If using H/O2, do they both use about the same scfh? I have seen 1350 scfh(H) and 450 scfh(O2) as typical.

Also, do they both have about equal DE%? (using wc-co-cr)

trying to figure out the best hvof gun.

Hi Jim

Sorry, not that familar with the JKote (assume you mean Deloro Stellite Jet Kote system) to answer your question. Sulzer Metco DJ2700 setup is primarily for propane, propylene type fuel gases and I assume you mean DJ2600 for hydrogen fuel. Hopefully, someone with gas usage data for Jet Kote will help. The gas flow figures you quote are roughly inline with the DJ system.

Deposit efficiency (DE%) will also be very dependent on the exact (WC-Co-Cr) powder grade used, so be careful comparing DE. One system may show better results with one powder, but results may reverse for a different powder. It depends on what process/equipment the powder has been optimised for.

Gordon,
Thanks for the reply.

Yes, I did mean the Stellite JK and the DJ2600.

If the powder is a "fine" WC (30/5 grain size) should I not get about the same results from either the JK or DJ? Both using H/O2.

Also, does the smaller/finer grain size translate into a higher DE%?

If the grain size is "coarse" what parameters are changed versus having a fine grain setup?

thanks again
Jim

Hi Jim

Quote:If the powder is a "fine" WC (30/5 grain size) should I not get about the same results from either the JK or DJ? Both using H/O2.

Sorry, don't know the answer to that one. For best results with DJ a coarser but narrower distribution would be better (~+38-15).

Quote:Also, does the smaller/finer grain size translate into a higher DE%?

No, I don't think so. The best DE's will be from powder optimised for the particular process.

Quote:If the grain size is "coarse" what parameters are changed versus having a fine grain set-up?

Generally coarse powders will require more heat, longer dwell time in flame than finer powders
Any particular HVOF set-up will tend to be quite limited to a small range of powder particle sizes it can handle to produce the very best coatings and good DE's (though best DE's and best quality don't always happen together ). Changing parameters like gas flows and ratios will only take you a little way, changing hardware like nozzles, barrels, air caps etc. (depending on your system) and/or fuel gas is more flexible. The point is that its best to get the best powder for the equipment rather than the best equipment for the powder

I remember doing tests on two WC/CoCr powders of the same composition but one coarse the other fine using the early air cooled DJ (1) using propylene and the early DJ hybrid (2) using hydrogen. Results for coarse powder were ok though slightly porous for (1) and excellent for (2). The fine powder gave good results for (1) but very poor for (2)
giving a very dense brittle coating with few WC carbides retained. If memory serves me right the coarse powder through the air cooled DJ won on DE (don't quote me on that though )

Comments from anyone with experience of the Jet Kote are more than welcomed