| Industry: |
Chemical Process |
| Specimen Description: |
310 stainless steel thermal oxidizer rain hat |
| Material: |
310 stainless steel |
| Environment: |
Atmospheric with hot oxidizer flue gases |
| Background: |
A 310 stainless steel "rain hat" shielding
the opening of a thermal oxidizer flue gas stack failed from cracking
at attachement welds while in service. |
| Time in Service: |
Unknown |
| Findings: |
Laboratory failure analysis results showed that failure of the 310 stainless steel rain hat was due to hot cracking and lack of fusion of the attachment welds. Many polythionic acid stress corrosion cracks were also observed in the microstructure. It was believed the polythionic acid stress corrosion cracking occurred when sulfur containing flue gases condensed on the rain hat. |
