Metal Terminology¹ I

IMPACT TEST
Test designed to determine, the resistance of metal to breakage by impact, usually by concentrating the applied² stress to a notched³ specimen⁴.

INCLUSION
Particles of impurities⁵ (usually oxides, sulfides, silicates⁶, etc.) that are held mechanically or are formed during the solidification⁷ or by subsequent reaction within the solid metal.

INDENTATION HARDNESS
The resistance of a material to indentation. This is the usual type of hardness test, in which a pointed⁸ or rounded indenter is pressed into a surface under a substantially static load.

INDUCTION⁹ HARDENING
A process of hardening a ferrous alloy¹⁰ by heating it above the transformation¹¹ range by means of electrical induction, and then cooling as required.

INDUCTION HEATING
A process of heating by electrical induction.

INGOT
A casting for subsequent rolling or forging.

INHIBITOR
A substance which retards¹³ some specific chemical reaction. Pickling inhibitors retard¹² the dissolution of metal without hindering the removal of scale from steel.

INTERLEAVING
The placing of a sheet of paper between two adjacent layers of metal to facilitate handling and shearing¹⁵ of rectangular sheets, or to prevent sticking or scratching.

INTERMEDIATE ANNEALING
An annealing treatment given to wrought¹⁶ metals following cold work hardening for the purpose of softness prior to further cold working. (See Process Annealing)

INTERRUPTED AGING
The aging of an alloy at two or more temperatures by steps, and cooling to room temperatures after each step. Compare with Progressive Aging.

IRON
(Chemical Symbol Fe.) Element No. 26 of the periodic system; Atomic weight 55.85. A magnetic silver-white metal of high tensile strength ductile¹⁷ and malleable¹⁸. Melting point of pure iron about 2795癋. Chemically iron is chiefly base forming. The principal forms of commercial iron are steel, cast iron and wrought iron.

IRONING
Thinning the walls of deep drawn¹⁹ articles by reducing the clearance²⁰ between punch and die.

ISOTHERMAL ANNEALING
A process on which a ferrous alloy is heated to produce a structure partly or wholly austenitic, and is then cooled to and held at a temperature that causes transformation of the austenite to a relatively²¹ soft ferrite-carbide aggregate²².

Metal Terminology J

JIG²³ SAW STEEL
Hardened, tempered and bright polished with round edges. Carbon content .85%. Range of sizes .039 to .393” in width and .016 to .039” in thickness.

Metal Terminology K

KILLED STEEL
The term “killed” indicates that the steel has been sufficiently²⁴ deoxidized to quiet the molten metal when poured into the ingot mold. The general practice is to use aluminum²⁵ ferrosilicon or manganese as deoxidizing agents. A properly killed steel is more uniform as to analysis and is comparatively free from aging. However, for the same carbon and manganese content Killed Steel is harder than Rimmed²⁶ Steel. In general all steels above 0.25% carbon are killed, also all forging grades, structural²⁷ steels from 0.15% to 0.25% carbon and some special steels in the low carbon range. Most steels below 0.1

Metal Terminology L

LADLE ANALYSIS
A term applied to the chemical analysis representative or in layers, as reported by the producer. Results are determined²⁸ by analyzing²⁹ a test ingot sample obtained during the pouring of the steel from a ladle.

LAMINATIONS
A defect appearing in sheets or strips as a segregation³⁰ or in layers. To become divided, caused by gas pockets in the ingot. (See Cold Shut)

LAP
A surface defect appearing as a seam, caused by folding over hot metal, fins³¹ or sharp corners and then rolling or forging them into the surface but not welding them.

LAP-WELD
A term applied to a weld formed by lapping two pieces of metal and then pressing or hammering, and applied particularly to the longitudinal joint³² produced by a welding process for tubes or pipe, in which the edges of the skelp are beveled or scarfed so that when they are overlapped³³ they can be welded together.

LATTICE
Space lattice. Lattice lines and lattice planes are lines and planes chosen so as to pass through collinear lattice points, and noncollinear lattice points, respectively.

LEAD ANNEALING
(See Bath Annealing)

LEVELING
Flattening rolled metal sheet or strip. (See Roller and Stretcher Leveling)

LIGHT METALS
Metals and alloys³⁴ that have a low specific gravity, such as beryllium, magnesium³⁵ and aluminum.

LITHOGRAPHIC SHEET ALUMINUM
Sheet having a superior surface on one side with respect to freedom from surface imperfections and supplied with a maximum degree of flatness, for use as a plate in offset³⁶ printing.

LONG TERNE
A term applying to steel sheets that have been terne coated (Lead and Tin) by immersion³⁷ in a bath of Terne Metal. (See Terne Plate)

LOW BRASS³⁸ - 80% cu.
A copper-zinc³⁹ alloy containing 20% zinc. Is a light golden color, very ductile, suitable for cupping, drawing, forming, etc. Because of its good strength and corrosion⁴⁰ resistance it is used for flexible metal hoses, metal bellows⁴¹, etc.

LOW CARBON STEELS
Contain from 0.10 to 0.30% carbon and less than 0.60% manganese. ( The product of Basic Oxygen, Bessemer, Open Hearth⁴² or Electric Processes.)

LUDERS LINES
(Steel) - Characteristic of No. 5 Temper - Not a defect in No. 5 dead soft temper. Long vein-like marks appearing on the surface of certain metals, in the direction of the maximum shear¹⁴ stress, when the metal is subjected to deformation⁴³ beyond the yield point. Also called stretcher strains, similar occurrence in certain aluminum alloys, etc. (See Stretcher Strains)

LUSTER FINISH
Refer to FINISHES