Corrosion and cracking characteristics upon aging of hyper duplex stainless steel weld

ABSTRACT

In this study, the effects of Mo content and aging temperature on the corrosion characteristics of newly designed hyper duplex stainless steel welds were investigated. Each specimen was aged at 600°C for 1–100 h, and weld cracking occurred when the 6 wt-% Mo specimen was aged for more than 40 h. In addition, electron backscatter diffraction and X-ray diffraction analysis found that the number of secondary phases increased as aging time increased. Based on the potentiodynamic polarisation test for assessing the corrosion characteristics according to the aging time, the corrosion resistance decreased sharply after 40 h, when cracking occurred.

Highlights

• When aging treatment for more than 40 h was performed on 6 wt-% Mo specimen, weld crack occurred.

• High hardness values above 450 Hv0.5 were measured in specimens aged more than 40 h.

• Secondary phases such as σ-phase and χ-phase were observed in specimens aged for more than 40 h.

• The specimens aged for more than 40 h showed a rapid decrease in corrosion resistance.

KEYWORDS:

• Hyper duplex stainless steel (HDSS)
• aging
• Mo content
• secondary phase
• potentiodynamic polarisation test
• cracking

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education under Grant Number NRF-2018R1D1A107050502.