school

UM E-Theses Collection (澳門大學電子學位論文庫)

check Full Text
Title

Effects of metallurgical variables on the cavitation erosion behaviour of AISI 304 austenitic stainless steel

English Abstract

In the present study, cavitation erosion (CE) tests were conducted to evaluate the cavitation erosion hehaviour of AISI 304 stainless steel. Four factors: grain size, synergism between CE and corrosion, carbide precipitation and martensitic transformation have been considered in this research. For the effect of grain size, the specimens studied in this thesis underwent different solution-treatment (1100°C and 1300°C). It was observed that the grain size of 1300°C sample are much bigger than 1100°C one. SEM examination and cumulative-mass-loss curve revealed that the specimen heat treated at 1300°C suffered from more serious mass loss relative to its 1100°C counterpart in 3.5wt.% NaCl solution. The cavitation erosion resistance of AISI 304 weaken with the increase of grain size. The synergistic effect of CE and corrosion was made known by conducting CE process at different media (3.5wt.% NaCl and distilled water). For the condition of annealing at 650°C, CE resistance of the sample immersed in distilled water is a little better than that of the NaCl one. For the condition of annealing at 1100°C, CE resistance of the specimen immersed in distilled water is good, while degrades rapidly in NaCl solution due to the presence of chlorine. Carbide precipitation was discovered in the specimen after sensitization heat treatment at 650°C for 50 days. CE damage sequence and the iii cumulative-mass-loss curve in this case demonstrated that the carbide precipitation effect of AISI 304 stainless steels had a positive influence in raising cavitation erosion resistance with respect to its 1100°C state. Martensitic transformation in 304 was induced by cryogenic treatment for 15min liquid-nitrogen immersion. The result showed that cryogenic treatment on AISI 304 stainless steels may reduce cavitation erosion.

Issue date

2016.

Author

Li, Jing Hui,

Faculty

Faculty of Science and Technology

Department

Department of Electromechanical Engineering

Degree

M.Sc.

Subject

Austenitic stainless steel -- Corrosion

Cavitation

Supervisor

Lo, Kin Ho

Files In This Item

Full-text (Intranet only)

Location
1/F Zone C
Library URL
991005808049706306