Abstract:
A method comprising an arc ignition phase (IP), an arc-stabilizing phase (AP) and a stable arc phase (SP). The arc stabilizing phase comprises an initial sub-phase (IS) comprising the step of feeding at least one hot wire (4, 12) at constant feed speed and a main sub-phase (MS) comprising the steps of feeding said hot wire at constant feed speed and feeding at least one cold wire (22) at constant feed speed. The stable arc phase comprises the steps of continuously adjusting the feed speed of the hot wire and continuously adjusting the feed speed of the cold wire. The invention also relates to a welding apparatus (1) for carrying out the method. The welding apparatus comprises a hot wire feeding means (150), a contact means (2), a cold wire feeding means (35) and a control unit (31). The control unit is adapted to control said hot wire feeding means to feed the hot wire at a constant feed speed during the initial sub-phase, feed the hot wire at a constant feed speed during the main sub-phase and to continuously during the stable arc phase adjust the feed speed of the hot wire. The control unit is adapted to control said cold wire feeding means to feed the cold wire at a constant feed speed during the main sub-phase and continuously during the stable arc phase adjust the cold wire feed speed.
Abstract:
A tubular welding wire includes a granular core and a metal sheath encircling the granular core. Furthermore, the metal sheath includes at least approximately 0.3% manganese by weight and at least approximately 0.05% silicon by weight.
Abstract:
A method of welding structural steel containing, by mass%, Cr: 1.5 to 3.5%, Mo: 0.5 to 1.5%, and V: 0.15 to 0.5%. It comprises preheating joint of the structural steel to be welded at temperatures of 150 to 250 degrees Celsius; multilayer welding the joint end portions; keeping the interpass temperature of the joint end portions during the multilayer welding at 150 to 350 degrees Celsius; then after welding completion, performing DHT by heat treating the weld zone before cooling down below 150 degrees Celsius under the conditions that the temperature is 250 to 340 degrees Celsius and that the treatment time is 5 to 10 hours.
Abstract:
A method for controlling an output current of a welding power supply includes detecting, using control circuitry of the welding power supply, a root mean square (RMS) current setting. The method also includes calculating, using the control circuitry, an average current command based on the RMS current setting. The method also includes controlling, using the control circuitry, the output current using the average current command to produce an output substantially the same as the RMS current setting.
Abstract:
Weld metals and methods for welding ferritic steels are provided. The weld metals have high strength and high ductile tearing resistance and are suitable for use in strain based pipelines. The weld metals are comprised of between 0.03 and 0.08 wt% carbon, between 2.0 and 3.5 wt% nickel, not greater than about 2.0 wt% manganese, not greater than about 0.80 wt% molybdenum, not greater than about 0.70 wt% silicon, not greater than about 0.03 wt% aluminum, not greater than 0.02 wt% titanium, not greater than 0.04 wt% zirconium, between 100 and 225 ppm oxygen, not greater than about 100 ppm nitrogen, not greater than about 100 ppm sulfur, not greater than about 100 ppm phosphorus, and the balance essentially iron. The weld metals are applied using a power source with pulsed current waveform control with 2 and
Abstract:
This disclosure relates generally to welding, and more specifically, to submerged arc welding (SAW). In an embodiment, a welding system (10) includes a gas supply system (16) configured to provide a gas flow. The system also includes a wire supply system (14) configured to provide welding wire, and a flux supply system (17) configured to provide flux near a welding arc during submerged arc welding (SAW). The system further includes a welding torch assembly (18) configured to receive the gas flow and the welding wire and to deliver the gas flow and the welding wire near the welding arc during SAW.