Although these stainless steel tubes may be used for fluid and gas transport like their cylindrical counterparts, square tubing is more often used for support and structural design schemes.
Architectural, construction, material handling, building, metal working, mounting and framing industries all make use of stainless steel square tubing for a wide variety of products such as support beams, racks, shelving, grids, partitions, stepladders and rails. While other materials may be used, stainless steel is extremely well suited to these specific applications. Known for its strength and durability, steel can meet the demands of most industrial applications and is one of the most popular alloys in use.
Stainless steel in particular offers increased heat, wear and corrosion resistance as compared to other alloys allowing its safe use in both high stress and highly corrosive environments. Although this alloyed tubing has a higher initial cost than many other options, the elemental structure of stainless steel significantly increases tube longevity, reducing long term expenses such as maintenance and replacements. Though square tubing will eventually need repair or replacement, this material is easily melted down and recycled, further reducing costs and waste.
Stainless steel is composed primarily of iron with varying amounts of carbon and a wide variety of additional metallic components. Chromium is the essential ingredient in the creation of this particular alloy as it provides the extreme resistance to wear and corrosion as well as the self-repairing properties of stainless steel alloys. To be classified as stainless, steel must be composed of at least 10% chromium.
The variable alloys can be placed into one of four major types of stainless steel and used to determine the proper composition required for a given tubing application. Ferritic, martensitic, duplex and austenitic are common categorizations of stainless steel with the latter being the most popular choice for stainless steel square tubes. Welding, seamless tubing via extrusion, die-cutting and metal spinning are common techniques employed in the production of stock shaped tubes.
While some extrusion and die-cutting processes make finished square tubes, secondary operations are often used to create these rectangular pipes from preformed round tubing. Turkshead and crush rolls are used to reshape cylindrical tubing, giving the finished product a square shaped cross-section.
The process and particular stainless steel alloy should be carefully considered with regards to the intended use of a square tube, especially when used for support and structure. Further considerations include inner and outer dimensions, wall thickness, pressure rating, maximum bend radius, temperature range, length and finishing.