Effect of Continuous Postheating Time of Reduction of Preheating Temperature

Continuous postheating for 1-5 hours at same temperature as preheating was carried out on weld cracking test of 80 kgf/mm2 tension steel, and following result were obtained. (1) Continuous postheating was recognized to be very useful to reduce the preheating temperature to prevent weld cracking. (2) The preheating temperature was reduced to 80°C by 1 hour postheating from 150°C which is the temperature without any postheating, and to 60°C by 5 hour postheating.