• NON-RIGID JOINT

    A joint designed so that the parts are free to move and absorb the stresses during welding. See RIGID JOINT. 

  • NONBUTTING MEMBER

    A joint member that is free to move in any direction perpendicular to its thickness dimension. For example, both members of a lap joint, or one member of a T-joint or corner joint. See also BUTTING MEMBER. 

     

  • NONCONSUMABLE ELECTRODE

    An electrode that does not provide filler metal. 

  • NONCORROSIVE FLUX

    A soldering flux that in either its original or residual form does not chemically attack the base metal. It usually is composed of rosin-base materials. 

  • NONDESTRUCTIVE EVALUATION

    A nonstandard term for NONDESTRUCTIVE EXAMINATION. 

  • NONDESTRUCTIVE EXAMINATION (NDE)

    The act of determining the suitability of some material or component for its intended purpose using techniques that do not affect its serviceability.

    Nondestructive testing (NDT) and Nondestructive Inspection (NDI) are terms sometimes used interchangeably with NDE and are generally considered synonymous. Nondestructive examinations are performed on weldments to verify that the weld quality meets the specification, and to determine if weld quality is degraded during service.

    Visual inspection should be the primary evaluation method of any quality control program. It can disclose flaws, signs of possible fabrication problems in subsequent operations, and can be incorporated in process control programs. Prompt and conscientious visual detection and correction of flaws or process deviations can result in significant cost savings, detecting continuities that would be found later by more expensive nondestructive examination methods.

    All NDE methods must include the following to render valid examination results:

    (1) A trained operator

    (2) A procedure for conducting the tests

    (3) A system for reporting the results

    (4) A standard to interpret the results

    The commonly used NDE methods that are applicable to the inspection of weldments are:

    (1) Visual Inspection (VT) with or without optical aids

    (2) Liquid penetrant (PT)

    (3) Magnetic particle (MT)

    (4) Radiographic inspection (RI)

    (5) Eddy current (ET)

    (6) Ultrasonic (UT)

    (7) Acoustic emission (AET)

    There are other NDE methods, such as heat transfer and ferrite testing, that are used for special cases. See also PENETRANT TESTING, MAGNETIC PARTICLE INSPECTION, METALLOGRAPHY, RADIOGRAPHIC EXAMINATION, and ULTRASONIC TESTING. 

     

  • NONDESTRUCTIVE INSPECTION

    A nonstandard term for NON DESTRUCTIVE EXAMINATION. 

  • NONDESTRUCTIVE TESTING

    A  nonstandard term for NONDESTRUCTIVE EXAMINATION.

  • NONFERROUS

    Metals containing no ferrite, or iron. Copper, brass, bronze, aluminum and lead are among the non-ferrous metals most commonly used in industrial production. 

  • NONMAGNETIC

    Materials that do not produce a field of force and are not attracted by iron. 

  • NONPRESSURE WELDING

    A group of welding processes in which the weld is made without pressure, i.e. arc, gas and thermite welding. 

  • NONSYNCHRONOUS INITIATION

    The closing of a resistance welding contactor without regard to the voltage wave form pattern. 

  • NONSYNCHRONOUS TIMING

    A nonstandard term for NONSYNCHRONOUS INITIATION. 

  • NONTRANSFERRED ARC

    An arc established between the electrode and the constricting nozzle of the plasma arc torch or thermal spraying gun. The workpiece is not in the electrical circuit. See also TRANSFERRED ARC. 

  • NONVACUUM ELECTRON BEAM WELDING (EBW-NV)

    An electron beam welding process variation in which welding is accomplished at atmospheric pressure. 

  • NORMALIZING

    See ANNEALING.

  • NORWAY IRON

    A very pure low carbon iron made in Norway. Its purity and low carbon content made it especially desirable for welding rods, and in the early days of the industry it was used almost exclusively for this purpose. The iron was imported from Norway in ingot form and drawn into wire in the United States.

  • NOZZLE ACCUMULATION

    Filler metal or surfacing material deposited on the inner surface and on the exit end of the nozzle. 

  • NOZZLE, Arc Spraying

    A device at the exit end of the gun that directs the atomizing air or other gas. 

  • NOZZLE, Flame Spraying

    A device at the exit end of the gun that directs and forms the flow shape of atomized spray particles and the accompanying air or other gases. 

  • NUCLEAR POWER PLANT

    Since all of the major components of a nuclear power plant are joined by welding in accordance with Section 111of the ASME Pressure Vessel Code, welding plays an important role in the delivery of nuclear power. Nuclear plant piping systems account for most of the welding, but it is also a major application in the reactors, steam generators, pressure vessels, and containment vessels, as well as the powerhouse structures; all are welded to specifications in Section 111.

    More engineering analysis, more care, and more safeguards are in place in the design and construction of nuclear plants than in any other method of power generation. The United States Nuclear Regulatory Commission is involved directly in the design, construction, licensing and operation of plants. 

  • NUGGET

    The weld metal joining the workpieces in spot, seam, or projection welds. 

  • NUGGET SIZE

    A nonstandard term when used for resistance spot weld size.