Useful terminology

Steel that, in addition to carbon, contains one or more elements in sufficient amounts to appreciably alter properties compared with those of carbon steel. Materials are alloyed to enhance physical and mechanical properties such as strength, dictility, and hardenability.

A heat treating operation wherein metal is heated to a temperature above its critical range, held at that temperature long enough to allow full recrystallization, then slowly cooled through the critical range. Annealing removes working strains, reduces hardness, and increases ductility.

Steels containing such proportion of an alloying element or elements that the austenitic structure is retained at room temperature.

Industry term commonly used to describe the mechanization of various aspects of the die casting process.

A semifinished product of square, rectangular, or even round cross section, hot rolled, or forged. Producing billets or blooms from ingots by forging is called cogging, while by rolling it is called blooming.

Excess of ladled metal remaining in the shot sleeve of a cold chamber die casting machine. It is part of the cast shot and is removed from the die with the casting.

A disc-type forging produced by upsetting and rounding starting stock.

A surface bubble caused by gas expansion (usually from heating) which was trapped within the die casting or beneath the plating.

Voids or pores which may occur due to entrapped gas or shrinkage during solidification, usually evident in heavy sections (see porosity).

Machining a hole or enlarging an existing one with the objective of producing a more accurate hole than by drilling.

An ingot produced by pouring molten steel into a vertical trumpet where the steel flows down the trumpet, through runners, and then enters the ingot mold from the bottom. This method provides substantially improved surface quality and internal soundness, as well as ingot yield advantages, over top-poured ingots.

A measurement of metal hardness. A steel ball is forced into the surface of the material tested under a specific load. The diameter of the depression is measured, and the hardness is the ratio of load to spherical area of the impression.

Steel that owes its properties chiefly to various percentages of carbon with only residual amounts of alloying elements (except those added for composition control such as silicon and manganese).

Process of pouring molten metal into a prepared mold cavity of a desired shape and allowing the metal to solidify.

The recess or impressions in a die in which the casting is formed.

Casting process that consists of pouring molten metal into the cavity of a rotating mold, which can be made of various materials.

An impact test in which a specially V-notched specimen is broken by the impact of a falling pendulum. The energy absorbed in fracture is a measure of the impact strength or notch toughness of the sample.

Also called Impression Die Forging. A forging that is formed to the required shape and size by machined impressions in specially prepared dies that exert three-dimensional control on the workplace.

A type of casting machine in which the metal injection mechanism is not submerged in molten metal.

Having a common centre.

Torch cutting or flame cutting a part to achieve a specific shape or contour.

Fine cracks on the surface of a die which produce corresponding raised veins on die castings. Caused by repeated heating of the die surface by injected molten alloys.

Plastic deformation of metals held for long periods at stresses lower than yield strength.

A forging die is a steel block with a flat or contoured working face, which is used in a hammer or press for shaping metal.

Liquid formulations applied to the die to facilitate casting release and prevent soldering.

Ability of a component to retain its shape and size over a long period in service.

A guide pin which assures registry between cavities in two die halves.

The property of a metal that enables it to stretch before rupturing.

Not having the same centre.

Rate at which electrons move through atoms causing current to flow.

The amount of permanent stretch in a tensile test specimen before rupture.

Marks left on castings by ejector pins.

A plate to which ejector pins are attached and which actuates them.

A part produced by any of a number of fabricating processes such as forming, rolling, punching or welding, but especially associated with weldments, the joining of two or more individual pieces by welding.

The ability of a metal to withstand repeated and varying loads.

Metals that contain iron as the major alloying element.

Curved junction of two surfaces, e.g., walls which would meet at a sharp angle.

A thin web or fin of metal on a casting which occurs at die partings, vents and around moveable cores. This excess metal is due to working and operating clearances in a die.

Process of working metal to the desired shape by impact or pressure from hammers, presses or forging machines. The metal object so produced is termed a forging.

Passage for molten metal which connects runner with die cavity. Also, the entire ejected content of a die, including castings, gates, runners, sprue (or biscuit) and flash.

A semi-finished gear fabrication including the outer ring, inner hub, and torch cut stiffening plates.

Spout connecting a metal pot or chamber with a nozzle or sprue hole in the die and containing a passage through which molten metal is forced on its way to the die. It is the metal injection mechanism in a hot chamber type of die casting machine.

The average size of the crystals or grains in metal as measured against an accepted standard.

Expansion of a casting as a result of aging or of intergranular corrosion, or both.

The machanical forming of metal by means of a hammer. The action of the hammer is that of an instantaneous application of pressure in the form of a sudden blow.

The ability of a metal to resist penetration, defined in terms of the measurement (Brinell, Rockwell, etc.)

A test used to determine the relative resistance to indentation or displacement of metals by pressure, or by resistance to abrasion. Common methods of testing include Brinell, Rockwell, and Vickers tests.

An operation or combination of operations involving the heating and cooling of a metal or alloy in the solid state to attain certain desired microstructure or properties.

The process of producing circular hollow, tube-like parts by expanding or lengthening the hot workpiece over a mandrel.

Die casting machines which have the plunger, gooseneck (metal pressure chamber) immersed in molten metal in the holding furnace.

Term used to describe an alloy which is brittle or lacks strength at elevated temperatures.

Part that has been upset forged using loose tools. This process produces a shape with a smaller diameter projection from either one or both sides of the major diameter of the part.

Ability to resist shock, as measured by a suitable testing machine.

Cavity in a die. Also, the mark or recess left by a ball, or penetrator of a hardness tester.

Metal or alloy cast in a convenient shape for storage, shipping and remelting.

The process of forcing molten metal into a die.

A piece of material, usually metal, which is placed in a die before each shot. When molten metal is cast around it, it becomes an integral part of the die casting.

A type of corrosion which preferentially attacks grain boundaries of metals or alloys, resulting in deep penetration.

A hardenability test for steel to determine the depth of hardening obtainable by a specified heat treatment.

A type of core (which forms undercuts) which is positioned in, but not fastened to a die. It is so arranged as to be ejected with the casting and from which it is removed. It is used repeatedly for the same purpose.

Process to remove excess or unwanted stock by the use of machine tools for rough or finish turning, boring, drilling, or milling.

A nondestructive method of inspection for determining the existence and extent of possible defects in ferro-magnetic materials. Finely divided magnetic paticles, applied to the magnetized part, are attracted to and outline the pattern of any magnetic leakage fields created by discontinuities.

A bar used to retain the cavity or enlarge the bore during hollow forging.

A mechanical device for handling an ingot or a billet during forging.

Study of the microscopic features of material surfaces that have been specially prepared by cutting, grinding, polishing, and etching.

Core used primarily to reduce amount of metal in a casting and to avoid sections of excessive thickness.

A type of machining operation used on flat surfaces.

A die having more than one duplicate impression.

Any type of testing performed on an object that leaves it unchanged.

Commonly used heat treatment that decreases pearlite interlamellar spacing and refines grain size. The process consists of heating steels above the transformation temperature range, holding at temperature, and then cooling in air.

Outlet end of a gooseneck or the tubular fitting which joins the gooseneck to the sprue hole.

A recess in a die connected to a die cavity by a gate to assist in proper venting.

The mechanical forming of metals between flat or shaped dies where flow of the metal is not completely restricted.

A forging press with a hydraulically operated ram.

A recess in a die connected to a die cavity by a gate to assist in proper venting.

A mark left on a die casting where the die halves meet; also, the mating surface of the cover and ejector portions of the die.

A round bar that has been centerless machined to remove its outer surface. The peeling process takes less than one-fourth the time of conventional lathe-turning operations.

A finishing operation used to obtain closer tolerances and a smoother surface on a round workpiece.

Mechanical forming of metals by means of a press. The action is that of kneading the metal by relatively slow application of force as compared with the action of hammering.

Ram or piston which forces molten metal into a die.

Opening through which molten metal enters the injection cylinder.

Voids or pores resulting from trapped gas, or shrinkage during solidification.

Where parameters of a process are studied and correctly applied in the manufacturing process to produce high quality parts.

Equipment used to produce forged rolled rings. A metal ring preform is rolled betweeen two rolls that move toward each other to form a continuously reducing gap.

Die passage connecting sprue or plunger holes of a die to the gate where molten metal enters the cavity or cavities.

That segment of the casting cycle in which molten metal is forced into the die.

Dimensional reduction that accompanies the freezing (solidification) of metal passing from the molten to the solid state.

A surface depression which sometimes occurs next to a heavy section that cools more slowly than adjacent areas.

A metal cleaning or finishing process in which a fluid blast blows abrasive steel balls against the surface.

The portion of the die arranged to move parallel to die parting. The inner end forms a part of the die cavity wall that involves one or more undercuts and sometimes includes a core or cores.

Adherence of molten metal to portions of the die.

Also referred to as a stepdown shaft. A longitudinal bar-type product with more than one diameter or cross section size.

A gate of castings having the sprue or plunger axis in the die parting.

A tapered pin with rounded end projecting into a sprue hole and acting as a core which deflects metal and aids in the removal of the sprue.

Linkage employed to mechanically multiply pressure when locking the dies of a casting machine.

A die for shearing or shaving flash from a die casting.

A die interchangeable with others in a common holder.

Recess in the side wall or cored hole of a casting disposed so that a slide or special form of core (such as a knockout) is required to permit ejection of the casting from the die.

Narrow passage at the die parting which permits air to escape from the die cavity as it is filled with molten metal.

A large pore or hole within the wall of a casting usually caused by entrapped gas. A blow hole.

A tube or passage through which water is circulated to cool a casting die.