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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]
The welder will modify the speed of welding travel to maintain a uniform bead width. Uniformity is a quality attribute indicating good workmanship. Trained welders are taught to keep the bead the same size at the beginning of the weld as at the end. If the bead gets too wide, the welder increases the speed of welding travel.
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 ...
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.
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]
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Rotary friction welding is widely implemented across the manufacturing sector and has been used for numerous applications, [17] [18] [19] including: Parts in gas turbine such as: turbine shafts, turbine discs, compressor drums, [20]