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Laboratory stress corrosion cracking studies in polythionic acid

Technical Report ·
OSTI ID:6346509

Stress corrosion cracking caused by polythionic acid and/or chlorides is a problem in coal liquefaction pilot plants. This problem is also common in refineries and has been the subject of extensive research. This study examines (1) the relationship of the ASTM standard ferric sulfate-sulfuric acid test for determining sensitization to resistance to polythionic stress corrosion cracking, (2) the cracking resistance of higher-alloy Fe-Ni-Cr materials in addition to the common austenitic stainless steels, and (3) the effect of chloride concentrations up to 1% in polythionic acid solutions on cracking behavior. We found that the ferric sulfate-sulfuric acid test can be used as an acceptance test for materials resistant to polythionic acid stress corrosion cracking because of its severity. The more highly alloyed materials were more resistant to sensitization than most of the austenitic stainless steels and were virtually unattacked in polythionic acid solutions containing up to 1% chloride. Chloride increased the corrosion rate and caused localized pitting, but it did not affect significantly the number of failures or the failure mode.

Research Organization:
Oak Ridge National Lab., TN (USA)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6346509
Report Number(s):
ORNL/TM-9116; ON: DE85002245
Country of Publication:
United States
Language:
English