. The included angle of the axis of rotation of the shaft is 30°, the radius of the top arc portion 6 is 12mm, and the angle between the axis of rotation of the linear portion B7 and the rotary wheel A4 is 35°.

As shown in Fig. 5 and Fig. 6, the operation method of the necking spinning process in the step S3 is as follows: install one end of the long thin-walled tube obtained in the step S2 on the main shaft 8 of the spinning machine, A traction motor 9 is installed on the other end of the wall pipe, and the traction motor 9 exerts an axial traction force on the tail end of the long thin-walled pipe. This axial traction force can greatly reduce the axial wrinkling tendency during the bellows forming process and improve The forming limit is driven by the main shaft 8 to rotate the long thin-walled tube. The rotating speed of the main shaft 8 is 100r/min. Three rotary wheels B10 are used for spinning forming. The wheel B10 feeds synchronously in the radial direction, the radial feeding speed is 0.5-5.0mm/s, and spins the tube wall of the long thin-walled tube. Give the movement, the axial feed rate is 1mm/r, when the trough of the spinning reaches the predetermined length, stop the axial feed, and the three rotary wheels B10 will retreat in the radial direction synchronously, and then feed a waveform width in the axial direction , the axial feed is stopped, and the three rotary wheels B10 are synchronously fed again in the radial direction, and the next cycle is performed, and finally the tunnel pipe 1 is obtained, as shown in FIG. 9 .

The said axial traction force F=7 tons.

As shown in Figures 7 and 8, the outer diameter of the rotary wheel B10 used in the necking spinning process is φ=126.5mm, and the edge of the rotary wheel B10 is cut from the plane of the rotary axis of the rotary wheel B10 by Three sections of circular arcs connected in sequence, the three sections of circular arcs connected in sequence are the arc B12 at the top and the arc A11 and arc C13 symmetrically arranged on both sides of the arc B12, the radius R of the arc B12 ₁ =3.5mm, and the radius R ₀ of arc A11 and arc C13 =14.5mm, this rotary wheel can better form the corrugated shape and avoid instability in the peak area.

Claims (7)

1. a bellows processing technology, is characterized in that: it comprises the following steps:

S1, employing shear spinning forming technology, be configured as length thin tube by short heavy wall pipe;

S2, the length thin tube obtained by step S1 heat-treat elimination work hardening, and heat treated condition is full annealing;

S3, the length thin tube obtained by step S2 adopt necking in technique to carry out necking down shaping;

The method of operating of the necking in technique in step S3 is: the length thin tube obtained by step S2 is installed on the main shaft (8) of spinning machine, and an axial thrust force is applied to the tail end of length thin tube, length thin tube is driven to rotate by main shaft (8), main shaft (8) rotating speed is 50r/min ~ 100r/min, adopt three spinning roller B(10) rotary press modelling, three spinning roller B(10) uniform along core (3) circumference, three spinning roller B(10 of spinning machine) synchronous radially feeding, radial feed speed is 0.5 ~ 5.0mm/s, spinning is carried out to the tube wall of length thin tube, spinning roller B(10) after rear side waveform rotary press modelling, start to make axial feed motion, axial feed rate is 1 ~ 2mm/r, after the trough of spinning reaches predetermined length, stop axial feed, three spinning roller B(10) synchronously radially return, again after the waveform widths of feeding vertically, stop axial feed, three spinning roller B(10) subsynchronous radially feeding again, carry out next one circulation.

2. a kind of bellows processing technology according to claim 1, it is characterized in that: the external diameter of the length thin tube that step S1 obtains is greater than 250mm, wall thickness is 2.7 ~ 3.5mm.

3. a kind of bellows processing technology according to claim 1, it is characterized in that: the method for operating of the shear spinning forming technology in step S1 is: short heavy wall pipe is installed on the core (3) of spinning machine, core (3) drives short heavy wall pipe blank rotary, the spinning roller A(4 of spinning machine) roll short heavy wall pipe and make axial feed motion, make short heavy wall pipe thinning continuously and the core that reclines (3) and become required length thin tube.

4. a kind of bellows processing technology according to claim 1, it is characterized in that: described shear spinning forming technology comprises 3 ~ 4 passage spinning, each passage reduction is 25% ~ 40%, and axial feed rate is 1.5 ~ 3.0mm/r, and core (3) rotating speed is 60r/min ~ 120r/min.

5. a kind of bellows processing technology according to claim 1, it is characterized in that: described shear spinning forming technology adopts three spinning roller A(4) spinning, three spinning roller A(4) uniform along core (3) circumference, spinning roller A(4) operating angle be 15 ° ~ 30 °, spinning roller A(4) receding angle be 25 ° ~ 35 °, spinning roller A(4) radius of corner be 0.4t ₀~ 1t ₀, t ₀for the original wall thickness of short heavy wall pipe.

6. a kind of bellows processing technology according to claim 1, is characterized in that: described axial thrust force F=0.3 σ S ~ 0.7 σ S, wherein, σ is the yield strength of length thin tube, and S is the cross-sectional area of length thin tube.

7. a kind of bellows processing technology according to claim 1, it is characterized in that: the spinning roller B(10 that described necking in technique adopts) external diameter φ=0.5D ~ 2D, D is the external diameter at finished product bellows part trough place, spinning roller B(10) edge by crossing spinning roller B(10) the profile that intercepts of the plane of revolution axial line be made up of the circular arc that three sections connect in turn, described three sections of circular arcs connected in turn are the circular arc B(12 at top) and be symmetricly set in circular arc B(12) the circular arc A(11 of both sides) and circular arc C (13), circular arc B(12) radius R ₁=1t ~ 3t, t is the wall thickness of length thin tube, circular arc A(11) and the radius R of circular arc C (13) ₀=1.0R ~ 1.2R, R is the radius of corner on finished product bellows waveform top.