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A continuous-type heat treating or sintering furnace consisting of two sets of rails, one stationary and the other movable, that lift and advance parts inside the hearth. With this system, the moving rails lift the work from the stationary rails, move it forward, and then lower it back onto the stationary rails. The moving rails then return to the starting position and repeat the process to advance the parts again.
A distinct pattern of intersecting sets of parallel lines, sometimes producing a set of V-shaped lines, sometimes observed when viewing brittle fracture surfaces at high magnification in an electron microscope. Wallner lines are attributed to interaction between a shock wave and a brittle crack front propagating at high velocity. Sometimes Wallner lines are misinterpreted as fatigue striations.
Deformation of metals at elevated temperatures below the recrystallization temperature. The flow stress and rate of strain hardening are reduced with increasing temperature; therefore, lower forces are required than in cold working. See also cold working and hot working.
(1) Deformation other than contraction that develops in a casting between solidification and room temperature. (2) The distortion that occurs during annealing, stress relieving, and high-temperature service.
(1) A coating applied to the face of a mold prior to casting. (2) An imperfection at a cast surface similar to a cut (3).
Molten metal used to wash out a furnace, ladle, or other container.
waterjet/abrasive waterjet machining
A hydrodynamic machining process that uses a high-velocity stream of water as a cutting tool. This process is limited to the cutting of nonmetallic materials when the jet stream consists solely of water. However, when fine abrasive particles are injected into the water stream, the process can be used to cut harder and denser materials. Abrasive waterjet machining has expanded the range of fluid jet machining to include the cutting of metals, glass, ceramics, and composite materials.
A quench in which water is the quenching medium. The major disadvantage of water quenching is its poor efficiency at the beginning or hot stage of the quenching process. See also quenching.
A wavelike variation from a perfect surface, generally much larger and wider than the roughness caused by tool or grinding marks.
A precise duplicate, allowing for shrinkage, of the casting and required gates, usually formed by pouring or injecting molten wax into a die or mold. See also investment casting.
Damage to a solid surface, generally involving progressive loss of material, due to a relative motion between that surface and a contacting surface or substance. Compare with surface damage.
Particles that become detached in a wear process.
In forming, an expendable pad of rubber or rubberlike material of nominal thickness that is placed against the diaphragm to lessen the wear on it. See also diaphragm (2).
Exposure of materials to the outdoor environment.
Copper-bearing high-strength low-alloy steels that exhibit high resistance to atmospheric corrosion in the unpainted condition.
A type of weld bead made with transverse oscillation.
(1) A relatively flat, thin portion of a forging that effects an interconnection between ribs and bosses; a panel or wall that is generally parallel to the forging plane. See also rib. (2) For twist drills and reamers, the central portion of the tool body that joins the lands. (3) A plate or thin portion between stiffening ribs or flanges, as in an I-beam, H-beam, or other similar section.
Percentage composition by weight. Contrast with atomic percent.
A localized coalescence of metals or nonmetals produced either by heating the materials to suitable temperatures, with or without the application of pressure, or by the application of pressure alone with or without the use of filler metal.
The capacity of a material to be welded under the imposed fabrication conditions into a specific, suitably designed structure and to perform satisfactorily in the intended service.
A deposit of filler metal from a single welding pass.
A crack in weld metal.
Intergranular corrosion, usually of stainless steels or certain nickel-base alloys, that occurs as the result of sensitization in the heat-affected zone during the welding operation. See also sensitization.
(1) Joining two or more pieces of material by applying heat or pressure, or both, with or without filler material, to produce a localized union through fusion or recrystallization across the interface. The thickness of the filler material is much greater than the capillary dimensions encountered in brazing. (2) May also be extended to include brazing and soldering. (3) In tribology, adhesion between solid surfaces in direct contact at any temperature.
The current in the welding circuit during the making of a weld.
The complete series of events involved in the making of a weld.
See electrode (welding).
Same as work lead.
The electrical cables that serve as either work lead or electrode lead of an arc welding circuit.
Equipment used to perform the welding operation. For example, spot welding machine, arc welding machine, seam welding machine, etc.
A form of filler metal used for welding or brazing that does not conduct the electrical current, and which may be either fed into the weld pool or preplaced in the joint.
The order in which the various component parts of a weldment or structure are welded.
Residual stress caused by localized heating and cooling during welding.
A welding torch tip designed for welding.
welding torch (arc)
A device used in the gas tungsten and plasma arc welding processes to control the position of the electrode, to transfer current to the arc, and to direct the flow of shielding and plasma gas. See also gas tungsten arc welding and plasma arc welding.
welding torch (oxyfuel gas)
A device used in oxyfuel gas welding, torch brazing, and torch soldering for directing the heating flame produced by the controlled combustion of fuel gases. See also oxyfuel gas welding.
A form of welding filler metal, normally packaged as coils or spools, that may or may not conduct electrical current depending on the welding process with which it is used. See also electrode (welding) and welding rod.
The interface between weld metal and base metal in a fusion weld, between base metals in a solid-state weld without filler metal, or between filler metal and base metal in a solid-state weld with a filler metal and in a braze.
See preferred term weld interface.
An assembly whose component parts are joined by welding.
That portion of a weld that has been melted during welding.
The weld metal in spot, seam or projection welding. See also nugget and resistance spot welding.
A single progression of a welding or surfacing operation along a joint, weld deposit, or substrate. The result of a pass is a weld bead, layer, or spray deposit.
The localized volume of molten metal in a weld prior to its solidification as weld metal.
See preferred term weld pool.
Weld metal in excess of the quantity required to fill a joint.
A rolling mill similar to a universal mill but where the edges and sides of a rolled section are acted on simultaneously.
A process for cleaning or finishing by means of a slurry of abrasive in water directed at high velocity against the workpieces.
(1) The spreading, and sometimes absorption, of a fluid on or into a surface. (2) A condition in which the interface tension between a liquid and a solid is such that the contact angle is 0° to 90°. (3) The phenomenon whereby a liquid filler metal or flux spreads and adheres in a thin continuous layer on a solid base metal.
(1) A substance that reduces the surface tension of a liquid, thereby causing it to spread more readily on a solid surface. (2) A surface-active agent that produces wetting by decreasing the cohesion within the liquid.
(1) A short single crystal fiber or filament used as a reinforcement in a matrix. Whisker diameters range from 1 to 25 m, with aspect ratios (length to diameter ratio) generally between 50 and 150. (2) Metallic filamentary growths, often microscopic, sometimes formed during electrodeposition and sometimes spontaneously during storage or service, after finishing.
A surface layer in a steel that, as viewed in a section after etching, appears whiter than the base metal. The presence of the layer may be due to a number of causes, including plastic deformation induced by machining or surface rubbing, heating during a metallographic preparation stage to such an extent that the layer is austenitized and then hardened during cooling, and diffusion of extraneous elements into the surface.
See malleable iron.
A cast iron that is essentially free of graphite, and most of the carbon content is present as separate grains of hard Fe3C. White iron exhibits a white, crystalline fracture surface because fracture occurs along the iron carbide platelets.
(1) Compound layer that forms in steels as a result of the nitriding process. (2) In tribology, a white-etching layer, typically associated with ferrous alloys, that is visible in metallographic cross sections of bearing surfaces. See also Beilby layer.
(1) A general term covering a group of white-colored metals of relatively low melting points based on tin or lead. (2) A copper matte of about 77% Cu obtained from smelting of sulfide copper ores.
Zinc oxide; the powder product of corrosion of zinc or zinc-coated surfaces.
A structure characterized by a geometrical pattern resulting from the formation of a new phase along certain crystallographic planes of the parent solid solution. The orientation of the lattice in the new phase is related crystallographically to the orientation of the lattice in the parent phase. The structure was originally observed in meteorites, but is readily produced in many alloys, such as titanium, by appropriate heat treatment.
A condition that exists when molten metal, during cooling, evolves so much gas that it becomes violently agitated, forcibly ejecting metal from the mold or other container.
Recovering a metal from an ore or chemical compound using any suitable hydrometallurgical, pyrometallurgical, or electrometallurgical method.
A hot dipped galvanized coating from which virtually all free zinc is removed by wiping prior to solidification, leaving only a thin zinc-iron alloy layer.
A joint made with solder having a wide melting range and with the heat supplied by the molten solder poured onto the joint. The solder is manipulated with a hand-held cloth or paddle so as to obtain the required size and contour.
wiper forming, wiping
Method of curving sheet metal sections or tubing over a form block or die in which this form block is moved relative to a wiper block or slide block.
Activation of a metal surface by mechanical rubbing or wiping to enhance the formation of conversion coatings, such as phosphate coatings.
(1) A thin, flexible, continuous length of metal, usually of circular cross section, and usually produced by drawing through a die. The size limits for round wire sections range from approximately 0.13 mm (0.005 in.) to 25 mm (1 in.). Larger rounds are commonly referred to as bars. See also flat wire. (2) A length of single metallic electrical conductor, it may be of solid, stranded or tinsel construction, and may be either bare or insulated.
A cast shape, particularly of tough pitch copper, that has a cross section approximately square with tapered ends, designed for hot rolling to rod for subsequent drawing into wire.
Reducing the cross section of wire by pulling it through a die.
wire flame spraying
A thermal spraying process variation in which the material to be sprayed is in wire or rod form. See also flame spraying.
Hot-rolled coiled stock that is to be cold drawn into wire.
Formation of a curl along the edge of a shell, tube, or sheet and insertion of a rod or wire within the curl for stiffening the edge. See also curling.
A macrostructure, found particularly in wrought iron and in extruded rods of aluminum alloys, that shows elongated surfaces of separation when fractured.
Same as strain hardening.
The test or specimen electrode in an electrochemical cell.
The electrical conductor connecting the source of arc welding current to the work. Also called work connection, welding ground, or ground lead.
An exudation (sweat) of molten metal forced through the top crust of solidifying metal by gas evolution. See also zinc worms.
See stretch forming.
A wavy condition obtained in deep drawing of sheet metal, in the area of the metal between the edge of the flange and the draw radius. Wrinkling may also occur in other forming operations when unbalanced compressive forces are set up.
A commercial iron consisting of slag (iron silicate) fibers entrained in a ferrite matrix.