HAYNES® 556® alloy exhibits reasonable resistance to neutral NaCl-KCl-BaCl2 type heat-treating salts at temperatures up to 1550°F (845°C) based upon actual field tests in a molten salt pot heat treating facility. Coupons were exposed for 30 days.
Based upon field tests performed in the combustion chamber of a fluid bed dryer used to dry sodium tripolyphosphate compounds, HAYNES® 556® alloy exhibits very good resistance to corrosion caused by formation of low-melting point eutectics involving phosphorus. Samples were exposed 30 days at a temperature of about 1475°F (800°C).
Resistance to molten zinc is an important consideration for structural components in galvanizing operations. Laboratory tests were performed at 850°F (455°C) for 50 hours in molten zinc to determine suitability for such operations. Results are given below:
*No internal attack noted for any of the alloys tested