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Reduction of corrosion of a metal in an electrolyte by galvanically coupling it to a more anodic metal; a form of cathodic protection.
Forming a seamless metal ring by forging a pierced disk over a mandrel (or saddle).
An increase or decrease in the section thickness of a casting caused by insufficient strength of the mold sand of the cope or of the core.
salt bath heat treatment
Heat treatment for metals carried out in a bath of molten salt.
salt fog test
An accelerated corrosion test in which specimens are exposed to a fine mist of a solution usually containing sodium chloride, but sometimes modified with other chemicals. Also known as salt spray test.
salt spray test
See salt fog test.
(1) One or more units of a product (or a relatively small quantity of a bulk material) withdrawn from a lot or process stream and then tested or inspected to provide information about the properties, dimensions, or other quality characteristics of the lot or process stream. (2) A portion of a material intended to be representative of the whole.
A granular material naturally or artificially produced by the disintegration or crushing of rocks or mineral deposits. In casting, the term denotes an aggregate, with an individual particle (grain) size of 0.06 to 2 mm (0.002 to 0.08 in.) in diameter, that is largely free of finer constituents, such as silt and clay, which are often present in natural sand deposits. The most commonly used foundry sand is silica; however, zircon, olivine, aluminum silicates, and other crushed ceramics are used for special applications.
Abrasive blasting with sand. See also blasting or blast cleaning and compare with shotblasting.
Metal castings produced in sand molds.
A pit in the surface of a sand casting resulting from a deposit of loose sand on the surface of the mold.
Rolling two or more strips of metal in a pack, sometimes to form a roll-welded composite.
A diffusely reflecting surface finish on metals, lustrous but not mirrorlike. One type is a butler finish.
In saw manufacture, grinding away of punch marks or milling marks in the gullets (spaces between the teeth) and, in some cases, simultaneous sharpening of the teeth; in reconditioning of worn saws, restoration of the original gullet size and shape.
Using a toothed blade or disk to sever parts or cut contours.
A defect on the surface of a casting that appears as a rough, slightly raised surface blemish, crusted over by a thin porous layer of metal, under which is a honeycomb or cavity that usually contains a layer of sand; defect common to thin-wall portions of the casting or around hot areas of the mold.
Surface oxidation, consisting of partially adherent layers of corrosion products, left on metals by heating or casting in air or in other oxidizing atmospheres.
(1) A surface depression formed on a forging due to scale remaining in the dies during the forging operation. (2) A pit in the ground in which scale (such as that carried off by cooling water from rolling mills) is allowed to settle out as one step in the treatment of effluent waste water.
(1) Forming a thick layer of oxidation products on metals at high temperature. Scaling should be distinguished from rusting, which involves the formation of hydrated oxides. See also rust. (2) Depositing water-insoluble constituents on a metal surface, as in cooling tubes and water boilers.
Removing surface layers from an ingot, billet, or slab.
scanning Auger microscopy (SAM)
An analytical technique that measures the lateral distribution of elements on the surface of a material by recording the intensity of their Auger electrons versus the position of the electron beam.
Cutting surface areas of metal objects, ordinarily by using an oxyfuel gas torch. The operation permits surface imperfections to be cut from ingots, billets, or the edges of plate that are to be beveled for butt welding. See also chipping.
Scleroscope hardness number (HSc or HSd)
A number related to the height of rebound of a diamond-tipped hammer dropped on the material being tested. It is measured on a scale determined by dividing into 100 units the average rebound of the hammer from a quenched (to maximum hardness) and untempered AISI W-5 tool steel test block.
Scleroscope hardness test
A dynamic indentation hardness test using a calibrated instrument that drops a diamond-tipped hammer from a fixed height onto the surface of the material being tested. The height of rebound of the hammer is a measure of the hardness of the material.
Oxidation, in the presence of fluxes, of molten lead containing precious metals, to partly remove the lead in order to concentrate the precious metals.
(1) The formation of severe scratches in the direction of sliding. (2) The act of producing a scratch or narrow groove in a surface by causing a sharp instrument to move along that surface. (3) The marring or scratching of any formed metal part by metal pickup on the punch or die. (4) The reduction in thickness of a material along a line to weaken it intentionally along that line.
(1) A wet or dry cleaning process involving mechanical scrubbing. (2) A wet or dry mechanical finishing operation, using fine abrasive and low pressure, carried out by hand or with a cloth or wire wheel to produce satin or butler-type finishes.
(1) Products that are discarded because they are defective or otherwise unsuitable for sale. (2) Discarded metallic material, from whatever source, that may be reclaimed through melting and refining.
The hardness of a metal determined by the width of a scratch made by drawing a cutting point across the surface under a given pressure.
(1) The woven wire or fabric cloth, having square openings, used in a sieve for retaining particles greater than the particular mesh size. U.S. standard, ISO, or Tyler screen sizes are commonly used. (2) One of a set of sieves, designated by the size of the openings, used to classify granular aggregates such as sand, ore, or coke by particle size. (3) A perforated sheet placed in the gating system of a mold to separate impurities from the molten metal.
A high-speed press in which the ram is activated by a large screw assembly powered by a drive mechanism.
(1) Localized damage caused by the occurrence of solid-phase welding between sliding surfaces, without local surface melting. (2) A mild degree of galling that results from the welding of asperities due to frictional heat. The welded asperities break, causing surface degradation.
Material applied to infiltrate the pores of a thermal spray deposit.
(1) Closing pores in anodic coatings to render them less absorbent. (2) Plugging leaks in a casting by introducing thermosetting plastics into porous areas and subsequently setting the plastic with heat.
Any weld designed primarily to provide a specific degree of tightness against leakage.
(1) On a metal surface, an unwelded fold or lap that appears as a crack, usually resulting from a discontinuity. (2) A surface defect on a casting related to but of lesser degree than a cold shut. (3) A ridge on the surface of a casting caused by a crack in the mold face.
A continuous weld made between or upon overlapping members, in which coalescence may start and occur on the faying surfaces, or may have proceeded from the outer surface of one member. The continuous weld may consist of a single weld bead or a series of overlapping spot welds.
See arc seam weld and resistance seam welding.
An obsolete historical term usually applied to stress-corrosion cracking of brass.
Any alloy whose major constituent is obtained from recycled scrap metal.
secondary ion mass spectroscopy (SIMS)
An analytical technique that measures the masses of ions emitted from the surface of a material when exposed to a beam of incident ions. The incident ions are usually monoenergetic and are all of the same species, for example, 5 keV Ne+ ions.
Metal recovered from scrap by remelting and refining.
The removal of a conveniently sized, representative specimen from a larger sample for metallographic inspection. Sectioning methods include shearing, sawing (using hacksaws, band saws, and diamond wire saws), abrasive cutting, and electrical discharge machining.
A die made of parts that can be separated for ready removal of the workpiece. Synonymous with split die.
(1) Nonuniform distribution of alloying elements, impurities, or microphases in metals and alloys. (2) A casting defect involving a concentration of alloying elements at specific regions, usually as a result of the primary crystallization of one phase with the subsequent concentration of other elements in the remaining liquid. Microsegregation refers to normal segregation on a microscopic scale in which material richer in an alloying element freezes in successive layers on the dendrites (coring) and in constituent network. Macrosegregation refers to gross differences in concentration (for example, from one area of a casting to another). See also inverse segregation and normal segregation.
Inhomogeneous distribution of alloying elements aligned in filaments or plates parallel to the direction of working.
The stopping of a moving part by a mating surface as a result of excessive friction.
The stopping of relative motion as the result of interfacial friction. Seizure may be accompanied by gross surface welding. The term is sometimes used to denote scuffing.
See Ugine-Sejournet process.
Intentionally heating only certain portions of a workpiece.
Corrosion in which one element is preferentially removed from an alloy, leaving a residue (often porous) of the elements that are more resistant to the particular environment. Also called dealloying or parting. See also decarburization , decobaltification , denickelification , dezincification , and graphitic corrosion.
Quenching only certain portions of an object.
Thermally activated movement of an atom to a new site in a crystal of its own species, as, for example, a copper atom within a crystal of copper.
See preferred term air-hardening steel.
Any solid material that shows low friction without application of a lubricant.
semiautomatic arc welding
Arc welding with equipment that controls only the filler metal feed. The advance of the welding is manually controlled.
Plating in which prepared cathodes are mechanically conveyed through the plating baths, with intervening manual transfers.
A solid crystalline material whose electrical resistivity is intermediate between that of a metal conductor and an insulator, ranging from about 10-3 to 108 · cm, and is usually strongly temperature dependent.
An impression in a series of forging dies that only approximates the finish dimensions of the forging. Semifinishers are often used to extend die life or the finishing impression, to ensure proper control of grain flow during forging, and to assist in obtaining desired tolerances.
Preliminary operations performed prior to finishing.
The bend obtained by applying a force directly to the specimen in the portion that is to be bent. The specimen is either held at one end and forced around a pin or rounded edge or is supported near the ends and bent by a force applied on the side of the specimen opposite the supports and midway between them. In some instances, the bend is started in this manner and finished in the manner of a free bend.
Steel that is incompletely deoxidized and contains sufficient dissolved oxygen to react with the carbon to form carbon monoxide and thus offset solidification shrinkage.
A permanent mold in which sand cores or plaster are used.
semisolid metal forming
A two-step casting/forging process in which a billet is cast in a mold equipped with a mixer that continuously stirs the thixotropic melt, thereby breaking up the dendritic structure of the casting into a fine-grained spherical structure. After cooling, the billet is stored for subsequent use. Later, a slug from the billet is cut, heated to the semisolid state, and forged in a die. Normally the cast billet is forged when 30 to 40% is in the liquid state. See also rheocasting.
In austenitic stainless steels, the precipitation of chromium carbides, usually at grain boundaries, on exposure to temperatures of about 540 to 845 °C (about 1000 to 1550 °F), leaving the grain boundaries depleted of chromium and therefore susceptible to preferential attack by a corroding medium. Welding is the most common cause of sensitization. Weld decay (sensitization) caused by carbide precipitation in the weld heat-affected zone leads to intergranular corrosion.
sensitizing heat treatment
A heat treatment, whether accidental, intentional, or incidental (as during welding), that causes precipitation of constituents at grain boundaries, often causing the alloy to become susceptible to intergranular corrosion or intergranular stress-corrosion cracking. See also sensitization.
A type of cluster mill with small-diameter work rolls and larger-diameter backup rolls, backed up by bearings on a shaft mounted eccentrically so that it can be rotated to increase the pressure between the bearing and the backup rolls. Used to roll precision and very thin sheet and strip.
Resistance welding in which two or more spot, seam, or projection welds are made simultaneously by a single welding transformer with three or more electrodes forming a series circuit.
(1) Separation of solids from suspension in a fluid of lower density, solely by gravitational effects. (2) A process for removing iron from liquid magnesium alloys by holding the melt at a low temperature after manganese has been added to it.
severity of quench
Ability of quenching medium to extract heat from a hot steel workpiece; expressed in terms of the Grossmann number (H).
Directional deposition of carbon or a metallic film on a plastic replica so as to highlight features to be analyzed by transmission electron microscopy. Most often used to provide maximum detail and resolution of the features of fracture surfaces.
Removal of castings from a sand mold. See also knockout.
A continuous type furnace that uses a reciprocating shaker motion to move the parts along the hearth.
(1) The portion of a die or tool by which it is held in position in a forging unit or press. (2) The handle for carrying a small ladle or crucible. (3) The main body of a lathe tool. If the tool is an inserted type, the shank is the portion that supports the insert.
A cutter having a straight or tapered shank to fit into a machine-tool spindle or adapter.
shape memory alloys
A group of metallic materials that demonstrate the ability to return to some previously defined shape or size when subjected to the appropriate thermal procedure.
Producing flat surfaces using single-point tools. The work is held in a vise or fixture or is clamped directly to the table. The ram supporting the tool is reciprocated in a linear motion past the work.
(1) As a finishing operation, the accurate removal of a thin layer of a work surface by straightline motion between a cutter and the surface. (2) Trimming parts such as stampings, forgings, and tubes to remove uneven sheared edges or to improve accuracy.
(1) The type of force that causes or tends to cause two contiguous parts of the same body to slide relative to each other in a direction parallel to their plane of contact. (2) A machine or tool for cutting metal and other material by the closing motion of two sharp, closely adjoining edges; for example, squaring shear and circular shear. (3) An inclination between two cutting edges, such as between two straight knife blades or between the punch cutting edge and the die cutting edge, so that a reduced area will be cut each time. This lessens the necessary force, but increases the required length of the working stroke. This method is referred to as angular shear. (4) The act of cutting by shearing dies or blades, as in shearing lines.
The angle that the shear plane, in metal cutting, makes with the work surface.
(1) Bands of very high shear strain that are observed during rolling of sheet metal. During rolling, these form at approximately 35° to the rolling plane, parallel to the transverse direction. They are independent of grain orientation and at high strain rates traverse the entire thickness of the rolled sheet. (2) Highly localized deformation zones in metals that are observed at very high strain rates, such as those produced by high velocity (100 to 3600 m/s, or 330 to 11,800 ft/s) projectile impacts or explosive rupture.
A mode of fracture in crystalline materials resulting from translation along slip planes that are preferentially oriented in the direction of the shearing stress.
See radial marks.
A narrow, slanting ridge along the edge of a fracture surface. The term sometimes also denotes a narrow, often crescent-shaped, fibrous region at the edge of a fracture that is otherwise of the cleavage type, even though this fibrous region is in the same plane as the rest of the fracture surface.
shear modulus (G)
The ratio of shear stress to the corresponding shear strain for shear stresses below the proportional limit of the material. Values of shear modulus are usually determined by torsion testing. Also known as modulus of rigidity.
A confined zone along which shear takes place in metal cutting. It extends from the cutting edge to the work surface.
The tangent of the angular change, caused by a force between two lines originally perpendicular to each other through a point in a body. Also called angular strain.
(1) The stress component tangential to the plane on which the forces act. (2) A stress that exists when parallel planes in metal crystals slide across each other.
A flat-rolled metal product of some maximum thickness and minimum width arbitrarily dependent on the type of metal. It has a width-to-thickness ratio greater than about 50. Generally, such flat products under 6.5 mm ( in.) thick are called sheets, and those 6.5 mm ( in.) thick and over are called plates.
The plastic deformation of a piece of sheet metal by tensile loads into a three-dimensional shape, often without significant changes in sheet thickness or surface characteristics. Compare with bulk forming.
Roughness on upward-facing surfaces where undissolved solids have settled on parts during a plating operation.
(1) A hollow structure or vessel. (2) An article formed by deep drawing. (3) The metal sleeve remaining when a billet is extruded with a dummy block of somewhat smaller diameter. (4) In shell molding, a hard layer of sand and thermosetting plastic or resin formed over a pattern and used as the mold wall. (5) A tubular casting used in making seamless drawn tube. (6) A pierced forging.
A shell-molded sand core.
A surface-hardening process in which a suitable steel workpiece, when heated through and quench hardened, develops a martensite layer or shell that closely follows the contour of the piece and surrounds a core of essentially pearlitic transformation product. This result is accomplished by a proper balance among section size, steel hardenability, and severity of quench.
(1) A term used in railway engineering to describe an advanced phase of spalling. (2) A mechanism of deterioration of coated abrasive products in which entire abrasive grains are removed from the coating that holds the abrasive to the backing layer of the product.
A foundry process in which a mold is formed from thermosetting resin-bonded sand mixtures brought in contact with preheated (150 to 260 °C, or 300 to 500 °F) metal patterns, resulting in a firm shell with a cavity corresponding to the outline of the pattern. Also called Croning process.
shielded metal arc cutting
A metal arc cutting process in which metals are severed by melting them with the heat of an arc between a covered metal electrode and the base metal.
shielded metal arc welding (SMAW)
An arc welding process that produces coalescence of metals by heating them with an arc between a covered metal electrode and the workpieces. Shielding is obtained from decomposition of the electrode covering. Pressure is not used, and filler metal is obtained from the electrode. Also commonly referred to as stick welding.
(1) Protective gas used to prevent atmospheric contamination during welding. (2) A stream of inert gas directed at the substrate during thermal spraying so as to envelop the plasma flame and substrate; intended to provide a barrier to the atmosphere in order to minimize oxidation.
A casting imperfection caused by mismatch of cope and drag or of cores and molds.
A thin piece of material used between two surfaces to obtain a proper fit, adjustment, or alignment.
See flat edge trimmer.
The sudden application of an external force that results in a very rapid buildup of stress–for example, piston loading in internal combustion engines.
(1) A metal block used in a variety of bending operations to form or support the part being processed. (2) An anvil cap or sow block.
Shore hardness test
Same as Scleroscope hardness test.
In consumable electrode arc welding, a type of metal transfer similar to globular transfer, but in which the drops are so large that the arc is short circuited momentarily during the transfer of each drop to the weld pool. Compare with globular transfer and spray transfer.
A form of brittleness in metal. It is designated as cold shortness or hot shortness to indicate the temperature range in which the brittleness occurs.
See transverse direction.
(1) Small, spherical particles of metal. (2) The injection of molten metal into a die casting die. The metal is injected so quickly that it can be compared to the shooting of a gun.
Blasting with metal shot; usually used to remove deposits or mill scale more rapidly or more effectively than can be done by sandblasting.
A method of cold working metals in which compressive stresses are induced in the exposed surface layers of parts by the impingement of a stream of shot, directed at the metal surface at high velocity under controlled conditions.
The production of shot by pouring molten metal in finely divided streams. Solidified spherical particles are formed during descent in a tank of water.
(1) The contraction of metal during cooling after hot forging. Die impressions are made oversize according to precise shrinkage scales to allow the forgings to shrink to design dimensions and tolerances. (2) See casting shrinkage.
A void left in cast metal as a result of solidification shrinkage. Shrinkage cavities can appear as either isolated or interconnected irregularly shaped voids. See also casting shrinkage.
Cracks that form in metal as a result of the pulling apart of grains by contraction before complete solidification. See also hot tear.
A measuring ruler with graduations expanded to compensate for the change in the dimensions of the solidified casting as it cools in the mold.
A protective, refractory-lined metal-delivery system to prevent reoxidation of molten steel when it is poured from ladle to tundish to mold during continuous casting.
For a metalforming press, the distance from the top of the bed to the bottom of the slide with the stroke down and adjustment up. In general, it is the maximum die height that can be accommodated for normal operation, taking the bolster plate into consideration. See also bolster.
Milling with cutters having peripheral and side teeth. They are usually profile sharpened but may be form relieved.
A standard wire mesh or screen used in graded sets to determine the mesh size or particle size distribution of particulate and granular solids. See also sieve analysis.
A method of determining particle size distribution, usually expressed as the weight percentage retained upon each of a series of standard screens of decreasing mesh size.
The separation of powder into particle size ranges by the use of a series of graded sieves. Also called screen analysis.
That portion of a powder sample that passes through a sieve of specified number and is retained by some finer mesh sieve of specified number. See also sieve analysis.
A hard, brittle, nonmagnetic intermediate phase with a tetragonal crystal structure, containing 30 atoms per unit cell, space group, P4/mnm, occurring in many binary and ternary alloys of the transition elements. The composition of this phase in the various systems is not the same, and the phase usually exhibits a wide range in homogeneity. Alloying with a third transition element usually enlarges the field homogeneity and extends it deep into the ternary section.
Embrittlement of iron-chromium alloys (most notably austenitic stainless steels) caused by precipitation at grain boundaries of the hard, brittle intermetallic phase during long periods of exposure to temperatures between approximately 560 and 980 °C (1050 and 1800 °F). Sigma-phase embrittlement results in severe loss in toughness and ductility and can make the embrittled material susceptible to intergranular corrosion. See also sensitization.
Diffusing silicon into solid metal, usually low-carbon steels, at an elevated temperature in order to improve corrosion or wear resistance.
A metal fracture in which the broken metal surface has a fine texture, usually dull in appearance. Characteristic of tough and strong metals. Contrast with crystalline fracture and granular fracture.
Nonpreferred term used to denote brazing with a silver-base filler metal. See preferred terms furnace brazing , induction brazing , and torch brazing.
A metalforming press that provides pressure from one side.
single impulse welding
A resistance welding process variation in which spot, projection, or upset welds are made with a single impulse.
A cutting tool having one face and one continuous cutting edge.
A rolling mill designed such that the product contacts only two rolls at a given moment. Contrast with tandem mill.
single welded joint
In arc and gas welding, any joint welded from one side only.
Same as riser.
(1) The operation of machining the impression of a desired forging into die blocks. (2) See tube sinking.
The quotient of the mass (weight) over the volume of the sintered body expressed in grams per cubic centimeter.
The bonding of adjacent surfaces of particles in a mass of powder or a compact by heating. Sintering strengthens a powder mass and normally produces densification and, in powdered metals, recrystallization. See also liquid phase sintering and solid-state sintering.
Effect of the dimensions of a piece of metal on its mechanical and other properties and on manufacturing variables such as forging reduction and heat treatment. In general, the mechanical properties are lower for a larger size.
(1) Secondary forming or squeezing operations needed to square up, set down, flatten, or otherwise correct surfaces to produce specified dimensions and tolerances. See also restriking. (2) Some burnishing, broaching, drawing, and shaving operations are also called sizing. (3) A finishing operation for correcting ovality in tubing. (4) Final pressing of a sintered powder metallurgy part to obtain a desired dimension.
The starting stock for making welded pipe or tubing; most often it is strip stock of suitable width, thickness, and edge configuration.
In foundry practice, a gating arrangement designed to prevent the passage of slag and other undesirable materials into a casting.
Removing or holding back dirt or slag from the surface of the molten metal before or during pouring.
A thin outside metal layer, not formed by bonding as in cladding or electroplating, that differs in composition, structure, or other characteristics from the main mass of metal.
In flat-rolled metals, a surface rupture resulting from the exposure of a subsurface lamination by rolling.
See temper rolling.
(1) Removal of a material in thin layers or chips with a high degree of shear or slippage, or both, of the cutting tool. (2) A machining operation in which the cut is made with a form tool with its face so angled that the cutting edge progresses from one end of the work to the other as the tool feeds tangentially past the rotating workpiece.
(1) A layer of solidified metal or dross on the walls of a pouring vessel after the metal has been poured. (2) The unmelted residue from a liquated weld filler metal.
A flat-shaped semifinished rolled metal ingot with a width not less than 250 mm (10 in.) and a cross-sectional area not less than 105 cm2 (16 in.2).
A primary mill that produces slabs.
See preferred term peripheral milling.
The incomplete hardening of steel due to quenching from the austenitizing temperature at a rate slower than the critical cooling rate for the particular steel, resulting in the formation of one or more transformation products in addition to martensite.
A nonmetallic product resulting from the mutual dissolution of flux and nonmetallic impurities in smelting, refining, and certain welding operations (see, for example, electroslag welding ). In steelmaking operations, the slag serves to protect the molten metal from the air and to extract certain impurities.
(1) Slag or dross entrapped in a metal. (2) Nonmetallic solid material entrapped in weld metal or between weld metal and base metal.
A type of fracture in metals, typical of plane-stress fractures, in which the plane of separation is inclined at an angle (usually about 45°) to the axis of applied stress.
The main reciprocating member of a metalforming press, guided in the press frame, to which the punch or upper die is fastened; sometimes called the ram. The inner slide of a double-action press is called the plunger or punch-holder slide; the outer slide is called the blankholder slide. The third slide of a triple-action press is called the lower slide, and the slide of a hydraulic press is often called the platen.
(1) A material of extremely fine particle size encountered in ore treatment. (2) A mixture of metals and some insoluble compounds that forms on the anode in electrolysis.
Plastic deformation by the irreversible shear displacement (translation) of one part of a crystal relative to another in a definite crystallographic direction and usually on specific crystallographic plane. Sometimes called glide.
A group of parallel slip lines so closely spaced as to appear as a single line when observed under an optical microscope. See also slip line.
The crystallographic direction in which the translation of slip takes place.
A tapered flask that depends on a movable strip of metal to hold foundry sand in position. After closing the mold, the strip is refracted and the flask can be removed and reused. Molds thus made are usually supported by a mold jacket during pouring.
Visible traces of slip planes on metal surfaces; the traces are (usually) observable only if the surface has been polished before deformation. The usual observation on metal crystals (under a light microscope) is of a cluster of slip lines known as a slip band.
The crystallographic plane in which slip occurs in a crystal.
Cutting or shearing along single lines to cut strips from a metal sheet or to cut along lines of a given length or contour in a sheet or workpiece.
An imperfection consisting of a very thin elongated piece of metal attached by only one end to the parent metal into whose surface it has been worked.
A common batch furnace for heat treating metals where stock is charged and removed through a slot or opening.
Cutting a narrow aperture or groove with a reciprocating tool in a vertical shaper or with a cutter, broach, or grinding wheel.
slow strain rate technique
An experimental technique for evaluating susceptibility to stress-corrosion cracking. It involves pulling the specimen to failure in uniaxial tension at a controlled slow strain rate while the specimen is in the test environment and examining the specimen for evidence of stress-corrosion cracking.
(1) A short piece of metal to be placed in a die for forging or extrusion. (2) A small piece of material produced by piercing a hole in sheet material. See also blank.
The act of adding a separate piece or pieces of material in a joint before or during welding that results in a welded joint not complying with design, drawing, or specification requirements.
A hollow casting usually made of an alloy with a low but wide melting temperature range. After the desired thickness of metal has solidified in the mold, the remaining liquid is poured out. Considered an obsolete practice.
Thermal processing wherein chemical reactions take place to produce liquid metal from a beneficiated ore.
See hand forge (smith forge).
A reaction product sometimes left on the surface of a metal after pickling, electroplating, or etching.
(1) Heavy stock removal of superfluous material from a workpiece by using a portable or swing grinder mounted with a coarse grain abrasive wheel. (2) Offhand grinding on castings and forgings to remove surplus metal such as gate and riser pads, fins, and parting lines.
(1) The product formed by twisting and bending of hot metal rod prior to its next rolling process. (2) Any crooked surface imperfection in a plate, resembling a snake. (3) A flexible mandrel used in the inside of a shape to prevent flattening or collapse during a bending operation.
A foundry flask hinged on one corner so that it can be opened and removed from the mold for reuse before the metal is poured.
A precautionary interim stress-relieving treatment applied to high-hardenability steels immediately after quenching to prevent cracking because of delay in tempering them at the prescribed higher temperature.
A plot of stress (S) against the number of cycles to failure (N). The stress can be the maximum stress (Smax) or the alternating stress amplitude (Sa). The stress values are usually nominal stress; i.e., there is no adjustment for stress concentration. The diagram indicates the S-N relationship for a specified value of the mean stress (Sm) or the stress ratio (A or R) and a specified probability of survival. For N a log scale is almost always used. For S a linear scale is used most often, but a log scale is sometimes used. Also known as S-N diagram.
Immersion cleaning without electrolysis.
In heat treating of metals, prolonged holding at a selected temperature to effect homogenization of structure or composition. See also homogenizing.
soft magnetic material
A ferromagnetic alloy that becomes magnetized readily upon application of a field and that returns to practically a nonmagnetic condition when the field is removed; an alloy with the properties of high magnetic permeability, low coercive force, and low magnetic hysteresis loss.
See preferred term soldering.
Same as dead soft temper.
A filler metal used in soldering that has a liquidus not exceeding 450 °C (840 °F).
The relative ease and speed with which a surface is wetted by molten solder.
Reduction in mechanical properties of a metal as a result of local penetration of solder along grain boundaries.
A group of processes that join metals by heating them to a suitable temperature below the solidus of the base metals and applying a filler metal having a liquidus not exceeding 450 °C (840 °F). Molten filler metal is distributed between the closely fitted surfaces of the joint by capillary action. See also solder.
A soldering tool having an internally or externally heated metal bit usually made of copper.
Cutters made of a single piece of material rather than a composite of two or more materials.
The change in state from liquid to solid upon cooling through the melting temperature or melting range.
The temperature between the liquidus and the solidus.
The reduction in volume of metal from beginning to end of solidification. See also casting shrinkage.
solidification shrinkage crack
A crack that forms, usually at elevated temperature, because of the internal (shrinkage) stresses that develop during solidification of a metal casting. Also termed hot crack.
Any solid used as a powder or thin film on a surface to provide protection from damage during relative movement and to reduce friction and wear.
solid metal embrittlement
The occurrence of embrittlement in a material below the melting point of the embrittling species. See also liquid metal embrittlement.
A single, solid, homogeneous crystalline phase containing two or more chemical species.
A sintering procedure for compacts or loose powder aggregates during which no component melts. Contrast with liquid phase sintering.
A group of welding processes that join metals at temperatures essentially below the melting points of the base materials, without the addition of a brazing filler metal. Pressure may or may not be applied to the joint. Examples include cold welding , diffusion welding , forge welding , hot pressure welding , and roll welding.
(1) The highest temperature at which a metal or alloy is completely solid. (2) In a phase diagram, the locus of points representing the temperatures at which various compositions stop freezing upon cooling or begin to melt upon heating. See also liquidus.
The component of either a liquid or solid solution that is present to a lesser or minor extent; the component that is dissolved in the solvent.
solution heat treatment
Heating an alloy to a suitable temperature, holding at that temperature long enough to cause one or more constituents to enter into solid solution, and then cooling rapidly enough to hold these constituents in solution.
Electrode potential where half-cell reaction involves only the metal electrode and its ion.
The component of either a liquid or solid solution that is present to a greater or major extent; the component that dissolves the solute.
In a phase or equilibrium diagram, the locus of points representing the temperature at which solid phases with various compositions coexist with other solid phases, that is, the limits of solid solubility.
A fine mixture of ferrite and cementite produced either by regulating the rate of cooling of steel or by tempering steel after hardening. The first type is very fine pearlite that is difficult to resolve under the microscope; the second type is tempered martensite.
A gaseous environment containing hydrogen sulfide and carbon dioxide in hydrocarbon reservoirs. Prolonged exposure to sour gas can lead to hydrogen damage, sulfide-stress cracking, and/or stress-corrosion cracking in ferrous alloys.
A block of heat-treated steel placed between the anvil of the hammer and the forging die to prevent undue wear to the anvil. Sow blocks are occasionally used to hold insert dies. Also called anvil cap.
A regular, periodic array of points (lattice points) in space that represents the locations of atoms of the same kind in a perfect crystal. The concept may be extended, where appropriate, to crystalline compounds and other substances, in which case the lattice points often represent locations of groups of atoms of identical composition, arrangement, and orientation.
See preferred term flat drill.
(1) Separation of particles from a surface in the form of flakes. The term spalling is commonly associated with rolling-element bearings and with gear teeth. Spalling is usually a result of subsurface fatigue and is more extensive than pitting. (2) The spontaneous chipping, fragmentation, or separation of a surface or surface coating. (3) A chipping or flaking of a surface due to any kind of improper heat treatment or material dissociation.
The characteristic crystalline form in which a hot dipped zinc coating solidifies on steel strip.
A method used for the classification of ferrous alloys according to their chemical compositions, by visual examination of the spark pattern or stream that is thrown off when the alloys are held against a grinding wheel rotating at high speed.
The metal particles expelled during arc or gas welding. They do not form part of the weld.
The metal lost due to spatter.
In cutting or grinding, the energy expended or work done in removing a unit volume of material.
A test object, often of standard dimensions and/or configuration, that is used for destructive or nondestructive testing. One or more specimens may be cut from each unit of a sample.
speed of travel
In welding, the speed with which a weld is made along its longitudinal axis, usually measured in meters per second or inches per minute.
Metallic arsenides and antimonides that result from smelting metal ores such as those of cobalt or lead.
Graphite of spheroidal shape with a polycrystalline radial structure. This structure can be obtained, for example, by adding cerium or magnesium to the melt. See also ductile iron and nodular graphite.
An aggregate of iron or alloy carbides of essentially spherical shape dispersed throughout a matrix of ferrite.
A microstructure consisting of a matrix containing spheroidal particles of another constituent.
Heating and cooling to produce a spheroidal or globular form of carbide in steel. Spheroidizing methods frequently used are: (1) Prolonged holding at a temperature just below Ae1. (2) Heating and cooling alternatively between temperatures that are just above and just below Ae1. (3) Heating to a temperature above Ae1 or Ae3 and then cooling very slowly in the furnace or holding at a temperature just below Ae1. (4) Cooling at a suitable rate from the minimum temperature at which all carbide is dissolved to prevent the reformation of a carbide network, and then reheating in accordance with method 1 or 2 above. (Applicable to hypereutectoid steel containing a carbide network.)
A pig iron containing 15 to 30% Mn and 4.5 to 6.5% C.
(1) Shaft of a machine tool on which a cutter or grinding wheel may be mounted. (2) Metal shaft to which a mounted wheel is cemented.
The forming of a seamless hollow metal part by forcing a rotating blank to conform to a shaped mandrel that rotates concentrically with the blank. In the typical application, a flat-rolled metal blank is forced against the mandrel by a blunt, rounded tool; however, other stock (notably, welded or seamless tubing) can be formed. A roller is sometimes used as the working end of the tool.
A fine, homogeneous mixture of two phases that form by the growth of composition waves in a solid solution during suitable heat treatment. The phases of a spinodal structure differ in composition from each other and from the parent phase, but have the same crystal structure as the parent phase.
Any of a series of longitudinal, straight projections on a shaft that fit into slots on a mating part to transfer rotation to or from the shaft.
A die made of parts that can be separated for ready removal of the workpiece. Also known as segment die.
A segmented punch or a set of punches in a powder metallurgy forming press that allow(s) a separate positioning for different powder fill heights and compact levels in dual-step and multistep parts. See also stepped compact.
A form of metal characterized by a porous condition that is the result of the decomposition or reduction of a compound without fusion. The term is applied to forms of iron, titanium, zirconium, uranium, plutonium, and the platinum-group metals.
A coherent, porous mass of substantially pure iron produced by solid-state reduction of iron oxide (mill scale or iron ore).
Making an initial indentation in a work surface, with a drill, to serve as a centering guide in a subsequent machining process.
Using a rotary, hole-piloted end-facing tool to produce a flat surface normal to the axis of rotation of the tool on or slightly below the workpiece surface.
A weld made between or upon overlapping members in which coalescence may start and occur on the faying surfaces or may proceed from the surface of one member. The weld cross section is approximately circular.
See arc spot weld and resistance spot welding.
A quenching process using spray nozzles to spray water or other liquids on a part. The quench rate is controlled by the velocity and volume of liquid per unit area per unit of time of impingement.
In consumable-electrode arc welding, a type of metal transfer in which the molten filler metal is propelled across the arc as fine droplets. Compare with globular transfer and short-circuiting transfer.
(1) The elastic recovery of metal after stressing. (2) The extent to which metal tends to return to its original shape or contour after undergoing a forming operation. This is compensated for by overbending or by a secondary operation of restriking. (3) In flash, upset, or pressure welding, the deflection in the welding machine caused by the upset pressure.
A temper of nonferrous alloys and some ferrous alloys characterized by tensile strength and hardness about two-thirds of the way from full hard to extra spring temper.
(1) The mold channel that connects the pouring basin with the runner or, in the absence of a pouring basin, directly into which molten metal is poured. Sometimes referred to as downsprue or downgate. (2) Sometimes used to mean all gates, risers, runners, and similar scrap that are removed from castings after shakeout.
The bombardment of a solid surface with a flux of energetic particles (ions) that results in the ejection of atomic species. The ejected material may be used as a source for deposition. See also physical vapor deposition.
Making square holes by means of a specially constructed drill made to rotate and also to oscillate so as to follow accurately the periphery of a square guide bushing or template.
A machining tool, used for cutting sheet metal or plate, consisting essentially of a fixed cutting knife (usually mounted on the rear of the bed) and another cutting knife mounted on the front of a reciprocally moving crosshead, which is guided vertically in side housings. Corner angles are usually 90°.
A hybrid liquid metal forging process in which liquid metal is forced into a permanent mold by a hydraulic press.