Abstract
Effect of microstructure on pitting corrosion of super duplex was
investigated in 3.5% NaCl solution at 90°C. The microstructures were
controlled by applying two different cooling rates of water quench and air from
the heat treatment temperatures of 1,000°C and 1,300°C. The amount of ferrite
and austenite and other precipitates were measured using optical and image
analyser. The results revealed that the ferrite percentage increased as the
heating temperature increased to 1300°C. Metallographic results showed the
presence of intermetallic phases. Back scattering analysis revealed presence of
sigma (s) and chi (¿) phase. The volume fraction of ferrite to austenite as well
as the precipitation of harmful intermetallic phase during cooling process
affected the corrosion resistance. Reformation of austenite during slow cooling
from 1,300°C enhanced corrosion resistance while intermetallic precipitates
promoted pitting damage and decreased pitting potential to more active values.
investigated in 3.5% NaCl solution at 90°C. The microstructures were
controlled by applying two different cooling rates of water quench and air from
the heat treatment temperatures of 1,000°C and 1,300°C. The amount of ferrite
and austenite and other precipitates were measured using optical and image
analyser. The results revealed that the ferrite percentage increased as the
heating temperature increased to 1300°C. Metallographic results showed the
presence of intermetallic phases. Back scattering analysis revealed presence of
sigma (s) and chi (¿) phase. The volume fraction of ferrite to austenite as well
as the precipitation of harmful intermetallic phase during cooling process
affected the corrosion resistance. Reformation of austenite during slow cooling
from 1,300°C enhanced corrosion resistance while intermetallic precipitates
promoted pitting damage and decreased pitting potential to more active values.
| Original language | English |
|---|---|
| Pages (from-to) | 39-51 |
| Number of pages | 13 |
| Journal | International Journal of Microstructure and Materials Properties |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - Apr 2010 |
Keywords
- heat treatment
- super duplex stainless steel
- volume fraction of austenite and ferrite
- sigma and chi phase