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| >> GLOSSARY OF TERMS |
| R |
| RADIANT TUBE ANNEALING BOX (See annealing) - A box which is heated, inside, by means of tubes on which gas is burned; the hot tubes radiate their heat to the covered pile of metal, standing on the base of the box. Usually a protective atmosphere is maintained in the box to protect the metal from oxidation. |
| RADIOGRAPHY A nondestructive method of internal examination in which metal objects are exposed to a beam of X-ray or gamma radiation. Differences in thickness, density or absorption, caused by internal defects or inclusions, are apparent in the shadow image either on a fluorescent screen or on photographic film placed behind the object. |
| RAGGED EDGES Edges of Sheet or Strip which are torn, split, cracked, ragged or burred or otherwise disfigured. |
| RECIPROCAL LATTICE (For a crystal) - A group of points arranged about a center in such a way that the line joining each point to the center is perpendicular to a family of planes in the crystal, and the length of this line is inversely proportional to their interplanar distance. |
| RECOVERY (1) The removal of residual stresses by localized plastic flow as the result of low-temperature annealing operations; performed on cold worked metals without altering the grain structure or strength properties substantially. |
| RECRYSTALLIZATION A process whereby a distorted grain structure of cold worked metals is replaced by a new, stress-free grain structure as a result of annealing above a specific minimum temperature for a specific time. |
| RED BRASS 85% Copper A copper-zinc allow containing approximately 15% zinc, used for plumbing pipe, hardware, condenser tubes. Because of its color, is used for vanity cases, coins, plaques, badges, etc. It is somewhat stronger than commercial bronze and if hardened more rapidly by cold working. |
| RED SHORTNESS Brittleness in steel when it is red hot. |
| REFINING TEMPERATURE A temperature, usually just higher than the transformation range, employed in the heat treatment of steel to refine the structure in particular, the grain size. |
| REFLECTOR SHEET An alclad product containing on one side a surface later of high-purity aluminum superimposed on a core or base alloy of commercial- purity aluminum or an aluminum-manganese alloy. The high-purity coating imparts good polishing characteristics and the core gives adequate strength and formability. |
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