Glossary 881 Stainless steels: Steel alloys that contain carbon (0.03% to 0.45%), chromium (11% to 32%), nickel (0.60% to 37%), molybdenum (0.35% to 4.0%), and smaller amounts of manganese, phosphorus, silicon, sulfur, and copper. These steels are resistant to corrosion. Static pressure: The pressure measured when the gas is not fl owing. Static volt-ampere curve: A graph of the electrical output of an arc welding machine. Steelmaking furnace: Furnace in which an oxidizing atmo- sphere removes carbon and impurities in iron. Steel Sheet Manufacturers Standard (SSMS): Gage system used to measure sheet steels. Step-down transformer: A device used to reduce a higher voltage to a lower voltage. As the voltage decreases, amperage increases, and vice-versa. Stepper motor: A motor that has the ability to rotate a specifi c number of degrees. By commanding the motor to move a certain number of steps, a known rotational distance is achieved. Stepping motor: See Stepper motor. Stickout: See Electrode extension. Stored energy spot welding machines: Welding machines that obtain energy for welding from service lines at a relatively slow rate. The energy is stored as it is drawn. Once the stored energy has reached the desired level, it can be released at a high rate for welding. Straight carbon steel: Alloy of iron and carbon. Straight down-and-up motion: Motion made with the electrode to strike the arc. Strain: Reaction of an object to a stress. Stress: A load imposed on an object. Stress relieving: A process involving even heating of a structure to a temperature below the critical tempera- ture followed by a slow, even cooling. Stringer bead: Narrow weld bead made without oscillating the weld pool. Stud arc welding: See Arc stud welding. Submerged arc: A weld pool that is lower than the surface of the surrounding metal. Submerged arc welding (SAW): Process in which an elec- tric arc is submerged in granular fl ux. Suffi x: A letter and number after the normal four or fi ve digit electrode number used with low-alloy steel elec- trodes to indicate the chemical composition of the depos- ited weld metal. Superfi cial Rockwell hardness test: Test for determining surface hardness of thin sections or small parts, or where a large hardness impression might be harmful. Superimposed high frequency: High-frequency voltage used to start a welding arc. Surface hardening: Producing as hard-wearing a surface as possible while the internal portion of the structure remains ductile and tough. Surface tension: The attraction of molecules for each other. Surfacing: Depositing material on a surface to obtain desired properties or dimensions. Swages: Enlarges the ends of metal pieces to be joined by forge welding. Sweating: The process of soldering in which heat is applied to assembled parts that have been previously tinned Swirl ring: A feature of most plasma arc cutting torches. The shape of the swirl ring causes the plasma passing through it to swirl, keeping the fl ow of plasma gas more concentrated. T Tack weld: Small weld used to temporarily hold compo- nents together. Tag-out: Procedure for locking out equipment and adding a tag that identifi es the equipment as being out of service and lists the party that authorized the lock-out. Tail: Part of the welding symbol used to give information on specifi cations, the welding process used, or other details required but not shown on the welding symbol. Tank: Thin-walled container of fl uids or gases. Usually weaker than a cylinder for pressurized gases. Tap: A tool used to cut threads in a hole. Also, an interme- diate point in an electrical circuit at which an electrical connection can be made. Tap drills: The drills used to prepare a hole for tapping. Tapped secondary winding: Welding transformer design in which the number of secondary windings used depends on where the tap or selector is placed. Tapping: The drawing off of molten metal from a cupola furnace. Tap setting: Setting on a resistance welding machine that is used to make large changes in the current settings. Teach pendant: A handheld device used to move and program a robot. Technical trade: An occupation that requires learned skills and a good understanding of related technologies. Temper: To heat-treat hardened steel or hardened cast iron by heating to a temperature below its melting point for purpose of decreasing the hardness and increasing the toughness. Temperature: Heat level determined by the rapidity with which molecules move. Temperature gradient: The drop in the metal temperature from the weld joint outward. Temper carbon: Nodules of graphite that form when white iron is heat treated to make malleable cast iron. Tempering: Reheating hardened or normalized ferrous alloys and then cooling at any desired rate. Tensile strength: Maximum pull stress, in pounds per square inch or megapascals (newtons per square millimeter), that a specimen will withstand. Tensile test: A test in which a prepared sample is pulled in a tensile testing machine until it breaks. Test coupons: Samples of a test weld. Test specimens: Samples of a test plate. Thermal spraying: Processes used to apply molten surfacing materials. These processes include arc spraying, fl ame spraying, plasma arc spraying, and detonation spraying.