Laser surface melting of martensitic stainless steel 440C for enhancing corrosion resistance

Chi-Tat Kwok; Ka-Hing Lo; Fai-Tsun Cheng; Hau-Chung Man

doi:10.1117/12.497599

3 March 2003 Laser surface melting of Martensitic stainless steel 440C for enhancing corrosion resistance

Chi-Tat Kwok, Ka-Hing Lo, Fai-Tsun Cheng, Hau-Chung Man

Proceedings Volume 4831, First International Symposium on High-Power Laser Macroprocessing; (2003) https://doi.org/10.1117/12.497599
Event: LAMP 2002: International Congress on Laser Advanced Materials Processing, 2002, Osaka, Japan

Abstract

Surface modification of martensitic stainless steel 440C was achieved by laser surface melting using a 2-kW continuous wave Nd:YAG laser. The corrosion characteristics of laser-melted specimens fabricated under different processing parameters in 3.5% NaCl solution at 23°C were studied by potentiodynamic polarization technique. The pitting corrosion resistance of all laser-melted specimens was significantly improved, as evidenced by a shift of the pitting potential in the noble direction, a wider passive range, and a lower passive current density. The pitting potential of the laser-melted specimen fabricated under a power density of 4.2 kW/cm² and a scanning speed of 25 mm/s (specimen P12-440C-25) was increased to 200 mV (SCE), which was much higher than that of annealed and conventionally heat-treated 440C. The pitting corrosion characteristics of the laser-melted specimens were strongly dependent on the processing conditions which resulted in different microstructures. The enhanced pitting resistance resulted from the combined effect of dissolution or refinement of carbide particles and the presence of retained austenite. By using different processing parameters, it was found that the pitting resistance of the laser-melted specimen P12-440C-25 was the highest by virtue of a high volume fraction of retained austenite and a small amount of precipitated carbide.

Citation Download Citation

Chi-Tat Kwok, Ka-Hing Lo, Fai-Tsun Cheng, and Hau-Chung Man "Laser surface melting of Martensitic stainless steel 440C for enhancing corrosion resistance", Proc. SPIE 4831, First International Symposium on High-Power Laser Macroprocessing, (3 March 2003); https://doi.org/10.1117/12.497599

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available