Abstract
Steam oxidation has become an important issue for steam
power plants as operating temperatures increase from
current to 650°C and even higher. Apart from the chemical
composition of the material, surface condition is a major
factor affecting the oxidation resistance in steam and
supercritical water. In this paper, stainless boiler
steels (UNS S34710, UNS S31035) are investigated in
elevated steam oxidation conditions. Tests were conducted
in a supercritical water autoclave environment (250 bar,
with 125 ppb dissolved oxygen and a pH of 7) at 625°C,
650°C and 675°C up to 1000 h. Materials were tested with
different surface finishes shot peened, milled and spark
eroded. The results show an influence of surface finish
on the early stages of oxidation. Oxides formed on more
rough surfaces were more adherent, and thinner than on a
ground surface. To that extent that the oxide formed on
the milled, most cold worked, surface of UNS S34710 (Cr
18 wt-%) was thinner than on the spark eroded and ground
surface of S31035 (Cr 22 wt-%). More variation on
oxidation rate could be seen with increasing temperature.
| Original language | English |
|---|---|
| Number of pages | 11 |
| Publication status | Published - 2014 |
| MoE publication type | Not Eligible |
| Event | 10th Liège Conference on Materials for Advanced Power Engineering - Palais des Congrès, Liège, Belgium Duration: 14 Sept 2014 → 17 Sept 2014 Conference number: 10 |
Conference
| Conference | 10th Liège Conference on Materials for Advanced Power Engineering |
|---|---|
| Country/Territory | Belgium |
| City | Liège |
| Period | 14/09/14 → 17/09/14 |
Keywords
- steam oxidation
- surface treatment
- superheater