Stainless steel coil is a common product that is formed from stainless steel strip or tubing that has been rolled, wrapped or spiraled for use in a number of industrial applications. Stainless steel coil can either be hot rolled or cold rolled, but is typically much thinner when cold rolled. When hollow coils are needed extrusion or other manufacturing methods may also be employed.
The benefits of stainless steel coil versus other metals include high corrosion resistance, high ductility, great strength-to-weight ratio, high temperature resistance, high tensile strength and low yield stress. As a result, stainless steel coils are often used in applications such as building materials, bicycles, consumer appliances, cooling and heating coils, steam and pipe coils, air tight casings, control systems and medical components. Through offering such a diverse range of applications, stainless steel coils function to serve industries such as automotive, chemical, petroleum, electronics, architecture, aerospace, HVAC and construction. Stainless steel coils can be formed from hardened, tempered and pre-hardened stainless steel as well as undergoing many secondary applications such as slitting, leveling, buffing, polishing, toll processing, oscillate winding, edge conditioning, shearing and hydrogen atmosphere annealing. It is important to consider the effects of processing as well as physical dimensions such as inner and outer diameter, length, gauge and more.
Stainless steel coils are most often formed using the cold rolling process. Stainless steel strip is pulled between rollers to be compressed and squeezed. After the strip is compressed it is wound into coil form. Cold rolling gets its name because the process is performed at temperatures lower than the material's re-crystallization temperature. Hot rolling is not often used for stainless steel because most grades cannot be heat treated. For the few grades that can undergo heat treatment, the process is very similar except it is performed at temperatures above the material's re-crystallization temperature. Typical grades that are used to form stainless steel coils include 201, 301, 304, 308, 316, 321, 347, 409,430, 434, 436, 439 and 444. These grades are classified as either austenitic stainless steel, ranging from the 100 series to the 300 series, or ferritic and martensitic stainless steel, which include the 400 series. Austenitic stainless steel coils are non-magnetic and provide excellent mechanical properties. Ferrite stainless steel coils are magnetic and are mainly composed of iron and chromium. Martensitic stainless steel coils are magnetic and are composed of chromium, molybdenum, nickel and carbon.
