Hastealloy C276 handling sulfuric acid at ambient T (4C-50C)

[Salghetet]

Gents
Hastealloy C276 handling sulfuric acid concentration is 98% but may be diluted due to leak of NRV at Ambient temperature (4C t0 50 C), the line cracked at welded joint at HAZ
My question is how to avoid failure in HAZ in Hastealloy C276 handling sulfuric acid at ambient temperature

 

[metengr]

The corrosion data I have seen from Haynes indicates C-276 is acceptable for various concentrations of relatively pure sulfuric acid below 70 deg C or approximately 150 deg F. If you have a maximum of 50 deg C, this material should be acceptable.

Two possibilities I can think of – most likely you have a contaminant in addition to the lower concentration of sulfuric acid OR there was a problem with the welding process. What was the condition of the C-276 material away from the base metal HAZ? Typically, the BM HAZ will be more susceptible to corrosion versus the BM.

 

[Metaljon]

I agree with Meteng comments this should work under your conditions. This alloy can show susceptibility to intergranular corrosion in the heat-affected zone of weldments under certain conditions. In environments where attack of the C-276 alloy weld joint is experienced, C-22 weld filler materials should be used. The C-22 alloy exhibits superior weldability and corrosion resistance. This can be used as an overlay.

 

[Salghetet]

Thanks a lot metengr and Metaljon
condition of C-276 material away from base metal HAZ is good and no evedince of corrosion.
Regarding the contaminant in Acid, i am not sure, contamination may come from sour water which is being injected by acid.
However, i am planning to use CS lined with PFA or PTFE rather than using C-276, so Gents what do you think about this idea.