Investigation of galvanic corrosion in laser-welded stainless steel sheets

Chi Tat Kwok, Siu Lung Fong, Fai Tsun Cheng, Hau Chung Man

Research output: Journal article publicationConference articleAcademic researchpeer-review

Abstract

In the present study, bead-on-plate specimens of 1-mm sheets of austenitic and duplex stainless steels were fabricated by laser penetration welding with a 2.5-kW CW Nd:YAG laser. The galvanic corrosion behavior of laser-weldment (LW) against as-received (AR) specimens with an area ratio of 1:1 in 3.5% NaCl solution was studied by means of a zero-resistance ammeter. The free corrosion potentials of as-received specimens were found to be considerably higher than those of laser weldments, indicating that the weldments are more active and always act as anodes. The ranking of galvanic current densities (IG) of the couples in ascending order is: AR S31603-LW S31603 < AR S31803-LW S31803 < AR S32760-LW S32760 < AR S30400-LW S30400. For the galvanic couple between AR S30400 and LW S30400, the IGis the highest (78.6 nA/cm2) because large amount of δ-ferrite in the weld zone acts as active sites. On the other hand, the IGof the galvanic couple between AR S31603 and LW S31603 is the lowest (-26 nA/cm2) because no δ-ferrite is present after laser welding. The recorded IGof all couples revealed constantly low values (in the range of nA/cm2) and sometimes stayed negative, which indicated polarity reversal.
Original languageEnglish
Article number51
Pages (from-to)325-330
Number of pages6
JournalProceedings of SPIE - The International Society for Optical Engineering
Volume5662
DOIs
Publication statusPublished - 1 Dec 2004
EventFifth International Symposium on Laser Precision Microfabrication - Nara, Japan
Duration: 11 May 200414 May 2004

Keywords

  • Delta ferrite
  • Galvanic corrosion
  • Penetration welding
  • Stainless steels

ASJC Scopus subject areas

  • Electrical and Electronic Engineering
  • Condensed Matter Physics

Cite this