Cold Forging

Cold forging (cold heading) plastically deforms metal at room temperature to produce strong, near-net-shape parts with excellent surface finish at high volumes.

Overview

Cold forging, or cold heading, forms metal at room temperature using high-pressure dies to displace material from wire or slug stock. It excels at producing small to medium, mostly axisymmetric parts with consistent grain flow, high strength from work hardening, and very good surface finish. Typical outputs are near-net-shape, often needing only minor machining or threading.

This process shines when you need millions of identical parts or at least medium production volumes, like automotive fasteners and pins. It delivers tight dimensional repeatability, excellent material utilization, and fast cycle times. Tradeoffs include high upfront tooling cost, limited part complexity, and the need for ductile materials that can be formed without cracking. Internal cavities, sharp corners, and extreme length-to-diameter ratios usually require redesign or secondary operations. If your part fits the geometry and material window, cold forging is one of the most cost-effective ways to make strong, precision metal components at scale.

Common Materials

  • Low carbon steel 1018
  • Alloy steel 4140
  • Stainless steel 304
  • Aluminum 6061
  • Copper

Tolerances

±0.002" to ±0.005" on forged dimensions; tighter possible on critical features with secondary coining or machining

Applications

  • Hex bolts and screws
  • Rivets and solid pins
  • Automotive suspension and engine fasteners
  • Small shafts and stepped studs
  • Gear blanks and bearing races
  • Cold-formed bushings and collars

When to Choose Cold Forging

Choose cold forging when you need high volumes of small to medium, mostly axisymmetric metal parts with high strength, good surface finish, and repeatable dimensions. It’s ideal when tooling can be amortized over long runs and the geometry can be achieved by progressive deformation from wire or slug stock. Parts should use ductile materials and avoid deep internal cavities or severe undercuts.

vs Open Die Forging

Pick cold forging over open die forging when you need small to medium parts in large quantities with tight, repeatable tolerances and clean surfaces. Open die suits large, low-volume shapes, while cold forging is effectively a high-speed, high-precision process for fasteners and similar components.

vs Closed Die Forging

Choose cold forging instead of hot closed die forging when the part is relatively small, symmetric, and made from a material that can be formed at room temperature. Cold forging gives better surface finish, tighter tolerances, and no scale, reducing or eliminating machining for high-volume parts.

vs Ring Rolling

Use cold forging rather than ring rolling when you are making solid or headed parts like bolts, pins, and small bearing races rather than large seamless rings. Ring rolling is optimized for big diameter rings; cold forging is better for compact parts that can be formed from wire or short slugs.

vs Upset Forging

Select cold forging (cold heading) over general upset forging when you need very high production rates of headed parts with relatively modest diameter increases. Multi-station cold headers can form complex head shapes quickly and consistently, while upset forging is better suited to larger sections or lower volumes with more flexibility in part geometry.

Design Considerations

  • Favor axisymmetric or near-axisymmetric shapes that can be formed in multiple heading stages from wire or slug stock
  • Avoid sharp corners, thin webs, and deep undercuts; use generous fillet radii to reduce tool stress and improve metal flow
  • Keep realistic length-to-diameter ratios (often ≤3:1 for unsupported sections) to avoid buckling during forming
  • Clearly mark critical-to-function dimensions and tolerances; allow looser tolerances on non-functional features to control cost
  • Design heads, chamfers, and transitions to be formed with simple punch and die geometries, avoiding features that require complex segmented tooling
  • Confirm material grade and condition are suitable for cold work, and specify any heat treatment or machining that will follow forging