How to Fuse a NiCrbSi (16C) in a oven?

[Joris Kraak]

Dear members,

Does anyone has experience on how to fuse a self fluxing NiCrbSi material (16C) succesfully in a oven? The coating we have applied onto the Capstan (wire drawing) is a HVOF sprayed coating and has a total thickness of 400 microns. The base material is a C45 steel.

The reason why I need to use a oven is because with Oxy/Acetylene torches I can't put enough heat into the part. Moreover there is a difference in thermal expansion between the upper part of the ring and the lower part. It is very difficult to heat the part equally and causes some cracking, for this reason I want to try the oven.

I have read something about Vacuum ovens but I guess it should be possible in a normal atmosphere oven as well. Any tips or heating curves TTT are highly appreciated.

[Stephen Booth]

Hi Joris, any discoveries on this?

A few years ago, one of my customers was making some wear components for Wood Debarking Machine. They were basically clueless on the Thermal Spray and Fusing Process. They just cleaned the substrate, sprayed with a normal powder flame torch, then put it in an oven.

The parts were relatively massive, 150 mm thick and about 1500 mm x 700 mm

they seem to have a good result,

how about you..

[shantanu]

Hi Joris, any discoveries on this?

A few years ago, one of my customers was making some wear components for Wood Debarking Machine. They were basically clueless on the Thermal Spray and Fusing Process. They just cleaned the substrate, sprayed with a normal powder flame torch, then put it in an oven.

The parts were relatively massive, 150 mm thick and about 1500 mm x 700 mm

they seem to have a good result,

how about you..

WOW!!

This may just be a co incidence but we are actually processing the same material- a huge 2200 mm dia wire drawing capstan with the same questions in mind!!!

Frankly I thought it would easier to weld using MIG with TC electrodes rather than spray NiCrBSi and fusing it in an oven...

Also these capstans-if we are talking about the same part, undergo huge impact load which I think welding would be able to tolerate better than a fused coating.....

Regards

Shantanu

[sreenuvundela]

Hi friends,

I am also in similar confusion.

Kindly share your thoughts in finding solution for the components (capstans etc) used in wet wire drawing industry.

The tungsten carbide coated with HVOF capstans are not performing up to the expectations.

I am also thinking either spray & Fuse (or) carbide deposition by welding may work for these applications.

Kindly share your experience in finding the optimum solution.


Regards,

SREENIVAS

[Stephen Booth]

Hi Sreeni

Just a couple of thoughts:

a) I once many years back visited a very large work shop in Asia, specializing in Thermal Spray, that had one area set up for Large Capstans. They placed the capstan on a large turntable, and built a fire brick oven enclosure around the capstan and turntable.

Through openings in the enclosure they used several large burners mounted on stands to do the preheat, and post heat.

One hand held man operated torch was used for fusing.

I supposed they used a NiCrBSi material.

I think it was too much work.

b) PTA would be good, but the substrate is often challenging to weld

c) Wire Flame spray has been good for some people using a Piano wire, with 1.2 percent carbon. not easy to find but you can. Seems its hard, cheap, and a bit ductile.

d) HVOF as you mentioned.

What do you think to do?

Hi friends,

I am also in similar confusion.

Kindly share your thoughts in finding solution for the components (capstans etc) used in wet wire drawing industry.

The tungsten carbide coated with HVOF capstans are not performing up to the expectations.

I am also thinking either spray & Fuse (or) carbide deposition by welding may work for these applications.

Kindly share your experience in finding the optimum solution.


Regards,

SREENIVAS