Improving intergranular corrosion resistance of sensitized type 316 austenitic stainless steel by laser surface melting
- 236 Downloads
An attempt was made to modify the surface microstructure of a sensitized austenitic stainless steel, without affecting the bulk properties, using laser surface melting techniques. AISI type 316 stainless steel specimens sensitized at 923 K for 20 hr were laser surface melted using a pulsed ruby laser at 6 J energy. Two successive pulses were given to ensure uniform melting and homogenization. The melted layers were characterized by small angle X- ray diffraction and scanning electron microscopy. Intergranular corrosion tests were carried out on the melted region as per ASTM A262 practice A (etch test) and electrochemical potentiokinetic reactivation test. The results indicated an improvement in the intergranular corrosion resistance after laser surface melting. The results are explained on the basis of homogeneous and nonsensitized microstructure obtained at the surface after laser surface melting. It is concluded that laser surface melting can be used as an in situ method to increase the life of a sensitized component by modifying the surface microstructure.
KeywordsAustenitic Stainless Steel Laser Surface A262 Practice Melted Region Laser Surface Melting
Unable to display preview. Download preview PDF.
- 2.V. Cihal,Intergranular Corrosion of Steels and Alloys, Elsevier Publishing, Amsterdam (1984).Google Scholar
- 6.K. Mukherjee and J. Mazumder,Lasers in Metallurgy, Metallur- gical Society of AIME, New York (1981).Google Scholar
- 8.E.I. Meletis and R.F. Hochman,J. Met., 39, 25–27 (1987).Google Scholar
- 9.D.S. Gnanamuthu,Applications of Lasers in Materials Processing, E.A. Metzbower, Ed., American Society for Metals, 177 (1979).Google Scholar
- 10.W.M. Steen, Proceedings of Second European Conference on Laser Treatment of Materials, Bad Nauheim, 60–64 (1988).Google Scholar
- 11."Standard Recommended Practices for Detecting Susceptibility to Intergranular Attack in Stainless Steels," ASTM A 262 Practice A, Vol 03.02, American Society for Testing and Materials, Phila- delphia, 2 (1986).Google Scholar
- 14.M. Lamb, W.M. Steen, and D.R.F. West, Proceedings of Interna- tional Conference on Stainless Steel 84, Gothernburg, Sweden, 295–302(1984).Google Scholar
- 15.T. Tsuru and R.M. Latanision,Corrosion and Corrosion Protec- tion, R.P. Frankenthal and F. Mansfeld, Ed., The Electrochemical Society, Pennington, 238 (1981).Google Scholar
- 17.B.D. Cullity,Elements of X-ray Diffraction, 2nd ed., Addison- Wesley, New York (1978).Google Scholar