Corrosion Reactivity of Laser-Peened Steel Surfaces

Laser-shock processing or laser peening (LP) is a novel process used to reinforce surfaces by generating compressive residual stresses that has been investigated to change the surface mechanical state and modify the electrochemical properties of three commercial steels. The first part of this paper relates to experiments where LP has been applied to G10380 and G41400 steels for corrosion testing in an acid HKSO4-0.3 M solution. Only in the case of G41400 martensitic steel is a reduction of the corrosion current observed, depending on the degree of work hardening and the amplitude of compressive stresses. This indicates a small mechanochemical effect of LP, which seems to be restricted to martensitic structure. Second, the effect of LP on stress corrosion cracking (SCC) of AISI 316L stainless steel is demonstrated by static tests in MgCl2 44% – 153 °C solution. The results confirm the applicability of LP to suppress cracks on all the areas processed without occurrence of any problems in the treated-nontreated transitions zones.