Knurling COBALT ALLOY

[ronbiv]

We are attempting to produce a Medium straight knurl on Stellite alloy 6B. After trying a number of different tools we are still having no success, any suggestions are welcome.

 

[btrueblood]

You'll need a knurling tool made from something much harder than typical tool steels; Stellite 6B is a very hard alloy (RC40-ish). Maybe a knurling tool made from diamond...

 

[tomwalz]

It also has a high lubricity and resists cutting so youi will need a very aggressive profile.

Thomas J. Walz
Carbide Processors, Inc.

http://www.carbideprocessors.com

Good engineering starts with a Grainger Catalog.

 

[MikeHalloran]

EDM it.


Mike Halloran
Pembroke Pines, FL, USA

 

[tygerdawg]

Yep, EDM.

Knurling is a material displacement process. If the material's really that hard, it may not be practical.

Or send it a laser etching house and let them try something.

Or take the easy route and just attach a knob to it.

TygerDawg
Blue Technik LLC
Virtuoso Robotics Engineering

http://www.bluetechnik.com

 

[TVP]

Can you provide a little more information on the item that is being knurled? Diameter, length, etc.? How many pieces need to be knurled? If you are using the flat die rolling process to create the knurls, then several of the comments already mentioned are very important:

1. You will need to create a profile with a high penetration rate, so that material is displaced as much as possible early in the process. Work hardening during the deformation process will make it extremely difficult to fill out the profile at the end of the cycle.

2. Die material will need to be very hard: M42 with a hardness of > 65 HRC would be my first choice. Have you discussed this with OSG, PTG, etc.?

3. Have you investigated warm rolling? I haven't looked at the strength vs. temperature characteristics of Stellite 6B, but difficult to roll materials are usually heated in the range of 480 C then introduced to tools that have been pre-warmed (~ 90 C). This is why M42 HSS tool steel would be a good idea, as it has very good resistance to softening (temper resistance) and hot strength.