B

Bending Strength:  Upper limit of normal stress of a beam at which fracture or excessive plastic deformation occurs.

Bentonite: A colloidal clay derived from volcanic ash and employed as a binder in connection with synthetic sands, or added to ordinary natural (clay-bonded) sands where extra strength is required.

BHN:  Brinell Hardness Number.

Bimetal: Casting, usually centrifugal, made of two different metals, fused together.

Blackening Scab:  A form of casting defect related to an improper coating rather than to the sand.

Blacking Carbon:  Carbonaceous materials such as plumbago, graphite or powdered coke usually mixed with a binder and frequently carried in suspension in water or other liquid; used as a thin facing applied to surfaces of molds or cores to improve casting finish.

Blacking Holes:  Irregular-shaped surface cavities in a casting containing carbonaceous matter. Caused by spalling off of the blacking from the mold surface.

Blacking Scab:  A casting defect formed by blacking flaking off due to sand expansion and being retained in or on the surface of the metal.

Black Lead:  A natural form of graphite used for sleeking green sand molds, or applied as a water suspension to skin dried molds.

Blasting (Blast Cleaning):  A process for cleaning or finishing metal objects by use of an air blast or centrifugal wheel that throws abrasive particles against the surface of the work pieces. Small, irregular particles of steel or iron are used as the abrasive in grit blasting; and in sandblasting, and steel or iron balls in shot blasting.

Bleeder:  A defect wherein a casting lacks completeness due to molten metal draining or leaking out of some part of the mold cavity after
pouring has stopped.

Blended Molding Sands:  Naturally bonded molding sands which have been mixed or modified by the supplier to produce desirable properties.

Blister:  A shallow blow with a thin film of the metal over it appearing on the surface of a casting.

Blocking:  Adding ferromanganese or other deoxidizing agent to an open hearth bath to stop all oxidizing reactions.

Blower, Core or Mold:  A device using air pressure to fill a corebox or flask with sand.

Blowholes (Blows):  Irregular shaped cavities with smooth walls produced in a casting when gas, entrapped while the mold is being filled, or evolved during solidification of the metal, fails to escape and is held in pockets within the metal.

Blow Holes:  Holes in the head plate or blow plate of a core-blowing machine through which sand is blown from the reservoir into the core box.

Blowing-Off a Mold:  Cleaning a mold cavity with a stream of compressed air.

Blowpipe:  A small pipe or tube through which the breath is blown in removing loose sand from small mold cavities.

Blow Plate:  The plate containing the core sand entrance holes or blow holes used in open-face core boxes.

Blows:  See Blowholes.

Bluing:  Formation of a thin film of oxide on polished steel to improve its appearance and protect its surface.

Blunging:  Mixing clay with water to a creamy slip.

Bob:  A riser or feeder, usually blind, to provide molten metal to the casting during solidification, thereby preventing shrinkage cavities.

Body Core:  The main core.

Boil:  Agitation of a bath of metal caused by the liberation of a gas beneath its surface usually resulting in formation of dross. May be caused by a wet furnace bottom or ladle or by dirty or cold ingots, or may be deliberately induced by the addition of oxidizing material to a bath containing excess carbon. In the latter case it is called a carbon boil and CO or CO,, are liberated.

Bond: 1.  Bonding substance or bonding agents-any material other than water, which, when added to foundry sands, imparts bond strength,

            2. The overlapping of brick so as to give both longitudinal and transverse strength.

Bond Strength:  Property of a foundry sand to offer resistance to deformation.

Bonding Clay (Bonderise):  Any clay suitable for use as a bonding material.

Boring:  A machining method using single point tools on internal surfaces of revolution.

Boss (Pad):  A projection of circular cross-section on a casting. Usually intended for drilling and tapping for attaching parts.

Bottom Pour Ladle:  See Ladle, Bottom Pour.

Bottom Running or Pouring:  Filling of the mold cavity from the bottom by means of gates from the runner.

Bracket:  Strengthening strip, rib or projection on a casting.

Breaker Ring:  An intentionally weak ring within mass of a ring shell mold to be broken by force of casting shrinkage. Prevents hot tear stress.

Breakoff Notch:  A thinner section of a gate or riser to facilitate and ensure clean breaking-off during the cleaning process of casting.

Bright Annealing:  A process carried out usually in a controlled furnace atmosphere, so surface does not oxidize, remaining bright.

Brinell Hardness:  The value of hardness of a metal on an arbitrary scale representing kg/MM2, determined by measuring the diameter of the impression made by a ball of given diameter applied under a known load. Values are expressed in Brinell Hardness Numbers, BHN.

Brittle Fracture:  Fracture with little or no plastic deformation.

Brittleness:   A tendency to fracture without appreciable deformation.

Broaching:  Smoothing machining holes or outside surfaces of castings by drawing or pushing one or more broaches (special cutting tools) through
the roughed out hole.

Buckle: 1.  Bulging of a large flat face of a casting; in investment casting, caused by dip coat peeling from the pattern.

               2.  An indentation in a casting, resulting from expansion of the sand, may be termed the start of an expansion defect.

Builtup Plate:  See Matchplate. A pattern plate of suitable material, with the cope pattern mounted on or attached to one side; the drag pattern may be attached to the other side or to a separate mounting.

Burn: 1. Process of cutting metal by a stream of oxygen, 2. To permanently damage a metal or alloy by heating to cause either incipient melting
or intergranular oxidation.

Burned Sand:  Sand in which the binder or bond has been removed or impaired by contact with molten metal.

Burned-On-Sand:  A misnomer usually indicating metal penetration into sand resulting in a mixture of sand and metal adhering to the surface of a casting.
See Penetration, Metal.

Burning In: See Penetration, Metal.

Burnishing: Developing a smooth finish on a metal by tumbling or rubbing with a polished hand tool.

Burnthrough: In shell molding, resin burned out too soon.

Butt-Off:  Operation performed at times to supplement ramming by jolting, either hand or air rammer.

Butt Rammer:  The flat end of the molder’s rammer.