10-10-2012, 10:35 AM,
|
|
sreenuvundela
Senior Member
![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png)
|
Posts: 76
Threads: 14
Joined: Aug 2011
Reputation:
1
| |
RE: Request for solution to reduce porosity in HVOF Tungsten Carbide Coatings
(10-09-2012, 05:56 PM)Spraytube Wrote: Hi ,
Assuming that you have checked your system, you could work on powder,
several factor could help you to reach the 1% :
Particle size distribution : use the narrowest distribution
Apparent density of the powder, I'm still surprising that this data is missing on several powder provider datasheet.
Primary carbide size included in your agglomerated and sintered powder
If you give more detail, it would be easier to help you.
Regards
Sir,
Thank you for your reply
Kindly forward the problems in HVOF GUN also which will be cause more porosity in coatings.
Kindly do the needful
Regards,
SREENVIAS
|
|
05-12-2017, 06:11 PM,
|
|
mmgerrie
Active Member
![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png)
|
Posts: 12
Threads: 2
Joined: Nov 2015
Reputation:
0
| |
RE: Request for solution to reduce porosity in HVOF Tungsten Carbide Coatings
(10-10-2012, 10:35 AM)sreenuvundela Wrote: (10-09-2012, 05:56 PM)Spraytube Wrote: Hi ,
Assuming that you have checked your system, you could work on powder,
several factor could help you to reach the 1% :
Particle size distribution : use the narrowest distribution
Apparent density of the powder, I'm still surprising that this data is missing on several powder provider datasheet.
Primary carbide size included in your agglomerated and sintered powder
If you give more detail, it would be easier to help you.
Regards
Sir,
Thank you for your reply
Kindly forward the problems in HVOF GUN also which will be cause more porosity in coatings.
Kindly do the needful
Regards,
SREENVIAS
Porosity is typically caused by the flame being too cold. One thing you can try is to increase your O2 & H2 flows to achieve a hotter flame. There will be a balancing act between oxides and porosity, but when you get the parameters set right you should be able to achieve what you're looking for.
Mike
|
|
05-22-2017, 11:12 AM,
|
|
Nesher
Active Member
![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png)
|
Posts: 24
Threads: 3
Joined: Oct 2016
Reputation:
1
| |
RE: Request for solution to reduce porosity in HVOF Tungsten Carbide Coatings
(10-09-2012, 01:00 PM)sreenuvundela Wrote: Dear Friends,
We are having Flame Spray Technologies make HVOF Spray Gun and when we depositing WC - Co Coatings with this gun, we are achieving porosity in the range of 2 to 2.5 % which is not acceptable for most of the customers.
The porosity should be less than 1%
Kindly suggest the factors which are affecting for higher porosity levels.
Regards,
SREENIVAS
Dear Sir
We strongly advise buyers of our equipment to pass the powder through a sieve, dry the powder before use and use a freezer to reduce moisture in the air.
90% of the quality of the coating depends on the quality of the powder.
Best Regards
A.Termika Ltd
|
|
05-23-2017, 06:46 PM,
|
|
loriolo
SuperMember
![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png) ![*](images/star.png)
|
Posts: 310
Threads: 1
Joined: Jan 2010
Reputation:
4
| |
RE: Request for solution to reduce porosity in HVOF Tungsten Carbide Coatings
Hi Sreenivas
For me isn't clear what is your problem, is necessary to know the equipment, parameters and gun you are using, because surely there is something wrong in your equipment or parameters, With serious HVOF system and a good parameters set, you must have porosity under 1%, even with HVCW 1000 (HVOF wire), you can have porosity under 1%, so if you really need help with coatings, you must share parameters, and equipment, in order to have the correct solution to your problem, otherwise we are loosing time.
Best regards
Luigi
|
|
|