Large spiral blades used in augers, turbines, and industrial conveyors are often formed from flat plate using cold processes rather than casting or hot forging. The goal is to achieve a precise helical geometry while preserving material strength, surface integrity, and dimensional repeatability. The process typically starts with high-strength steel plate that is cut into annular discs or segmented rings using CNC plasma or laser cutting. These blanks are then slit radially and fed into a cold forming system. Through controlled mechanical deformation, the flat geometry is transformed into a continuous helical flight. Key forming methods include: * Progressive roll forming, where a sequence of rollers incrementally induces curvature and pitch * Press forming with custom dies to initiate helix geometry * Stretch forming to refine pitch uniformity and reduce residual stress gradients Because the material is not heated above recrystallization temperature, strain hardening occurs. This i...