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Stripping Tungsten Carbide thermal spray coatings from 300M steel

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 eBay or Amazon affil links] will do this. Any advice from out there?

Thanks in advance for your help.

Richard H [last name deleted for privacy by Editor]
Aerospace sheet metal, welding & thermal spray - Blainville, QC, Canada

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


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".

- Winnipeg, Manitoba, Canada

thumbs up sign James surely meant no disrespect, Jason. But for him to assume that a stranger knows what he knows is dangerous! Over the years he has warned a half-dozen people here who wanted to install chrome plating tanks in their garage/basement about the safety issues they were totally unaware of -- should he have assumed they are "not less knowledgeable than himself", and just give them the raw mechanics of how to install plating tanks in their basement?

One benefit of reading our short & simple guideline before posting -- as we request of all posters -- is that it prevents unintended slights which raise hackles, and end up insulting one of this site's most helpful responders whose advice hundreds of readers have benefitted from.

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

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

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

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

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.


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey
October 2017

Metalx nickel stripper

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