CORROSION BEHAVIOR IN AMMONIUM SULFITE SOLUTION OF HEAT-AFFECTED ZONE WELD SEAM OF Q235 STEEL WITH J420 ELECTRODE FOR PAPER PULP ROTARY SPHERICAL DIGESTER
J420焊接的造纸蒸球热影响区耐蚀性研究

The corrosion behavior of heat-affected zone of the weld seam of Q235 steel with J420 electrode in ammonium sulfite solution was researched, aiming at the serious corrosion of welding seam in the solution, by using electrochemical measurements and metallurgical microstructure analysis. The results showed that the corrosion rate of heat-affected zone was accelerated with increasing temperature and the concentration of ammonium sulfite solution. With the change of pH value of the solution from acidic to basic, the anodic areas of the heat-affected zone seem to be passivated, the corrosion rate was reduced. The poor corrosion resistance heat-affected zone was related with its microstructure after the Q235 steel was weld by J420 electrode.