Nickel alloy bars reach their final section and properties through a small set of forming routes: forging, hot rolling, cold drawing, and extrusion. Each route suits a different diameter band and a different balance of strength, dimensional accuracy, and cost. Southerly Alloy supplies nickel alloy bars across this full range of processes and delivery conditions, with full mill certification on every heat.
Forging
Forging shapes nickel alloy bars from heated ingots or blooms under compressive force. It is the route of choice for large diameters, typically above 100 mm, where it refines the cast structure and aligns the grain flow along the bar axis. The result is excellent fatigue strength and toughness for shafts, pressure parts, and offshore service. Radial forging (GFM-type machines) is used to hold tighter tolerances on very large sections.
Hot Rolling
Hot rolling is the most economical route for mid-size diameters, generally from about 20 mm to 100 mm. The alloy is worked above its recrystallization temperature, which breaks up the cast grain and delivers a uniform structure at a competitive cost. Hot-rolled bars are supplied as hot-finished (black) or turned and peeled for better size control and a cleaner surface.
Cold Drawing
Cold drawing pulls hot-rolled or hot-finished bar through a die at room temperature. It is the route for smaller diameters, up to about 40 mm, where it lifts dimensional accuracy to roughly ±0.05 mm and produces a bright, smooth surface. Drawn bars are supplied in bright, peeled, turned, or centreless-ground condition for valves, fasteners, shafts, and machined components.
Extrusion
Extrusion forces heated billet through a shaped die, making complex and custom cross-sections that rolling or drawing cannot reach. It is the process behind special-profile bars — star, omega, T, Z, L, and hat-channel sections. Southerly Alloy supplies extruded special profiles for tooling, structural, and engineered applications where a standard round or flat bar will not fit the design.
Diameter and Process Overlap
The same nickel alloy bar can be reached by more than one route, and the bands overlap. The map below is a practical guide for specifying and quoting.
| Diameter | Primary route | Overlap | Typical use |
|---|---|---|---|
| 3–12 mm | Cold drawn, bright, ground | — | Fasteners, pins, instrument parts, springs |
| 13–40 mm | Cold drawn, peeled, turned, hot-finished | Hot-rolled bar drawn down, or drawn direct | Valve stems, bolts, shafts, fittings |
| 41–100 mm | Hot rolled, peeled, turned, forged | 80–100 mm may be hot rolled or forged | Pump shafts, couplings, heat-exchanger parts |
| 101–250 mm | Forged, rough-turned, peeled | — | Large shafts, pressure parts, offshore |
| >250 mm | Heavy forged, custom blank | — | Industrial equipment, turbine parts |
Surface and Heat-Treatment Conditions
The forming route decides the starting section, but the delivered condition also depends on surface finishing and heat treatment. Bright, peeled, ground, and mirror surfaces are covered in our Bar Surface Finishes & Finishing guide. Solution-annealed, age-hardened, and stress-relieved conditions are covered in our Heat Treatment Services guide.
Bar Shapes We Supply
Round, square, hex, flat, rectangle, and special-profile bars are all available across the nickel alloy grades. The shape pages list the sizes and standards for each grade:
- Bars and rods by grade — the full nickel alloy bar and rod catalogue
- (Per-grade shape pages such as inconel-625-round-bar will be added to this silo as the pilot batch is built.)
Frequently Asked Questions
Which process fits a 90 mm bar?
Either hot rolling or forging can produce a 90 mm bar. Hot rolling is the lower-cost choice for standard stock; forging is preferred when fatigue strength or a clean grain flow matters.
Can you supply cold-drawn bars in large diameters?
Cold drawing is practical up to about 40 mm. Above that, bars are hot rolled or forged and then turned, peeled, or ground to reach the needed accuracy.
Do you supply extruded special profiles?
Yes. Extrusion is the route for star, omega, T, Z, L, and hat-channel sections in nickel alloys. Send the section drawing and we will quote against it.
Are mill certificates provided?
Every heat travels with an EN 10204 3.1 mill certificate.
Request a Quote
Tell us the grade, shape, diameter, condition, and quantity. Southerly Alloy returns a quoted price, lead time, and the certificate package in one reply.