feed screw reinforcing
08-19-2009, 06:10 AM,
#1
feed screw reinforcing
Hello,
I am looking for suggestions how to increase durability of feed screw which work in very abrasive environment - fine cut wood with ground impurities. I see two ways here one is HVOF -WC-12Co and another spray fuse NiCrBSiWC coating. But both of them have their advantages and disadvantages.
Thank You
Arturas


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08-19-2009, 09:10 PM,
#2
RE: feed screw reinforcing
We spray these feed screws for one of our customers. We use 86WC-10Co-4Cr, and it works over 1 year moving fly ash. I like 86WC-10Co-4Cr better than 88WC-12Co because, in my experience, it provides better wear resistance, and is easier to apply. I don't like spray and fuse because it introduces an extra complicated step which can lead to part deformation. Stick with a carbide coating. You will be glad you did.
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08-20-2009, 03:46 AM,
#3
RE: feed screw reinforcing
Arturas, interesting question, one we face on a daily basis. Obviously you understand well the pluses and minuses of each process, so I will not go into that. In my experience, the process selected for this application (maybe a MDF feedscrew), will depend on the end user operational controls. Meaning, if the end user, the customer, will operate the screw in more or less constant condition, with little foreign material like rocks, gravel, or overloading the screw, then I think a Thermal Spay Coating, liike the 861004 would be excellent, and so much easier to apply.

However, if the customer cannot guarantee the operation of the screw, then I would use the spray fuse coating, or plasma welding, or laser cladding. In some cases we even use the Corded WC brazing material coupled with a spray fuse, trying to match up the WC size to the abrasive particle.
Stephen James Booth
www.ipsteknokraft.com
www.teknokraft.com
Indonesia WhatsApp +6281905603262

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08-20-2009, 07:57 AM, (This post was last modified: 08-20-2009, 07:58 AM by Arturas.)
#4
RE: feed screw reinforcing
(08-20-2009, 03:46 AM)Stephen Booth Wrote: Arturas, interesting question, one we face on a daily basis. Obviously you understand well the pluses and minuses of each process, so I will not go into that. In my experience, the process selected for this application (maybe a MDF feedscrew), will depend on the end user operational controls. Meaning, if the end user, the customer, will operate the screw in more or less constant condition, with little foreign material like rocks, gravel, or overloading the screw, then I think a Thermal Spay Coating, liike the 861004 would be excellent, and so much easier to apply.

However, if the customer cannot guarantee the operation of the screw, then I would use the spray fuse coating, or plasma welding, or laser cladding. In some cases we even use the Corded WC brazing material coupled with a spray fuse, trying to match up the WC size to the abrasive particle.
[/q[/u]
[quote='Stephen Booth' pid='3772' dateline='1250736414']
Arturas, interesting question, one we face on a daily basis. Obviously you understand well the pluses and minuses of each process, so I will not go into that. In my experience, the process selected for this application (maybe a MDF feedscrew), will depend on the end user operational controls. Meaning, if the end user, the customer, will operate the screw in more or less constant condition, with little foreign material like rocks, gravel, or overloading the screw, then I think a Thermal Spay Coating, liike the 861004 would be excellent, and so much easier to apply.

However, if the customer cannot guarantee the operation of the screw, then I would use the spray fuse coating, or plasma welding, or laser cladding. In some cases we even use the Corded WC brazing material coupled with a spray fuse, trying to match up the WC size to the abrasive particle.

uote]

As I see both coating could work. I asked customer about quantity of gravel in wood cutting. It takes about 1% , but also there is very big pressure to screw and abrasive wear fully dominate here. Sad
I dont know what is better - to spray WCCrCo more easier and it will take less time but I am affraid due to coating spalling but at the same time to fuse coating on such screw with torches also is very complicate job (deformation and etc.)
If I spray WCCrCo what should be the thickness of coating ?
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08-20-2009, 01:44 PM,
#5
RE: feed screw reinforcing
The coating should be as thick as the customer is willing to pay for. I would like to see 250 um of coating thickness here, but half of that would be the minimum acceptable thickness for trial.
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08-22-2009, 04:40 PM,
#6
RE: feed screw reinforcing
Hi,
For woodcutting with around 1%gravel TC spray coating should be good enough.In severe abrasive condition PTA or Laser coating of HSS+TiC has been found to have long life.For details you can refer to my book on 'advanced thermally assisted surface engineering processes'
ram chattopadhyay
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