OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
Table 5: Corossion rate for un-treated, shot peened and nitrided specimen.
S. No. Un-treated specimen
(mpy)
Shot peened
specimen at 5A
(mpy)
Nitrided
specimen (mpy)
Carburized
specimen (mpy)
1 0.928 0.855 0.521 1.421
2 0.956 0.862 0.484 1.736
3 0.992 0.846 0.498 1.319
4 0.908 0.843 0.501 1.901
Average 0.946 0.852 0.501 1.594
3.2. Corossion Rate
Corrosion test was conducted under salt spray chamber at 40-45 0 C for 48 hours under 5% NaCl mist. Un-treated
specimen & nitrided specimen showed no corrosion but red rust was observed in shot peened specimen. This
shows that shot peening & nitriding improves surface hardness and corrosion resistance however carburizing
decreases the surface hardness as well as corrosion resistance (table 5 and fig 4).
Fig 4. Corossion rate for un-treated, shot peened and nitrided specimen.
4. Conclusion
It is seen experimentally that shot peening, nitriding and carburizing effects on surface hardness and corrosion
rate of welded 304L austenitic stainless steel. The following conclusions were made:
1. Surface hardness of welded 304L austenitic stainless steel specimen improves with shot- peening and
nitriding.
2. Increase in surface hardness is more after nitrding as compared to that with shot-peening.
3. The shot peening & nitriding improves surface hardness and corrosion resistance however carburizing
decreases the surface hardness as well as corrosion resistance.
4. Carburizing softens the welded joint of 304L austenitic stainless steel.
References
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