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Best steel for springs


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I'm sure this info has already been posted somewhere, I just can't seem to find it. I need to make a spring. Not the traditional coil type, more in the shape of a hair pin only larger. Is there an alloy of steel that would work well for this and what is the best way to heat treat the piece once it forged? I do have a section of leaf spring (alloy unknown) and several types of known tool steel although perhaps I'm barking up the wrong tree all together? Any help or links to where to find help are appreciated. Thanks

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Conditions of use?  Fatigue life?  Do you mind if it costs more than a new car?


*BEST* totally depends on the details!


For fairly small springs I would look at re-using garage door coil springs, if you spring will support several tons---you didn't say---then you probably need to engineer it as it probably would be a critical use and failure might cause harm.

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The spring would be in the shape of a hairpin,  made from 1/8x3/8 parent stock, each leg of the pin being 3" long. Perhaps "best" was not the "best" word to use. How about good? I'm not forging parts for the lunar rover, I just want to keep tension on 2 discs (an elbow of sorts), allowing movement yet strong enough to keep them from slipping. The weight would be negligible, perhaps a few lbs. I plan to lightly chisel in some groves between the discs to help lock the elbow in place when needed, yet still be loose enough to be able to articulate or adjust  the elbow with a little force. 

Am I basically just looking for a high carbon content steel and if so, after forging, what would be the process for heat treating be it oil or water quench?

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What you quench in depends on the alloy you use; however you most likely will be doing a warm oil quench


For that size: I have run across some old car hood springs that were pretty much that size to start with.


After taking up to non-magnetic and quenching in around 140 degF vegetable oil---probably need at least a gallon and used fry oil is perfectly ok---then you will need to ASAP draw the temper on it by heating to above 500 degF  How far depends on the alloy and use requirements; but probably not over say 650 degF


If it is too soft after you draw temper you can re do the heat treat starting with heating and quenching and then draw to a lower temperature.

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