Alloy 20 Corrosion in H2SO4
Alloy 20 Corrosion in H2SO4
(OP)
We have 3% Sulfuric Acid being injected into our Alloy 20 stock line. Downstream of the injection, the heat affected zones of some of the welds are being eaten away. Could this possibly be from the line not being pickeled and passivated after welding? Is this the right material for the application? This line is between a brown stock (brown paper) chest and the pump suction.





RE: Alloy 20 Corrosion in H2SO4
RE: Alloy 20 Corrosion in H2SO4
This alloy is Nb stablized, isn't it? If not then sensitization could be the problem.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Alloy 20 Corrosion in H2SO4
The material is Columbium Stabalized.
RE: Alloy 20 Corrosion in H2SO4
www.a
The columbium stabilized grade is fine, and would reduce susceptibility to sensitization in the weld HAZ.
The only other possibility is what you had mentioned earlier, if the heat tint or surface oxidation was not removed after welding it is possible that this could be the reason for the preferential attack along the base metal HAZ's.
RE: Alloy 20 Corrosion in H2SO4
Since you don't generally see sulfuric attacking areas of Cr deleation I doubt that surface oxide has anything to do with this.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm