The roll forming process

Roll forming in detail

Cold roll forming is a method of shaping hard metals, such as steels and stainless steels. Very precise, complex cross-sections can be created, and long lengths of these sections can be consistently reproduced.  

Roll forming involves uncoiling a long strip of metal, and sending it through several stacks of rollers set up in a long line. It is performed at room temperature, hence the moniker ‘cold’, which is often dropped. Roll forming at room temperature maintains or even improves the properties of the feedstock material.

Each stack of rollers adds a small additional forming step to the strip, so that by the end of the line, the width of the strip has been formed into the required cross-sectional shape, which can then be cut into the desired lengths. 

The more complex the shape to be formed, the more roller stacks can be added, and at Welser Profile, 60 stacks is not unusual. The finished shape is generally called a roll formed section, a profile or sometimes just a steel tube

For those new to the technology, a single stack of rollers can look similar to an old-fashioned clothes mangel, but with shaped, hardened steel roller tooling rather than flat wooden rollers.

Here at Welser Profile, we build our own tools, including the particularly sophisticated punching tools, which can come in considerable number of sizes. This not only means that our profiles can be reproduced with a consistently high quality but also that you benefit from short response times in the event of short-notice changes.

When manufacturing your specific profile, it is sometimes possible to integrate perforations, holes with or without thread, embossing or even nuts, automatically and precisely into the steel strip at the beginning of the roll forming process – i.e. before the strip of sheet metal is guided in between the pairs of rollers.

Next, the steel strip is shaped into the desired cross-section. Depending on the level of complexity, 60 shaping steps or more are not uncommon.

For closed profile cross-sections, the longitudinal welding method (using laser or HF welding systems) is used during the roll forming to weld the edges of the strip to each other.

Integration into the production process (“inline”) makes the manufacturing of the laser or HF-welded profile tubes or special profiles especially cost-effective and economical.

Softer metals would probably use extrusion to create similar shapes, but roll forming comes with distinct advantages over extrusion; not least that hard metals such as steels, including duplex steels and stainless steels, can be very accurately formed into complex cross-sections of the tightest tolerances.

Roll forming is also an excellent technology for the economical integration of further finishing steps either during or after the forming process.

Diverse laser cutting or welding tasks, end machining, profile bending and joining methods allow us to form the metal sections into semi-finished components that are more readily integrated into your production processes, saving your time and money. 

Along with our service package, this makes Welser Profile an all-in-one metal section producer for customers demanding large quantities.