Cold Forging

Cold forging (cold heading) forms ductile metals at room temperature in dies, delivering high strength, good surface finish, and fast, high-volume production.

Overview

Cold forging (often called cold heading) plastically deforms metal at or near room temperature using punches and dies to create near-net-shape parts. The process work-hardens the material and aligns grain flow, so parts typically come out stronger than machined equivalents, with excellent repeatability and minimal material waste.

Choose cold forging for high-volume production of axisymmetric or fastener-like geometries: bolts, pins, rivets, and small drive components. It excels when you want high throughput, good surface finish, and consistent dimensions with limited secondary machining.

Tradeoffs: tooling is expensive and lead times are longer, so it rarely makes sense for low volumes or frequent design changes. Geometry is constrained by die fill, flow limits, and ejection; thin webs, sharp corners, and large undercuts drive risk and cost. Some parts need trimming, piercing, thread rolling, heat treat, or finish machining to hit final features.

Common Materials

  • Carbon steel
  • Alloy steel
  • Stainless steel 304
  • Aluminum 6061
  • Copper
  • Brass

Tolerances

±0.002" to ±0.005"

Applications

  • Hex-head bolts and screws
  • Rivets and solid pins
  • Cold-formed bearing races (preforms)
  • Automotive gear blanks and hubs
  • Electrical terminals and contact pins
  • Nuts and collars (with secondary operations)

When to Choose Cold Forging

Cold forging fits high-volume parts where tooling cost is amortized and cycle time matters. It works best for compact, mostly axisymmetric shapes with generous radii and stable designs that won’t change after tool build. Plan on secondary operations when you need holes, threads, tight critical dimensions, or complex non-axisymmetric features.

vs Open Die Forging

Choose cold forging when the part is small-to-medium, needs tight repeatability, and production volume is high enough to justify dedicated dies. Open die forging suits large, simple shapes and low-volume work where flexibility matters more than near-net accuracy.

vs Closed Die Forging

Choose cold forging when you want room-temperature processing, excellent surface finish, and high-rate production of smaller parts with limited feature depth. Closed die forging is better for larger or more complex shapes that need hot/warm flow to fill details and reduce forming loads.

vs Ring Rolling

Choose cold forging when the part is a solid or short axisymmetric component (fastener, pin, hub) rather than a seamless ring. Ring rolling targets large-diameter rings with controlled cross-sections and is not efficient for solid, headed geometries.

vs Upset Forging

Choose cold forging when the part benefits from multi-station forming (heading, extrusion, sizing) with high repeatability and minimal machining. Upset forging is a good fit for simpler upset-only shapes or larger diameters where dedicated cold-heading tooling and multi-station progression aren’t required.

Design Considerations

  • Keep geometry axisymmetric where possible and avoid undercuts that prevent ejection
  • Use generous corner radii and smooth transitions to reduce forming load and die wear
  • Control length-to-diameter ratios and thin-wall sections to prevent buckling or incomplete fill
  • Specify which dimensions are critical and allow noncritical features to float within standard forging tolerances
  • Plan secondary ops up front (piercing, trimming, thread rolling, heat treat) and call out where machining stock is allowed
  • Provide expected annual volume and material/heat-treat condition so suppliers can select the right header tonnage and die steel