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In the 1930s metallurgists Albert Portevin and D. Seferian attempted to experimentally determine heat transfer characteristics in welding. [1] They correlated the effects of several factors—material properties, welding process, and part dimensions—on temperature distribution, by performing oxyacetylene (gas) and covered electrode (arc) welds on plates and bars of various profiles, and ...
where Q = heat input (kJ/mm), V = voltage , I = current , and S = welding speed (mm/min). The efficiency is dependent on the welding process used, with gas tungsten arc welding having a value of 0.6, shielded metal arc welding and gas metal arc welding having a value of 0.8, and submerged arc welding 1.0. [1]
Higher weld travel speed can be obtained using a speed tip. Localization of high temperature gas on the weld surface allows for thermoplastics to heat up faster and flow easier, resulting in an increase in capable welding speed. [2] Too fast of a welding speed can stretch the weld rod, unevenly filling the joint and compromising the overall ...
With hot wedge welding, the speed of travel is an added parameter as the wedge unit is self-propelled by the rollers. The typical temperature range when welding high-density polyethylene (HDPE) is 220 to 400 °C (428 to 752 °F); the travel speed is typically 0.7 to 4 metres per second (2.3 to 13.1 ft/s). [5]
Welding speed – The welding equipment enables adjustment of the relative speed of motion of the workpiece with respect to the beam in wide enough limits, e.g., between 2 and 50 mm/s. Material properties – Depending on conditions, the extent of evaporation may vary, from negligible to complete.
Plasma arc welding is an arc welding process wherein coalescence is produced by the heat obtained from a constricted arc setup between a tungsten/alloy tungsten electrode and the water-cooled (constricting) nozzle (non-transferred arc) or between a tungsten/alloy tungsten electrode and the job (transferred arc). The process employs two inert ...
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Many metals and thermoplastics can be welded, but some are easier to weld than others (see Rheological weldability). A material's weldability is used to determine the welding process and to compare the final weld quality to other materials. Weldability is often hard to define quantitatively, so most standards define it qualitatively.