Ferralium® 255 was the only alloy to come through MacMillan Bloedel's corrosion tests for bark-drying vessels intact, and was chosen to line the dryers and form their internal baffles and lifters.
At Powell River, British Columbia, MacMillan Bloedel Pulp and Paper Company had serious corrosion problems with the carbon steel vessels used to dry bark and wood waste (hog fuel) for burning in power boilers. The bark is stripped from pulp logs that have been transported and stored in seawater, then dried in rotating cylindrical vessels heated with flue gas from the hog-fuel boilers. Chlorides from the salt water are very corrosive to carbon steel.
A test programme sought a suitable alternative. Ferralium® 255 was the only alloy that showed no uniform corrosion, pitting, crevice attack or chloride stress corrosion cracking; even some of the more expensive super stainless steels suffered some degree of corrosion. It was selected as a liner material for the carbon steel dryers, and for all the internal baffles and lifters, for its corrosion resistance and cost effectiveness. Approximately 48T (105,000 lbs) were used in total.
After 12 months' service, a visual inspection found no evidence of corrosion. MacMillan Bloedel subsequently used Ferralium® 255 for follow-on units.
