Glossary of Terms

Glossary

ANNEAL

As applied to stainless steel a process involving heating and rapid cooling to return the precipitated carbides into solution to restore full corrosive resistance. Also relieves stresses.

BRIGHT ANNEALING

Using a furnace with an inert atmosphere no scale is formed and the resulting surface has a bright finish.

BRIGHT GRINDING

Grinding the cross section of wire/bar to achieve a uniform finish to a tight tolerance.

COLD ROLLED SOFTENED & DESCALED

Sometimes known as 2B finish. A smooth finish for general applications pressed on polished rolls.

DRAWING
  • Forming recessed parts by forcing the plastic flow of metal in dies.
  • Reducing the cross section of wire/bar or tubing by pulling it through a die.

EXTRUSION

Production process in which metal is forced by compression through a die and into solids (round or special shapes) or through a die and over a mandrel to form a tubular shape.

FREE MACHINING GRADES

Brought about by the addition of sulphur or selenium increases cutting speeds by approximately 75% on stainless steel. Sulphur is preferred for heavy machining because of the large and fairly continuous inclusions. Selenium is better for light work where a good finish is required.

HOT ROLLED SOFTENED & DESCALED

Sometimes known as No 1 finish. Used where smoothness and uniformity of finish are not important.

INTERGRANULAR CORROSION

Preferential corrosion at the grain boundaries as a result of carbide precipitation. Allowing more rapid attack of the corrosive liquids in the chromium depleted area between the grains.

MECHANICAL PROPERTIES

Defined as the properties of a material that reveal its elastic or plastic behaviour where stress is applied thereby indicating its suitability for mechanical applications, e.g. modulus of elasticity, tensile strength, elongation and fatigue limit.

NOMINAL BORE

A term used only to describe a pipe size, not to be confused with actual internal diameter.

PHYSICAL PROPERTIES

Defined as the properties other than mechanical that pertain to the physics of a material, e.g. density, electrical conductivity, thermal expansion.

ROUGH/SMOOTH TURNING

A method for removing the surface from a circular bar by bringing the cutting edge of a tool against it while the bar is rotating.

TENSILE STRENGTH

A measure of the maximum pulling stress which a substance can endure before breaking. Tensile strength is rated as a given load across a unit area, in the U.K. as Newtons per square millimetre in the U.S.A. as pounds per square inch; on the Continent as kilograms per square millimetre.

YIELD STRENGTH

Is defined as the stress at which a material deforms and will no longer return to its original state.