Rectangular tubing is formed from coils and then run through a several types of dies. These tubes are welded from the inside to form their shape. Rectangular tubes are generally used for maintenance and structural purposes. Some examples of applications would be truck frames, railings, construction of structures, guardrails, support columns and storage systems. Their measurements are taken by calculating their outside dimensions and their wall thickness.
The abbreviation ERW or Electric Resistance Welded to be precise refers to a specific type of welding process known as seam welding. Seam welding is used to manufacture rectangular steel tubing. The steel strips are unwound from coils and side-trimmed to maintain width and prepare the edges for welding. The strip then passes through a series of contoured rollers which cold-form the material into a rectangular shape. The edges are forced together under pressure and then welded by heating the material to temperatures above 2000° F. The flash weld that has formed is then removed from the outside diameter of the tube. Once the weld has been tested, the tube then passes through a series of sizing rolls to attain its exact size, after which the tube is straightened and cut to specification.
Hot rolling is the process of creating sheet metal by passing the steel through rollers which is well above its recrystallization temperature to the required dimensions. Multiple passes through the rollers is necessary to produce the final dimensions.
Steel rolled at room temperature, which is well below its recrystallization temperature is known as cold rolled steel. This process yields increased strength and hardness within the steel. In addition to improvement of mechanical properties, cold rolling results in more control over the dimensions of the end product. Furthermore, it has improved surface finish and a stronger tolerance compared to its hot rolled variant.
When acquiring Rectangle ERW tubes or pipes from Steelco you receive:
- Affordability, durability and longevity
- A product with consistent quality and attribute
- A superior finish to the products surface
- A guarantee that all quality control standards are met