Effect of Heat Input on Microstructure and Corrosion Resistance of X80 Laser Welded Joints

Using fiber laser welding technology, X80 pipeline steel welded joints with different heat inputs were obtained. Their microstructure, mechanical properties, and corrosion resistance (in NACEA solution saturated hydrogen sulfide) studied. Findings indicated that the increase in input, proportion of ferrite, strength, elongation, increased within a certain range sum martensite bainite hardness decreased. The input has greater effect on microstructure weld metal (WM) coarse-grained heat-affected zone (CGHAZ), while fine-grained (FGHAZ) is basically unchanged. Obvious differences are also found regions joints, among which FGHAZ strongest resistance, followed by WM CGHAZ. mainly affects type joint to affect resistance. Therefore, we model as function Rct icorr from this relationship. In addition, products film produced long-term immersion H2S can hinder development enhance extent.