Anyone use concrete saw blades?

B

BluesHarp

Joined
Oct 14, 2007
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I posted something on this subject a few years ago, but I wanted to see if anything new comes up. For several years I have had a pretty unlimited supply of worn-out diamond-edge saw blades that are used by an industrial concrete cutter. It's 3/16 inch steel, and my experiences with it for knifemaking have been terrific. Knifemaker Ed Caffrey replied to me once that it might be 4140 steel. This is relatively low carbon compared to something like L6, but I really get good results. I've been using it for years now, and it takes a great edge and holds up as well as anything I have. I cut it out with an angle grinder and cutting disc, then anneal it. It drills nicely and grinds very quickly. I have to do a pretty severe heat treatment. I take it up to non-magnetic and then quench it in room-temp brine (water super-saturated with salt). I do this twice. It comes out of the quench squeaky clean, and if there's any warping I can hand straighten it if I'm careful. It snaps off cleanly if I try to break it in the vise. So by all indications it has been good knife steel.

I don't know exactly what the composition is, and I don't know what Rockwell I'm getting it up to, but the performance speaks for itself. Has anyone else had experience with this stuff?
 
I've never used any but, if your getting good results and have a bunch of it, it would be worth sending out to be annelized.
 
I've got a bunch of them hanging on the smithy wall. From what I was able to get from the makers, the standard alloy is something around 4140. That does not mean they are 4140, just that that is a common alloy for concrete saw bodies.

4140 is an interesting steel, in that it is a fairly high hardenability steel with only .35 to .40 carbon. It reaches Rc 54 to 59. Oil is the preferred quenchant as there is no need to cool real fast. The nose is about 3 seconds. Temper at about 500F.

They look good where they are, and I don't plan on cutting them up. I had considered making wrap style hawks from them, but found out that 4140 does not weld well. 4140 forges well,though.

Stacy
 
I've done some pretty extensive field testing with this steel. If I quench it in oil I don't get near the hardness I do if I use brine. I also get good results from quenching twice in the brine. It seems to refine the grain even more. I temper the spine with a torch to color after the quench. I don't have a way to Rockwell test, but my file tests indicate it's not as hard as my knives made from files. Obviously more carbon content there. What I like about the 4140 (if that's what it is) is that the edge is easily touched up with a ceramic rod. I can really keep a razor edge on it without much trouble.

Most of my knives here were made with the 4140 or from files:

gallery


Thanks for the comments.
Mark
 
bladsmth said:
I've got a bunch of them hanging on the smithy wall. From what I was able to get from the makers, the standard alloy is something around 4140. That does not mean they are 4140, just that that is a common alloy for concrete saw bodies.

4140 is an interesting steel, in that it is a fairly high hardenability steel with only .35 to .40 carbon. It reaches Rc 54 to 59. Oil is the preferred quenchant as there is no need to cool real fast. The nose is about 3 seconds. Temper at about 500F.

They look good where they are, and I don't plan on cutting them up. I had considered making wrap style hawks from them, but found out that 4140 does not weld well. 4140 forges well,though.

Stacy
Click to expand...


Stacy,
I havn't made any 'hawks from it, but 4140 welds up in damascus really well. I made some prototype bars for Smith & Wesson last year.
Del
 
Modified 4130-4150 frequently has machining aids such as sulfur that ruin it for welding (but not brazing). Otherwise almost identical. Something like a saw blade would benefit from modified (that is a lot of little cuts and surface area you want a good finish) and the steel cost is about the same. So it may not always be straight cro-mo

edit:

4150 can achieve HRC 63. Bet youda never guessed that.
 
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