AN IMPROVED PROCESS OF DEEPER PENETRATION WELDING OF STUB TO HEADER JOINTS FOR HIGH TEMPERATURE AND HIGH PRESSURE APPLICATIONS LIKE BOILERS AND TO REDUCE THE WELD CYCLE TIME

摘要

The invention relates to n improved process of a deeper penetration welding of stub to header joints for high temperature and high pressure applications like boilers and reducing the weld cycle time, the improvement comprising the steps of adapting a deep penetration mode to weld in stubs with a short arc weld having a longer short-circuit phases with the welding torch traveling to a distance to reach the root of the stub profile; alternatively implementing a process capable to deliver the desired welding parameters to ignite the arc even at longer contact compared to the tube distance; intervening the said process at a faster control speed with a shorter arc with longer short-circuit phases, wherein the current is run down quickly on re-ignition until the programmed nominal arc voltage is reached, which interalia reducing the power time period of the short-circuit phase including a minimum spaller formation; and fine tuning the resultant arc length control to adjust the random variation in CTWD with the changing arc length. { FIGURE 3 }