Effect of Weld Thermal Cycles on Second Phase Particles in X-60 Pipe line Steel
By using carbon extraction replica technology and welding therma l simulation, the second phase particles in parent metal,weld metal and simulate d CGHAZ of Ti-Nb-V microalloyed steel were investigated. Experiment results and analysis show that the particles in the steel are less than 100 nm, irregular in shape , and have a slight size-dependence in that the relative content of Ti in crease with the increase of particle size. A large quantity of carbonnitride par ticles are still in CGHAZ after welding cycle , the shape of remaining particles change from irregular shape to cubicle one, all the particle in CGHAZ was rich in Ti.