problems spraying metco 320NS with F4 gun
01-08-2009, 11:34 AM,
problems spraying metco 320NS with F4 gun
Hi guys,

we have recently started spraying metco 320NS and are having major problems with it.

Hardly any powder adheres to the workpiece.
Most of the powder bounces back and builds up VERY RAPIDLY on the front of the gun.

I don't have the parameters we are using to hand at the moment but I will post them up later.

Does anyone else have any experience with this powder?


01-08-2009, 04:22 PM,
RE: problems spraying metco 320NS with F4 gun
Hi Sam

Sign0016 to the Surface Engineering Forum.

Sorry, no practical experience with Metco 320NS through F4 gun. It would help to know set-up and parameters (Sulzer Metco recommended parameters or other?) used.

If your deposit efficiency is very poor as it sounds from your description, it would seem as though your powder particles are not being heated enough. This could be influenced by a number of parameter settings (gas flows, power, feed rate, spray distance etc.). If you are using equipment in good condition and parameters recommended by Sulzer Metco you should not really be having this problem. Not saying necessarily that SM parameters are optimal or best for your application, but a good starting point for a fairly balanced coating (coating quality and efficiency).

Anybody with 320NS/F4 experience? your comments would be appreciated Smile
01-08-2009, 11:47 PM,
RE: problems spraying metco 320NS with F4 gun
Hi Gordon,

I did write down the paramaters we are using in work earlier but unfortunately i neglected to bring them home. the ones I can remember though:

F4MB gun with 8mm nozzle.
2mm powder injector set 6mm away from the nozzle at an angle of 90 degrees.
Spray distance of 125mm.
Powder feed rate 40g/min
601 suction piece/spreader
Carrier gas Ar 2.8slpm

can't really remember the flow rates for the hydrogen and argon for the gun though. doh.

We also have a 3MB gun although we have not tried it with 320, anybody have any experience spraying 320NS with one of these?
01-13-2009, 11:52 AM,
RE: problems spraying metco 320NS with F4 gun
Dear Aerosam,

Do you have the data sheet that SM released at the ITSC last year on the 320NS. It only mentions a few parameters but one difference was a 6mm nozzle. Also the only bond strength they mention was over a 450NS bond coat. I assume you are using this?

01-13-2009, 04:39 PM,
RE: problems spraying metco 320NS with F4 gun
Hi Adam, thanks for your reply.

The specs we recieved from SM stated an 8mm nozzle was required. We did try a 6mm but the lab found we had a serious issue with undermelts.

We have done some experimenting with it and have found adjusting the injector angle to 105 degrees has significantly improved things.
02-24-2009, 10:58 PM,
RE: problems spraying metco 320NS with F4 gun

you should try those :

Noozle [mm] : 6 (std)
Injector Diameter [mm] : 1,8
Injector Angle [�]: 90
Injector Distance [mm] :6

Current [A] : 600
Ar [slpm] : 47
H2 [slpm] : 6,5

Spreader / Suction piece : L/L
Powder carrier Gas [slpm] : 4
Rate [g/min] : 50
Stirrer speed : 60

Spray distance[mm] : 125
Translation speed [mm/min] : 75
Step [mm/pass] : 4

(Deposition efficiency [%] 70 Toungue)



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