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Welding Glossary


 * Radiation ** - Energy from heat or light that you cannot see.


 * Railroad Thermite Welding **

**Rated Load** - The amperage and voltage the power source is designed to produce for a given specific duty cycle period. For example, 300 amps, 32 load volts, at 60% duty cycle.

Reporting an Incident

Resistance Spot Welding (RSW)- A process in which two pieces of metal are joined by passing current between electrodes positioned on opposite sides of the pieces to be welded. There is no arc with this process.


 * Reaction Stress - ** The residual stress, which could not otherwise exist if the members or parts being welded were isolated as free bodies without connection to other parts of the structure.


 * Reactor (arc welding) ** - A device used in arc welding circuits for the purpose of minimizing irregularities in the flow of welding current.


 * Reinforcement of Weld ** - Weld metal in excess of the quantity required to fill a joint. See face Reinforcement and Root reinforcement.


 * Residual Stress ** - Stress remaining in a structure or member as a result of thermal or mechanical treatment or both. Stress arises in fusion welding primarily because the melted material contracts on cooling from the solidus to room temperature.


 * Reverse Polarity ** -The arrangement of direct current arc welding leads with the work as the negative pole and the electrode as the positive pole of the welding arc. A synonym for Direct Current is Electrode Positive.


 * Root Crack ** - A crack in the weld or heat-affected zone occurring at the root of a weld.


 * Root Edge ** - A root face of zero width. See root face.


 * Root Face ** - That portion of the groove face adjacent to the root of the joint.


 * Root of Joint ** - That portion of a joint to be welded where the members approach closest to each other. In cross section the root of the joint may be either a point, a line or an area.


 * Root Opening ** - The separation between the members to be joined at the root of the joint.


 * Root Penetration ** - Root Penetration is the depth that a weld extends into the root of a joint measured on the centerline of the root cross section.


 * Root Reinforcement ** - Reinforcement of weld at the side other than that from which welding was done.


 * Root Surface ** - The exposed surface of a weld on the side other than that from which welding was done.


 * Root of Weld ** - The points, as shown in cross section, at which the back of the weld intersects the base metal surfaces.


 * RMS (Root Mean Square) ** - The "effective" values of measured AC voltage or amperage. RMS equals 0.707 times the maximum, or peak value.

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