I have a titanium part that is glas 2

[Delly]

I have a titanium part that is glass bead peaned prior to passivation. The bead blast media is also used on 300, 400 series stainless steels as well as 14-4 PH and MP35N materials.
Will the passivation remove any imbedded particles in the titanium from the other materials or is there still a chance for cross contamination?

 

[arunmrao]

In order to reduce the risk of a localised corrosion,due to embeddment of blast particles, such chemically inert media like glass bead or silica sand are commonly used. There should not be any problem after passivation treatment.

 

[metman]

arunmrao, I respectfully suggest you re-read Delly's question. He is already using glass beads. He is talking about contamination from pick up onto the beads from previous blasting on dissimilar material which is being transferred to the Ti.

Delly, If the passivation will not remove the transferred contamination, can you use fresh beads on the Ti? But I think I understand your question to mean that hopefully you can reuse the same beads if your assured the passivation will remove the cross contamination.

 

[Delly]

Metman, Yes we can use a seperate chamber for titanium material only. But before I do that, my question is whether I can be 100% sure passivation removes these metals from the titanium surface so the surface will only be a titanium oxide without any trace of the other metals (or elements of those metals) being present?
Thanks Delly

 

[arunmrao]

I am sorry for having read and understood the question wrongly.

 

[BarryMartin]

To remove embedded material you might try pressure washing the surface or using a short etch to remove any residual material.

 

[bruv]

Delly

If you need a procedure for checking for surface contamination, take a look at ASTM A380, Standard Practice for Cleaning, Descaling and Passivation of Stainless Steel Parts, Equipment and Systems.

Section 7 (Inspection after Cleaning) gives a couple of tests for detection of iron contamination. We have used the Ferroxyl Test very succesfully on titanium alloys.

Regards

Bruv

 

[Delly]

Gentlemen
Thanks for your input. The issue has been resolved.
Delly

 

[Andy4T]

Does anybody know of a Passivation Specification that is used with, or specifically calls out MP35N? Most are written for stainless steels, but do not specifically detail how to process MP35N. This application is for a spacecraft structure, and the completed item is showing signs of corrosion, probably from the cutting tool that was used. Thanks for any help.

Andy T.

 

[TVP]

I am unaware of any standard or specification that specifically deals with passivation of MP35N. I would discuss this with one of the companies that manufactures or works this alloy:

Carpenter

http://www.cartech.com

Timken Latrobe

http://www.timken.com/products/specialtysteel/engineering/tech_info/PDF_Files/MP35N_Alloy.pdf

SPS Technologies

http://www.spstech.com/business_groups/specialty.html

or

http://www.spstech.com/aero/tech_support/engineer.html