M

Malleable Founders’ Society:  Union Commerce Building, Cleveland, Ohio 44114, Lowell Ryan, Executive Vice President.

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.

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.

Metalistatic Pressure: A compound phase referring to hydrostatic pressure, substituting Metall since Hydro connotes water.

Metallurgy:  The science of metals, a broad field that includes but is not limited to the study of internal structures and properties of metals and the effects of them of various processing methods, from ore refining to consumer product. Its principal branches are process metallurgy and physical metallurgy.

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 part 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 of melted metals.

Mexico Bay Sand:  A sand similar to Michigan City dune sand mined at Selkirk Beach, near Mexico, N.Y., 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:  See Transformation Temperature; the end of martensite formation.

MFS: See Malleable Founders’ Society.

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.

Microcast Process: A patented method of precision casting alloys, as Vitallium, monel, Inconel and the Haynes Stellite 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  in., 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.

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.

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 objects 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.

Microspectroscopy:  A method of identifying metallic constituents using spectographic arc.

Microstructure:  The structure of polished and etched metal and alloy specimens as revealed by the microscope at magnifications over 10 diameters.

Microtome (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.

Mill Scale:  Iron oxide scale formed on steel during hot working processes, cooled in air.

Mill Stars: Multipointed 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 submultiple 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% cerium with 50% lanthanum, neodynium and similar elements.

Miscibility: Solubility; ability of two or more liquids to form a homogeneous solution.

Misrun:  A defective, not fully formed casting resulting from such malfunctions as metal poured so cold it solidifies before filling the mold completely.

Mitis Casting:  Castings of very mild 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: In tension it is the ratio of stress to the corresponding strain within the limit of elasticity of a material. For carbon and low alloy
steels of any composition and treatment, the value is approximately 29,000,000 psi.

Modulus of Resilience: The modulus of resilience is proportional to the area under the elastic portion of the stress-strain diagram.

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.

Mogullizer: Equipment for sealing by vacuum impregnation of small pores in castings.

Moh’s Scale:  A scratch hardness test for determining comparative hardness using ten standard minerals, from talc to diamond.

Moisture Content: 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 sands.

Moisture, 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.

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.

Moldability Controller:  A patented device for controlling water additions to sand mix to maintain a consistent moldability index.

Mold Blower: A shell molding instrument 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:  In a mold, the hole which becomes the casting when filled with metal. Gates and risers are not considered part of the mold cavity.

Mold Clamps:  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 too 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 made in a snap or slip flask to support the sides during pouring.

Mold Shift:  A casting defect which results when a mold does not match at parting lines.

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 producing castings 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 Sands: Sands containing over 5% natural clay, usually between 8 and 20%. See also Naturally Bonded Molding Sand.

Molding Sand Mixture:  A sand mixture suitable for making molds into which molten metal can be cast.

Molecular Weight: Weight of the smallest quantity of a substance possessing 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 a hardening element for steel, widely used to im ‘ Dart Red Hardness to the
steel and for diecasting dies. Melting point 2620 C (4748 F),

Molybdic Oxide:  The oxide of molybdenum; added to the furnace in briquetted form as an important finishing constituent in nitriding steels.

Monel Metal:  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 dose rate in an occupied area (area monitoring) or of the dose 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 operations 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 resinbonded sand to line the flask in the production of centrifugally cast pipe. The resin-bonded layer is thinner than the conventional sand lining.

Monotectic: An isothermal reversible reaction in a binary system where a liquid, during cooling, forms a solid and a second liquid of different composition.

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 cast iron and white cast iron; such a material has a mottled fracture.

MP:  Melting Point.

M: The temperature of the start of martensite formation.

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 solid and liquid in alloys which freeze over a wide range of temperatures