Technical Analysis: Strength Distribution Across Bolt Sections by Forming Methods
2026,05,08
In the precision manufacturing of micro-fasteners (M0.6–M6), the forming process is the primary factor determining a bolt’s mechanical performance. Ningbo Yijun Technology has analyzed how different cold-heading methods influence the strength limits of the bolt head, shank, and threaded portions.
The Impact of Forming Methods (A–D)
Method A: Single-die Two-blow Heading Standard high-speed forming where strength is primarily derived from the raw cold-drawn material properties.
Method B: Multi-station Single Reduction Initial radial compression increases grain density in the shank and threads, offering a moderate strength boost.
Method C: Multi-station Double Reduction Consecutive reductions intensify the work-hardening effect, significantly enhancing fatigue life and hardness for high-demand applications.
Method D: Multi-station Extrusion & Reduction The Premium Process: Features full-length forward extrusion of the shank, followed by precise reduction of the threading section and extrusion of the hex head. This optimizes fiber flow lines for peak mechanical integrity.
