Methods for calculating the preheat temperature welding the high strength steels

Abstract

With preheating of steel, the cooling speed of a heat-affected zone decreases, which prevents the appearance of a structure prone to cold cracks. On the other hand, too small a cooling speed in this area results in the growth of the metal grains, which also leads to a higher proneness to cracks. Commonly used methods for calculation of preheating temperature for high-strength steels are the Itto–Bessyo method and the method by standard SRPS EN 10112. This paper presents the methods for calculating the preheating temperature of microalloyed steel P460 NL1. Analysis of the results obtained from both methods shows significant differences in the amounts calculated for preheat temperature. It was concluded that both methods have limitations that must be taken into account in their application in practice.