Microbiologically influenced corrosion of stainless steel weld and base metal -- 4 year field test results

Book · Sat Dec 31 04:00:00 EST 1994

OSTI ID:80061

Felder, C M; Stein, A A ^[1]

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1. Stone and Webster Engineering Corp., Boston, MA (United States)

This paper presents the results obtained from a 4-year test program to determine the effects of microbiologically influenced corrosion (MIC) on piping materials under service conditions representative of a fresh water cooling water system. The test was performed in a field installed test loop and was constructed to operate under four typical flow conditions: continuous flow at 4--6 fps (1.2--1.8 m/s), continuous flow at 0.5--1 fps (0.15--0.3 m/s), intermittent flow, and stagnant. Test materials consisted of pipe spools as well as coupons fabricated from Type 304, Type 316, Type 316L, and 6-percent molybdenum stainless steel, and titanium pipe. The pipe spools and coupons contained girth welds; the stainless steel girth welds were made with high and low heat inputs. Two types of bacterial colonization, bulbous nodules and shiny flat deposits, were observed in both weld metal and base metal of the Type 300 series materials, including Type 316L. Three different MIC morphologies were observed: pits with small openings and extensive tunneling, open pits, and shallow surface attack. A correlation was found to exist between the type of bacteria colonization, the MIC morphology, and the metallurgical characteristics of the materials. The MIC was not preferential to sensitized regions but was found to be related to residual cold work in the material.

• OSTI ID: 80061
• Report Number(s): CONF-940222--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BACTERIA
BIOLOGICAL FOULING
CHEMICAL REACTION KINETICS
COOLING SYSTEMS
CORROSION
CORROSION PRODUCTS
EXPERIMENTAL DATA
FLOW RATE
MICROSTRUCTURE
MOLYBDENUM ALLOYS
MORPHOLOGY
SCANNING ELECTRON MICROSCOPY
STAINLESS STEEL-304
STAINLESS STEEL-316
STAINLESS STEEL-316L
TITANIUM
WELDED JOINTS