Laser transformation hardening of AISI 440C martensitic stainless steel for higher cavitation erosion resistance

K. H. Lo, F. T. Cheng, Hau Chung Man

Research output: Journal article publicationJournal articleAcademic researchpeer-review

71 Citations (Scopus)

Abstract

Surface hardening of AISI 440C martensitic stainless steel was achieved by laser transformation hardening (LTH) using a high-power CW Nd:YAG laser. A hardened layer of a few 100 μm thick, composed of martensite, retained austenite and fine carbides was formed. The microstructure and hardness of the laser-treated layer were dependent on the laser processing parameters, with the hardness values reaching the range 600-800 HV. Compared with conventionally heat-treated samples, the laser-treated samples contained more retained austenite and finer carbides due to a higher degree of carbide dissolution. The cavitation erosion resistance of AISI 440C was significantly improved after laser treatment, and was approximately three-fold higher compared with that achieved by conventional heat treatment. The high erosion resistance was attributable to a desirable microstructure, which exhibited a favorable combination of hardness and toughness, and contained fewer weak sites for erosion attack.
Original languageEnglish
Pages (from-to)96-104
Number of pages9
JournalSurface and Coatings Technology
Volume173
Issue number1
DOIs
Publication statusPublished - 1 Aug 2003

Keywords

  • AISI 440C stainless steel
  • Cavitation erosion
  • Laser transformation hardening
  • Retained austenite

ASJC Scopus subject areas

  • Surfaces, Coatings and Films
  • Condensed Matter Physics
  • Surfaces and Interfaces

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