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Title: The implications of thermomechanical processing for microbiologically influenced corrosion

This work examined the effect of systematic variation in the amounts of cerium, sulfur and silicon on corrosion resistance in an AISI 8630 base material and weldments exposed to sterile and biologically active anaerobic aqueous solutions. Significant correlation between microbiologically influenced corrosion (MIC) susceptibility and sulfide inclusion size, shape, chemical stability and spatial distribution were found in these materials. In addition, significant correlation was found between these factors and bacterial attachment, particularly during a critical time period in film evolution. These factors were found to affect the evolution of microbial consortia at metal surfaces and subsequent corrosion at attachment sites, as measured by pit initiation and maximum pit size. The results suggest mitigation strategies based on microstructural design. A two-level, three-factor full factorial experiment, with AISI 8630 (UNS G86300) as the master composition, was used to relate minor element composition to both MIC susceptibility and microbial attachment in weld composite zones, partially melted zones (PMZ) and adjacent base metal regions. In all cases studied, MIC susceptibility was greatest in the PMZ. In addition, the MIC susceptibility of materials tested was significantly altered by differences in fabrication procedure as measured by changes to heat input. Samples exposed to sterile solutions weremore » significantly less corroded. Higher energy density processes and lower heat inputs diminished MIC sensitivity. In both base metal and welded samples the addition of Cerium was found to diminish MIC susceptibility. Cerium creates this benefit through its profound effect on inclusion geometry, chemical stability and thermal stability.« less
Authors:
 [1]
  1. California Polytechnic State Univ., San Luis Obispo, CA (United States). Materials Engineering Dept.
Publication Date:
OSTI Identifier:
696953
Report Number(s):
CONF-990401--
TRN: IM9946%%339
Resource Type:
Conference
Resource Relation:
Conference: Corrosion 1999 conference, San Antonio, TX (United States), 25 Apr 1999; Other Information: DN: 1 CD-ROM. Operating Systems: Windows 3.1, `95, `98 and NT; Macintosh; and UNIX; PBD: 1999; Related Information: Is Part Of Corrosion 99: Proceedings; PB: [3500] p.
Publisher:
NACE International, Houston, TX (United States)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; LOW ALLOY STEELS; CERIUM ADDITIONS; SULFUR ADDITIONS; SILICON ADDITIONS; METALLURGICAL EFFECTS; CORROSION RESISTANCE; WELDED JOINTS; BIOLOGICAL FOULING; CORROSION; MICROSTRUCTURE; THERMOMECHANICAL TREATMENTS