Hydraulic Shaft - Thermal Spray - Advice needed
10-01-2013, 05:00 PM,
#1
Information  Hydraulic Shaft - Thermal Spray - Advice needed
I recently thermal sprayed a hydraulic shaft for a CAT machine OD 90mm.
We machined the worn out area to about 1mm under the size required.
The area was then threaded and was cleaned making sure there was no contamination
We then pre-heated the worn piece to about 70 - 80 degrees
Then sprayed the item with proxon 21031.
After we finished we then grinded the item with coolant and it really looked cool and job complete.
The client the fixed the item and complained about it leaking and after some time the coating came off.
Any advice on how this happened.

I mean if the coating was not right it would have come off will grinding.

I understand that after a part has been thermal coated you can then use a product made by diamanti know as dichtol. They say it seal cracks and small porous holes. can with stand pressure of about 8000 p.s.i.

Any comments, has any one tired this.


Reply
10-07-2013, 11:24 PM, (This post was last modified: 10-07-2013, 11:25 PM by KevGarty.)
#2
RE: Hydraulic Shaft - Thermal Spray - Advice needed
I'm would doubt that Flame Spray is a good enough process for Hard Chrome Replacement. This is a hard chrome replacement job yeah ?

If it is you would have to go to HVOF rather than conventional flame spray as the bond strength of the proxon powder will only be in the region of 4000 psi where an HVOF hard chrome coating your looking at 9000-10,000 psi.

Flame sprayed coatings generally have around 10% porosity in them the dichtol would help that a great deal but the coating is still generally soft probably around 150-180 HV an HVOF coating would be around 800HV with less than 2% in some cases 1% porosity

Dichtol works very well if applied correctly but this has to be applied before finish machining.

I would think that the coating isnt good enough for the application IF, it is a hard chrome replacement application.

All the best

Kev
Reply
10-09-2013, 07:16 PM,
#3
RE: Hydraulic Shaft - Thermal Spray - Advice needed
(10-07-2013, 11:24 PM)KevGarty Wrote: I'm would doubt that Flame Spray is a good enough process for Hard Chrome Replacement. This is a hard chrome replacement job yeah ?

If it is you would have to go to HVOF rather than conventional flame spray as the bond strength of the proxon powder will only be in the region of 4000 psi where an HVOF hard chrome coating your looking at 9000-10,000 psi.

Flame sprayed coatings generally have around 10% porosity in them the dichtol would help that a great deal but the coating is still generally soft probably around 150-180 HV an HVOF coating would be around 800HV with less than 2% in some cases 1% porosity

Dichtol works very well if applied correctly but this has to be applied before finish machining.

I would think that the coating isnt good enough for the application IF, it is a hard chrome replacement application.

All the best

Kev

I would agree with Kev....cannot replace hard chrome with flame spray- specially for hydraulic piston rods of earth moving equipments which generally work under a decent amount of stress and load...
If HVOF is not available, the least you require would be an ARC spray- say a good metcoloy II coating over a well blasted surface with a bond coat of Ni Al. May be a TAFA 95 MXC kind of material may also help

Regards

Shantanu
Reply




Possibly Related Threads…
Thread Author Replies Views Last Post
  Arc spray or HVOF for bearing of turbine generator shaft Youssef 0 341 06-15-2020, 06:08 AM
Last Post: Youssef
  Hydraulic Piston rod demionkrishan 2 829 10-14-2019, 05:51 PM
Last Post: velocity
  Info needed on Bond Strength for Thermal Spray powders hereticgame 1 1,932 10-10-2017, 11:39 AM
Last Post: Vadim Verlotski
  Propeller shaft repair by flame spray in the cones area Iwan Sedaryawan CA 1 1,727 12-09-2016, 04:56 AM
Last Post: Stephen Booth
  WC-Co+NiCrBSi Applying on hydraulic piston rod Met.Eng. 4 2,925 05-09-2016, 05:45 PM
Last Post: Vadim Verlotski
Rolleyes Calculate powder weight needed to spray surface area Zacadoom 2 5,722 11-10-2014, 02:58 PM
Last Post: Zacadoom
  Need advice on unmelt particles in Metco 58 coating vivian 2 3,975 01-09-2013, 06:25 PM
Last Post: loriolo
  Engineering student looking for advice Q23Q 1 2,525 10-10-2011, 11:36 AM
Last Post: EmaEsabel
  Repair Pump Shaft on Base Material Nitronic50 Piyapong 1 3,706 03-03-2010, 05:53 PM
Last Post: djewell
  Turbine high speed shaft RPM 6000 to be coating iwan-sedaryawan 4 6,023 12-10-2009, 03:46 PM
Last Post: Gordon
  Corrosion Potential - Help and advice needed! freckle 4 5,154 08-11-2009, 05:17 PM
Last Post: freckle
  Marine Shaft Repair istech 0 4,267 11-13-2008, 10:52 PM
Last Post: istech
  Making new thread in a shaft of Jumbo Roll iwan-sedaryawan 1 6,616 08-22-2008, 02:40 PM
Last Post: Gordon
Question 88WC - 8Co - 4Cr Removal Advice Batsy 2 6,107 02-05-2007, 09:21 AM
Last Post: Batsy



Users browsing this thread: 1 Guest(s)





Surface Engineering Forum Sponsor - Alphatek Hyperformance Coatings Ltd