Introducing nitrogen into the surface layer of a solid ferrous alloy. This is done to increase hardness, wear resistance and fatigue strength.
Any of several processes in which both nitrogen and carbon are absorbed into the surface layers of a ferrous material and, by diffusion, create a concentration gradient. Nitrocarburizing is done mainly to provide an antiscuffing surface layer and to improve fatigue resistance. See carbonitriding.
nondestructive inspection (nondestructive examination)
Inspection by methods that do not destroy the part or impair its serviceability.
nondestructive testing (NDT)
Same as nondestructive inspection but implying use of a method in which the part is stimulated and its response measured quantitatively or semiquantitatively.
Variety of chemical, electrical, mechanical and thermal processes for machining workpieces. Originally applied to new or emerging processes, it designates any process developed since 1945.
nonuniform rational B-splines (NURBS)
Type of curve or surface for which the difference between successive knots (parameter values) need not be expressed in uniform increments of 1. See B-spline.
Heating a ferrous alloy to a temperature above the transformation range and then cooling in air to a temperature below the transformation range.
numerical control (NC)
Any controlled equipment that allows an operator to program its movement by entering a series of coded numbers and symbols. See CNC, computer numerical control; DNC, direct numerical control.