| Status | 已發表Published |
| Laser Surface Alloying of AISI 304 Austenitic Stainless Steel with Niobium | |
Chan, M. C. ; Chan, W. K.; Kwok, C. T.; Lo, K. H.
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| 2013-11-01 | |
| Source Publication | Proceedings of NACE International East Asia & Pacific Rim Area Conference & Expo 2013
 |
| Publication Place | Japan |
| Publisher | NACE International |
| Abstract | Austenitic stainless steel (ASS) AISI 304 is the most versatile and widely used in engineering applications due to its good mechanical properties and weldability. But its shortcoming includes susceptibility to pitting corrosion in chloride-containing media, and intergranular corrosion (IGC) of welded assemblies and improperly heat-treated work pieces at 600 to 950 degC. The effective measures to avoid IGC are: (i) reducing carbon content and (ii) adding stabilizers such as niobium (Nb) and titanium (Ti). Laser surface alloying (LSA) is a feasible method for achieving interstitial stabilization of the 304, and Nb is selected as the alloying element adding into 304 by LSA. In the present study, the feasibility of LSA of 304 with Nb for enhancing pitting corrosion and IGC resistances was investigated. Nb powder was pre-pasted on the surface of specimens and then the specimen was successfully achieved by a 2.3-kW high power diode laser (HPDL). The laser-alloyed specimens were then put in a furnace and aged for 40 h. Cyclic potentiodynamic polarization tests for the various specimens were done in 3.5 wt% NaCl solution at 25 C were perform ed by using a potentiostat. The degree of sensitisation (DOS) of the specimens was determined by the double loop electrochemical potentiokinetic reactivation (DL-EPR) method in solution of 0.5 M H2SO4 and 0.01 M KSCN at 25 degC by a potentiostat. The pitting corrosion resistances of the Nb-alloyed 304 were comparable to the annealed 304. IGC resistance was found to be significantly enhanced as reflected by the decrease in DOS due to the addition of Nb which reduced the formation of chromium carbides. The corrosion morphology and surface hardness were also investigated. |
| Keyword | pitting corrosion intergranular corrosion AISI 304 laser surface alloying HPDL |
| Language | 英語English |
| The Source to Article | PB_Publication |
| PUB ID | 12804 |
| Document Type | Conference paper |
| Collection | DEPARTMENT OF ELECTROMECHANICAL ENGINEERING |
| Recommended Citation GB/T 7714 | Chan, M. C.,Chan, W. K.,Kwok, C. T.,et al. Laser Surface Alloying of AISI 304 Austenitic Stainless Steel with Niobium[C], Japan:NACE International, 2013. |
| APA | Chan, M. C.., Chan, W. K.., Kwok, C. T.., & Lo, K. H. (2013). Laser Surface Alloying of AISI 304 Austenitic Stainless Steel with Niobium. Proceedings of NACE International East Asia & Pacific Rim Area Conference & Expo 2013. |
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