What's a good metal to work with?

[Pcmaker]

I have 1018 and 1045 cold rolled steel.

What's a good type of steel that can be hardened after being machined to where it's practically tool steel after or close to it?

Right now I have a piece of flat bar that I want to machine to fit into a ratchet to open up rusted plumbing cleanout covers. It's 1/4" thick and 2" wide, 3" in length. I machined it into specc, tried heat treating it and use a file to kind of gauge its hardness and it's pretty soft. I have a feeling it'll just twist if I put a lot of torque to it.

What's generally a good type of steel for this kind of work? 1045 seems like it's not hard enough after I heat treat it.

 

[benmychree]

1045 should harden quite enough to stand up to the sort of use that you are posting, perhaps you are not heating it high enough temp., and it should be water quenched; as suggested by another member, use a magnet to discover when it is no longer attracted to the heated part, then quench and possibly draw the temper to about blue for a tool of that sort.

 

[RJSakowski]

Actually a tool steel is what you need. It sounds like you want something closer to a screwdriver than a cold chisel. Screwdrivers usually aren't that hard and can be cut with a file. You want something approaching a spring temper. If drawing the temper by color it would be a straw to bronze color. If the tool is too hard, it may crack, if too soft it will bend. Personally, I prefer my screw drivers more on the hard side.

 

[benmychree]

A spring temper is generally considered to be a blue temper color.

 

[addertooth]

O1, D2, or for the easiest hardening is 1095. As well as the hardening step, you have to do the tempering step... but MOST kitchen ovens will get hot enough to temper. Just calibrate your oven with an accurate digital thermometer, AND turn it on an hour before it is needed so the temperature stabilizes. Initially, most kitchen ovens have about a 50 degree temperature swing for the first half hour. That is too much swing to hit the desired curve for tempering.

If you want the current king of heat treat, hot molten salts for the quench, with L6 produces L6-Bainite, which is the best of ALL worlds, but few know how to do it right.

 

[Pcmaker]

I forgot to mention something easy to get. I'm going to ask my local steel supplier tomorrow if they can get 1095.

 

[addertooth]

Every online shop for knife makers carry it. Leaf springs from pre-1990 cars were uniformly made from it (because of the easy heat treat curves). Keep in mind those already turned into leaf springs are curved, and hardened to a "spring temper". You would need to anneal and straighten it to use a recycled leaf spring. Places that make leaf springs carry it as well, that was where I bought mine at the lowest price.

 

[Masterjuggler]

Annealing leaf springs usually requires an actual oven to set a slow ramp down cycle after angle grinding into pieces if it's 5160 or similar. You want to get a good spheroidized structure to make it machine well. Last time I did it I followed the schedule on the cashenblades site and it worked pretty well in my small heat treat oven. "1380 °F (750 °C), cool rapidly to 1300 °F (705 °C), then cool to 1200 °F (650 °C) at a rate not exceeding 10 °F (6 °C) per hour"

I've tried just heating past its critical temp (non-magnetic) and air cooling, the stuff still hardens enough to destroy a saw blade. You then still have to straighten it if you want to machine a flat piece. If they're well used, they also sometimes have cracks that may not be visible until heat treatment, or after the part (or knife) is finished and you go to use it and it breaks.

On the other hand, I got some giant truck spring, about 100 pounds worth, for $30. So maybe it's worth it to you to go through the trouble, maybe you just want to buy some pre-annealed tool steel. The eutectoid (perfect iron to carbon ratio) steels are the absolute easiest, brain dead steels to heat treat. Go for 1080 or 1084. Cheap too. No special heat treat cycles, easy to temper with a torch or your kitchen oven. To anneal heat them and stick in some wood fire ashes.

 

[westerner]

I have a pretty good pile of leaf springs I would be happy to donate to a worthy cause....
Thickness from 3/16 ish to 1/2 ish. All are from the 80's earliest.