Summary for tungsten carbide coating removal Discussion
tungsten carbide coating removal from 300M steel is discussed as a problem with few easy chemical answers. Richard asks whether citric acid could strip a Diamalloy 2005 HVOF tungsten carbide coating from aerospace 300M steel. James Watts warns that aerospace parts should only be processed under the OEM overhaul/repair manual or an approved alternate method, because unapproved stripping can create major liability. Bakker Sven says nitric acid may not remove HVOF coatings and notes that, in practice, they have removed HVOF by grinding it off with the same special grinding stones used to apply the required roughness. Later questions about removing other carbide coatings draw a response that the substrate and geometry matter, and Jeff Shaffer suggests ultrasonically pulsed waterjet technology for hard coatings without substrate damage. Overall, the thread points more toward approved mechanical removal methods than simple acid stripping.
Q. We have a need to strip a tungsten carbide HVOF thermal spray coating (Diamalloy 2005) from a 300M alloy steel components. Somebody said citric acid
⇦ on
or
Amazon [affil link] will do this. Any advice from out there?
Thanks in advance for your help.
Richard H [surname deleted for privacy by Editor]
Aerospace sheet metal, welding & thermal spray – Blainville, QC, Canada
2004
A. Since you are Aerospace, you must follow the overhaul/repair manual of the OEM or get an approval for an alternate method (which can be lengthy and tough to come by). If you do not use the approved methods, and a part fails, just the law suit (lawyer cost) would break many companies. The downside of this type of individual effort is massive.
James Watts
– Navarre, Florida
2004
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, EIT
We ask all posters to please read our short & simple guidelines before posting because introducing yourself prevents these unintended slights which raise hackles, and in turn have now insulted one of this site’s most helpful responders, whose advice hundreds upon hundreds of readers have benefitted from.
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Don’t assume, James Watts, that the person asking an honest question is less knowledgeable than yourself. Dick knows a thing or two about “aerospace”.
Hi Jason. James surely meant no disrespect, but for him to assume that a stranger knows everything that he knows himself is dangerous! Over the years James has warned at least a half-dozen posters here who wanted to install chrome plating tanks in their garage/basement of the safety issues they were completely unaware of … should he have assumed they were “not less knowledgeable than himself”, and just offered them the raw mechanics of how to go ahead and install those chrome plating tanks in their basement?
A. Nitric acid may not do the job as the Nital Etch process used nitric acid and nital etching is used on HVOF layers to verify NO burning as result of grinding.
What we have done to remove the HVOF is just grind it off with the same grinding stones as used to grind the HVOF layer initially to it’s roughness requirements. due to the hardness of HVOF coatings, these are special grinding stones.
I hope this is of help.
Bakker Sven
– EINDHOVEN, NETHERLANDS
2006
Q. Nital etch inspection on PH 13-8 Mo and 17-4 PH steel. Is the Nital etch inspection on precipitation hardening steels effective? is there any influence from burning marks (grinding) on the outside diameter like on carbon steel heat treated products?
Peter Aarts
Aerospace – Geldrop, Holland
2006
Q. I need to remove chromium carbide coating from steel sample using any chemical methods without causing changes to the substrate. Thickness of coating is 20µ. Does anyone have information about it? Thanks.
Elena Sparrow
– Moscow, Russia
January 14, 2013
A. Ultrasonically pulsed waterjet technology will remove hardcoating such as Chrome and HVOF using normal tap water without causing damage to the substrate.
Jeff Shaffer
Pratt & Whitney PurePulse Technology – San Antonio, Texas, USA
January 31, 2013
Stripping Titanium and Chromium Carbide
Q. Can anyone help me the procedure to strip Ti and Cr carbide coated through PVD route?
Ramasubramanian Sankara Bhatter
– Bangalore, India
February 14, 2013
Ed. note: Hi Ramasubramanian. Please tell us the substrate. It isn’t possible to advise a proper stripping solution unless we know what both the substrate and the coating are. Thanks.
Q. Dear Sir,
The problem is stripping of chrome carbide embedded on steel substrate. It is not going with HF and caustic-peroxide mixture. Can you suggest to me some other strippers?
Ramasubramanian Sankara Bhatter [returning]
– Bangalore, Karnataka, India
March 31, 2013
Stripping Tungsten Carbide from I.D housing
Q. Stripping Tungsten Carbide from I.D housing what methods can be used.
Any suggestions would be greatly appreciated.
Sashi Kumar
– Edmonton, Alberta, Canada
October 26, 2017
? Hi Sashi. Your housing is made of 300M steel, or something else? What is the length and diameter of this I.D.? Is it open on both ends, or a blind hole? It’s not yet clear to me what is inapplicable about the earlier suggestions … can you comment on them please? Thanks.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com – Pine Beach, New Jersey
Need quick confidential answers? $25
Need project assistance? $100/hr.
October 2017
adv.
