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Corrosion of friction rock stabilizer steels in underground coal mine waters.
MISSING :14 pages
In an effort to better predict the useful service life of friction rock stabilizer mine roof bolts in coal mine environments, the Bureau of Mines has evaluated the corrosion resistance of stabilizer steels in air-saturated and deaerated waters from seven eastern and midwestern underground coal mines. Accelerated electrochemical corrosion tests were used to estimate corrosion rates for the two high-strength, low-alloy (hsla) steels used to fabricate split set stabilizers and for galvanized steel. Long-term static-immersion weight-loss tests were also conducted with the hsla steels. Corrosion rates developed from the weight-loss tests (steady-state air dissolution) were roughly comparable to rates determined from electrochemical testing in aerated waters. Although the highest rates occurred in waters with the highest chloride contents, rates in the other waters were low (equal to or less than 2.0 Mpy) and exhibited little correlation to the widely varied chloride contents of the waters. The generally low corrosion rates are attributed in part to the tendency to deposit a protective caco3 film, reflecting susceptibility to carbonate precipitation as indicated by positive langelier (saturation) index values for the waters. With one exception, corrosion rates for the galvanized steel were equal to or less than 2.0 Mpy. Rates with aerated waters were higher than those with deaerated waters. Pitting tendencies of the steels were also estimated.
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Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division