THE INFLUENCE OF MICRO-STRUCTURE AND INCLUSION ON TOUGHNESS OF HAZ OF LOW ALLOY STEEL WITH VARIOUS WELDING HEAT INPUT

The toughness of the HAZ coarse grained zone of low alloy steel might lose heavily with high welding heat input.This is closely related to the micro-structure transformation in HAZ.The present paper investigates the relation between the microstructure,inclusion and toughness by using optical microscope,scanning electron microscope and foil transmission electron microscope for examining normalized 14MnCuNiV steel.