Glossary A – C
Abrasion resistance
Degree of resistance of a material to abrasion.
Acid
A chemical substance that yields hydrogen ions (H+) when dissolved in water.
AD-WO / TRB 100 / TRD 00 / TRB 801
German pressure vessel code regulations monitoring pressure equipment and services. SF&E received its certification in July of 1998.
AFS
American Foundry Society.
Age hardening
Hardening by holding at ambient to moderately elevated tempertures, usually after rapid cooling.
Aging
The change in the properties of certain metals and alloys that occurs at ambient or moderately elevated temperatures after a solution heat treatment. The change in properties is often, but not always, due to a phase change, but never involves a change in chemical composition of the metal or alloy.
Air-set Process
No-bake process; molds/cores made with resin-bonded sand that hardens, or “sets”, without baking.
Alloy
A substance with metallic properties and composed of two or more chemical elements, at least one of which is a metal.
Alloy steel
Steel containing specified quantities of Alloying elements added to effect changes in mechanical or physical properties.
Aluminum
A metal commonly used as a deoxidizer in steels and other Alloys. Element 13; Symbol: Al.
Annealing
Heating to and holding at a suitable temperature, then cooling at a suitable rate; used primarily to soften metallic materials.
ANSI
American National Standards Institute.
Arc cutting
Metal cutting using an arc between an electrode and the metal being cut.
As cast
The condition of a casting which has not received any kind of heat treatment; also, the condition of a casting which has not received any finishing such as polishing or machining.
ASM
American Society for Materials; now ASM International.
ASNT
American Society for Non-destructive Testing.
ASTM
American Society for Testing and Materials, now ASTM International.
Atomic number
The number of protons in an atomic nucleus, which determines the individuality of the atom as a chemical element; used to identify the element unambiguously, i.e., the “element number.”
Atomic Symbol
One, two, or three letters used to represent a chemical element.
Austempering
Quenching a ferrous Alloy from the austenitizing temperature at a rate fast enough to avoid formation of ferrite or pearlite and then held at a temperature just above that of martensite formation until transformation to bainite is complete.
Austenite
Generally, a solid solution of one or more Alloying elements in face centered cubic iron (γ-iron). Unless otherwise designated, the solute is assumed to be carbon.
AWS
American Welding Society.
Bainite
A structure consisting of ferrite and cementite (carbide) resulting from the transformation of austenite at temperatures below the pearlite range but above that at which martensite begins to form.
BHN
Brinell Hardness Number.
Binder
Bonding agent in sand or in ceramic slurry.
Blasting
Cleaning or finishing metals by impingement with abrasive particles moving at high speed and usually carried by gas or liquid or thrown from a centrifugal wheel.
Boring
A machining operation that applies a single-point tool to create a cylindrical.
Brazing
Joining solid materials together by heating them to a suitable temperature and using a filler metal having a liquidus above about 450 degrees C (840 degrees F) and below the solidus temperatures of both base materials. The filler metal is distributed between the closely fitted surfaces of the joint by capillary attraction.
Bright annealing
An annealing process carried out in a controlled atmosphere furnace, so that the surface does not oxidize, remaining bright.
Brinell hardness test
A method for determining the hardness of a material by forcing a hard steel or carbide ball of specified diameter into it under a specified load. The result is expressed as the Brinell hardness number, which is the value obtained by dividing the applied load in kilograms by the surface area of the resulting impression in square millimeters.
Broaching
Enlarging or finishing machined holes or outside surfaces of castings by drawing or pushing tapered cutting tools in the axial direction.
Buildup sequence
The order in which weld beads are deposited.
Burned-on Sand
A mixture of sand and metal adhering to the surface of a sand casting.
Carbide
A binary compound of the element carbon and a more electropositive element.
Carbon
Carbon is the most important and influential Alloying element in steel. It is the principal hardening element in carbon and low Alloy steels. It is normally removed to extremely low levels in Stainless steels to allow welding without post-weld heat treatment. Element 6; Symbol: C.
Carbon steel
steel containing up to about 2% carbon and only incidental amounts of other elements except those added for deoxidation.
Case hardening
Hardening a ferrous Alloy so that surface layer or case is made substantially harder than the interior or core. Typical case hardening processes are carburizing and quenching, cyaniding, carbonitriding, nitriding, induction hardening, and flame hardening.
Casting
Pouring molten metal into a mold to produce an object of desired shape; also, the resulting object.
Casting shrinkage
(1) “Liquid shrinkage” — the reduction in volume of liquid metal as it cools before solidification. (2) “Solidification shrinkage” — the reduction in volume of metal from beginning to end of solidification. (3) “Solid contraction” — the reduction in dimension (and volume) as the metal cools to room temperature after solidification.
Cavitation damage
The wearing away of metal through the formation and collapse of cavities in a liquid.
Cementite
A compound of iron and carbon (iron carbide) that has the approximate chemical structure, Fe3C.
Chamfering
Machining an angle or bevel to eliminate an otherwise sharp corner
Chaplet
Insert in a mold cavity used to support a core. If metal, it becomes part of the casting.
Charpy test
A pendulum-type, single-blow impact test in which the specimen, usually notched, is supported at both ends as a simple beam and broken by a falling pendulum. The energy absorbed, as determined by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.
Chill
A metal insert embedded in the surface of a mold or core, or placed in the mold cavity to hasten solidification of heavy sections.
Chromium
Chromium provides corrosion resistance; it is the element which makes Stainless steel “Stainless.” In steels, it increases hardenability by reducing the cooling rate required for martensite formation. Element 24; Symbol: Cr.
Cleaning
Removing residual mold material, excess metal (gates, risers, etc.), and scale from a casting. Sometimes called “fettling.”
CNC
Computerized Numerical Control. Guidance of machine tool operation by programmed instructions on tape or from a computer.
Coalescence
The growth of particles of a dispersed phase by solution and reprecipitation.
Cobalt
An element added to steels to inhibit grain growth at elevated temperatures and to improve retention of temper and high temperature strength. It is the base element for specialty Alloys such as “Stellite.” Element 27; Symbol: Co.
Columbium
It is a very pronounced carbide former, thus added to Stainless steels to stabilize the carbon, freeing the chromium for corrosion resistance. It is also a strong nitride former and is added to some steels to improve strength at elevated temperatures through the formation of fine nitrides. Element 41; Symbol: Cb. It is also known as Niobium, Symbol: Nb.
Compacted graphite cast iron
Cast iron having a graphite shape intermediate between the flake form typical of gray cast iron and the spherical form of ductile cast iron.
Conductivity
The quantity of energy that flows through a material measured in thermal or electrical units per unit time per cross-sectional area per unit of length.
Copper
Copper is added to Stainless steels to improve resistance to reducing acids. Element 29, Symbol: Cu.
Corrosion
The deterioration of a metal by chemical or electrochemical reaction with its environment.
Corrosion embrittlement
The severe loss of ductility of a metal resulting from corrosive attack, usually intergranular and often not visually apparent.
Creep
Time-dependent strain occurring under stress. The creep strain occurring at a diminishing rate is called primary creep; that occurring at a minimum and almost constant rate, secondary creep; and that occurring at an accelerating rate, tertiary creep.
Crystalline fracture
A pattern of brightly reflecting crystal facets on the fracture surface of a polycrystalline metal, resulting from cleavage fracture of many individual crystals.
