878 Modern Welding Pumped: Stimulated or excited. Punch: A tool that applies force to metal in order to reshape it. Purge switch: A feature on the wire feed control box that, when activated, causes shielding gas to fl ow. Used to purge air from the shielding gas lines prior to welding. Purging: Passing the proper gas through a system to ensure that there is no air or foreign substances in the system. Purging is recommended before welding. Purifi ed air breathing apparatus: A device worn by a welder that will provide pure, clean air that contains no undesirable particles or chemicals. Push angle: The welding end of the electrode points forward in the direction of travel. Also called push travel angle. Push travel angle: The welding end of the electrode points forward in the direction of travel. Also called push angle. Pyrometer: Device for determining temperatures over a wide range. Q Qualitative analysis: A test that determines the different kinds of chemicals in a metal. Quantitative analysis: A test that determines the kind and amount of each chemical in a metal. Quench aging: A change in metal produced by rapid cooling after heat treating. Quench annealing: The process used to soften austenitic ferrous alloys by solution heat treatment. Quench hardening: Hardening an iron alloy by austen- itizing followed by rapid cooling, so that some or all of the austenite becomes martensite. Quenching: Rapid cooling of metal in a heat treating process. Quick disconnect couplers: Spring-loaded and gasketed fi ttings that enable quick assembly and dismantling of tubing systems without loss of fl uid. R Radiograph: Photograph made by passing x-rays or gamma rays through the object to be photographed and recording the variations in density on a photographic fi lm. Radiographer: Person who performs radiographic operations. Radiographer’s exposure device: Instrument containing the x-ray source for making radiographic records on sensi- tized fi lm. Radiographic interpretation: Reading radiographic images to determine cause and signifi cance of discon- tinuities below the surface of the material being exam- ined. One of the determinations of the reading is the suitability of the material for use. Radiographic screens: Sheets, either metallic or fl uores- cent, that are used to intensify the radiation effect on fi lm. Radiography: Use of radiant energy found in x-rays or gamma rays to examine opaque objects and make a record of the examination. Rated load voltage: The power requirements for an arc welding power source. Rated output current rating: The amount of current (amperage) that a welding machine is rated to supply at a given voltage. Reactance: Opposition to the fl ow of alternating current as a result of inductance or capacitance. Reaction fl uxes: A special group of fl uxes that cause a chem- ical reaction with the base metal that cleans and displaces oxides and leaves a metallic fi lm on the metal surface that enhances wetting and capillary fl ow. Reactive gases: Gases that mix or react with metals in a weld. Rear view: A view that is possible on an orthographic drawing, but very seldom used. Also referred to as back view. Recarburize: To add carbon to molten cast iron or steel. Also, the process of adding more carbon to a surface that has lost some carbon in processing. Rectifi ed: Made unidirectional. Rectifi ed alternating current: Alternating current made to fl ow in one direction only by use of a device like a diode to stop normal reversing. Rectifi er: A device, such as a diode or a circuit, that acts like a one-way valve. It converts one half of a waveform of alternating current to useful current fl owing in the same direction as the other half of the waveform. Rectilinear robot: A robot that moves in the X, Y, or Z axes. Each axis is a joint or a degree of motion. Rotation around these axes is also possible. Reducing fl ame: Oxyfuel gas fl ame with a slight excess of fuel gas. Reducing gases: Gases, such as carbon monoxide or hydrogen, that prevent oxygen in the air from combining with molten metal. Reduction of area: Difference in cross-sectional area of a specimen after fracture as compared to original cross- sectional area. Reference line: A horizontal line that is placed on a drawing near the joint to be welded. All information to be given on the welding symbol is shown either above or below this line. Refractory: A material that is resistant to heat or diffi cult to melt. Refractory oxides: Surface oxides that occur quickly and easily on aluminum, magnesium, and some other nonferrous metals and melt at a higher temperature than the base metal. Regulators: See Acetylene regulator, Oxygen regulator. Reinforcement: Additional metal on the face or root of a weld. Reinitiate: Restart. Repeatability: The ability of a robot to go from one point to another point exactly the same way every time. Residual stress: Stress that is still present in a body freed of external forces or thermal gradients. Resistance seam welding (RSEW): A resistance welding process that typically uses round, rotating electrodes to make a continuous seam or overlapping spot welded seam.