Silvaloy 13 parameter.

[shabisyed]

Hi Gordon,

Could you give me a parameter for spraying Silvaloy 13 (GE Spec. B20A4).
Compositon of this wire is 30Ag,38Cu,32Zn and its 1/8 inc. in dia.
We are using metco 14E gun.please also let me know Aircap and wire feeding for this wire.
I would be very thankful to you.
Shabi.

[Gordon]

Hi Shabi

I don't know of any specific parameters for that material. I can only suggest using the standard recommended parameters for 1/8" copper wire as a starting point.

[shabisyed]

Hi Gordon,
I used copper wire parameter.But I got oxide and separation.
Could you tell me how can I minimize the oxide and separation.
Shabi.

[aioa]

Hi Shabi,
can you tell me which parameters exactly you used for copper because i try lots of them and i found many differences at coating's characteristics, when i changed the ratio acetylene/oxide and the spray distance. Maybe i can help you.

Regards..

[Gordon]

Hi Shabi

I used copper wire parameter.But I got oxide and separation.
Could you tell me how can I minimize the oxide and separation.

Oxide and coating separation problems may well have different causes and may not be connected.

Coating separation may be linked to substrate preparation, spraying technique, coating thickness, temperature control. So, look at improving cleaning and grit blasting of substrate and application technique/temperature control.

Oxide will be effected by oxygen/fuel ratio and flows, wire feed rate (length of wire tip in flame) and air cap/atomising air flow. So, reducing oxygen in flame, using longer visible wire tip in flame (higher feed rates), keep spray distance normal ie excessive spray distance will increase oxide.

[shabisyed]

Hi GOrdon,

My parameter for Braze 300 Wire is given below (Silveraloy 13).

Oxygen Flow= 43
Acteleyne Flow= 40
Oxygen Pressure= 35psi
Fuel pressure= 15 psi.
Distance=5 to 6 inches.
Wire speed is 3 inches per 5 sec.
CH nozzle i am using.
Test piece temperature during spray 200 F.
Test piece material 5504 Steel.
But I am getting oxide and separation.Plz let me know how can I reduce oxide and separation.
I am using same parameter for Sprabronze AA on 4026 Aluminum Alloy and getting also Oxide and separation.
I also reduce the oxygen flow to 42 Cfh but I couldnt fix the problem.
Hope you will reply me soon
Regard,
Shabi.
;

[Gordon]

Hi Shabi

My parameter for Braze 300 Wire is given below (Silveraloy 13).

Oxygen Flow= 43
Acteleyne Flow= 40
Oxygen Pressure= 35psi
Fuel pressure= 15 psi.
Distance=5 to 6 inches.
Wire speed is 3 inches per 5 sec.
CH nozzle i am using.
Test piece temperature during spray 200 F.
Test piece material 5504 Steel.
But I am getting oxide and separation.Plz let me know how can I reduce oxide and separation.
I am using same parameter for Sprabronze AA on 4026 Aluminum Alloy and getting also Oxide and separation.
I also reduce the oxygen flow to 42 Cfh but I couldnt fix the problem.

First thing I notice from your parameters is that you are using a "CH" air cap. This is a non-load nozzle primarily for use with zinc and very low melting point alloys to reduce nozzle/air cap fouling during repetitive stop-start operation. Use the "EC" air cap with the standard 14E 7-48 ( NOT 14E-7-26) for 1/8" wire if you are not already using this nozzle.

I would cut oxygen pressure back to 30 psi and set to flow of 44. Set wire speed to give ~10 - 20 mm of solid wire tip extension (point which wire melts off) beyond air cap and aim for a smooth sharp melting tip. Adjustment of wire tip length may effect coating texture and quality, so adjust to give desired qualities. Aim to get a "good quality" coating ie one that does not separate first, before worrying about oxide content. Little point having low oxide if coating does not stick.

Good luck

[shabisyed]

Hi GOrdon,
Could you tell me in detail,What do you mean by set wire speed 10 to 20mm of solid wire tip extension beyond aircap.
Does it mean during spraying wire suppose to out of aircap almost 10 to 20mm.Actually I am using wire speed 3 inches per 5 sec.
Thanks,
Regard.
SHabi.

---

Hi Aioa,
Actually I am using copper parameter for Silvaloy 13 Wire(Braze300).SOme time i got good result but some time I get oxide and separation.I am using Metco 14E gun.
My parameters is
Oxygen=43 CFH
Acetelyene= 40 Cfh
Oxygen Pressure=35
Acetelyene=15
Distance=5 to 6 inches.
Aircap= CH
Wire speed=3 inches per 5 sec.
those are my parameters.
Plz let me know your parameters.
and also give me reason of separation and how can I reduce oxide,
Regard,
Shabi

Hi Shabi,
can you tell me which parameters exactly you used for copper because i try lots of them and i found many differences at coating's characteristics, when i changed the ratio acetylene/oxide and the spray distance. Maybe i can help you.

Regards..

[Gordon]

Hi Shabi

Could you tell me in detail,What do you mean by set wire speed 10 to 20mm of solid wire tip extension beyond aircap.
Does it mean during spraying wire suppose to out of aircap almost 10 to 20mm.Actually I am using wire speed 3 inches per 5 sec.

The length of the wire tip that you see extending into the flame before melting off is directly connected to the wire speed that you select for specific combustion parameters. Higher wire feed rates give longer wire tip. The position of the wire tip in the flame will effect the way the wire melts and atomises, effecting quality of coating.

[aioa]

Hi Shabi,
My parameters for copper are:
Acetylene: 35slpm/15psi
Oxygen: 45slpm/35psi
Air: 74slpm/55psi
Spray distance: 100mm
Air cup: EC
Nozzle: 14E 7-48
Gun sweep speed: 500mm/sec
Sweep step: 6mm
Before you spray try to clean your substrate with ultrasound technique if you can. You will minimize the possibility of seperation..

Regards..
AioA

[Gordon]

Hi Shabi and Aioa

I'm a little concerned about possible confusion arising from the use or misuse of flow measurement units.

First, Shabi quotes numerical flows only which I interpret as being Metco 2GF flow meter readings.

Second, Shabi quotes CFM readings, which are not necessarily the same as Metco 2GF flow meter readings.

Third, Aioa quotes slpm possibly from different flow meter set-up. slpm not easily converted for use on say 2GF flow meter, which I suspect Shabi may be using.

I think we need to be very specific about how we obtain these flow meter readings, otherwise they are pretty much meaningless, except perhaps for the person that quoted them.

[shabisyed]

Hi Gordon,
Could you tell me indetail how the lenght of wire tip effect the coating.I means if its small what happen with coating and if its big i.e 20mm what happen with coating.I sprayed yesterday one test coupon for Sprabronze AA with very sharp wire tip with EC aircap but I got oxide and some hole in coating by 200X magnification.I used same parameter which metco 14E books says.
regard,
Shabi

Hi Shabi

Could you tell me in detail,What do you mean by set wire speed 10 to 20mm of solid wire tip extension beyond aircap.
Does it mean during spraying wire suppose to out of aircap almost 10 to 20mm.Actually I am using wire speed 3 inches per 5 sec.

The length of the wire tip that you see extending into the flame before melting off is directly connected to the wire speed that you select for specific combustion parameters. Higher wire feed rates give longer wire tip. The position of the wire tip in the flame will effect the way the wire melts and atomises, effecting quality of coating.

[aioa]

Third, Aioa quotes slpm possibly from different flow meter set-up. slpm not easily converted for use on say 2GF flow meter, which I suspect Shabi may be using.

I think we need to be very specific about how we obtain these flow meter readings, otherwise they are pretty much meaningless, except perhaps for the person that quoted them.

Hi Gordon,
I use Metco 2GF and 3AF flowmeters.As for wroted slpm is my mistake and sorry for that, it will not happen again. (the result of doing too many thinks at the same time..)

[Gordon]

Hi Shabi

Hi Gordon,
Could you tell me indetail how the lenght of wire tip effect the coating.I means if its small what happen with coating and if its big i.e 20mm what happen with coating.I sprayed yesterday one test coupon for Sprabronze AA with very sharp wire tip with EC aircap but I got oxide and some hole in coating by 200X magnification.I used same parameter which metco 14E books says.
regard,
Shabi

Generally the tendency is for shorter wire tips to produce more oxide and longer tips less. Porosity, particle splat size/shape, bonding and surface texture will also probably be effected by excessively short or long wire tips.

Many years ago I sprayed and evaluated 13Cr steel (Metcoloy 2) coatings with varying parameters with the Metco 12E gun. Below are a few illustrating effect of wire tip length. Forgive quality they are 30 year old polariod photos.

   

Metcoloy 2 coating sprayed with standard parameters.
Hardness 29 HR45N (28 HRC equiv)

   

Metcoloy 2 coating sprayed with standard parameters except for very short wire tip length/low spray rate (only just extending air cap).
Hardness 43 HR45N (40 HRC equiv)
Note higher oxide content

   

Metcoloy 2 coating sprayed with standard parameters except for very long wire tip length/high spray rate (~ 25 mm)
Hardness 23 HR45N (23 HRC equiv)
Note higher porosity and lower oxide content.

My advice would be to do your own evaluation with your specific coatings. Different materials may yield different results. You could also include tests on effect of different gas flows/mix, spray distance etc. Nothing better for learning and getting a "good feel" about the process, than doing it yourself. Call it a DIY training course

[shabisyed]

Hi,
Now I have a porblem to spray Sprabronze AA wire by Metco 14E Gun.I got my metallographic test pass from Lab.but on ENgine Gearbox I sprayed the same coating but I am getting a porosity after machining.I am following the 14E book parameters.Plz let me know how can I get rid of porosity from SprabronzeAA.
Shabi/.

Hi Shabi

Hi Gordon,
Could you tell me indetail how the lenght of wire tip effect the coating.I means if its small what happen with coating and if its big i.e 20mm what happen with coating.I sprayed yesterday one test coupon for Sprabronze AA with very sharp wire tip with EC aircap but I got oxide and some hole in coating by 200X magnification.I used same parameter which metco 14E books says.
regard,
Shabi

Generally the tendency is for shorter wire tips to produce more oxide and longer tips less. Porosity, particle splat size/shape, bonding and surface texture will also probably be effected by excessively short or long wire tips.

Many years ago I sprayed and evaluated 13Cr steel (Metcoloy 2) coatings with varying parameters with the Metco 12E gun. Below are a few illustrating effect of wire tip length. Forgive quality they are 30 year old polariod photos.



Metcoloy 2 coating sprayed with standard parameters.
Hardness 29 HR45N (28 HRC equiv)



Metcoloy 2 coating sprayed with standard parameters except for very short wire tip length/low spray rate (only just extending air cap).
Hardness 43 HR45N (40 HRC equiv)
Note higher oxide content



Metcoloy 2 coating sprayed with standard parameters except for very long wire tip length/high spray rate (~ 25 mm)
Hardness 23 HR45N (23 HRC equiv)
Note higher porosity and lower oxide content.

My advice would be to do your own evaluation with your specific coatings. Different materials may yield different results. You could also include tests on effect of different gas flows/mix, spray distance etc. Nothing better for learning and getting a "good feel" about the process, than doing it yourself. Call it a DIY training course

[LEN WOOD]

Shabi,
Are you sure it's the coating and not the machinist?

[shabisyed]

Actually my superviser told me its coating fault not machinist fault.Could you tell me how can I controll the porosity in coating.How does the machining effect on coating?

[Gordon]

Hi Shabi

How does the machining effect on coating?

Machining will effect surface finish and appearance. Poor machining may give rise to a false perception of high porosity/poor coating.

I got my metallographic test pass from Lab.but on ENgine Gearbox I sprayed the same coating but I am getting a porosity after machining.

First, all coatings will have some degree of porosity. Machining should not alter the porosity content of your coating, though it can cause surface pluck-outs that can make it appear more porous. How is the porosity after machining being judged? If your coatings are the same as the metallographic test then there should be no problem with the coating.

Could you tell me how can I controll the porosity in coating

When you have established good coatings/parameters, then its down to repeating these process parameters accurately and consistently. Is the gun handling automated or are you manually hand spraying?

[shabisyed]

Hi Gordon,

I am doing a manually coating.Plz let me know how can I controll porosity when I spray manually.
Thanks.
Shabi

Hi Shabi

How does the machining effect on coating?

Machining will effect surface finish and appearance. Poor machining may give rise to a false perception of high porosity/poor coating.

I got my metallographic test pass from Lab.but on ENgine Gearbox I sprayed the same coating but I am getting a porosity after machining.

First, all coatings will have some degree of porosity. Machining should not alter the porosity content of your coating, though it can cause surface pluck-outs that can make it appear more porous. How is the porosity after machining being judged? If your coatings are the same as the metallographic test then there should be no problem with the coating.

Could you tell me how can I controll the porosity in coating

When you have established good coatings/parameters, then its down to repeating these process parameters accurately and consistently. Is the gun handling automated or are you manually hand spraying?

[Gordon]

Hi Shabi

I am doing a manually coating.Plz let me know how can I controll porosity when I spray manually.

If your gun is set-up with good parameters, that leaves you controlling gun motion, spray distance and time spraying, all important parameters. So its down to you to develop the skill/experience and to be able to apply this consistently. Hand spraying is a skill and requires a lot of practice for most people.