Technical Terms

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Glossary

• 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 is 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.

• Tempered (or Tempering)

  This is a heat treatment process that is often used to improve hardness, strength, toughness, as well as decrease brittleness in fully hardened steel.