Cold Forging and Aluminum Forging Services

Cold forging is a metal forging process that plastically deforms metal at or near room temperature under compressive force, using a press and dies. Other routes are hot, warm, open-die and closed-die (impression-die) forging, plus ring rolling. ASTM A788 classifies steel forgings as cold-worked, hot-cold-worked, or hot-worked.

Use cold forging for tight dimensional control, good surface finish and efficient material use on small, high-volume parts such as fasteners, fittings and small shafts. It is less suitable for very large parts or low-ductility alloys, where hot or warm forging is usually the better route for forged steel.

The cold forging process follows a defined sequence: material selection, tooling, forming, secondary operations and inspection. The drawing and the applicable forging standard set each step.

1. 1. Review the drawing and application The supplier reviews geometry, alloy, tolerances, load path and any standard called out, such as ASTM A788, to confirm the practical route.
2. 2. Confirm material and route Alloy, grade and temperature classification (cold-worked, hot-cold-worked or hot-worked) are fixed.
3. 3. Design and build tooling Dies are designed for the part and press. Draft, parting lines and die-fill limits govern the achievable tolerances.
4. 4. Prepare the stock Bar, wire or billet is cut to weight and may be annealed, coated or lubricated for the cold forming loads.
5. 5. Form the part The press deforms the stock in one or more stations. High forming loads make press capacity and tooling condition important. Excess material, called flash, is trimmed afterward where the die design produces it.
6. 6. Heat treat and finish Heat treatment is applied where specified, followed by trimming, shot blasting, coating or machining.
7. 7. Inspect and document Visual examination is standard. Magnetic-particle testing (MT) or penetrant testing (PT) is added where required, and ultrasonic testing where specified. Mechanical testing covers tensile, elongation, reduction of area and hardness as specified.

Material choice drives both the forming route and the final properties. The table lists common forging materials from the fact pack; AA 6061 is the aluminum alloy listed for aluminum forging, and its properties depend on temper.

Finishes and secondary operations

Finishes are specified on the drawing, not assumed. Common options are as-forged with scale and flash removed, shot blasted, machined on critical surfaces, coated (plating, anodizing or paint), or heat treated as specified. Cold forging gives good surface finish and dimensional control, so parts often need less machining than hot-forged equivalents.

There is no universal forging tolerance. Dimensional tolerance is part-specific and depends on route, size, geometry, die capability, and machining allowance. The table lists the specification parameters buyers should control, with the standard or source for each.

Lead time is quoted per part and supplier. Factors include tooling build, material availability, heat treatment, testing, and machining. SR returns quotes within 5-7 working days of a complete RFQ, and the quoted lead time covers the full route to delivery.

Most cold forging cost is set at the design stage. These rules reduce tooling, forming, and finishing cost without weakening the part.

• Keep the shape symmetrical and simple. Cold forging needs high forming loads, and complex geometry drives press capacity and tooling cost.
• Allow draft and respect die-fill limits. Plan parting lines where they will not sit on a critical surface.
• Specify tolerances only where they matter. Part-specific tolerances on non-critical features add cost with no functional gain.
• Add machining allowance only to critical surfaces. Extra stock on every surface increases weight, material use, and cycle time.
• Choose an alloy that suits the route. Cold forging needs ductility; limited-ductility alloys may push the part to warm or hot forging.
• Design for one or few forming stations. Extra stations add tooling and press time.
• State testing and inspection up front. Visual examination is standard; MT, PT, or ultrasonic testing add cost, so specify them only where required.

Custom forgings are typically used for fasteners, fittings, shafts, gears and structural parts where directional strength, fatigue resistance and material integrity matter. Cold forging suits high-volume parts with tight dimensions, while aluminum forging suits lightweight structural parts.

Forging route selection

Forging cost is driven by the route, the tooling, the material, and the amount of secondary work. Cold forging reduces material waste through high material utilization but requires substantial tooling and high forming loads. Hot forging carries lower tooling cost but adds scale, distortion, energy use, and post-forging heat treatment.

• Route: cold, warm, hot, open-die, closed-die, or ring rolling, each with different tooling and energy profiles.
• Tooling: die design and build, plus tooling life at the required forming loads.
• Material: alloy, grade, and stock weight, including any machining allowance left on the part.
• Forming: number of stations, press capacity, and cycle time.
• Heat treatment: normalizing, quenching and tempering, or solution treatment where specified.
• Machining: how much stock must be removed to hit drawing tolerances and surface finish.
• Inspection and testing: visual examination as standard, plus MT, PT, ultrasonic testing, and mechanical testing where specified.
• Volume and lot size: setup and tooling are spread across the production run.

Ordering cold and aluminum forgings through SR gives you one point of contact and a vetted supplier network, because SR is a manufacturing broker, not a factory. SR collects quotes, manages quality and inspection, and delivers parts, so you do not manage separate suppliers for forging, heat treatment, machining and testing.

How to get a useful quote

Send the items below with your request. Ask for heat number traceability if you need each forging linked to its melt, material certificate, processing records, heat treatment and inspection results.

• Drawing with tolerances and surface finish.
• Alloy and grade, with the applicable forging standard.
• Annual quantity and lot size.
• Heat treatment and machining requirements.
• Testing and certification, including any MT, PT, or ultrasonic testing.
• Delivery location and required date.