Flow Forming Technology: Principles, Process Details, and Applications

# Flow Forming Technology: Principles, Process Details, and Applications ## 1. Technical Definition **Power Spinning (Flow Forming)** is defined according to DIN 8583 as a process that processes rotationally symmetrical hollow body parts using cylindrical, conical, or curved tubular or cup-shaped blanks. **Application:** Seamless tubular metal parts. ## 2. Process Details ### Operation Process 1. The preform is fixed and clamped onto a mandrel 2. Generally, three or more rotating flow forming rollers are radially pressed into the rotating workpiece 3. Material spreads axially, achieving wall thickness reduction and workpiece elongation This process is also commonly referred to as the **cylindrical flow forming process** or **stretching process**, with two primary modes: - **Forward Stretching** - **Backward Stretching** The fundamental criterion for selecting the process: whether the workpiece is purely tubular or has a bottom that can be clamped. ### Gear Forming In the forward stretching process, tooth profile machining can also be performed, producing a range of different internal gear components. ## 3. Advantages of Power Spinning The purpose of spinning is to reduce workpiece wall thickness. The final state is achieved through pure unidirectional compression. The pressure applied to the material first increases workpiece strength while also extending material length. ### Benefits - Compared to parts produced by metal cutting processes, material properties and load-bearing capacity are improved - Extended service life ## 4. Application Industries Flow forming technology is applied across numerous industries: - **Automotive:** Wheel rims, drive shafts, transmission components - **Aerospace:** Rocket motor casings, aircraft structural components - **Wind and Energy:** Wind turbine towers, pressure vessels - **Pipelines, Oil and Gas:** High-pressure pipes and vessels - **Agriculture and Construction:** Equipment components - **Lighting:** Lighting fixtures and housings - **HVAC:** Heat exchangers and ducting - **Food and Chemical:** Processing equipment ## 5. Equipment Requirements ### Recommended Equipment Types | Equipment Type | Application | Suitable Process | |----------------|-------------|------------------| | Three-roller frame-type power spinning machine | Preferred for cylindrical parts and conical parts with half-angle < 5 degrees | Shear spinning | | Double-roller power spinning machine | Optional for conical parts with half-angle > 5 degrees | Flow forming | ### Key Process Parameters - **Shear Spinning:** Applicable to conical parts (requires half-cone angle > 5 degrees), typical single-pass thinning rate 500mm, use Cr12MoV material with hardness HRC 58-62 - **Shear Roller:** Corner radius of 1-3 times wall thickness - **Flow Forming Roller:** Lead-in angle range of 15-30 degrees ## 6. Conclusion Flow forming is a highly efficient, precise metal forming process that produces seamless, rotationally symmetrical hollow components with superior mechanical properties. Through proper process control, tooling design, and equipment selection, manufacturers can achieve high-quality results across a wide range of applications.