Optimum Travers speed

[Metallurgy_eng]

Hi Gordon,

Acceleration: 4,0 m/s2
Scan: 4 mm
Surface speed: 60 m/min = 1,0 m/s
6 Layer 77 μm

Powder Feed 40 gr/min

This is our reccomended spray parameter.

For a flat surface what do you think about optimum travers speed. -x,+x and -y,+y

[Gordon]

Hi Metallurgy_eng

Depends on spray material and process. Assuming you are using HVOF and carbide based powders, I would use the fastest possible speeds within sensible capability of your handling equipment for doing ladder scans.

13 μm per pass seems fair for ladder scan. 5 μm per pass I consider optimum, so you are not far away

[Metallurgy_eng]

What is meant by acceleation? (4mm/s2)

5 micron is to difficult to make per pas May be we have to down to the powder feeder dick rotation speed and Carrier gas. I think this recomended parameter is for cylinder surfacees. You say if I coat flat surface, I must as high as travers speed up and down to the coating deposition. Am I correct understand?

And last thing, What do you think about coating thickness tampering with it for WC Co for HVOF topgun c2h2? What do you think we can get so thick surface? Can I up to 1 mm thickness

[Simon Kim]

In my experience, stacking deposited thin layers have high impact resistance than thick layers with same thickness.
Because thin layers are more dense microstructure.

Simon

[Gordon]

Hi Metallurgy_eng

Quote:You say if I coat flat surface, I must as high as travers speed up and down to the coating deposition. Am I correct understand?

Yes, mainly because this technique is somewhat limited in generating high surface speeds compared to traversing a rotating component. Which brings me to answer

Quote:What is meant by acceleation? (4mm/s2)

With ladder scans it is necessary for the gun to reverse direction every pass. So it needs to slow down to a stop and accelerate again. High accelerations are needed (I think you mean 4m/s2) to get the gun up to spraying speed in the shortest distance/time possible.

Quote:And last thing, What do you think about coating thickness tampering with it for WC Co for HVOF topgun c2h2? What do you think we can get so thick surface? Can I up to 1 mm thickness

With your system I am unsure. It is also dependant on factors other than specific equipment, like specific powder, parameters and technique. You also need to appreciate that in the majority of cases there is little point to using 1mm + thick TS coatings unless of course if you are restoring dimensions. In this case often a low stress and high thickness tolerant base coating can be used to make up most of the thickness and be topped off with an optimal thickness of WC/Co.