Submerged arc welding of high strength structural steels

This report discusses test results obtained in single and multiwire SAW-tests of five different high strength steels (Re = 370 - 690 N/mm2) of type StE 690, StE 470 V, StE 460 N, E StE 355 and RR St 52-3U, all having a plate thickness of 40 mm. The arc energies studied in the tests were 17, 30, 50 and 80 kJ/cm, the two highest values being somewhat in excess of up-to-day practice usually applied in industry. The studied steels E StE 355 and RR St 52-3U were new modifications developed especially for low operating temperatures and high heat input welding, respectively. The three other steels were conventional ones. The test results showed that the arc energy should be reduced to 15 - 25 kJ/cm to obtain sufficient HAZ toughness (i.e. T27J</= -40 °C) in SA-welded butt joints of steel StE 690 (Re = 690 N/mm2). Correspondingly, the recommended arc energy range for steels StE 470 and StE 460 (Re = 500 N/mm2) was found to be 10 - 30 kJ/cm. The steels E StE 355 and RR St 52-3U (Re = 370 N/mm2) resulted in favourable toughness behaviour (T27J<-50 °C) for all the arc energies studied, i.e. 17 - 50 kJ/cm for E StE 355 and 80 kJ/cm for RR St 52-3U. The arc energy was, however, recommended to be reduced to values between 10 - 40 kJ/cm when a transition temperature T27J less than -60 °C is required with these steels. The transition behaviours of weld metals were found to be in all cases more favourable than those of heat affected zones in the arc energy range recommended for HAZ toughness.