Glossary

Take-up

Steel block where material is wound when rolling or slitting.

Tandem Mill

Arrangement of rolling mills, in direct line, allowing the metal to pass from one set of rolls into the next.

Tarnish

Surface discoloration on a metal, usually from a thin film of oxide or sulfide.

Telescoping

Transverse slipping of successive layers of a coil so that the edge of the coil is conical rather than flat.

Temper Rolling

Light cold-rolling of sheet steel. The operation is performed to improve flatness, to minimize the formation of stretcher strains, and to obtain a specified hardness or temper.

Tempering

Carefully selected and controlled heat-treating operation performed on steel after it has been fully hardened by heat treatment. The operation results in a desired degree of change in the internal structure and mechanical properties. The mechanical properties resulting from tempering are usually intermediate between the fully hardened and the annealed properties.

Tensile Strength

The value obtained by dividing the maximum load observed during tensile testing by the specimen cross-sectional area prior to test initiation. Tensile strength is expressed in psi (pounds per square inch), ksi (1000 pounds per square inch) or a metric equivalent such as mpa (milli pascals) or N/mm (newtons per square millimeter). Simply put, tensile strength is the maximum load a given cross-section of material can withstand before breaking apart.

Tensile Testing

Tensile testing is a procedure to calculate the yield strength and the ultimate tensile strength or the material. The procedure begins with a specially prepared specimen, usually 8 inches long and with a half-inch reduced section in the middle. The specimen is put into a machine which grips the ends, and then pulls the specimen apart. As the machine does this, it measures the load required to make the material go from the elastic to plastic deformation and the load required to actually break the material. By factoring in the original cross-sectional area of the reduced section at the middle of the specimen, it is possible to calculate the pounds per square inch when the material went from the elastic to plastic deformation. This is the yield strength. Again using the cross- sectional area and the load required to break the specimen, you can calculate the ultimate tensile strength (or simply tensile strength).

Tension Level

Mechanical operation where coiled metal or alloys are stretched beyond their yield points. Tension level can improve flatness and camber.

Tension Leveling

A mechanical operation where coil metal is stretched beyond its yield point.

Tension Testing (Tensile Testing)

A mechanical test employed to determine both strength and ductility properties of material. Measurements obtained from a tensile test include ultimate tensile strength, yield strength and percent elongation.

Tolerance

Specified limits of deviation from a measurement can be dimensions, strength, analysis.

Tolerance Limit

The permissible deviation from the desired value.

Tool Steel

Any high carbon or alloy steel capable of being suitably tempered for use in the manufacture of tools.

Tool Wear

A gradual deterioration of tools and dies. In the case of fabrication of stainless steels, the surface oxides of the stainless gradually either abrade or build up on the tooling. Other factors (high hardness, non-metallic inclusions) can also accelerate tool wear.

Torsion

A twisting action resulting in shear stresses and strains.

Toughness

Toughness may be defined as the ability of a material to accept applied stresses by either elastic or plastic deformation, depending on the stress level, without sudden brittle failure.

Transformation

A constitutional change in a solid metal, e.g., the change from gamma to alpha iron, or the formation of pearlite from austenite.

Transverse

Literally, ‘across’, usually signifying a direction or plane perpendicular to the direction of working.

Trepanning

A type of boring where an annular cut is made into a solid material with the coincidental formation of a plug or solid cylinder.

Tumbling

Cleaning articles by rotating them in a cylinder with cleaning materials.

Turning

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

Two-High Mill

A stand having only two rolls. Some two-high mills are reversing with screw-downs to adjust the rolls; others are one way only and may or may not have screw-downs for roll adjustment and may or may not be a part of a continuous mill.