Low DE of DJ2700
07-28-2008, 09:19 AM,
#1
Low DE of DJ2700
Dear Gordon and Forum, I am using Sulzer's DJ2700 to spray WC-10Co-4Cr, powder from WOKA. The problem is I had sprayed over 50 passes but still cannot see the coating grows its thinkness, the coating is still less than 0.2m. Could you tell by what parameters adjustment that I can make the DE higher? By: 1. Changing the propane or oxygen flow? 2. Changing the powder feeding rate? 3. Changing turntable's rotating speed(now its 120rpm)? 4. Or any else? Thank you in advance.
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07-28-2008, 01:56 PM,
#2
RE: Low DE of DJ2700
Hi Jeff,

0.2m? thats not badSmile I'm having a similar problem with Metco 450, I've got the correct power/voltage for the plasma but not getting the build up I'd expect.
As for turn table speed I've got a natty calculator which gives you the correct rotational speed and traverse rate for a given work piece diameter. I don't think its proprietary so I can post it if Gordon doesn't mind?
Jim
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07-28-2008, 04:46 PM,
#3
RE: Low DE of DJ2700
Hi Jeffsays163

Which Woka grade powder are you using? Some of the Woka WC-10Co-4Cr HVOF grade powders may not be give optimal performance through DJ2700, while being good for say liquid fuel systems like WokaStar or JP5000. If in fact the Woka powder is recommended for DJ use, I would still consider comparing to Diamalloy powders. Cheaper powders do not always mean cheaper coatings (is Woka still cheaper than Diamalloy?)

Have you conducted any deposit efficiency tests? Stating 50 passes to give 0.2m? (is that 0.2mm) really is not telling us much, as we would really need to know spray rate, part size, speeds and feeds to get an idea of your deposition rate. Actually, 4 microns of coating per pass sounds good, but it does not indicate whether it is efficient.

I will wait for your reply, before thinking about parameter changes.

Hi Jim

Metco 450 usually has very good deposit efficiency ~80-90% if memory serves me right. May be you could provide us with more info on your problem.

The calculator sounds great. If there are no copyright issues, please post.

I am actually trying to do a thermal spray calculator at the moment, but the programming side of it is very complex and has gone well well past my capabilities. My daughter, bless her, is going to write the program. So not sure when this will see the light of day though Happy0193.
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07-29-2008, 06:26 AM, (This post was last modified: 07-29-2008, 07:56 AM by jeffsays163.)
#4
RE: Low DE of DJ2700
Hi, Gordon, Thank you very much for your time. I am using Woka3653 powder, its now more expensive than Diamalloy 5847, as it's in Euro; the spray rate was follwoing Sulzer's recommendation 5lb/hour, grain size is -45 +11 (recommended for DJ2700), the turn table rotation is 120r/m, gun goes with robot is 3-4mm/second. The part is like a big ring, 400mm distance of centers of circles, flat surface.

I am new with real coating operation, maybe it's as you said 4microns per pass is normal?

Looking forward your calculator too!
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08-05-2008, 10:33 AM,
#5
RE: Low DE of DJ2700
Hi Jeffsays163

Looking at your parameters I feel that it is probably about right. To be sure you will need to do a deposit efficiency test though. Your deposit rate per pass is ideal for this material, so I would not change this part. Big Grin
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08-05-2008, 10:40 AM,
#6
RE: Low DE of DJ2700
Hi Jim

TurbineRepair Wrote:As for turn table speed I've got a natty calculator which gives you the correct rotational speed and traverse rate for a given work piece diameter. I don't think its proprietary so I can post it if Gordon doesn't mind?
Jim

Thank you so much for the calculator Jim. I have made it available for download in a new thread:

rpm-traverse-calculator-for-thermal-spray-t-575.html

Cheers
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08-05-2008, 01:09 PM, (This post was last modified: 08-06-2008, 03:08 PM by plasmajet1990.)
#7
RE: Low DE of DJ2700
jeffsays163 Wrote:Hi, Gordon, Thank you very much for your time. I am using Woka3653 powder, its now more expensive than Diamalloy 5847, as it's in Euro; the spray rate was follwoing Sulzer's recommendation 5lb/hour, grain size is -45 +11 (recommended for DJ2700), the turn table rotation is 120r/m, gun goes with robot is 3-4mm/second. The part is like a big ring, 400mm distance of centers of circles, flat surface.

I am new with real coating operation, maybe it's as you said 4microns per pass is normal?

Looking forward your calculator too!

Hi,

The grain size <25 um is very good, < 30 um is good, =,>45 um is not so good.

Kind regards,
Ion
Reply
08-05-2008, 05:19 PM,
#8
RE: Low DE of DJ2700
Hi All

Quote:Hi,

The grain size -25 um is very good, -30 um is good, -45 um is not good.

Kind regards,
Ion

Woka 3652 WC/10Co4Cr -45+15 Recommended for JP5000, HV2000, TopGun

Woka 3653 WC/10Co4Cr -45+11 Recommended for DJ hybrid

Woka 3654 WC/10Co4Cr -30+10 Recommended for Thermico CJS

Source Sulzer Metco Materials Guide. So according to that jeffsays163 is using the correct Woka powder.

Problem is -45+11 tells us a size range, it does not tell us what the distribution is (the important information). It could be mostly composed of say 40um sized particles or maybe 15um or more probably somewhere in between Question So from an average particle size I would tend to agree with Ion. But, possibly Woka 3653 average particle size may be 25um or not Happy0193
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