What is cold heading?

What is cold heading?

The cold heading is an increasingly widespread technology in sectors that require manufacturing large volumes of metal parts with speed, precision and low cost. From industrial fasteners to technical subassemblies in automotive or household appliances, more and more companies are integrating solutions based on cold metal stamping in their production processes.

Although in Spanish there is a tendency to include everything under the same term, it is important to distinguish between sheet metal stamping and cold heading of parts obtained from wire. It is on the latter that we will focus throughout this article.

🔍 It is also known as cold heading, cold forming or cold metal stamping.
In this article we will talk exclusively about its application in parts, not in sheet metal.

What is the process of cold heading?

Cold metal stamping is a plastic forming process carried out at room temperature, without metal removal. It is based on the progressive deformation of the metal by controlled compressive forces acting on a cylindrical billet cut from wire.

In this process, the metal wire is cut into segments called blanks, which are sequentially deformed at various stations of an automatic press. Through the combined action of punches and dies, the material is compressed and flowed into the desired shape.

The most common principles involved in cold heading are:

• Upsetting: localized thickening of the material, as in the formation of a head
• Cold extrusion: reduction of section to form thinner or hollow zones
• Coining: printing of details, marks or geometries in specific areas

This method is highly efficient for manufacturing parts with tight tolerances, good repeatability and excellent material utilization.

Raw materials: materials for cold heading

The basic raw material is metal wire in coils, which is precisely cut before starting the process.

The most common materials are:

• Steel for cold heading, especially low- and medium-carbon steels
• Alloy steels for higher strength parts (e.g. fasteners grade 10.9 or 12.9)
• Stainless steels (300 and 400 series)
• Aluminum and light alloys
• Brass and copper, in technical parts or connectors

Prior to processing, the wire is annealed to improve its ductility, pickled to remove oxides, and coated with solid lubricants (phosphates + stearates, technical polymers, etc.) to protect the tool and reduce friction.

Machinery used in the cold heading

The machines at cold heading are automatic horizontal presses, also called cold headers or cold formers. They consist of:

• A wire feeding and cutting system
• Multiple workstations with dies and punches
• Automatic part transfer systems between stations
• Ejectors and outlet channel

Depending on the complexity of the part, they can have 2 to 7 stations and produce from 60 to more than 300 parts per minute. The quality of the tooling (die materials, coatings, design) is key to the durability of the system.

Key steps of the cold stamping process

The cold heading is developed in a sequence of chained operations inside an automatic press. These are the main stages:

1. Wire cutting: the material is cut to the precise length (blank) that the final piece will occupy.
2. Initial upsetting: localized thickening of the blank to form elements such as screw heads or retention zones.
3. Direct or inverse extrusion: the blank is deformed to modify sections, reduce diameters or generate hollows.
4. Coining of details: specific marks, geometries or shapes are printed by means of controlled compression.
5. Ejection and quality control: the finished part is automatically ejected and can be inspected online.

During the process of cold heading, the material hardens by deformation, which increases its strength. However, it is essential to control critical aspects such as:

• Blank cutting accuracy
• Matrix heating due to accumulated friction
• Progressive wear of tools (critical maintenance)
• Constant lubrication to avoid seizure

Operations after the stamping process

Once the stamped part is obtained, additional processes can be applied depending on the type of component:

• Heat treatments: quenching and tempering to achieve final mechanical properties
• Thread rolling: applied after cold heading on bolts and stud bolts.
• Cleaning/deburring: removal of lubricant residues
• Anti-corrosion coatings: such as electrolytic zinc plating, geometric or lamellar treatments
• Complementary machining: for details that cannot be obtained by stamping

Advantages of the cold heading

The cold heading has multiple industrial benefits, especially in high production:

• Very low material waste (no chips)
• High productivity and automation
• Excellent dimensional repeatability
• Better mechanical properties than machined parts
• Lower emissions by not requiring heating

These advantages have led to its massive adoption in companies of cold heading specialized in big batches for the fastening, automotive or household appliance sector.

What are the disadvantages of cold heading?

Like any technology, cold heading has some limitations:

• Not suitable for extremely complex or asymmetrical geometries
• Requires initial investment in tooling (only profitable for big batches)
• Post-treatments may be necessary to meet final requirements

Even so, its benefits pay off in most industrial environments where efficiency and product strength are paramount.

Do you want to know if your parts can be manufactured using cold heading?

The cold heading of metal parts is one of the most efficient processes in modern industry to manufacture components accurately, quickly and without waste. From steels for cold heading to state-of-the-art automated machinery, the process has evolved to meet the needs of industries such as fasteners, automotive and technical fasteners.

At Lemec we are specialists in manufacturing parts by cold heading. If you have an existing design or are considering incorporating cold forged parts into your supply chain, we can help you evaluate its technical and economic feasibility.