O1 Tool Steel Query

[marchyman]

I was watching a video where a one time use tool was needed and made from O1 tool steel. The order of operation was to first harden the end of the steel and then grind the tool. I'd have thought it would have been easier to first grind the desired shape and then heat and quench to harden.

Is there a reason why the steel should be hardened before grinding or was it just the tool makers choice?

 

[Christian Poulsen]

Depends on size and shape (detail and dims (what be it?)
IE It might make more sense to hrdn 1st then grind like the video shows...or, like you ask, vicy vercy (grinding that end to (whatever it is) 1st might make more sense for instance ifn' you're home heat treating it, like if it has some size to it, in case you don't get that end hard through and through, if the working shape (end) is there already it for sure will be hard (for needed depth anyway...
...but back again to the order the video says may be correct, like depending if the "working end" is a small OD and/or detail and already there before HT, you have a greater chance of cracking, warping/distorting it when you plunge that 01 into the oil plus will you have to "touch up" grind the end detail after HT anyway? (Or at least bead ("sand") blast it)

Think about it and yeah, it's your choice.

 

[Ulma Doctor]

a thought that comes to mind,
if you are going to harden a thin section of material, it may warp badly-
pre-hardening may limit or eliminate the warpage of the finished part

 

[Subwayrocket]

Metal has a tendency to move around when heated ...and even more when cooled quickly. In welding it's called distortion ...and it's a real PITA ...lol
If it's heat treated, quenched and tempered first, then it's shape is pretty much "locked in" when you go to shape and grind it.
If you ground the part first, it would likely bend or twist when heat treated quenched .

 

[RJSakowski]

Warpage is the primary reason for pre-hardening followed by grinding to final dimensions. Also, If some means is not used to protect the surface from scaling during the hardening process, the scale will change the dimensions and surface finish of the piece.

 

[marchyman]

Thanks, all. I think I understand. I hadn't thought about warpage and scale. Maybe you can tell I know nothing about welding, too

I think I'll go play and make some random shaped tool for the fun of it. Love learning new stuff.

 

[Whyemier]

If this helps, here is a 'ClickSpring' video showing how its might be done.

 

[Christian Poulsen]

If this helps, here is a 'ClickSpring' video showing how its might be done.

Thx here too! It's sweet to see and refer to again (especially when needed for the home shop!)
I got spoiled (again) with a blank (carbide or HSS), set up (indicate the long side, and wire EDM the contour (complete with relief (angles) on the newer machines)