T800 coating enquiry

[howied]

Hi All,

I am testing T800 coating (Praxair Co-111 POWDER)with 3MB and 9MB.

I found 3 MB is not able to get qualfied coating as the oxide level is much higher than expected.

So i want to turn to 9MB.is there anyone who has the qualfied spraying parameter for this coating for GE-Aviation?THe coating shall meet GE F50TF45 CL-A.

Urgent!!

Thanks.

[Alexangel1226]

Howied,

There is so much challenge to deal with this powder type. It's not as easy as other powder like Inco718, T400 or other metallic powders.

Talk this aside, pls let me know your system set up for your 9MB gun, Pri-Secondary gas type, are u using robotic spraying? What is your hopper type? Closed loop or not? what is your initial parameter set-up you intent to try? Nozzle type, feedrate, carrier gas flow, stand-off....etc.

I suppose you can also get some hint as a start from the powder supplier on the recommended parameter from Sulzer Metco or Praxair. Provide this info, try all ways out, if you still can't get any hint, let me know. Txs

Regards,
Alexangel1226

[William]

Hi Howied,
I am studying T-800 Coating now.
This is really very difficult.
I tried by Metco 9MC Plasma spray system. My parameter as follow:
Gas: Ar/ H2 Ar/He
Nozzle:732, 733, 728
Powder shaft type: B
Powder port: #5

The test result:
The oxided and unmelt were not meet GE specification.
It is very difficult to find the result of equalization.

If you have Praxair SG-100 Gun, you can try it.

Best regards,
William

[Alexangel1226]

Howied - Hi there!! How's the progress? Any improvement or new discoveries?

[howied]

Alex,

I've already tested coating with our new equipped 9MB gun.

Please find my parameter.
Nozzle:732,
Powder port:#2
Primary gas:Ar @ 167 scfh
Secondary Gas:H2 @15 scfh
carrier Gas :Ar @ 7scfh
Current:500A
Voltage:70 from plasma gun reading
Feedrate:@ 36 gram/min,
Spray distance(stand off):@ 3.5 inch
Surface speed:290ft/min=88m/min
Gun traverse speed(FANUC robot):13.3inch/min

The control system is called CITS,which is designed by Progressive Technologies.Inc,PTI for short,a small thermal spray equipment manufacturer,and powder feeder is his copied product,kind of TAFA sort,wheel disk powder feeder,closed-loop.

After polished,i found that the oxide is still highed than expected,and more unmelts and porosity.

1,I am not sure about my surface speed and traverse speed.

2,and i guess my carrier is much less than Praxair recommendation:35 scfh.
However i did tried 35 scfh and it is too high to get powder to be center of flame.It is kind of too expended flame.terrible.

3, any good polishing procedure for sharing which is approved by GE-CCL or Metcet.I tried two different method.
I am concerned ahout my metallographic preparation may have any bad effect on coating itself.

one is
1 : CLOTH : NAPLESS CLOTH (TEXMET 1000 OR EQUIVALENT)
???? ABRASIVE: 6 MICRON DIAMOND ABRASIVE
???? LUBRICANT : WATER LUBRICANT OR DIAMOND EXTENDER
???? PRESSURE : 5 PSI/MOUNT, 30 TO 60 SECONDS AT 150 RPM

2 : CLOTH : NAPLESS CLOTH (TEXMET 1000 OR EQUIVALENT)
???? ABRASIVE: 1 MICRON DIAMOND ABRASIVE
???? LUBRICANT : WATER LUBRICANT OR DIAMOND EXTENDER
???? PRESSURE : 5 PSI/MOUNT, 30 TO 60 SECONDS AT 150 RPM

3 : CLOTH : NAPLESS CLOTH (TEXMET 1000 OR EQUIVALENT)
???? ABRASIVE: COLLOIDAL SILICA
???? LUBRICANT : WATER LUBRICANT
???? PRESSURE : 5 PSI/MOUNT, 20 TO 40??SECONDS AT 150 RPM



Please help to review the process and advise what to do next.

[Gordon]

Hi Howied

Looking through your 9MB parameters

carrier Gas :Ar @ 7scfh

Is this really scfh? in which case I think 7 is too low. If it is NLPM then 7 is possibly a little too high.

2,and i guess my carrier is much less than Praxair recommendation:35 scfh.
However i did tried 35 scfh and it is too high to get powder to be center of flame.It is kind of too expended flame.terrible.

This setting is way off the mark, unless it refers to the old Metco flow meter settings (Metco units not scfh or nlpm) on 3/4MP type powder feeders which typically would be set around 37. This would equate roughly to about 5.5 nlpm or 12.5 scfh.

Looking at old parameters for Metco 68F may suggest lowering primary Ar gas flow to around 150.

Don't know about polishing procedures which is approved by GE-CCL or Metcet, but I like using unbacked silk clothes for diamond and finally Mastertex with colloidal silica. I found the old Texmet type clothes rather poor with most coatings, but most of my experience is with manual polishing rather than automated. Try impregnating coatings with epoxy resin prior to or during mounting (this does help a lot).

[Alexangel1226]

Howied,

Other than the anomaly pointed out by Gordon, pls look into your spray distance of 3.5" I guess that's a lil too short, that is why you have alot of unmelted particles.

Increase it to 4~4.5 and see how..as the atomization of particle is not optimum at this distance and increasing distance would increase the particle dwell time in the flame thus reduce unmelted particle.

Aleanagel1226

[howied]

Howied,

Other than the anomaly pointed out by Gordon, pls look into your spray distance of 3.5" I guess that's a lil too short, that is why you have alot of unmelted particles.

Increase it to 4~4.5 and see how..as the atomization of particle is not optimum at this distance and increasing distance would increase the particle dwell time in the flame thus reduce unmelted particle.

Aleanagel1226

Now my big problem is porosity and oxides.

I can not reduce porosity with every method i tried.Is there any one who has experience to reduse porosity.

Also oxides is problem.I tried to reduce stand off,however porosity is becoming higher than before,with the same level oxides.

I am not myself these days with testing T-800 coating.

[Gordon]

Hi Howied

Are we talking about oxide clusters or the normal well dispersed type? This is important as their formation mechanism I think are very different. Oxide clusters and associated porosity tend to go together.

[Alexangel1226]

Howied,

To understand more about forming of porosity we did discussed before, pls see advice from Gordon @ http://www.gordonengland.co.uk/sef/cause...t-215.html

And for oxide clusters formation @ http://www.gordonengland.co.uk/sef/about...tml#pid590

1. Look into the variable that causes porosity in abovementioned link, you should be able to find clue and try it out with a better understanding.

2. Oxide itself should be easier to tackle with...oxidation process takes place when the powder is dwell in the flame too long or at the much" hotter" flame condition. So, you can try either shorten the stand-off distance, you should be able to reach a optimum which give you a well balance between oxide level and unmelted particles limit.

3. Or you can try to increase the powder feedrate to allow more powder to bu melted and share the excessive heat load, so that the heat capacity can commensurate with the quantity of spray material in the atomizing flame...and give you a considerably goodoxide condition.

Hope it helps and all the best.

Regards,
alexangel1226

[bost123]

Your spray dist should be in hte 4.75 to 5.25 range for best results
ar flow of 150 and h2 flow of 15 and 85 volts and 500 amps 33 carrier flow and 33 grms powder should give you what your looking for on t800 oyeah 9mb 4mp system. it works for me for ge class A coating and class B.

K

Alex,

I've already tested coating with our new equipped 9MB gun.

Please find my parameter.
Nozzle:732,
Powder port:#2
Primary gas:Ar @ 167 scfh
Secondary Gas:H2 @15 scfh
carrier Gas :Ar @ 7scfh
Current:500A
Voltage:70 from plasma gun reading
Feedrate:@ 36 gram/min,
Spray distance(stand off):@ 3.5 inch
Surface speed:290ft/min=88m/min
Gun traverse speed(FANUC robot):13.3inch/min

The control system is called CITS,which is designed by Progressive Technologies.Inc,PTI for short,a small thermal spray equipment manufacturer,and powder feeder is his copied product,kind of TAFA sort,wheel disk powder feeder,closed-loop.

After polished,i found that the oxide is still highed than expected,and more unmelts and porosity.

1,I am not sure about my surface speed and traverse speed.

2,and i guess my carrier is much less than Praxair recommendation:35 scfh.
However i did tried 35 scfh and it is too high to get powder to be center of flame.It is kind of too expended flame.terrible.

3, any good polishing procedure for sharing which is approved by GE-CCL or Metcet.I tried two different method.
I am concerned ahout my metallographic preparation may have any bad effect on coating itself.

one is
1 : CLOTH : NAPLESS CLOTH (TEXMET 1000 OR EQUIVALENT)
ABRASIVE: 6 MICRON DIAMOND ABRASIVE
LUBRICANT : WATER LUBRICANT OR DIAMOND EXTENDER
PRESSURE : 5 PSI/MOUNT, 30 TO 60 SECONDS AT 150 RPM

2 : CLOTH : NAPLESS CLOTH (TEXMET 1000 OR EQUIVALENT)
ABRASIVE: 1 MICRON DIAMOND ABRASIVE
LUBRICANT : WATER LUBRICANT OR DIAMOND EXTENDER
PRESSURE : 5 PSI/MOUNT, 30 TO 60 SECONDS AT 150 RPM

3 : CLOTH : NAPLESS CLOTH (TEXMET 1000 OR EQUIVALENT)
ABRASIVE: COLLOIDAL SILICA
LUBRICANT : WATER LUBRICANT
PRESSURE : 5 PSI/MOUNT, 20 TO 40 SECONDS AT 150 RPM



Please help to review the process and advise what to do next.

[Gordon]

Hi Bost123

to the Surface Engineering Forum.

Hope you don't mind me editing your post. I was little confused who was saying what hope I got it right.

Your spray dist should be in hte 4.75 to 5.25 range for best results
ar flow of 150 and h2 flow of 15 and 85 volts and 500 amps 33 carrier flow and 33 grms powder should give you what your looking for on t800 oyeah 9mb 4mp system. it works for me for ge class A coating and class B.

K

Thanks for your input. I think those parameters sound about right (voltage seems a bit high though, more like 75V ? ) if applied directly to Metco 7MC/4MP systems running 9MB guns.


Hi All
I think we better make it clear that the parameters for the Metco 7M and 4MP type systems for the 9MB gun (Metco flow meter reading units, are not SCFH), are different to the 9MC and 9MP system which has different flow meter set-ups, so flow meter readings will require corrections. Howied's system may be different again, he quotes SCFH flows. I think we need to make sure that we all know strictly what flow units we are all taking about. When were sure of what the units are, it is a fairly simple matter of conversion of one type to another. (see https://www.gordonengland.co.uk/conversion/gasflow.htm and https://www.gordonengland.co.uk/conversion/pgcalc.htm).

Hi Howied, can you confirm that your flow meter readings are actually in SCFH. Are you using mass flow meters? in which case your SCFH readings are probably correct. If you are using flow meter tubes, then you need to be careful in case your readings need a correction factor to give true SCFH.

[howied]

Bost123,

could you please advise your flow unit,all scfh?i mean ar,h2,carrier gas.

The parameters my using is scfh only.actually there is no other setting of our console which allows me to set other than scfh.

and i found that my parameter spraying now is pretty much the same as yours,except spraying distance is shorter.cause the shorter the stand off is,the less oxides i will get.THat is why my spraying at 4 or even 3 inch.

My paremeter spraying now is following:

Gun Type 9MB
Nozzle GH
Powder port #2

Primary gas Ar 150scfh
Secondary H2 19 scfh
Current 500A
VOLTAGE 74V at gun
Gun mounted cooling Parallel 50 PSI
AUX cooling none
Carrier gas Ar 13.5 scfh
Powder feedrate 45 g/min
Stand off 4 inch
Test coupon holding fixture 10 inch diameter
Test coupon rotation speed 63 rpm
Surface speed 10X63X3.14/12=165 feet/min
Gun traverse speed-Robotic 15 inch/min
Gun traverse length 2.5 inch
Deposited rate per pass 0.0005 inch per pass


However even though I sprayed with 13.5 scfh of carrier gas, I am still not happy with this setting. Because 13.5 SCFH is so high that putting powder over shoot, away from center of flame.

Which I think is not right. The good spraying condition should get powder into the center of flame.right?

One more concern is after coating application; I found that the surface is not that clean enough. Looks like some powder or dust, I am not sure.

[/quote]
[quote=bost123]
Your spray dist should be in hte 4.75 to 5.25 range for best results
ar flow of 150 and h2 flow of 15 and 85 volts and 500 amps 33 carrier flow and 33 grms powder should give you what your looking for on t800 oyeah 9mb 4mp system. it works for me for ge class A coating and class B.

K

[howied]

Gordon,

alll parameters set up here are scfh,no flow meter readings.

So what is your advice now?

I am not sure about so many equipment as i havn't touch so many machines ever.Know few about this setting.However i do convert the carrier gas flow from 37 flow meter reading,i think, to 13.5 scfh.

Hi Bost123

to the Surface Engineering Forum.

Hope you don't mind me editing your post. I was little confused who was saying what hope I got it right.

Your spray dist should be in hte 4.75 to 5.25 range for best results
ar flow of 150 and h2 flow of 15 and 85 volts and 500 amps 33 carrier flow and 33 grms powder should give you what your looking for on t800 oyeah 9mb 4mp system. it works for me for ge class A coating and class B.

K

Thanks for your input. I think those parameters sound about right (voltage seems a bit high though, more like 75V ? ) if applied directly to Metco 7MC/4MP systems running 9MB guns.


Hi All
I think we better make it clear that the parameters for the Metco 7M and 4MP type systems for the 9MB gun (Metco flow meter reading units, are not SCFH), are different to the 9MC and 9MP system which has different flow meter set-ups, so flow meter readings will require corrections. Howied's system may be different again, he quotes SCFH flows. I think we need to make sure that we all know strictly what flow units we are all taking about. When were sure of what the units are, it is a fairly simple matter of conversion of one type to another. (see https://www.gordonengland.co.uk/conversion/gasflow.htm and https://www.gordonengland.co.uk/conversion/pgcalc.htm).

Hi Howied, can you confirm that your flow meter readings are actually in SCFH. Are you using mass flow meters? in which case your SCFH readings are probably correct. If you are using flow meter tubes, then you need to be careful in case your readings need a correction factor to give true SCFH.

[Gordon]

Hi Howied

First I will try to convert parameters supplied by Bost123:

Ar 150 MFR (Metco Flowmeter Reading) @100 psi = 167 SCFH
H2 15 MFR @ 50psi will roughly give 19.5 SCFH
Ar Carrier gas 33 MFR @100psi will roughly give 10.5 SCFH or @ 50 psi ~ 8 SCFH

Old Metco 68F-NS-1 parameters for 9MB gun using 7MC:

Ar - 150 MFR @100 psi = 167 SCFH
H2 - 10 MFR @ 50 psi ~ 13 SCFH
Ar Carrier gas - 37 MFR @100 psi ~ 12.5 SCFH or @ 50 psi ~ 9.5 SCFH

It is normal with the 9MB gun to get "target point deviation" sideways powder injection causes the spray stream to go slightly off axis and the argon swirl tends to slightly rotate the spray stream about the axis. So expect to something like a 5 degree deviation, this is normal. It is useful to view the powder injection close up (make sure you use a good welding visor), generally the spray stream will be at its brightest when the carrier gas is set right for any particular parameter set.

It looks as though there is scope for reducing the carrier flow a little. I would try the standard Metco 68F-NS parameters and may be even try Metco 68F-NS powder instead of the Praxair powder to see if that makes any difference.