| Abstract |
| The effect of PWHT time on the pitting behavior in NaCl solution was evaluated in the weld of Mod. 9Cr-1Mo steels. Specimens were fabricated using autogeneous gas tungsten arc welding (GTAW) and tested using various post weld heat treatment (PWHT) times (i.e., 30 min, 1 h, and 2 h). More retained δ -ferrite was produced adjacent to the fusion line than the weld center. The polarization curves shifted to low Ecorr and large Icorr, therefore decreasing the pitting corrosion resistance of the weld as the PWHT holding time increased. The ‘as-welded’ specimens showed random pitting at the martensite lath. With increasing PWHT time, pitting was also found at the δ-ferrite/tempered martensite (δ/TM) interface. This is because more coarse and dense Cr-rich M23C6 carbides were formed along the δ/TM interface than at the TM/TM interface as the PWHT holding time increased. |
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| Key Words |
| metals, welding, corrosion, transmission electrn microscopy, TEM, Mod. 9Cr-1Mo steel |
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