Summary for alpha case removal Discussion
alpha case removal process on titanium is discussed as a matter of removing actual metal, not just cleaning the surface. Ravikumar Subramanian asked how to remove alpha case and what effects it has. James Watts replied that alpha case can vary greatly in depth, so it must be machined off or chemically removed, and verifying complete removal usually requires destructive metallography or blue etch anodize by a highly qualified operator. Years later, GHORPADE KETAN VITTHAL asked whether a 437-micron layer could be removed by shot blasting. The only answer in the excerpt suggested immersion in a nitric/hydrofluoric acid bath as the best approach, while noting that the acid ratio is critical and that the details were not recalled. Overall, the thread emphasizes that alpha case removal is not a simple blasting job and that depth control and verification are important.
Q. Can you please explain about the process of Alpha removal process from titanium and its impacts?
Ravikumar Subramanian
Buyer – Chennai
June 30, 2010
A. Alpha case is in the metal, so you have to machine or chemically remove that metal. Alpha case can vary massively in depth, so how are you going to know if you got it all? Either destructive metallographic evaluation or blue etch anodize require a very highly qualified operator. Neither is for 99% of journeyman qualified people.
James Watts
– Navarre, Florida
July 1, 2010
Q. If alpha case depth is 437 microns, can we remove this layer by shot blasting?
GHORPADE KETAN VITTHAL
forge – Pune, Maharashtra, India
July 26, 2016
A. I believe that this is best done by immersion in a nitric/hydrofluoric acid bath. I looked into this a few years back on behalf of a client. Don’t recall the details, though I do remember that having the proper ratio of the two acids is critical.
Dave Wichern
Consultant – The Bronx, New York
July 27, 2016