Does 1045 tool bar work harden?

[carlquib]

I have a bunch of 2 1/4" square tool bar. It is a bar that is used in ag to set tillage tools on. The guy that I got it from said that it was just 1045 steel and shouldn't be too hard. I can cut it with the bandsaw, but it eats HSS tools and makes the carbide squeel and throw sparks. I thought that since the bandsaw cut it so easy it would be a breeze to mill and turn. I know that this stuff will harden if you cut it with a torch or an abrasive saw but it seems to be work hardening even with an agressive cut it leaves a hard surface at least it is hard enough my file wants to skip a little. I don't have any way to test the hardness. I tried a file on it and it seems to file ok where I haven't cut yet, not soft but the file cuts it. So has anyone played with any of this "toolbar" before? Can I anneal and make it easier to cut? Any ideas before I pitch this stuff into the scrap pile? Thanks.

-brian

 

[metlmunchr]

Generally if a manufacturer is using medium carbon stock its because they are heat treating it for additional strength. There's little difference in the strength of 1045 vs 1018 when both are in the annealled state, so the majority of things would be made from low carbon stock if annealled or as-drawn strength is adequate.

It could also be induction hardened for a combination of wear resistance and toughness. If that's the case, you'd likely see a marked difference in cutting from the exterior to the center of the bar.

In any case, its easy enough to harden 1045 to the mid 40's, and while that's still capable of being sawed, it would be at the upper limit of what hss can survive for long assuming proper cutting speed reduction. It should be well within the range of carbide, but speed allowances have to be made there as well. Lacking a hardness tester, you might try heating a small chunk to the red heat range and allowing it to cool slowly to get some idea of whether or not the material is heat treated. My WAG is that it probably is.

 

[precisionworks]

With a machinability rating of 60%, it should be about as easy (or as hard) as 4150.

In the annealed condition, it runs about 150 HBn. As-rolled hardness is 200 HBn.

Here's some info from MatWeb.

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Barry Milton

 

[ottoluck]

In the virgin state it machines easily, but if you let it heat up while you are machining it, it surface harden's real fast and I beleive that is what has happened to you!. Gotta let it cool down between cuts and don't let it get to hot when you are taking a cut. If it does work harden you can usually take a deep cut and get under the surface hardness, but you have to keep coolant on it so it don't happen again!. When your done if you want to harden it and make it tougher, take a torch to it or get it professionally heat treated!. Anything over 1018 can work harden, especially 1040-1045, it does'ent get as hard as tool steels, but it get's really tough, more so on the surface, and can take a lot of abuse on the surface and still remain soft enough so it won't shatter, so it's great for stuff like farm equipment and so forth!. You can get it annealed soft again, but it has to be done properly and that usually means by a professional!.