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Manganese Steel (Austenitic)
See Hadfield Manganese Steel
Machine Allowance
Stock added to the part to permit machining of the part to final dimensions.
Machine Drawing
An engineering drawing which depicts the final size and shape of the part for its end use.
Magnetic Particle Inspection
A nondestructive method of inspecting the surface integrity of ferromagnetic materials.
Maraging Steel
A high alloyed steel that is hardened by both martensite transformation and by age hardening.
Martempering (Interrupted Quenching)
A hardening treatment of a steel involving a slow cool through the martensitic transformation range to reduce stresses associated with the quenching of austenite. An important aspect of martempering is that no transformation product other than martensite should form.
Martensite
A generic term used for microstructures formed by diffusionless phase transformations. A constituent found in hardened steel; has a needle like microstructure.
See also Mf and Ms.
Martensitic Stainless Steels
A corrosion-resistant ferrous alloy with a predominant martensitic phase. Mass Effect . . . The effect that the mass of a component has on the properties of the material from which the part is made. In castings, such effects may arise due to the effect of mass on the solidification rate and on the rate of temperature change during heat treatment.
Mass Effect
The effect that the mass of a component has on the properties of the material from which the part is made. In castings such effects may arise due to the effect of mass on the solidification and on the rate of temperature change heat treatment.
Matchplate
A plate of metal or other materials on which patterns and gating systems, split along the parting line, are mounted back to back to form an integral piece.
Meallographic Structure
The nature, distribution, and amounts of the metallographic constituents in a metal.
Mechanical Properties
Properties of a material that reveal its strength and elastic behavior.
Metalloid
1) An element intermediate between metals and nonmetals possessing both metallic and nonmetallic properties, as arsenic, 2) sometimes applied to elements commonly bonded in small amounts in steel, as carbon, manganese, boron, silicon, sulfur, and phosphorus.
Metallstatic Pressure
A compound phase referring to hydrostatic pressure, substituting Metall since Hydro connotes water.
Metallurgical Bond
The bond between two metals whose interface is free of voids, oxide films, or discontinuities.
Metallurgy
The science and technology of metals, a broad field that includes but is not limited to the study of internal structures and properties of metals and the effects on them of various processing methods.
Metalock
A method of cold repair of castings and forgings.
Metals Comparator
An instrument for testing or identifying metallic and nonmetallic parts. Parts are placed in an electromagnetic field and a standard parts in a matched electromagnetic field. Distortions of the magnetic fields are compared on an oscilloscope.
Metamic
A metal ceramic high in Cr-Al2O3.
Metastable (Unstable)
A state of pseudo-equilibrium.
Mexico Bay Sand
A sand similar to Michigan City dune sand mined at Selkirk Beach, near Mexico NY., on Lake Ontario. It has a silica content of 90% and over.
Meyer Hardness Test
A test to determine tendency of a metal to harden when deformed plastically. A series of indentations are made in the metal using a fixed-diameter ball and progressively increasing loads.
Mf
The temperature at which martensite formation finishes during cooling.
Mica Schist
A type of micaceous refractory rock used for lining cupolas and other melting furnaces.
Mica Strainer
A skim core made of thin mineral silicates crystallizing in monoclinic form.
Michigan Sand
Core sands of dune or lake sand and bank sands found in Michigan.
Micro Pipes (Brit.) (Microshrinkage)
Tiny cavities, a fraction of a millimeter in diameter, with irregular outlines, which occur in castings. Etching shows they occur at intersections of convergent dendritic directions.
Microcast Process
A patented method of precision-casting alloys, as Vitallium, Monel, Inconel and the Haynes Stelite alloys.
Microetching
Etching of metal samples for examination under the microscope.
Microformer
A type of extensometer for measuring elongation of test piece in a tensile test.
Micrography
Examination by means of a microscope.
Microhardness
The hardness of microconstituents of a material.
Microinch
0.000001 (1/1,000,000th) of an inch. A common unit of measurement in surface measurement research and in standard roughness (surface) unit values of performance of machinery.
Microlug
A test coupon used to give rapid indication of the effectiveness of magnesium treatment of ductile iron.
Microporosity
See Microshrinkage
Microradiography
The process of passing x-rays through a thin section of an alloy in contact with a photographic emulsion, and then magnifying the radiograph 50 to 100 times to observe the distribution of alloying constituents and voids.
Microscopic
Minute object or structures which are invisible or not clearly distinguished without the use of a microscope.
Microsection
A metal specimen whose surface has been polished and etched to reveal the microstructure.
Microshrinkage
Very finely divided porosity resulting from interdendritic shrinkage resolved only by use of the microscope; may be visible on radiographic films as mottling. Etching shows they occur at intersections of convergent dendritic directions.
Microspectroscopy
A method of identifying metallic constituents using spectrographic arc.
Microstructure
The structure of polished and etched metal and alloy specimens as revealed by the microscope at magnifications over 10 diameters.
Micro-Tester
A low load hardness tester, suitable for both Vickers and Knoop tests, working with loads of between 10 to 3000 grams.
Microtone (Brit.)
An instrument for cutting thin sections of soft specimens.
Migra Iron (Brit.)
A special pig iron for high quality castings.
Mikro-Tester
A low load hardness tester, suitable for both Vickers and Knoop tests, working with loads of between 10 to 3000 grams.
MIL STD
United States Government military standards, specifications, usually requiring rugged, exacting testing equal to the exigencies of combat usage.
Mild Steel
Plain carbon steel of about 0.25% carbon or less.
Mill Scale
Iron oxide scale formed on steel during hot working processes, cooled in air
Mill Stars
Multi-pointed white iron or hard iron bodies used in a Tumbling Barrel to assist in polishing and cleaning.
Milling
Removing metal with a milling cutter.
Milliroentgen (mr)
A sub-multiple of the roentgen equal to one-thousandth (1/1000th) of a roentgen.
Milliscope (Brit.)
An instrument which gives an electrical warning when melt reaches a predetermined temperature.
Mineral
Natural inorganic substance which is either definite in chemical composition and physical characteristics or any chemical element or compound occurring naturally as a product of inorganic processes.
Mischmetal
An alloy of rare earth metals containing about 50% lanthanum, neodymium, and similar elements.
Miscibility
Solubility; ability of two or more liquids to form a homogeneous solution.
Misrun
Denotes an irregularity of the casting surface caused by incomplete filling of the mold due to low pouring temperature, gas back-pressure from inadequate venting of the mod, and inadequate gating.
Mitis Casting
Casting of very mold steel.
Mock-Up
A full-size model built accurately for study, testing or display.
Model
A proportional representation of an object in any scale.
Modell Number
A value giving a measure of wear resistance.
Modification
A process in which the eutectic temperature, structure, and composition of aluminum-silicon alloys are apparently altered by the addition of small amounts of a third element, such as sodium. A similar phenomenon can be effected by chill casting.
Modulus Of Elasticity (E)
In tension it is the ration of stress to the corresponding strain within the limit of elasticity (Yield Point) of a material. For carbon and low alloy steels any composition and treatment, the value is approximately 30,000,000 psi.
Modulus of Resilience (ur)
The amount of strain energy per unit volume required to stress a material from zero to the yield stress limit. The modulus of resilience is proportional to the area under the elastic portion of the stress-strain diagram. Units are Pa or psi.
Modulus of Rigidity
In a torsion test the ratio of the unit shear stress to the displacement caused by it per unit length in the elastic range.
See Shear Modulus
Modulus of Rupture
Used in both bending and torsion testing. In bending, the modulus of rupture is the bending moment at fracture divided by the section modulus. In torsion, modulus of rupture is the torque at fracture divided by the polar section modulus.
Modulus of Toughness (ut)
Amount of work per unit volume of a material required to carry that material to failure under static loading. Equal to the area under the entire stress-strain curve. Units are Pa or psi.
Mogullizer
Equipment for sealing by vacuum impregnation of small pores in castings.
Moh's Scale
A scratch hardness test for determining comparative harness using ten standard minerals, from talc to diamond.
Moisture Content
The amount of water contained in a substance that can be driven off by heating at 220 - 230°F (104.4 - 110°C).
Moisture Teller
A patented apparatus for the rapid determination of moisture content of molding sand.
Mosture, Workable
That range of moisture content within which sand fills, rams, draws, and dries to a satisfactory mold, and within which the sand does not dry out too fast to mold and patch.
Molasses Water
A solution of water and molasses sprayed on sand molds to strengthen mold surface and yield a fine finish layer.
Mold Blower
Molding equipment for blowing sand mixture onto the pattern with compressed air; allows for faster production than gravity rollover dump.
Mold Board (Follow Board)
The board upon which the pattern is placed to make the mold.
Mold Cavity
The space in a mold which is filled with liquid metal to form the casting upon solidification. The channels through which liquid metal enters the mold cavity (sprue, runner, gates) and reservoirs for liquid metal (risers) are not considered part of the mold cavity proper.
Mold Clamp
Devices used to hold or lock cope and drag flask parts together.
Mold Coating (Mold Facing, Dressing)
1) Coating to prevent surface defects on permanent mold castings and die castings, 2) coating on sand molds to prevent metal penetration and improve metal finish.
Mold Cover Half (Cover Die)
1) The top half of the mold, the cope, 2) in die casting, the front half of the die, which remains stationary as the die is opened.
Mold Facing
See Mold Coating
Mold Jacket
A wooden or metal form slipped over a mold to support the side during pouring.
Mold Shift
A casting discontinuity resulting from misalignment of the cope and drag halves.
Moldability
Ability of sand to flow into a flask and around a pattern; measured in the amount of sand falling through an inclined screen or slot.
Moldabilty Controller
A patented device for controlling water additions to sand mix to maintain a consistent moldability index.
Molding, Bench
Making sand molds by hand tamping loose or production patterns at a bench without assistance of air or hydraulic action.
Molding, Floor
Making sand molds from loose or production patterns of such size that they cannot be satisfactorily handled on a bench or molding machine, the equipment being located on the floor during the entire operation of making the mold.
Molding Gravel
The coarser and more permeable grades of molding sand generally used in production casting of exceptional size and weight.
Molding Material
A material suitable for making molds into which molten metal can be cast.
Molding, Pit
Molding method in which the drag is made in a pit or hole in the floor.
Molding Sand Mixture
A sand mixture suitable for making molds into which molten metal can be cast.
Molding Sands
Sands containing over 5% natural clay, usually between 8 and 20%.
See also Naturally Bonded Molding Sand
Molecular Weight
Weight of the smallest quantity of a substance processing all its normal physical properties.
Molecule
The smallest particle of a substance that can exist in the free state and which has the same composition as any larger mass of the substance.
Molybdenum
A metal used widely in alloying of other metals. It is used as hardening element for steel, and for diecasting dies. Melting point 2620°C (4748°F), atomic number 42.
Molybdic Oxide
The oxide of molybdenum; added to the furnace in briquetted form as an important finishing constituent in nitriding steels.
Monel
A high nickel alloy, approximately 67% Ni, 28% Cu, the balance Fe, Mn, Si and other elements. Monel metal is resistant to corrosion and is widely used to resist the action of acids.
Monitoring
1) Periodic or continuous determination of the does rate in an occupied area (area monitoring) or the does received by a person (personnel monitoring), 2) periodic or continuous determination of the amount of ionizing radiation or radioactive contamination present in an occupied region, as a safety measure for purposes of health protection, 3) personnel - monitoring any part of any individual, his breath, or excretions, or any part of his clothing.
Monitoring Area
Routine monitoring of the level of radiation or of radioactive contamination of any particular area, building, room or equipment. Usage in some laboratories or operation distinguishes between routine monitoring and survey activities.
Monkey Cooler (Brit.)
In a blast furnace, the smaller of a series of three water coolers protecting the cinder notch. The largest is the cooler, while the in-between cooler is the intermediate cooler.
Monocast Process
A patented application of resin-bonded sand to line the flask in the production of centrifugal cast pipe. The resin-bonded layer is thinner than the conventional sand lining.
Monotectic
An isothermal reversible reaction in a binary system, in which a liquid on cooling, decomposes into a solid and a second liquid of different composition.
(Compare with Eutectic.)
Monotron
An instrument for measuring indentation hardness. It is fitted with two dials, one to measure depth of penetration, the other the load.
Montmorillonite
A very plastic clay, more siliceous than kaolinite; the principal constituent of bentonite.
Moore, R. R., Fatigue Machine
A constant load rotating bending type fatigue testing machine.
Mother Metal
The molten alloy just before final solidification and freezing out of the solid.
Motorized Variac
An autotransformer for stepless voltage control in shell molding.
Mottled Cast Iron
Iron which consists of a mixture of variable proportions of gray iron and white cast iron; such a material has a mottled fracture.
MP
Melting point.
Ms
The temperature at which transformation of austenite to martensite starts during cooling.
Mud
A term frequently used to designate plastic lining materials.
See also Daubing
Mud Daub
See Daubing
Muffle Furnace (Kiln)
A furnace in which the heating is indirect; the material to be heated is contained in a refractory container heated from the outside.
Muller
A type of foundry sand-mixing machine.
Mulling and Tempering
The thorough mixing of sand with a binder, either natural or added, with lubricant of other fluid, as water.
Muliductor Power Source
A device to convert standard 3-phase, 60 cycle current to single- phase, 180-cycle current, so-called medium frequency; produces a strong, controlled stirring action for induction melting.
Multiple Mold
A composite mold made up of stacked sections, each of which produces a complete gate of castings, and poured from a central downgate.
Mushet Steel
An air hardened steel containing about 2% c, 2% Mn, and 7% W, developed by Scotsman Robert Mushet in 1870.
Mushy Stage
The state between sold and liquid in alloys which freeze over a wide range of temperatures.