Effect of Thermal Welding Cycle on High-Strength Steel Resistance to Cold Cracking.

The effect of the thermal cycle of welding on the resistance of bainitic, martensite-aging, medium carbon, and chromium steels to the formation of cold cracks during welding is investigated. The thermal welding cycle was evaluated in accordance with the weld metal cooling rate within the range of 600-500 degree C. When well dried argon was used as the protective gas, cold cracking did not occur in martensite-aging steels during welding under all conditions, in bainitic steels - under mild conditions (cooling rate less than equivalent to 40 degree C/s), in chromium low carbon steels - under mild conditions (cooling rate less than equivalent to 15 degree C/s). Humidification of argon resulted in cold cracking in bainitic, chromium, and martensite-aging steels during welding under all conditions.