Custom tool tweaking - who knows their metallurgy?

[Sticks]

We all do it. We need a wrench bent or modified to reach something.

What is the proper treatment for a wrench after you put a few bends in it, or weld it to a custom handle?

Fast cool?

Oil Bath?

Rinse and repeat?

The few that I have done are usually a one or two time use then they break at point of adjustment. I would like to know how to get the strength back into it somewhat so I don't have to do up another one.

 

[wishihadatalon]

You would need to know the material that it is made out of to know what needs to be done to to treat it.

I will say that if they are breaking without bending, you probably made them more brittle and quenching them would probably only make the issue worse.

 

[Warrenator]

I would think wrenches are made out of a high carbon steel. Here's an interesting article on heat treating with a propane torch after making bends in it for wood turning application....

http://www.woodcentral.com/russ/russ10.shtml

Sounds like what is happening is you are making your tools brittle at the bend, you need to retemper by heating and annealing and stuff. Complicated, and as you're not exactly sure what alloy the wrench is made from, tricky. But since it's cheap to play around with propane torch, letting it sit, reheating and quenching, why not try it?

 

[MoonRise]

Depends on EXACTLY what you do, how you do it, and what you do it to.



For the most part, if you intensly heat a 'tool' steel (whether plain high carbon steel or an alloy tool steel) you WILL change the temper of the steel. That intense heat could be from welding (arc or torch) or from heating in order to bend it.

If you "quench" a hot high(er) carbon steel, you harden it. Quench it too 'aggressively' for the actual (exact) alloy and you make it too brittle that it cracks and/or shatters (like says quenching an O1 oil-hardening steel in water, or an air-hardening tool steel in a liquid, etc). Even if quenched 'properly', the steel is usually much too hard in the as-quenched state and must be "tempered" to get the correct/desired balance between hardness and strength and 'toughness' and so forth.

For a 'one-shot' tool, go for it.

If you want the modified tool to last, you have to pretty much make it as if you WANT it to last. And that means the 'proper' materials and processes.

 

[cdent]

If I were trying to bend something that I thought was hardened, I'd stick the jaws of the wrench in water and heat the area you want to bend with a torch. I'd try to keep it in a 'black' heat or just occasional slight bit of dull red.

I'd try to soak it for ten/fifteen minutes to try to get the anneal through and through. Then bend with slow steady pressure in a vise with a good radius on temporary jaw inserts. Don't know if it would work for your wrenches.

I'd also do the torch anneal around a welded on extension just in case it gets a little brittle around the weld due to a bit of air hardening. I don't think I'd quench any hot parts or need an oil bath for this example. Good luck with it.

 

[MBeaty]

If I were trying to bend something that I thought was hardened, I'd stick the jaws of the wrench in water and heat the area you want to bend with a torch. I'd try to keep it in a 'black' heat or just occasional slight bit of dull red.

Like others have said, much of it comes down to exactly what type of steel the tool is already made from. Most likely it will be a higher carbon steel that is able to be hardened, but there are still vast differences in the proper processes to harden different types of steel.

One thing to consider though, is that very minimal to no changes will occur in the steels structure until it is heated up quite a bit. In order for steel to undergo significant hardening, it has to be heated to the point where the actual lattice structure of the steel atoms change. In many alloys this temperature range can be from 900 deg F to 1600 deg F. So if the steel is not heated up to this temperature, for the most part it will retain its original mechanical properties. Heat treating processes involve exceeding this temperature and then controlling the rate of cooling in order to change structure of the steel. After hardening a piece of steel, in most cases it will need some sort of tempering process to make it tougher and less brittle. This process can occur at a lower temperature than you have to heat it when you are hardening the steel. Again though, the temperature used for tempering depends on what type of steel it is and how much tempering needs to be done.

Again though, heat treatment can be quite a finicky process and is hugely dependent on what the original material is. My advice would be to try to heat the part as little as you have to and to try to keep the part that does not need to be bent as cool as possible. Without knowing exactly the heat treating processes for the type of steel, you could end up damaging it just as easily as improving it.

A great source of information on just about any material and the appropriate heat treating processes are the ASM Handbooks. You should be able to find these at any college with an engineering program, or you can access them online, but I think you have to subscribe to gain access to it.

Good luck with your project.

 

[cdent]

....In order for steel to undergo significant hardening, it has to be heated to the point where the actual lattice structure of the steel atoms change. In many alloys this temperature range can be from 900 deg F to 1600 deg F. So if the steel is not heated up to this temperature, for the most part it will retain its original mechanical properties. Heat treating processes involve exceeding this temperature and then controlling the rate of cooling in order to change structure of the steel....

I believe that to harden most nonstainless tool steels, the minimum heat is well above 1300*. Then, cooled or quenched in a quick enough way to harden. I think it's unnecessary in this situation to try to harden jaws of the wrench.

If a steel is hardened and is heated to any temp below that 1300*+ then it'll soften of temper, which is maybe something that would help this tool handle to not break after it's bent. Most simpler tool steels should show a little color, dull red, at around 900*.

Since I don't know the steel or how it was heat treated,it might be a good idea to protect the working end (keep as cool as possible),and attempt to soften the handle as much as it might be able to. Then bend it cold so there's less chance of damaging the working end.

Another reason to not try to change the heat treating on the wrench jaws is that it's probably not a high carbon tool steel (bits and cutters). I'd guess midcarbon picked for economy and toughness without mushrooming like mild steel would.

Not trying to argue or pick on anything, just wondering out loud on how I'd look at it.

 

[Sticks]

Thanks for all the tips everyone.

The ones that I have the most problems with are when I bend just behind the working end. The jaws or box holds, but the handle snaps.

 

[MBeaty]

The ones that I have the most problems with are when I bend just behind the working end. The jaws or box holds, but the handle snaps.

What is your current process when making these and also how are they breaking? You say they are snapping, but when they do let go, do they usually break quickly, or do they deform, then break. In most cases a brittle fracture in steel will look different than softer steel that has yielded then broken. It sounds to me like the problems you are having are due to the steel being too hard after the modifications, leading to a brittle fracture.

 

[Sticks]

Heating with an Oxy/Acety torch to an orange color, make the bend, water or oil bath cool after I verify that it fits where needed.

 

[diesel research]

Just gotta reheat for a temper after the quench then. Usually in a normal oven temp range. Not saying to use an oven, although a toaster oven might do the trick.

 

[MBeaty]

Just gotta reheat for a temper after the quench then. Usually in a normal oven temp range. Not saying to use an oven, although a toaster oven might do the trick.

Either that, or completely avoid quenching it so aggressively and see what happens. For some steels water quenching, or even oil quenching is too aggressive. I would probably just let it air cool and see what the durability is like. If you find that the business end of the tool is too soft, then you will know that you need some sort of quench and temper. The hard part is going to be finding the happy medium there, but if you have always quenched in the past and had bad luck, I would try something different.