Technical Terms of Products
Originally known as the Society of Automotive Engineers, SAE International is a US-based organization that sets technical standards for engineering professionals in many industries, including automotive, aerospace and commercial vehicles, as well as many others. Additionally, SAE publishes technical books and papers on a variety of subjects, in print and digital formats. Reports include general accepted engineering data and other information for many industries.
Stainless Steel Sheet (Grade 304), #8 Polished finish
This material is not magnetic and has the most reflective polish that is commonly produced, and is often referred to as a “mirror finish,” although it is not a true mirror. This is a special order material.
Stainless Steel Sheet (Grade 304), Brushed Polished finish
This material is not magnetic and looks like you might see on a kitchen appliance. It is characterized by short, parallel polishing lines, which extend uniformly along the length of the coil. Also known as a #4 polished finish.
Stainless Steel Sheet (Grade 304), Mill finish
This material is not magnetic and is unpolished. It is dull in appearance, resembling a cloudy mirror. Also known as a #2B finish.
Stainless Steel Sheet (Grade 430), Bright Annealed finish
This material is magnetic and it has a mirror-like appearance, but it is not a true mirror. It has been bright annealed and then passed between highly polished rolls. Also known as a BA or 2BA finish.
Steel Bar, Annealed
Annealing is a heat treatment process in which the metal is heated to a specific temperature and then allowed to cool slowly. This increases the ductility of the material and reduces its hardness, so it can be easier to work with. May be known as Condition C when associated with aircraft alloy steel.
Steel Bar, Cold Finished
This is basically an umbrella term for steel bar that has had some sort of surface treatment. It can be cold drawn (CD); turned and polished (T&P); turned, ground and polished (TGP); or centerless ground (CG). Certain steel bar grades could be available as either Cold Finished or Hot Rolled. When compared to Hot Rolled steel bars, Cold Finished bars are produced to tighter tolerances, are straighter, and have a smoother surface finish. They are generally more expensive and may be harder to work with than Hot Rolled bars due to the increased carbon content.
Steel Bar, Hot Rolled
This is a steel bar product that is produced at a high temperature (minimum 1700 deg F) and is softer and more pliable than Cold Finished material. It may have a rougher surface finish, as well as impurities or imperfections, and more rounded edges (in flats and squares).
Steel Bar, Normalized & Tempered
Normalizing refers to the process of heating the steel bar above its critical temperature and then cooling it in open or standing air. Tempering is the process of reheating the material below the transformation range and then cooling it to the desired rate. The primary reasons are to decrease the hardness and increase the strength, as well as to relieve internal stresses. Abbreviated as “N & T” and also known as Condition E4 when associated with aircraft alloy steel. 4340 is a common grade of steel that may be supplied in this condition.
Steel Bar, Quenched & Tempered
Quenching and tempering are processes that strengthen and harden materials like steel and other iron-based alloys. Quenching involves heating the material and then rapidly cooling in water, oil, forced air or inert gases such as nitrogen. Tempering is accomplished by heating that material to below the critical point for a set period of time, then allowing it to cool in still air. Abbreviated as “Q & T” and also known as Condition F4 when associated with aircraft alloy steel. Although used only in specific situations, 4130 is a common grade of steel that may be supplied in this condition.
Steel Bar, Vacuum Melted
This generally applies to alloy steel bars, and may be referred to as “Vac Melt” or “VM.” The material is melted in a vacuum to prevent contamination from air, as well as to remove gases already dissolved in the metal; the solidification may also be carried out in a vacuum or at low pressure. Although used only in specific situations, 4340 is a grade of steel that may be supplied in this condition.
Steel Sheet, Cold Rolled
This refers to the procedure for metal forming a steel ingot, cooled to a temperature making the metal no longer pliable or plastic, to be forged or rolled into sheets or other shapes. It is sometimes called cold worked steel.
Steel Sheet, Hot Rolled
This refers to the procedure for forming steel at a high temperature above steel's recrystallization temp (minimum 1700 deg F), allowing the metal to be formed or shaped more easily. Hot Rolled steel is typically less expensive than Cold Rolled steel, because it can be finished much faster and to looser tolerances.
Steel Sheet, Pickled and Oiled
This refers to Hot Rolled steel that is further treated by using an acid-based solution to remove impurities (such as scale, inorganic contaminants, stains, etc.) from the surface. Oil is applied to prevent rusting. Abbreviated as P&O or HRPO, and it is typically cleaner than plain Hot Rolled steel.
Steel Tube, Cold Drawn Seamless
This refers to a seamless steel tube that produced by piercing a hollow using a die. It has a better surface finish and more precise dimensional tolerances. Often abbreviated as CDS, this material can be a mild steel or an alloy steel.
Steel Tube, DOM Round
DOM (“Drawn Over Mandrel”) refers to a welded mechanical round steel tube with the internal weld seam removed creating a smooth internal surface. It is often perceived as a “seamless tube,” because the seam is practically invisible. It is cold drawn over a mandrel to have more accurate dimensional tolerances, higher mechanical properties and a smoother inside surface. This may also be called a Welded and Drawn tube. Material grades include 1020 and 1026, among others.
Steel Tube, ERW
This is a mechanical steel tube that is produced by Electric Resistance Welding steel strip or coil longitudinally into a round, rectangle or square shape. It is distinguished by a seam that runs along the length of the inside of the tube. This material may be Cold Rolled (CREW) or Hot Rolled (HREW), depending on size and availability. Material grades include 1008 and 1010, among others.
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