Annealing - Generally a heat treatment to soften metals; for iron and steel, consists of heating above the critical temperature followed by slow cooling usually in the furnace. Acicular Iron - An iron generated by an alloy addition of Moly, Nickel and Copper Brinell Hardness - The value of hardness of a metal determined by measuring the diameter of the impression made by a ball of given diameter under a known load. Values are expressed in Brinell Hardness Numbers (BHN). Chaplets - Metal supports or spacers used in molds to maintain cores, or parts of the mold that are not self-supporting in their proper positions during the casting process. They become a permanent part of the casting. Chills - Metal inserts in molds or cores at the surface of a casting or within the mold that serve to hasten solidification of heavy sections and cause the casting to cool at a uniform rate. Draft (Pattern) - The taper on the sides of a pattern which are perpendicular to the parting plane that allows the pattern to be withdrawn from the mold without breaking the edges of the mold. Ductile Iron - Gray iron treated with a special alloy while in the liquid state so that the graphite is spherulitic rather than flake. Also called spherulitic graphite iron or S. G. iron. Elongation - Amount of permanent extension in the vicinity of the fractures in the tensile test; usually expressed as a percentage of original gauge length, such as 35% in 2 inches. Flask - Metal or wood frame, without a top and without a fixed bottom, used to hold the sand of which a mold is formed; usually consists of two parts, the cope and the drag. Gating System - The complete assembly of sprues, runners, and gates in a mold through which metal flows to enter the casting cavity. This term also applies to equivalent portions of the pattern. Gray Iron - Cast iron that contains a relatively large percentage of the carbon present in the form of flake graphite. The metal has a gray fracture. Green Sand - Molding sand that has been tempered with water and is employed for castings when still in the damp condition. Inoculants - Materials which, when added to molten metal, modify the structure, and thereby change the physical and mechanical properties to a degree not explained on the basis of the change in composition resulting from their use. Loose Piece Core box; part of a core box that remains embedded in the core, and is removed after lifting off the core box. Pattern; laterally projecting part of a pattern so attached that it remains in the mold until the body of the pattern is drawn. Back-draft is avoided by this means. Part of a permanent mold that remains on the casting and is removed after the casting is ejected from the mold. Internal Stresses - A system of balanced forces existing within a part when not subjected to a working load. These stresses are frequently caused by the differential contraction between parts of a casting as it cools. Match Plate - A plate of metal or other material on which patterns and gating systems split along the parting line are mounted back-to-back, or cast to form an integral piece. Mechanical           Properties - Those properties of a material that reveal the elastic and inelastic reaction when force is applied, or that involve the relationship between stress and strain; for example, the modulus of elasticity, tensile strength, and fatigue limit. These properties have often been designated as physical properties but the term mechanical properties is preferred. Nodular Iron - Another name for Ductile Iron Parting Line - A line on the pattern or casting corresponding to the separation between the parts of a mold. Patternmaker's           Shrinkage - Contraction allowance made on patterns to compensate for the decrease in dimensions as the solidified casting cools in the mold from freezing temperature of the metal to room temperature. Pattern is made larger by the amount of contraction that is characteristic of the particular metal to be used. Rig - To prepare a pattern and flask equipment for molding. Riser - A reservoir of molten metal provided to compensate for the contraction of the metal in a casting as it solidifies. Runner - The portion of the gate assembly that connects the downgate (sprue) with the casting ingate or riser. The term also applies to the part of the pattern that forms the runner. Semi-Steel - A misnomer. The term refers to a gray iron, the melting charge for which contains a percentage of steel scrap. Sprue - The vertical channel from the top of the mold to the parting line. Also, a generic term to cover all gates, risers, etc., returned to the melting unit for re-melting. Also applies to similar portions of patterns. Stress Relieving - A sub-critical heat treatment to reduce residual stresses in a casting. Tensile Strength - The maximum load in tension that a material will withstand prior to fracture. It is calculated from the maximum load applied during the tensile test divided by the original cross-sectional area of the sample. Tie Bar - A bar shaped connection added to a casting to prevent distortion caused by uneven contraction between two separated members of the casting. Yield Strength - The stress at which a material exhibits a specified limit of permanent strain; often the maximum unit load with a 0.2% deviation from a proportional stress-strain relation.