Cold-Working of Metal Wire

Cold-Working of Metal Wire

The purpose of cold-working metal wire is to change its size and shape through plastic deformation at room temperature, while improving its structure and giving it a smooth surface and tight tolerances. The two main methods are cold drawing and cold rolling—which is exactly how cold drawn stainless steel and cold rolled stainless steel are made.

Cold Drawing vs. Cold Rolling

(1) Cold drawing

Drawing uses simple equipment and gives very precise dimensions, which is why it suits fine sections where tolerance matters—cold drawn sections and cold drawn stainless steel are typical. The downside is small per-pass reduction, so many passes are needed; friction at the surface is high and lubrication must be well controlled.

(2) Cold rolling

Rolling gives a large per-pass reduction and low tool wear, and handles larger-diameter wire well—cold rolled special sections and cold rolled stainless steel mostly use this route. The trade-off is more complex machinery and tighter process control.

General Process Flow

A cold-working line for wire usually runs through these steps, with stages added or skipped as needed:

1. Scale removal—chemically (pickling) or mechanically (shot blasting, peeling);
2. Surface coating—chemical or physical, to aid deformation and lubrication;
3. Plastic deformation—cold or warm working;
4. Intermediate heat treatment—annealing, solution annealing, patenting (sorbite) or stress relieving as required;
5. Plastic deformation—further cold or warm working if needed;
6. Final heat treatment—oil quenching and tempering, etc., as required.

The forming equipment is mainly wire drawing machines, draw benches and cold rolling mills; drawing and rolling are the two main routes.

Scale Removal and "Acid-Free" Treatment

Shot blasting is a common mechanical way to remove scale. As environmental rules tighten, "acid-free" surface treatment is gaining attention—it skips the pickling step before forming, cutting acid impact and raising throughput. A bar-peeling machine that clears the surface by machining is another non-acid option.

Coating and Heat Treatment

After cold-working, wire is often supplied with a surface coating or plating, depending on the end use. For heat treatment, continuous annealing lines are the standard form, used for both intermediate and final treatment.

This article is prepared by the technical team at Hubei ERQI New Materials Co., Ltd. We manufacture stainless shaped wire and profile wire in materials such as 304, 316L and 2205 duplex, and offer both cold drawing and cold rolling, made to your drawing and tolerance.

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• Shaped Wire Materials
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• Shaped Wire Manufacturing Process

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