Forging

Forging plastically deforms heated or cold metal into strong, near-net-shape parts with excellent grain flow and fatigue performance for demanding structural applications.

Overview

Forging shapes metal by compressive force, usually with hammers or presses, to refine grain structure and improve strength. Processes include open die, closed die, cold forging, ring rolling, and upset forging. The result is tough, fatigue-resistant parts with directional grain flow and minimal internal defects compared to stock shapes. As-forged geometry is near-net-shape, with critical surfaces finished by machining.

Use forging for safety-critical or highly loaded parts where mechanical properties and reliability matter more than ultra-tight as-formed tolerances. It excels for medium to high production volumes, moderately complex 3D shapes, thick sections, and parts that see impact, cyclic loading, or harsh environments. Tradeoffs: higher tooling cost than simple forming, more design constraints on part geometry, and the likely need for secondary machining and heat treatment. Done right, it delivers low per-part cost and long service life.

Common Materials

  • Carbon steel 1045
  • Alloy steel 4140
  • Stainless steel 304
  • Aluminum 6061
  • Titanium Ti-6Al-4V
  • Copper

Tolerances

±0.010" to ±0.030" on as-forged features; tighter tolerances require post-machining

Applications

  • Crankshafts and connecting rods
  • Landing gear and structural aircraft fittings
  • Gears and sprockets
  • Hand tools and impact tools
  • Seamless rings and bearing races
  • Heavy construction and mining hardware

When to Choose Forging

Choose forging when you need high-strength, fatigue-resistant parts with good grain flow and toughness in critical load paths. It fits medium to high volumes, thick or highly loaded sections, and geometries that can accept draft, parting lines, and some post-machining. It is especially suited to safety-critical parts in automotive, aerospace, oil and gas, and heavy equipment.

vs Stamping

Pick forging instead of stamping when you need three-dimensional thickness, high section strength, and superior fatigue life rather than thin sheet features. Forging tolerates heavier loads, impact, and higher safety factors, at the cost of more expensive tooling and generally lower geometric detail on fine features.

vs Extrusion

Choose forging over extrusion when the part does not have a constant cross-section or when you need localized grain flow around features like bosses, flanges, or holes. Forging is better for net-shaped, heavily loaded joints and transitions, while extrusions are best for prismatic profiles later cut to length and machined.

vs Wire Forming

Use forging instead of wire forming when the design requires bulk sections, complex 3D shapes, or structural performance beyond what bent wire can provide. Forging is appropriate for load-bearing parts with varying thickness and critical interfaces; wire forming suits lighter duty clips, springs, and brackets from round or shaped wire.

vs CNC Machining

Select forging over machining from bar when material utilization, strength, and grain flow matter more than maximum geometric flexibility. A forged preform can drastically reduce machining time and scrap for high-volume production, while still allowing tight tolerances and fine details via finish machining.

vs Casting

Choose forging instead of casting when you need superior toughness, impact resistance, and low defect rates in critical sections. Forgings handle shock and fatigue better and are preferred where internal porosity or inclusions in castings would pose a failure risk, provided the geometry is compatible with forging rules.

Design Considerations

  • Define a clear, logical parting line and allow the shop to adjust it for manufacturability while preserving critical interfaces
  • Include generous fillet radii and avoid sharp internal corners to promote proper material flow and reduce die stress
  • Provide sufficient draft (typically 3–7° on walls) to allow part ejection and reduce die wear
  • Avoid thin, deep ribs or isolated heavy sections; aim for smooth section transitions and relatively uniform wall thickness
  • Specify realistic as-forged tolerances and clearly identify surfaces to be finish machined, with appropriate machining stock
  • Share load paths, grain-flow requirements, and critical areas early so the forger can orient fiber flow and choose the right forging process