An integral forming process for thin-walled gas cylinder liner

Abstract

The present invention discloses an integral forming process for a thin-walled gas cylinder liner, comprising the following steps: Step 1, selecting an initial blank, the initial blank comprising a bottle body preforming area and a bottle mouth preforming area fixedly connected to both ends of the bottle body preforming area; Step 2, spinning the outer diameter of the bottle body preforming area; Step 3, installing a forming mold, using a push head and a pull head to push and pull the two bottle mouth preforming areas respectively, so that the bottle mouth preforming areas are radially contracted inward to form an intermediate workpiece; the outer diameter of the intermediate workpiece is uniform, and the wall thickness at the bottle mouths at both ends of the intermediate workpiece is greater than the wall thickness at the bottle body; Step 4, closing the bottle mouths at both ends of the intermediate workpiece to form a thin-walled gas cylinder liner. The present invention can realize the integral processing of a thin-walled gas cylinder liner, while ensuring the thin wall of the bottle body, realize the thickening of the bottle mouth, reduce the risk of gas leakage due to fatigue, and improve the bearing capacity of the bottle mouth.

Description

Technical Field

[0001] The invention belongs to the technical field of gas cylinder forming, and in particular relates to an integral forming process for a thin-walled gas cylinder liner. Background Art

[0002] Thin-walled metal cylinder liners require a thin body to reduce weight. However, the necks at both ends experience high stresses due to the arc transition zone, and the necks also need to meet the strength requirements of the threads, so they need to be thickened. Traditionally, the body, neck, and end caps are welded together. However, pressure burst tests and field applications have shown that welded joints are prone to fatigue, leading to gas leaks.

[0003] Existing stamping and neck-spinning technologies can achieve the overall forming of the liner and thicken the bottle mouth. However, it is difficult to achieve thickening the bottle mouth through neck-spinning while ensuring the thin wall of the bottle body. Therefore, it is urgent to find an overall processing method that can solve the above problems.

[0004] Therefore, an integral forming process for thin-walled gas cylinder liner is proposed. Summary of the Invention

[0005] The object of the present invention is to provide an integral forming process for a thin-walled gas cylinder liner, aiming to solve or improve at least one of the above-mentioned technical problems.

[0006] To achieve the above object, the present invention provides the following solution: The present invention provides an integral forming process for a thin-walled gas cylinder liner, comprising the following steps:

[0007] Step 1: Select an initial blank, which includes a bottle body pre-forming area and a bottle mouth pre-forming area fixed to both ends of the bottle body pre-forming area;

[0008] Step 2: thinning the outer diameter of the preformed area of ​​the bottle body;

[0009] Step 3: Install the forming mold, use the push head and pull head to push and pull the two bottle mouth pre-forming areas respectively, so that the bottle mouth pre-forming areas shrink radially inward to form an intermediate workpiece; the outer diameter of the intermediate workpiece is uniform, and the wall thickness of the bottle mouth at both ends of the intermediate workpiece is greater than the wall thickness of the bottle body;

[0010] Step 4: Close the bottle mouths at both ends of the intermediate workpiece to form a thin-walled gas cylinder liner.

[0011] Preferably, in the fourth step, when performing the closing process, a rotary clamp is used to clamp one end of the intermediate workpiece, a shaping surface friction block is used to abut against the outer wall of the bottle mouth at one end of the intermediate workpiece, and the distance between the upper surface of the shaping surface friction block and the bottom of the outer wall of the bottle mouth of the intermediate workpiece is adjusted according to the diameter reduction amount;

[0012] The rotary fixture drives the intermediate workpiece to rotate, and at the same time the friction block on the forming surface rotates 90 degrees, so that the bottle mouth at one end of the intermediate workpiece is closed and formed;

[0013] Swap the bottle openings at both ends of the middle workpiece, repeat the above steps, and close the bottle opening at the other end of the middle workpiece to form a thin-walled gas cylinder liner.

[0014] Preferably, in step four, the rotary fixture drives the intermediate workpiece to rotate around the axis of the rotary fixture; the forming surface friction block is set to rotate 90° along the rotation center line; the rotation center line is perpendicular to the axis of the rotary fixture and the upper and lower surfaces of the forming surface friction block, and the rotation center line is set close to the bottle body of the intermediate workpiece.

[0015] Preferably, in step 3, the pushing head includes a chuck, and a plurality of claws are circumferentially equidistantly provided on the chuck; the forming mold is installed in the bottle body preforming area, the plurality of claws abut against the end of one bottle mouth preforming area, the pull head clamps the outer wall of the other bottle mouth preforming area, the plurality of claws push, and the pull head pulls, and the plurality of claws simultaneously contract radially during the pushing process, always maintaining contact with the end surface of the bottle mouth preforming area; the bottle mouth preforming area close to the claws passes through the inner wall of the forming mold under the pushing of the plurality of claws, so that the bottle mouth preforming area contracts radially inward;

[0016] The two bottle mouth preforming areas are swapped and the above steps are repeated to shrink the other bottle mouth preforming area radially inward to form an intermediate workpiece.

[0017] Preferably, in step 3, the forming mold includes two oppositely arranged clamping blocks, and the opposite end surfaces of the two clamping blocks are provided with clamping grooves, and the two clamping grooves are combined to form a cylindrical clamping groove; when installing the forming mold, the two clamping blocks are fixedly sleeved outside the pre-forming area of ​​the bottle body;

[0018] When the plurality of clamping claws push, the outer wall of the bottle mouth preforming area contacts with the cylindrical clamping groove and is squeezed, so that the bottle mouth preforming area contracts radially inward.

[0019] Preferably, in the step 2, the initial blank is placed on the core rod, the spinning head is placed at one end of the bottle body preforming area, and the initial pressing and thinning amount is adjusted;

[0020] The spinning head rotates along its own axis and simultaneously rotates around the outer wall of the core rod, and simultaneously moves along the axis of the core rod to spin and thin the outer diameter of the preformed area of ​​the bottle body;

[0021] The distance between the spinning head and the outer wall of the bottle preforming area is radially adjusted to adjust the amount of downward pressure thinning. The spinning head moves back and forth. After several passes of spinning thinning, the outer diameter of the bottle preforming area is thinned to the finished product size. After spinning thinning, the inner diameters of the bottle preforming area and the bottle mouth preforming area are unified, and the wall thickness of the bottle mouth preforming area is greater than that of the bottle body preforming area.

[0022] Preferably, in the step 2, after the outer diameter of the pre-formed area of ​​the bottle body is spun and thinned, the pre-formed area of ​​the bottle mouth is heat treated to facilitate metal plastic deformation.

[0023] Preferably, in step three, the pushing speed of the claws is 0.3-0.7 mm / s, and the pulling speed of the pull head is 0.3-0.7 mm / s.

[0024] Preferably, in step 2, the thinning rate of the spinning head per pass is 8-15%, the moving speed of the spinning head along the axis of the core rod is 3-4 mm / s, and the rotating speed of the spinning head around the outer wall of the core rod is 80-120 r / min.

[0025] Preferably, in step three, arc transition sections are provided at both ends of the cylindrical clamping groove.

[0026] The present invention discloses the following technical effects: the present invention thins the outer diameter of the bottle body preforming area of ​​the initial blank, so that the inner diameters of the bottle body preforming area and the bottle mouth preforming area are unified, while the bottle mouth preforming area still retains the initial wall thickness, so that the bottle mouth preforming area can reach the required wall thickness requirement during subsequent processing; then the bottle mouth preforming area is pushed and pulled, so that the bottle mouth preforming area shrinks radially inward to form an intermediate workpiece, the outer diameter of the intermediate workpiece is unified, and the wall thickness at the bottle mouths at both ends of the intermediate workpiece is greater than the wall thickness at the bottle body; finally, the bottle mouth of the intermediate workpiece is closed and spun to form a thin-walled gas cylinder liner. The whole process realizes the overall processing of the thin-walled gas cylinder liner, and achieves the purpose of thickening the bottle mouth while ensuring the thin wall of the bottle body; the present invention can reduce the risk of gas leakage due to fatigue of the bottle body and the bottle mouth area, and improve the bearing capacity of the bottle mouth; and the process of the present invention is simple, the process difficulty is low, the time consumption is short, and it is easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 Schematic diagram of the structure of the initial blank in the present invention;

[0029] Figure 2 This is a three-dimensional schematic diagram of the present invention performing spinning thinning on the preformed area of ​​the bottle body;

[0030] Figure 3 This is a cross-sectional view of the initial spinning of the preformed area of ​​the bottle body according to the present invention;

[0031] Figure 4 This is a cross-sectional view of the bottle body pre-molding area after spinning according to the present invention;

[0032] Figure 5 This is a three-dimensional schematic diagram of the pushing and pulling of the bottle mouth preforming area in the present invention;

[0033] Figure 6 Schematic diagram of the structure of the forming mold in the present invention;

[0034] Figure 7 This is a schematic diagram of the installation of the bottle mouth preforming area before pushing and drawing;

[0035] Figure 8 This is a schematic diagram of the installation of the bottle mouth preforming area after pushing and pulling;

[0036] Figure 9 Schematic diagram of the structure of the intermediate workpiece in the present invention;

[0037] Figure 10 A three-dimensional schematic diagram of the necking spinning process of the present invention;

[0038] Figure 11 A top cross-sectional view of the present invention performing closing spinning;

[0039] Figure 12 This is a schematic diagram of the structure of the friction block on the shaping surface of the present invention after being rotated 90°;

[0040] Figure 13 This is a schematic structural diagram of a thin-walled gas cylinder liner of the present invention;

[0041] Among them, 1. initial blank; 2. bottle body pre-forming area; 3. bottle mouth pre-forming area; 4. rotary fixture; 5. shaping surface friction block; 6. chuck; 7. claw; 8. pull head; 9. cylindrical clamping groove; 10. arc transition section; 11. core rod; 12. spinning head; 13. rotation center line; 14. intermediate workpiece; 15. clamping block. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0044] Reference Figure 1-13 The present invention provides an integral forming process for a thin-walled gas cylinder liner, comprising the following steps:

[0045] Step 1: Select an initial blank 1, which includes a bottle body pre-forming area 2 and a bottle mouth pre-forming area 3 fixed to both ends of the bottle body pre-forming area 2;

[0046] Based on the geometric dimensions of the final thin-walled gas cylinder liner, a straight seamless tube is selected as the raw material for the initial blank 1. The wall thickness of the initial blank 1 is not less than the wall thickness of the mouth area of ​​the thin-walled gas cylinder liner, and the inner diameter of the initial blank 1 is consistent with the inner diameter of the body area of ​​the thin-walled gas cylinder liner. Based on the lengths of the mouth area and body area of ​​the thin-walled gas cylinder liner, the initial blank 1 is divided into a body pre-forming area 2 and a mouth pre-forming area 3 located at both ends of the body pre-forming area 2.

[0047] The length of the thin-walled gas cylinder liner is 300mm. The length of the bottle mouth area of ​​the thin-walled gas cylinder liner is required to be 24mm, the wall thickness is required to be 5mm, the inner diameter of the bottle body area is required to be 37.1mm, and the wall thickness is required to be 0.7mm. Therefore, a pipe with an inner diameter of 37.1mm, a wall thickness of 5mm, and a length of 300mm is selected as the initial blank 1;

[0048] Step 2: thinning the outer diameter of the bottle body preforming area 2;

[0049] Step 3: Install the forming mold, use the push head and pull head 8 to push and pull the two bottle mouth preforming areas 3 respectively, so that the bottle mouth preforming areas 3 shrink radially inward to form an intermediate workpiece 14; the outer diameter of the intermediate workpiece 14 is uniform, and the wall thickness at the bottle mouth at both ends of the intermediate workpiece 14 is greater than the wall thickness at the bottle body;

[0050] Step 4: Close the ends of the intermediate workpiece 14 to form a thin-walled gas cylinder liner;

[0051] The present invention thins the outer diameter of the bottle body preforming area 2 of the initial blank 1, so that the inner diameters of the bottle body preforming area 2 and the bottle mouth preforming area 3 are unified, and the wall thickness of the bottle mouth preforming area 3 is greater than the wall thickness of the bottle body preforming area 2; then the bottle mouth preforming area 3 is pushed and pulled, so that the bottle mouth preforming area 3 is radially inwardly contracted to form an intermediate workpiece 14, the outer diameter of the intermediate workpiece 14 is unified, and the wall thickness at the bottle mouths at both ends of the intermediate workpiece 14 is greater than the wall thickness at the bottle body; finally, the bottle mouth of the intermediate workpiece 14 is closed and spun to form a thin-walled gas cylinder liner. The whole process realizes the overall processing of the bottle mouth preforming area 3 and the bottle body preforming area 2, and achieves the purpose of thickening the bottle mouth while ensuring the thin wall of the bottle body; the present invention can reduce the risk of gas leakage due to fatigue of the bottle body and the bottle mouth area, and improve the bearing capacity of the bottle mouth; and the process of the present invention is simple, the process difficulty is low, the process cost is short, and it is easy to promote; the present invention is also applicable to thin-walled gas cylinder liners with only one end closed.

[0052] Further optimizing the solution, in step 4, when performing the closing process, use the rotary clamp 4 to clamp one end of the intermediate workpiece 14, use the shaping surface friction block 5 to press against the outer wall of the bottle mouth at one end of the intermediate workpiece 14, and adjust the distance between the upper surface of the shaping surface friction block 5 and the bottom of the outer wall of the bottle mouth of the intermediate workpiece 14 according to the reduction amount;

[0053] The rotary fixture 4 drives the intermediate workpiece 14 to rotate, and at the same time the shaping surface friction block 5 rotates 90 degrees, so that the bottle mouth at one end of the intermediate workpiece 14 is closed and formed;

[0054] The bottle openings at both ends of the intermediate workpiece 14 are swapped, and the above steps are repeated to close the bottle opening at the other end of the intermediate workpiece 14 to form a thin-walled gas cylinder liner;

[0055] In step 4, the rotary fixture 4 drives the intermediate workpiece 14 to rotate around the axis of the rotary fixture 4; the shaping surface friction block 5 is set to rotate 90 degrees along the rotation center line 13; the rotation center line 13 is perpendicular to the axis of the rotary fixture 4 and the upper and lower surfaces of the shaping surface friction block 5, and the rotation center line 13 is set close to the bottle body of the intermediate workpiece 14;

[0056] The rotary fixture 4 rotates around its own axis at a high speed of 300r / min, so that the distance between the upper surface of the shaping surface friction block 5 and the bottom of the outer wall of the bottle mouth area of ​​the intermediate workpiece 14 is 10mm. After the bottle mouth of the intermediate workpiece 14 is closed and formed, the outer diameter of the bottle mouth is 18.5mm and the wall thickness is at least 5mm, realizing the precise forming of the thin-walled gas cylinder liner; when performing the closing spinning process, the roller spinning method or the like can also be used to make a reciprocating motion according to the prescribed shape trajectory to gradually close the bottle mouth area.

[0057] Further optimizing the solution, in step 3, the pushing head includes a chuck 6, and the chuck 6 is provided with a plurality of claws 7 at equal intervals in the circumferential direction; the forming mold is installed on the bottle body preforming area 2, the plurality of claws 7 abut the end of one bottle mouth preforming area 3, the pull head 8 clamps the outer wall of the other bottle mouth preforming area 3, the plurality of claws 7 push, and the pull head 8 pulls, and the plurality of claws 7 simultaneously contract radially during the pushing process, always maintaining contact with the end surface of the bottle mouth preforming area 3; the bottle mouth preforming area 3 close to the claws 7 passes through the inner wall of the forming mold under the pushing of the plurality of claws 7, so that the bottle mouth preforming area 3 contracts radially inward;

[0058] The two bottle mouth preforming areas 3 are swapped and the above steps are repeated to shrink the other bottle mouth preforming area 3 radially inward to form an intermediate workpiece 14;

[0059] The forming mold includes two oppositely arranged clamping blocks 15, and the opposite end surfaces of the two clamping blocks 15 are provided with clamping grooves, which together form a cylindrical clamping groove 9; when installing the forming mold, the two clamping blocks 15 are fixedly sleeved outside the bottle body preforming area 2;

[0060] When the plurality of claws 7 push, the outer wall of the bottle mouth pre-forming area 3 contacts the cylindrical clamping groove 9 and is squeezed, causing the bottle mouth pre-forming area 3 to shrink radially inward;

[0061] The pushing speed of the claw 7 is 0.3-0.7 mm / s, and the pulling speed of the slider 8 is 0.3-0.7 mm / s. In this embodiment, the pushing speed of the claw 7 is 0.5 mm / s, and the pulling speed of the slider 8 is 0.5 mm / s.

[0062] In step 3, arc transition sections 10 are provided at both ends of the cylindrical clamping groove 9;

[0063] The diameter of the bottle mouth preforming area 3 after pushing and drawing is equal to the diameter of the cylindrical clamping groove 9, so the diameter of the bottle mouth preforming area 3 changes during the pushing process; the radial movement speeds of the plurality of clamping claws 7 on the chuck 6 are equal, and the radial movement speeds of the clamping claws 7 on the chuck 6 are adjusted to match the diameter change speed of the bottle mouth preforming area 3, so that the plurality of clamping claws 7 always keep in contact with the end surface of the bottle mouth preforming area 3 during the pushing process; the diameter of the cylindrical clamping groove 9 is 38.5mm, and the two clamping blocks 15 are symmetrical up and down. Disassembly connection; arc transition sections 10 are provided at both ends of the cylindrical clamping groove 9. The outer wall of the bottle mouth preforming area 3 is squeezed after contacting the arc transition section 10 of the cylindrical clamping groove 9, which facilitates the bottle mouth preforming area 3 to shrink radially inward. The surface of the claw 7 has a certain arc surface that coincides with the arc transition section 10 to avoid conflict with the clamping block 15 during the advancement process. The outer diameter of the intermediate workpiece 14 is uniformly 38.5mm, the wall thickness of the bottle mouth area at both ends of the intermediate workpiece 14 is about 5mm, and the wall thickness of the bottle body area is 0.7mm.

[0064] To further optimize the solution, in step 2, the initial blank 1 is placed on the core rod 11, the spinning head 12 is placed at one end of the bottle body preforming area 2, and the initial pressing and thinning amount is adjusted;

[0065] The spinning head 12 rotates along its own axis and simultaneously rotates around the outer wall of the core rod 11, and simultaneously moves along the axis direction of the core rod 11 to spin and thin the outer diameter of the bottle body preform area 2;

[0066] The distance between the spinning head 12 and the outer wall of the bottle body preforming area 2 is radially adjusted to adjust the amount of downward pressure thinning. The spinning head 12 moves back and forth, and after several passes of spinning thinning, the outer diameter of the bottle body preforming area 2 is thinned to the finished product size. After spinning thinning, the inner diameters of the bottle body preforming area 2 and the bottle mouth preforming area 3 are uniform, and the wall thickness of the bottle mouth preforming area 3 is greater than that of the bottle body preforming area 2.

[0067] The thinning rate of each pass of the spinning head 12 is 8-15%, the moving speed of the spinning head 12 along the axis of the mandrel 11 is 3-4 mm / s, and the rotating speed of the spinning head 12 around the outer wall of the mandrel 11 is 80-120 r / min. In this embodiment, the thinning rate of each pass of the spinning head 12 is 10%, the moving speed of the spinning head 12 along the axis of the mandrel 11 is 3.3 mm / s, and the rotating speed of the spinning head 12 around the outer wall of the mandrel 11 is 100 r / min.

[0068] The spinning head 12 can be a rotary wheel, a rotary ring or a ball. After several spinning passes, the outer diameter of the bottle body preforming area 2 is thinned and extended, and the outer wall of the bottle body preforming area 2 is thinned to a target wall thickness of 0.7 mm. When spinning reaches the two ends of the bottle body preforming area 2, the spacing between the spinning head 12 and the outer wall of the bottle body preforming area 2 is radially adjusted to achieve a transition from thin to thick wall thickness at both ends of the bottle body preforming area 2. After spinning, the inner diameters of the bottle body preforming area 2 and the bottle mouth preforming area 3 are both 37.1 mm, and the wall thickness of the bottle mouth preforming area 3 is 5 mm. The thinning of the bottle body preforming area 2 can also be achieved by machining. The thinning rate is calculated as the thickness thinned by this spinning divided by the total thickness before thinning. After the bottle body preforming area 2 is thinned, the bottle mouth preforming area 3 still retains the original wall thickness, which facilitates the bottle mouth preforming area 3 to achieve the required wall thickness requirement in subsequent processing.

[0069] To further optimize the solution, in step 2, after the outer diameter of the bottle body preforming area 2 is spun and thinned, the bottle mouth preforming area 3 is heat treated to facilitate metal plastic deformation; in this embodiment, the bottle mouth preforming area 3 is heated to 900°C. When the bottle mouth preforming area 3 is pushed after heating, the metal strength is reduced, which facilitates the bottle mouth preforming area 3 to shrink radially inward.

[0070] In the description of the present invention, it should be understood that the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0071] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. An integral forming process for a thin-walled gas cylinder liner, characterized by: The following steps are involved: Step 1: Select an initial blank (1), the initial blank (1) comprising a bottle body pre-forming area (2) and a bottle mouth pre-forming area (3) fixed to both ends of the bottle body pre-forming area (2); Step 2: reducing the outer diameter of the bottle body preforming area (2); Step 3: Install the forming mold, use the push head and the pull head (8) to push and pull the two bottle mouth preforming areas (3) respectively, so that the bottle mouth preforming areas (3) shrink radially inward to form an intermediate workpiece (14); the outer diameter of the intermediate workpiece (14) is uniform, and the wall thickness of the bottle mouth at both ends of the intermediate workpiece (14) is greater than the wall thickness of the bottle body; Step 4: Close the bottle openings at both ends of the intermediate workpiece (14) to form a thin-walled gas cylinder liner.

2. The integral forming process of the thin-walled gas cylinder liner according to claim 1 is characterized in that: In the fourth step, when performing the closing process, a rotary clamp (4) is used to clamp one end of the intermediate workpiece (14), a shaping surface friction block (5) is used to abut against the outer wall of the bottle mouth of one end of the intermediate workpiece (14), and the distance between the upper surface of the shaping surface friction block (5) and the bottom of the outer wall of the bottle mouth of the intermediate workpiece (14) is adjusted according to the amount of reduction; The rotary fixture (4) drives the intermediate workpiece (14) to rotate, and at the same time the shaping surface friction block (5) rotates 90 degrees, so that the bottle mouth at one end of the intermediate workpiece (14) is closed and formed; The bottle openings at both ends of the intermediate workpiece (14) are exchanged, and the above steps are repeated to close the bottle opening at the other end of the intermediate workpiece (14) to form a thin-walled gas cylinder liner.

3. The integral forming process of the thin-walled gas cylinder liner according to claim 2, characterized in that: In the fourth step, the rotary fixture (4) drives the intermediate workpiece (14) to rotate around the axis of the rotary fixture (4); the shaping surface friction block (5) is set to rotate 90 degrees along the rotation center line (13); the rotation center line (13) is perpendicular to the axis of the rotary fixture (4) and the upper and lower surfaces of the shaping surface friction block (5), and the rotation center line (13) is set close to the bottle body of the intermediate workpiece (14).

4. The integral forming process of the thin-walled gas cylinder liner according to claim 1 is characterized in that: In the step three, the pushing head includes a chuck (6), and a plurality of claws (7) are provided on the chuck (6) at equal intervals in the circumferential direction; the forming mold is installed on the bottle body preforming area (2), the plurality of claws (7) abut against the end of one bottle mouth preforming area (3), the pull head (8) clamps the outer wall of another bottle mouth preforming area (3), the plurality of claws (7) push, and the pull head (8) pulls, and the plurality of claws (7) simultaneously contract radially during the pushing process, and always keep in contact with the end face of the bottle mouth preforming area (3); the bottle mouth preforming area (3) close to the claws (7) passes through the inner wall of the forming mold under the pushing of the plurality of claws (7), so that the bottle mouth preforming area (3) contracts radially inward; The two bottle mouth preforming areas (3) are exchanged and the above steps are repeated to make the other bottle mouth preforming area (3) shrink radially inward to form an intermediate workpiece (14).

5. The integral forming process of the thin-walled gas cylinder liner according to claim 4 is characterized in that: In the step 3, the forming mold includes two clamping blocks (15) arranged opposite to each other, and the two clamping blocks (15) have clamping grooves on their opposite end surfaces, and the two clamping grooves are combined to form a cylindrical clamping groove (9); when the forming mold is installed, the two clamping blocks (15) are fixedly sleeved outside the bottle body preforming area (2); When the plurality of claws (7) push, the outer wall of the bottle mouth preforming area (3) contacts the cylindrical clamping groove (9) and is squeezed, so that the bottle mouth preforming area (3) contracts radially inward.

6. The integral forming process of the thin-walled gas cylinder liner according to claim 1 is characterized in that: In the second step, the initial blank (1) is placed on the core rod (11), the spinning head (12) is placed at one end of the bottle body preforming area (2), and the initial downward pressure thinning amount is adjusted; The spinning head (12) rotates along its own axis while rotating around the outer wall of the core rod (11), and simultaneously moves along the axis of the core rod (11), spinning and thinning the outer diameter of the bottle body preformed area (2); The spacing between the spinning head (12) and the outer wall of the bottle body preforming area (2) is radially adjusted to adjust the amount of downward thinning. The spinning head (12) performs a reciprocating motion. After several passes of spinning thinning, the outer diameter of the bottle body preforming area (2) is thinned to the finished product size. After the spinning thinning, the inner diameters of the bottle body preforming area (2) and the bottle mouth preforming area (3) are unified, and the wall thickness of the bottle mouth preforming area (3) is greater than the wall thickness of the bottle body preforming area (2).

7. The integral forming process of the thin-walled gas cylinder liner according to claim 1 is characterized in that: In the second step, after the outer diameter of the bottle body pre-forming area (2) is thinned by spinning, the bottle mouth pre-forming area (3) is heat treated to facilitate metal plastic deformation.

8. The integral forming process of the thin-walled gas cylinder liner according to claim 4, characterized in that: In the step 3, the pushing speed of the claw (7) is 0.3-0.7 mm / s, and the pulling speed of the pull head (8) is 0.3-0.7 mm / s.

9. The integral forming process of the thin-walled gas cylinder liner according to claim 5, characterized in that: In the step 2, the thinning rate of each pass of the spinning head (12) is 8-15%, the moving speed of the spinning head (12) along the axis direction of the core rod (11) is 3-4 mm / s, and the rotation speed of the spinning head (12) around the outer wall of the core rod (11) is 80-120 r / min.

10. The integral forming process of the thin-walled gas cylinder liner according to claim 5, characterized in that: In the step three, arc transition sections (10) are provided at both ends of the cylindrical clamping groove (9).

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