|MTI ENGINEERING CORPORATION
Precision Sheet Metal Fabrication
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Abbreviation for Society of Automotive Engineers. This organization has specified common and alloy steels and copper base alloys in accordance with a numerical index system allowing approximation of the composition of the metal. The last two digits indicate the carbon content, usually within 0.05%.
An accelerated corrosion test in which the metal specimens are exposed to a fine mist of salt water solution either continuously or intermittently.
(See Scratch Brushed Finish)
(Scabby) - A blemish caused on a casting by eruption of gas from the mold face or by uneven mold surface or occurring where the skin from a blowhole has partly burned away and is not welded.
(See Black Oil Tempered Spring Steel)
(1) Oxidation of metal due to heat resulting in relatively heavy surface layers of oxide. (2) Removal of scale from metal.
Machining the surface layers from ingots, billets and slabs before fabrications.
Cutting surface areas of metal objects, ordinarily by using a gas torch. The operation permits surface defects to be cut from ingot, billets, or the edges of plate that are to be beveled for butt welding. (See Chipping)
A method for measuring the hardness of metal; a diamond-pointed hammer drops from a fixed distance through a tube onto the smoothed metal surface and the rebound distance, with a specified high-carbon steel as 100.
Material unsuitable for direct use but usable for reprocessing by remelting.
Finish obtained by mechanically brushing the surface with wire bristle brushes, by buffing with greaseless compound or by cold rolling with wire bristled rolls of scratch etched finish.
(A defect.) - On the surface of metal a crack that has been closed but not welded; usually produced by some defect either in casting or in working, such as blowholes that have become oxidized or folds and laps that have been formed during working. Similar to cold shut and laminations.
An electric-resistance type of welding process, in which the lapped sheet is passed between electrodes of the roller type while a series of overlapping spot welds is made by the intermittent application of electric current.
The designation given to sheet or strip that has imperfections in moderate degree or extent, which may be classified in two general groups imperfections in the base material, or other manufacturing defects. This term not used in connection with non-ferrous alloys.
Used for laminated piston rings. Carbon content about .70%. Hardened and blue tempered with round edges. Hardness usually Rockwells 30 N 68 to 71, width sizes vary from .058 to .163 and thickness are .020, .024 and .030.
In an alloy, concentration of carbon or 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.
A steel containing sufficient carbon or alloying element, or both, to form martensite either through air hardening or, as in welding and induction hardening, through rapid removal of heat from a locally heated portion by conduction into the surrounding cold metal. (See Air-Hardening Steel)
Steel in the form of billets, blooms, etc., requiring further working before completion into finished steel ready for marking.
Steel incompletely deoxidized, to permit evolution of sufficient carbon monoxide to offset solidification shrinkage.
Cast iron (not steel) of high quality, obtained by using a large percentage of steel scrap with the pig iron.
A type of cutting operation in which the metal object is cut by means of a moving blade and fixed edge or by a pair of moving blades that may be either flat or curved.
A diagonal, transgranular track caused by shear stresses.
A thin flat hard metal strip produced to close tolerances; used primarily for tool, die and machine alignment purposes. In steel there are four general types: (1) Low Carbon Rockwell B 80/100; (2) Hard Rolled High Carbon Rockwell C 28/33; (3) Hardened and Tempered Spring Steel Rockwell C 44/51; (4) Austinitic Stainless Steel Rockwell C 35/45. Brass shim of commercial quality is also used and most generally specified as 2 Nos. Hard but may be 4 Nos. Hard.
(See Scleroscope Hardness)
A term applying to terne coated (Lead and Tin) sheets with reference to Base Box sizes (14 x 20). (See to Terne Plate)
Cleaning surface of metal by air blast, using metal shot as an abrasive.
A void left in cast metals as a result of solidification shrinkage and the progressive freezing of metal towards the center.
(Chemical Symbol Si) - Element No. 14 of the periodic system; atomic weight 28.06. Extremely common element, the major component of all rocks and sands; its chemical reactions, however, are those of a metalloid. Used in metallurgy as a deoxidizing scavenger. Silicon is present, to some extent, is all steels, and is deliberately added to the extent of approximately 4% for electric sheets, extensively used in alternating current magnetic circuits. Silicon cannot be electrodeposited.
Steel usually made in the basic open-hearth or electric furnace, with about 0.50-5.% silicon, other elements are usually kept as low as possible. Because of high electrical resistance and low hysteresis loss, silicon sheet and strip are standard in electric magnet manufacture.
A steel fracture that has a very smooth fine train or silky appearance.
Alloys of silver, copper, zinc and other metals, melting between 650 and 875°C. used for making strong yet moderately ductile joints that resist corrosion.
A forming press that operates with a single function, such as moving a punch into a die with no simultaneous action for holding down the clank or ejecting the formed work.
Used for making sinkers in hosiery making machinery. Supplied both hardened and tempered and cold rolled and annealed. Usually extra precision rolled and extra flat. Carbon content about 1.25%.
A reservoir insulated to retain heat and to hold excess molten metal on top of an ingot mold in order to feed the shrinkage of the ingot. Also called shrink head or feeder head.
Composite, containing carbides of extremely refractory metals, such as tungsten, tantalum, titanium, etc., cemented together by a relatively low-melting metal, such as cobalt acting as a matrix.
Converting powder into a continuous mass by heating to a temperature considerably below fusion, usually after preliminary compacting by pressure.
A plate of steel or wrought iron from which pipe or tubing is made by rolling the skelp into shape longitudinally and welding or riveting the edges together.
A thin surface layer that is different from the main mass of a metal object, in composition structure or other characteristics.
A product resulting from the action of a flux on the nonmetallic constituents of a processed ore, or on the oxidized metallic constituents that are undesirable. Usually slags consist of combinations of acid oxides with basic oxides, and neutral oxides are added to aid fusibility.
The edges of sheet or strip metal resulting from cutting to width by rotary slitters.
Cutting sheet or strip metal to width by rotary slitters.
(Defect) - Loose metal piece rolled down onto the surface of the metal during the rolling operations.
Prolonged heating of a metal at selected temperature.
(No.4 Temper) - In low carbon-rolled strip steel, soft and ductile. Produced by subjecting annealed strip to a pinch pass or skin rolling (a very light rolling).
Reduction in ductility of a metal or alloy, associated with local penetration by molten solder along grain boundaries.
Joining metals by fusion of alloys that have relatively low melting points most commonly, lead-base or tin-base alloys, which are the soft solders. Hard solders are alloys that have silver, copper, or nickel bases and use of these alloys with melting points higher than 800°F. is generally termed brazing.
A process in which an alloy is heated to a suitable temperature, is held at this temperature long enough to allow a certain constituent to enter into solid solution and is then cooled rapidly to hold the constituent in solution. The metal is left in a supersaturated, unstable state and may subsequently exhibit age hardening.
Structure of steel, resulting from the tempering of martensite. In a truly sorbitic structure, the cementite is completely dispersed in the matrix. The trend is to call this structure tempered martensite.
Structure of steel resulting, on cooling under the proper conditions from the decomposition of austenite; has a fine, Lamellar appearance.
(Concerning space lattices) - Body-centered.
(Crystal) - A system of equivalent points formed by the intersections of three sets of planes parallel to pairs of principal axes; the space lattice may be thought of as formed by the corners of the unit cells.
A numerical value representing the weight of a given substance as compared with the weight of an equal volume of water, for which the specific gravity is taken as 1.0000.
(X-rays) - An instrument using an extended surface - a photographic plate or film, or a fluorescent screen - for receiving the X-ray diffraction pattern.
(Prime Western Specter). A low-grade of Virgin Zinc containing approximately 98% Zinc used in Galvanizing processes.
Any process of prolonged heating and slow cooling of steel which will convert the carbide content into rounded or spheroid form.
High-manganese pig iron, containing 15-30% manganese, approximately 5% carbon, and less than 1% silicon, used in the manufacture of steel by the Bessemer, or basic open-hearth process.
The procedure of making sheet metal discs into hollow shapes by pressing the metal against a rotating form (spinning chuck) by a tool.
An electric-resistance welding process in which the fusion is limited to a small area. The pieces being welded are pressed together between a pair of water-cooled electrodes through which an electrical current is passed during a very short interval so that fusion occurs over a small area at the interface between the pieces.
An indicator of elastic stresses, frequently measured as the increase in diameter of a curved strip after removing it from the mandrel about which it was held. The measurement is employed as an indicator of the extent of recovery or relief of residual stresses that has been achieved by the transformation of elastic strain to plastic strain during heating or stress relieving,
Steel, normally of the high-carbon or alloy type, used in the manufacture of springs, lending itself to appropriate heat treatment; usually made is the open hearth or electric furnace.
Any of a number of strip steels produced for use in the manufacture of steel springs or where high tensile properties are requires marketed in the annealed state, hard rolled or as hardened and tempered strip.
In brass mill terminology, Spring Temper is eight numbers hard or 60.50% reduction.
A treatment applied to austentic stainless steels that contain titanium or columbium. This treatment consists of heating to a temperature below that of a full anneal in order to precipitate the maximum amount of carbon at titanium carbide or columbium carbide. This eliminates precipitation at lower temperatures, which might reduce the resistance of the steel to corrosion.
A thermal treatment designed to precipitate material from solid solution, in order to improve the workability, to decrease the tendency of certain alloys to age harden at room temperature, or to obtain dimensional stability under service at slightly elevated temperatures.
Corrosion resistant steel of a wide variety, but always containing a high percentage of chromium. These are highly resistant to corrosion attack by organic acids, weak mineral acids, atmospheric oxidation, etc.
A term used to refer to various press forming operations in coining, embossing, blanking, and pressing.
Iron, malleable in at least one rang of temperature below its melting point without special heat treatment substantially free from slag, and containing carbon more than about 0.05% and less than about 2.00%. Other alloying elements may be present in significant quantities, but all steels contain at least small amounts of manganese and silicon, and usually as undesirable constituents, also sulfur and phosphorus.
Steel sheets or strip adhering. Usually by fusion spots caused by overheating during box annealing.
An iron alloy. A term indicating a group of stainless steels the principal alloying element of which is chromium in varying amounts from 4.00 to 27.00%.
Deformation produced on a body by an outside force. (See also Stress and Hookes Law.)
Aging induced by cold working. (See Aging)
An increase in hardness and strength caused by plastic deformation at temperatures lower than the recrystallization range.
Deforming force to which a body is subjected or the resistance which the body offers to deformation by the force. (See also Strain and Hookes Law)
Low temperature annealing for removing internal stresses, such as those resulting in a metal from work hardening or quenching.
Reducing residual stresses by heating.
A process of forming panels and cowls of large curvature by stretching sheet over a form of the desired shape. This method is more rapid than hammering and beating.
(Also termed patent leveling.) A method of making metal sheet or strip dead flat by stretching.
Long vein-like marks appearing on the surface of certain metals, in the direction of the maximum shear stress, when the metal is subjected to deformation beyond the yield point. Also termed Luders Lines. (Not a defect in No. 5 dead soft temper.)
(Cold Rolled) - A flat cold rolled steel product (Other than Flat Wire) 23 15/16 and narrower; under .250 in thickness, which has been cold reduced to desired decimal thickness and temper on single stand, single stand reversing, or tandem cold mills in coil form from coiled hot rolled pickled strip steel.
The arrangement of parts; in crystals, especially the shape and dimension of the unit cell, and the number, kinds and positions of the atoms within it.
(Chemical Symbol S.) - Element No. 16 of the periodic system; atomic weight 32.06. Non-metal occurring in a number of allotropic modifications, the most common being a pale-yellow brittle solid. In steel most commonly encountered as an undesired contaminant. However, it is frequently deliberately added to cutting stock to increase machinability.
|MTI ENGINEERING CORPORATION
Precision Sheet Metal Fabrication
15678 Graham St. Huntington Beach, CA 92649
Telephone: (714) 891-4619
Marc Grismer Ext 105
Fax: (714) 891-7570
|Web Site: http://www.mtiengineering.com|
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