Metal Glossary

Finstock

Narrow strip in the thickness range 0.2mm to 0.4mm used for finning of heat exchanger tubes in applications such as air conditioning.

Fixed Mandrel

A device for producing hollow extrusions of regular cross section. The tapered mandrel is attached to the main extrusion ram and passes through the hollow billet. As the ram moves forward the mandrel passes, with the billet, through the die giving a product slightly tapering in wall thickness along its length. The mandrel is tapered to facilitate its removal when extrusion is complete.

Flaring Test, Drift Test

A test for the weld integrity of a welded tube, usually carried out to BS1139. All batches of Scaffolding Tube undergo this test.

Related terms: Scaffolding Tube

Flash Annealing

Annealing of a work-piece by rapid heating and a short dwell time at the appropriate temperature.

Flatness Tolerance

A three-dimensional geometric tolerance that controls how much a product surface can deviate from a flat plane. The permitted deviation will depend upon the thickness of the sheet or plate varying between 0.2% and 0.5% of its width and length, usually measured over a 1 metre length.

Flatness

The property of having a horizontal surface without any slope, tilt, or curvature, i.e. that of a flat plane. In practice a perfectly flat surface is probably unobtainable so there will be a flatness tolerance.

Related terms: Flatness Tolerance

Floating Mandrel

A tapered mandrel that is inserted into the hollow extrusion billet. It is not attached to the extrusion ram so is left free to centre itself in a hollow billet as it moves forward through the die as the ram advances and extrusion proceeds. The resulting product tapers slightly in wall thickness along the length.

Related terms: Fixed Mandrel

Foil, Cooking Foil, Kitchen Foil, Tin Foil

Cold rolled aluminium flat product less than 250 microns in thickness. Usage includes kitchen foil (cooking foil) and foil trays for food. Kitchen Foil is often incorrectly referred to as Tin Foil.

Forging

Hot working using a forge with shaped tools that ‘hammers’ the work-piece into a predetermined shape.

Fracture Test, Charpy Test, Impact Test, Izod Test

A test in which the test piece is notched and broken. The fracture surface examined to assess grain structure and freedom from defects. Also used to determine toughness, often at varying temperatures to establish at what reduced temperature the material becomes brittle.

Free Machining Alloy (FMA)

An alloy designed to give, when machined, small broken chips, lower power consumption, better surface finish and/or longer tool life. Chemical composition and microstructure both influence this property.

Fretting, Traffic Marks

Abrasions, usually dark in colour, resulting from relative movement, or rubbing, between contacting metal surfaces during transit.

Full Heat Treatment

For alloys in the 2xxx, 6xxx, 7xxx and 8xxx series this is the heat treatment cycle consisting of solution treatment followed by artificial age hardening.