Metal Terminology T
TANDEM MILL
Arrangement of rolling mills, in direct line, allowing the metal to pass from one set of rolls into the next.
TAPPING
Transferring molten metal from melting furnace to ladle.
TARNISH
Surface discoloration on a metal, usually from a thin film of oxide or sulfide.
TEEMING
Pouring metal into ingot molds.
TELESCOPING
Transverse slipping of successive layers of a coil so that the edge of the coil is conical rather than flat.
TEMPER
The state of or condition of a metal as to its hardness or toughness produced by either thermal treatment or heat treatment and quench or cold working or a combination of same in order to bring the metal to its specified consistency. Each branch of the metal producing industry has developed its own system of temper designates. In flat rolled products including sheet and strip steel, tin mill products, stainless strip, aluminum sheet and copper base alloy strip; they are shown as follows:
ALUMINUM SHEET - (See Aluminum)
COPPER BASE ALLOYS (Cold Rolled) - B S Gage Numbers.
NOTE - Hardness is indicated condition while hardness varies with alloy changes.
Temper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hardness
Annealed ......................................................................Commercially Soft
Quarter Hard ................................................................One Number Hard
Half Hard .....................................................................Two Numbers Hard
Hard Temper ................................................................Four Numbers Hard
Extra Hard ....................................................................Six Numbers Hard
Spring Temper ..............................................................Eight Numbers Hard
Extra Spring Temper .....................................................Ten Numbers Hard
SHEET STEEL (Low Carbon Cold Rolled) - Temper Classifications.
Temper . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Rockwell
Full Hard . .................................................................... .069 and thinner B 90 min.
..................................................................................... .070 and thinner B 84 min.
Half Hard ..................................................................... Approx. R/B 70/85
Quarter Hard ............................................................... Approx. R/B 60/75
Soft Commercial Quality .............................................. Approx. R/B 66 max.
Drawing Quality ........................................................... Approx. R/B 55 max.
STAINLESS STRIP STEEL (Cold Rolled Temper Classification) - Type 301.
NOTE - The various stainless strip tempers are based on specified minimum values for tensile strength or yield strength or both. However, because of custom, both distributors and customers alike rely on approximate Rockwell readings for temper classification. To illustrate:
Temper (Type 301) . . . . . . . . . . . . . . . Rockwell . . . . . . . . . . . . . . . . Tensile Psi
Soft ................................................ Approx. B 75/85 ...................... 110,000 Min.
Quarter Hard .................................. Approx. C 25/30 ..................... 125,000 Min.
Half Hard ........................................ Approx. C 30/35 ..................... 150,000 Min.
Three Quarters Hard ....................... Approx. C 35/40 ..................... 175,000 Min.
Full Hard ......................................... Approx. C 40/45 ..................... 185,000 Min.
Extra Hard (Type 301) .................... Approx. C 45 min .................... 200,000 Min.
Type 430 Soft ................................. Approx. B 75/85 ...................... 75/85,000
STRIP STEEL (Low Carbon Cold Rolled) - Temper Classifications.
Temper . . . . . . . . . . . . . . . . . . . . . . . . Rockwell . . . . . . . . . . . . . . . . Means Tensile
No. 1 Full Hard .................. .069 and thinner B 90 min. ..................... 80,000
........................................... .070 and thicker B 84 min. ..................... 80,000
No.2 Half hard ............................................. B 70/85 ....................... 64,000
No.3 Quarter Hard ...................................... B 60/75 ........................ 54,000
No.4 Skin Rolled ......................................... B 65 max. ..................... 48,000
No. 5 Dead Soft .......................................... B 55 max.
TEMPERED SPRING STEELS (Strip) - Temper indication is to Rockwell Hardness only.
TIN MILL PRODUCTS (Steel) Temper Classifications - NOT STANDARDIZED. FOR INFORMATION ONLY. (Not to be confused with the Cold Rolled Strip Steel Temper Numbering System wherein No. 1 Temper indicates Full Hard, while in the TIN MILL Product Numbering System No. 1 Temper indicates a soft condition.) The following Rockwell ranges are approx. only.
Temper-Number . . . . . . . . . . . .. . . . . Rockwell - 30 T Scale . . . . . . . .Rockwell B Scale
No. 1 Temper ........................................ Aim at 46/52 ............................ Aim at 45/53
No. 2 Temper ........................................ Aim at 50/56 ............................ Aim at 51/59
No. 21/2 Temper ................................... Aim at 52/58 ............................ Aim at 53/62
No. 3 Temper ........................................ Aim at 54/60 ............................ Aim at 56/66
No.4 Temper ......................................... Aim at 58/64 ............................ Aim at 62/71
*No. 5 Temper ...................................... Aim at 62/68 ............................ Aim at 68/77
*No. 6 Temper ...................................... Aim at 62/73 ............................ Aim at 75/84
*NOTE: Tempers 5 and 6 are temper rolled from rephosphorized steel in order to develop desired hardness and stiffness. The above temper classifications are used principally by producing mills and can manufacture but are not in general use in the sheet and strip industry.
TEMPERED and POLISHED SPRING STEEL STRIP
90/1.03% carbon range (Also known as clock spring steel.) - This product, while similar to general description under heading of Tempered Spring Steel Strip, is manufactured and processed with GREat and extreme care exercised in each step of its production. Manufactured from carbon range of .90/1.03% with Rockwell range C 48/51. Clock spring quality has been ground and polished with edges dressed. It is usually supplied dark blue in color and has a wide range of uses, such as coiled and flat mechanical springs, ignition vibrator springs, springs for timing devices, springs for the electric and electronic fields, steel tapes, rules, etc.
TEMPERED SPRING STEEL STRIP
Any medium or high carbon (excluding clock spring) strip steel of spring quality which has been hardened and tempered to meet specifications. Where specification calls for blue or straw color, same is accomplished by passing through heat prepared at proper temperature depending on color required. Blue is developed at approximately 600癋.
TEMPERING
(Also termed “drawing.”) - A process of re-heating quench-hardened or normalized steel to a temperature below the transformation range and then cooling at any rate desired. The primary purpose of tempering is to impart a deGREe of plasticity or toughness to the steel to alleviate the brittleness of its martensite.
TEMPER ROLLING
Subjecting metal sheet or strip to a slight amount of cold rolling following annealing (usually ?to 1 ?%) to forestall stretcher strains. Also termed “Pinch Pass” or “Skin Rolled.” (See Cold Rolling)
TENSILE STRENGTH
(Also called ultimate strength) - Breaking strength of a material when subjected to a tensile (stretching) force. Usually measured by placing a standard test piece in the jaws of a tensile machine, gradually separating the jaws, and measuring the stretching force necessary to break the test piece. Tensile strength is commonly expressed as pounds (or tons) per square inch of original cross section.
TENSILE TEST
(See Tensile Strength)
TERNARY ALLOY
An alloy that contains three principal elements.
TERNE PLATE
Sheet steel, coated with a lead-tin alloy. The percentage of tin is usually kept as low as possible because of its high cost; however, about 15% is normally necessary in order to obtain proper coating of the steel, since pure lead does not alloy with iron and some surface alloying is necessary for proper adhesion.
THERMOCOUPLE
A device for measuring temperatures by the use of two dissimilar metals in contact; the junction of these metals gives rise to a measurable electrical potential with changes in temperature.
THICKNESS GAGE OR FEELER STOCK
A hardened and tempered, edged, ground, and polished thin section, high carbon strip steel. Usually ?#148; in width and in thicknesses from .001 to .050” manufactured to extremely close tolerances. It is used primarily for determining measurement of openings by tool and die makers, machinists, and automobile technicians. It is prepared in handy pocket size knife-like holders containing an assembly of various thicknesses. Also prepared in standard 12” lengths with rounded ends in 10’ and 25’ coils. Universally used in the metal industry.
THREE-QUARTER HARD TEMPER
(A) In stainless steel strip tempers are based on a minimum tensile or yield strength. For Chromium-Nickel grades three-quarter hard temper is 175,000 T.S., 135,000 Y.S. min. (B) In Brass mill terminology, this temper is three B & S numbers hard or 29.4% thickness reduction.
TIN
(Chemical Symbol Sn) - Element No. 50 of the periodic system; atomic weight 118.70. Soft silvery white metal of high malleability and ductility, but low tensile strength; melting point 449癋., boiling point 4384癋., yielding the longest molten-state range for any common metal; specific gravity 7.28. Principal use as a coating on steel in tin plate; also as a constituent in alloys.
TINNING
Coating with tin, commonly either by immersion into molten tin or by electrodeposition; also by spraying.
TIN PLATE BASE BOX
A Tin Plate Base Box is measured in terms of pounds per Base Box (112 sheets 14” x 20”) a unit peculiar to the tin industry. This corresponds to its area of sheet totaling to 31.360 square inches of any gage and is applied to tin plate weighing from 55 to 275 pounds per base box. To convert to decimal thickness multiply weight per base box by .00011.
TIN PLATING
Electroplating metal objects with tin; the object to be coated is made cathode (negative electrode) in an electrolytic bath containing a decomposable tin salt.
TITANIUM
(Chemical Symbol Ti) - Element No. 22 of the periodic system; atomic weight 47.90, melting point about 3270癋.; boiling point over 5430癋; specific gravity 4.5. Bright white metal, very malleable and ductile when exceedingly pure. Its principal functions as an alloy in the making of steel (1) Fixes carbon in inert particles (a) reduces martensitic hardness and hardenability in medium chromium steel (b) prevents formation of austenite in high-chromium steels (c) prevents localized depletion of chromium in stainless steel during long heating. Now finding application in its own right because of its high strength and good corrosion resistance.
TOLERANCE LIMIT
The permissible deviation from the desired value.
TOOL STEEL
Any high carbon or alloy steel capable of being suitable tempered for use in the manufacture of tools.
TOUGHNESS
Property of resisting fracture or distortion. Usually measured by impact test, high impact values indicating high toughness.
TRACE
Extremely small quantity of an element, usually too small to determine quantitatively.
TRANSFORMATION
A constitutional change in a solid metal, e.g., the change from gamma to alpha iron, or the formation of pearlite from austenite.
TRANSFORMATION RANGE
Temperature range over which a chemical or metallurgical change takes place.
TRANSFORMATION TEMPERATURE
The temperature at which transformation occurs. The term is sometimes used to denote the limiting temperature of a transformation range.
TROOSITE
Tempered martensite that etches rapidly, usually appears dark, and is not resolved by the microscope.
TROWEL STEEL
Hardened and tempered spring steel. .90 to 1.05% carbon content. Ordinary tolerances, but rolled extra flat - Rockwell C 50. Used in the manufacture of plastering trowels.
TRUSS SPRING STEEL
Supplied cold rolled and bright annealed. Carbon content about .70% - Manganese .74%. Must be formed very severely and must be as free as possible from decarburization.
TUKON HARDNESS TEST
A method for determining micro-hardness by using a Knoop diamond indenter or Vickers square-base pyramid indenter.
TUMBLING
Cleaning articles by rotating them in a cylinder with cleaning materials.
TUNGSTEN
(Chemical symbol W) - Element No. 74 of the periodic system; atomic weight 183.92. Gray metal of high tensile strength, ductile and malleable when specially handled. It is immune to atmospheric influences and most acids, but not to strong alkalies. The metal is used as filament and in thin sheet form in incandescent bulbs and radio tubes. (1) Forms hard abrasion resistant particles in tool steels. (2) Promotes hardness and strength at elevated temperatures.
TUNGSTEN CARBIDE
Compound of tungsten and carbon, of composition varying between WC and W2C; imbedded in matrix of soft metal, such as cobalt, extensively used for Sintered Carbide Tools.
TWIST
A winding departure from flatness.
Metal Terminology U
ULTIMATE STRENGTH
(See Tensile Strength)
UTILITY SHEET ALUMINUM
Mill finish coiled or flat sheet of unspecified composition and properties produced in specific standard sizes and suitable for general building trade usage.
UPSETTING
(1) A metal working operation similar to forging. (2) The process of axial flow under axial compression of metal, as in forming heads on rivets by flattening the end of wire.
