Abstract
In the previous report, it was indicated that the usage of 19Cr-2Mo-0.25Zr steel filler metal for the first layer and 30Cr-2Mo steel filler metal for the upper layers respectively was effective to ensure a good weld ductility in the overlay welds of the 30Cr-2Mo steel cladding steel.
The corrosion resistance of the overlay welds is also important in the practical use of this material.
Therefore, the corrosion resistance in such overlay welds has been investigated in this report.
The corrosion resistance was compared with ones of 30Cr-2Mo steel base metal and cladding metal of 30Cr-2Mo clad steel. Measurement of anodic polarization curves and pitting corrosion potentials, grain boundary corrosion test, stress corrosion cracking test and crevice corrosion test were performed.
The excellent corrosion resistance, which was almost same level as ones of 30Cr-2Mo steel base metal and cladding metal of 30Cr-2Mo clad steel, was obtained by using 19Cr-2Mo-0.25Zr steel filler metal for the first layer and 30Cr-2Mo steel filler metal for 2nd, 3rd and 4th layers.
On the basis of these results, the overlay welding procedure by using 30Cr-2Mo steel filler metal for the upper 3 layer after using 19Cr-2Mo-0.25Zr steel filler metal for the first layer was recommended in order to ensure a good corrosion resistance of the overlay welds.
