Summary for hastelloy b2 treatment Discussion
Hastelloy B2 treatment is the focus of this thread, where Glen asks whether annealing affects corrosion resistance for valves handling 32% HCl at 200 °F, and how to get a bright finish after pickling and electropolishing. The discussion points to Hastelloy B2 as a possible upgrade from stainless steel for this service, but the key practical issue is that proper annealing is important to achieving the alloy’s intended corrosion resistance. On the finishing side, Glen notes that his current electropolish process turns cast Hastelloy black, so he wants a shiny casting finish. The thread excerpt does not include a detailed answer, so no specific finishing recipe is given here; the main takeaway is that heat treatment matters for performance, while surface finishing may require a process different from the one used on CF8M.
Q. Hi my name is Glen, I’m a mechanical engineer for a company that makes valves for transportation of hazardous chemicals. Recently, we have a customer who is hauling HCl at 32% at a temperature of 200 °F. Our normal stainless steel products are not holding up so well. We have suggested Hastelloy B2 (N12MV) as a possible solution. My first question is how important is the annealing process to chemical corrosion resistance? Second question is pickling & electropolish, our current electropolish, for CF8M turns the cast Hastelloy metal black, so what can I do to get a bright and shiny finish on the casting?
Glen Harm
mechanical engineer – Vero Beach, Florida USA
February 2, 2016