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Welder’s Handbook
Shear – A force which causes deformation or fracture of a member by sliding one section against another in a plane or planes which are substantially parallel to the direction of the force. Shielded Metal Arc Welding (SMAW) – An arc-welding process wherein coalescence is produced by heating with an arc between a covered metal electrode and the work. Shielding is obtained from decomposition of the electrode covering. Pressure is not used and filler metal is obtained from the electrode. Shield / Shielding Gas – Unlike the plasma gas, the secondary gas (also referred to as secondary gas) does not pass through the orifice of the nozzle. It passes around the nozzle and forms a shield around the arc. Short Circuit Gas Metal Arc Welding (GMAW-S) – A gas metal arc welding process variation in which the consumable electrode is deposited during repeated short circuits. Short Circuiting Transfer – Mode of metal transfer in gas metal arc welding at low voltage and amperage. Transfer takes place each time the electrode touches or short- circuits to the weld puddle, extinguishing the arc. The short-circuiting current causes the electrode to neck down, melt off, and then repeats the cycle. Slag – The brittle mass that forms over the weld bead on welds made with coated electrodes, flux cored electrodes, submerged arc welding and other slag producing welding processes. Welds made with the gas metal arc and the gas tungsten arc welding processes are slag free. Less oxidation generally makes slag more difficult to remove. Reducing speed usually helps. Slag Follow – Refers to how the slag follows the puddle. If the slag is close, it “crowds” the puddle, making it more difficult for the welder to observe the arc. If the slag follows fast, it allows for faster travel speeds. “Good” slag follow is when the puddle is clear with the travel speed at a rate that keeps the puddle oblong.
Spark Test – A test used to identify a metal. The metal is brought into contact with a power driven, high speed grinding wheel which produce spark patterns. These patterns are unique to several classes of ferrous metals.
Spatter – Weld reinforcement opposite the side from which welding was done.
Spiral Arc Welding (SAW) – arc welding process / procedure used in the pipe industry.
Spot Welding – A resistance welding method commonly used to join thin sheet materials by overlapping joints.
Spray Arc Transfer – Mode of metal transfer across the arc where the molten metal droplets are smaller than the electrode diameter and are axially directed to the weld puddle. Requires high voltage and amperage settings and a shielding gas of at least 80% argon. Spray Arc Welding – A welding process by which molten material is transferred in the form of many small droplets, the diameter of which is less than that of the filler wire. Stabilized Stainless Steel – A high-chromium steel that does not lose its chromium from solid solution by precipitation, because of the addition of elements that have a greater attraction for carbon than does chromium.
Standoff Distance – The distance between the outer most portion of the torch and the work surface.
Standoff Guide – Used with plasma torches to drag cut. It maintains a fixed distance from the torch tip to the workpiece.
Steel – An alloy of iron with up to 1.4% carbon, usually less.
Straight Polarity – Welding condition when the electrode is connected to the negative terminal and the work is connected to the positive terminal of the welding power source.
Strain – The physical effect of stress, usually evidenced by stretching or other deformation of the material.
Slag Inclusion – A weld defect where slag is entrapped in the weld metal before it can float to the surface.
Stress – The load, or amount of a force, applied to a material, tending to deform or break it.
Slope or Slope Control – A necessary feature in welding power sources used for short circuiting arc welding.
Stress Crack – See “radial crack”.
Slope Control reduces the short circuiting current each time the electrode touches the weld puddle.
Stress Relieved – The reheating of a weldment to a temperature below the transformation temperature and holding it for a specified period of time. A frequently used temperature and time is 1150°F. for 1 hr. per inch of thickness. This reheating removes most of the residual stresses put in the weldment by the heating and cooling during welding.
Smooth – The arc transfer is very consistent.
Spalling – The loss of particles or pieces from a surface due to cracking.
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