It is primarily used for shaping and forming cylindrical or tubular metal components, such as pipes, tubes, and shafts, to achieve specific dimensions and properties.
The process typically involves the following steps:
A cylindrical metal blank or preform is loaded into the machine.
The machine uses a combination of rollers and spinning or rotating dies to gradually shape the metal blank into the desired form. This process can be likened to a controlled, incremental deformation of the metal.
The metal is typically heated during the process to make it more malleable and easier to form.
The combination of pressure and rotation reduces the thickness of the metal, elongates it, and changes its dimensions while retaining its structural integrity. The specific shape and dimensions are determined by the design of the machine and the dies used.
Flow forming is often used in industries such as aerospace, automotive, and manufacturing, where precision and strength are crucial. It allows for the production of high-quality components with reduced material waste and cost compared to traditional machining methods. The resulting parts often have improved mechanical properties, including increased strength and reduced weight, making them valuable in various applications.
Flow forming is commonly used to produce items like wheels, exhaust pipes, hydraulic cylinders, and other cylindrical or tubular components. It's known for its efficiency, precision, and the ability to create complex shapes with a high degree of accuracy.
Forming process of Aluminum Liner for a Composite High Pressure Hydrogen Cylinder
2.Strong forming usually uses a three wheel forming machine for multiple passes of forming pressure.The thickness of the blank is determined based on the minimum thickness of the product,It is generally suitable to control the thinning rate at around 70%.
3.Before forming,the blank must have a smooth inner and outer surface without defects such as scratches or bumps. Generally,the weight of the blank should be equal to the weight of the finished product+60mm long blank.
4.After forming,the pipe material is required to have no slag inclusion,peeling,or internal defects no scratches or other defects.
After forming and ready to next step,spinning:
Chemical of Composition of Aluminum Alloy Blank/Pipe 6061:
Mechanical Property of Composition of Aluminum Alloy Blank/Pipe 6061:
Strong Flow Forming
Hydrogen gas cylinder blanks are generally prepared using reverse extrusion technology. Due to process limitations, the wall thickness is generally relatively thick, usually around 18-24 millimeters. Hydrogen gas cylinders require a wall thickness of around 5-7 millimeters, and the closing part of the bottle mouth generally needs a thickness of 10-12 millimeters. Therefore, it is necessary to perform strong rotation on thicker blanks.
Strong spinning usually uses a three wheel spinning machine for multi pass spinning. The thickness of the raw material is determined based on the minimum thickness of the product, and it is generally suitable to control it at a thinning rate of about 70%.
Before spinning, the raw material must have a smooth inner and outer surface, without any defects such as scratches or bumps. In general, it is advisable for the weight of the raw material to be equal to the weight of the finished product plus a length of 60mm of raw material of tube. After spinning, the pipe material is required to have no defects such as slag inclusion, peeling, and internal scratches.
Pipe material after flow forming:
1. The inner and outer surfaces of the strong rotary tube blank should be smooth, without cracks, corrosion, inclusions, peeling, bubbles, scratches, bumps, scratches, folds, straight lines, pits and other defects
2. Internal surface quality requirements, roughness Ra2.0, no defects such as cracks, dents, heavy skin, bumps, scratches, etc. on the surface, and consistent polishing patterns on the inner wall (circumferential)
3. The straightness of the strong rotary tube shall not exceed 0.15%
4. The deviation between the average inner diameter of the strong spiral tube and the nominal outer diameter shall not exceed 1% of the nominal outer diameter
5. The difference between the maximum and minimum diameters on the same section of the strong spiral tube exceeds 2% of the average outer diameter of that section
6. Each strong rotary tube shall be inspected and recorded according to the diagram, and inspection documents shall be provided
7. The macrostructure of the strong rotary tube meets the requirements of GB/T4437, and the grain size is not lower than level-2
Strong Flow Forming Machine for Raw Materials
Technical requirements and related parameters
Equipment: Three wheel flow forming machine
Effective diameter of rotary press: 600mm/800mm
Effective length of rotary press: maximum 3200mm
Forming method: Three wheel flow forming
Forming temperature: room temperature, special coolant
Spinning Closure(Cylindrical blank shrink):
Spinning closure is the process of heating and spinning both ends of a pipe material. Due to the need for thread processing inside the small mouth after spinning, and to ensure the strength of the mouth, the thickness of the small mouth after spinning needs to be maintained at around 20mm. Therefore, the thickness of the closing end of the blank pipe is also relatively thick. The hot spinning process is used for the necking of the spinning, and it is necessary to maintain a relatively uniform temperature at the necking area during spinning. The temperature should generally be controlled between 350C-450C, and should not be too high for a long time to prevent coarse material grains from affecting the strength performance of the gas cylinder.
Spinning Closure(Cylindrical blank shrink)
1.The nominal volume of the aluminum alloy inner liner is 210L, and the head surfaces at both ends are symmetrical and consistent with the bottle mouth structure and threads
2.The front and bottom of the aluminum alloy inner liner adopt a gradient thickness design, with smooth transitions between the cylinder and the front, as well as between the cylinder and the bottom
3.The thread of the aluminum alloy liner is 2-12UN-2B, and the dimensions and manufacturing tolerances should comply with GB/T20668 Unified Thread;The requirement is that the surface of the thread should be smooth, and there should be no inverted or disordered teeth;The effective length of the thread should not be less than 22mm
4.The inner and outer surfaces of the aluminum alloy liner are free from visible surface indentation, protrusions, overlaps, cracks, and inclusions;The transition part between the neck and the end is free from sudden changes or obvious wrinkles, and the transition between the cylinder and the end is smooth
5.If surface defects are removed by machining or mechanical grinding, the defect removal area should have a smooth transition and the wall thickness should not be less than the minimum design wall thickness
6.Mark the aluminum inner liner number clockwise on any bottle back end face (near the outer circle) of the aluminum alloy inner liner (to ensure traceability), with a font height of 5-8 and a depth of no more than 0.3mm, with clear marking
7.The deviation between the maximum outer diameter and the maximum inner diameter on the same section of the cylinder shall not exceed 2% of the nominal diameter, and the straightness of the cylinder shall not exceed 0.3% of its length
Technical requirements and parameters
Spinning equipment: Special CNC spinning machine
Maximum shrink diameter: 480,640
Maximum length: 3500mm
Spining temperature: 350~450C
Heating method: Flame
Single cylinder time: 12 minutes * 2 ends
Loading and unloading method: Robotic arm
TW800 CNG & Hydrogen Cylinder Flow Forming Machine Parameters
TW800 Three Wheel Horizontal Strong Forming Machine
Cylindrical blank diameter: 280mm-800mm
Positive rotation length: 3500mmReverse rotation length: 4500mm
Control method: Siemens 840DSL system
Feed power: Siemens servo motor 1FT7 series
Drive control: Siemens S120
Spindle motor power: 200KW
Spindle speed: 200rpm
Two speed transmission,variable transmission in gear continuously
Hydraulic station power 20KW
Radial stroke: 260mm
Axial stroke: 3500mm
Lateral axis thrust: 350KN * 3
Longitudinal axis thrust: 500KN
Long 12.5 meter * width 5.5 meter * height 4.7 meter
Equipment weight: approximately 130 tons
Total power of equipment: 260kw
Manual adjustment of three wheel offset method, with a distance of 10mm
Tail top - main shaft - tail top double center distance 5500mm
Tail top longitudinal stroke
Base 3000mm + top rod 500mm
Tailstock lateral offset 600mm
Tail jacking force max 100kn (adjustable)
Discharging method - slide return stroke 3500mm.