Heat treating saw blade made of M2, or M4

[TonyBuser]

We are trying to work with a potential customer who would like us to wire cut some saw blades out of M2 or M4. They would like the body of the blade to be a hardness of 44 to 52 on the Rockwell C scale, and the cutting edge or teeth to have a hardness of 62 to 65 on the Rockwell C scale.

Does anyone have experience in induction hardening to this type of requirement??

 

[Goahead]

Hi,
instead of selectively hardening and tempering the edge, you could possibly consider to retemper to the lower hardness range the remaining portion of the blade (after it has been heat treated in full to the higher range). This can be done by preventing the edges to heat up by means of suitable chills.
Laser heat treatment also could probably provide acceptable results.

http://www.welding-advisers.com/

 

[tomwalz]

Typically they are laser cut.

The cutting creates aheat effected zone at the edge of the cut that has to be considered.

If it is carbide, ceramic or diamond tipped then the brazing will alter the metal again.

Often the saw blades are annealed after brazing.

You might conider getting quotes and subbing this out.
Peerless in Groveport Ohio and Western Saw (Steve Bergerson 503 781-5013) are both very good.

 

[Maui]

You'll never get that kind of hardness variation in a thin narrow saw blade made from M2 or M4. These grades harden far too readily to retard the transformation that much. Even tempering the body of the blade back after hardening to the higher range as suggested by Goahead would be very difficult to do in practice. I am not aware of any industrial techniques that are available to achive these results in these grades. I would be very interested to learn from others if there are any reproducible means of accomplishing this.


Maui

 

[BobUXL]

I have seen this done a couple of ways. One is to treat just the teeth of the blade. Second is welding the M2/M4 to a more ductile body. I am not sure of the welding techniques used, but it is possible. Commerically, these are called bi-metal blades.

 

[rockmet]

I've never heard of a successful local hardening technique for high speed steel. Even if you managed to reduce the hardness away from the edge, you wouldn't increase toughness / flexibility, which is what you're trying to do (I guess).

Welded edge blades are the stock answer to this problem. They're usually welded using electron beam welding, but laser would probably do too.