When ordering and purchasing cold rolled steel coil for roll-formers and steel building applications these are the basics that you will be required to know:
Is the natural thickness of steel before any protective coating i.e. galvanizing or paint is applied. (See Diagram A).
Is the base metal steel with coating applied. For example “0.95mm BMT” becomes “1.0mm TCT” after galvansing cover is applied to ‘base metal thickness’ steel. (See Diagram A).
Normally refers to houses and buildings constructed of ‘light gauge’ steel that use gauges (thicknesses) of steel between .75mm and 1.95mm BMT.
Cold-formed steel (CFS) is the common term for steel products constructed by rolling or pressing steel into semi-finished or finished goods at relatively cool or low temperatures (i.e. cold working). Cold-formed steel goods can be created by rolling (i.e “roll forming”) of steel sheet into a shape that is usable for i.e. a metal stud for framing or a long run roof or steel wall / cladding.
Cold-formed steel members (profiles) are typically used in houses and buildings. These types of sections are cold-formed from steel sheet and normally fed from steel coils into roll forming machines. The material thicknesses for such thin-walled steel members usually range from 0.0147 in. (0.373 mm) to about ¼ in. (6.35 mm).
Tensile measures the strength of steel and its ability to withstand breaking or deforming. High tensile steels i.e. G550 are stronger (and subsequently lighter) and have less tendency to “spring back” towards their original shape if roll formed correctly, therefore making them more ideal for the roll-forming and shaping process.
Normally measured between 0.40mm to .55mm for roofing and walling applications .75mm through to 1.95mm for framing and .95mm and 2.95mm for purlin applications.
This refers to the size of the profile required for building and typically relates directly to the web size. For a framing application this might be “89mm” for a small house through “150mm” for a larger building.
This refers to the width of steel coil required for input into your machine. For example a typical 89mm framing profile would require a 182mm slit coil to produce this profile size. (See diagram A).
The inside of the diameter is considered important as this will dictate the size and type of decoiler (uncoiler) that the steel coil will be able to sit on for feeding into roll forming machinery. Standard steel mill sizes are typically 508mm or 610mm.
MTR’s are provided by the steel mill manufacturing the steel and contain important traceability and assurance to the end user related directly to that batch of steel produced. The MTC should specify the type of certificate, the grade of steel and any addenda. It will also specify the results of chemical and physical examination to allow the purchaser or end user to compare the plate to the requirements of the relevant standards. The MTC should also contain the following information: steel mill's name, heat number, batch number, final test result, quantity, steel grade, standard/specification, chemical analysis composition results, and mechanical test properties results.
Hot-dip galvanization is a type of galvanization. Steel is coated with a layer of zinc by placing the metal in a bath of molten zinc at a temperature of around 840 °F (449 °C). When re-exposed to the atmosphere, the pure zinc (Zn) reacts with oxygen (O2) to create zinc oxide (ZnO), which further reacts with carbon dioxide (CO2) to create zinc carbonate (ZnCO3), a usually dull grey, fairly strong material that protects the steel under the coating from additional corrosion in most circumstances. Galvanized steel can be identified by the crystallization patterning on the surface often called a "spangle".
Galvanizing protects steel by acting as a barrier between steel and the atmosphere. Zinc however is a stronger electronegative metal in comparison to steel. This is a unique characteristic for galvanizing, and means that when a galvanized coating is damaged or steel is exposed to the atmosphere, zinc can continue to protect steel through galvanic corrosion (often within an annulus of 5 mm, above which electron transfer rate decreases).
Galvanizing is measured by the amount of zinc coating applied to both surfaces of the sheet i.e. G90 contains 90 ounces of zinc for every 1 square foot of metal panel. The higher the number the better the anti-corrosion capabilities.
Galvalume is an anti-corrosion resistance that consists of aluminum, zinc alloy and silicon. Like Galvanized Steel, the thicker the amount of coating, the greater the amount of corrosion protection for the Galvalume steel panel. Galvalume is also produced using the hot dip method for applying the coating to the base steel. The number in the designation relates to the thickness of the coating on both sides of the steel panel surface, for example AZ-55 coating has a thickness of 0.0018, while an AZ-50 would have 0.0016 coating. Both AZ-55 and AZ-50 coatings contains 55% aluminum, 43.40 % zinc alloy and 1.60% silicon.
The primary purpose for the silicon to be added is to minimize the growth of brittle intermetallic layer that forms when the product is being coated. Furthermore, without the addition of silicon Galvalume Steel could not be produced by the hot dip method.
Is a an ultra-strong anti-corrosion coating. Metal is hot dipped to provide a coating layer of Zinc, Aluminum (6%) and magnesium (3%). Zam is often used in harsh environments requiring extremely high levels of corrosion protection.
Please contact us directly for help and further information regarding your steel order.
