What belt for grinding HT'ed D2 steel???

RokJok

RokJok

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I got some D2 in the form of end-cutter plates from a paper mill and it is HARD STUFF. My guess from cutting it in half with a handheld angle grinder & carbide wheel is that it is somewhere over 60 RC all the way through. I don't have a forge, so want to do strict stock-removal grinding to make some blades out of the plates. I figure it'll work if I go slow & dip in cold water often.

For now my grinding is being done on a 3"x18" woodworking belt sander clamped upside-down to my bench. So these are obviously going to be working blades for me, not art pieces or anything that'll ever see the light of day commercially. :)

Question 1:
What belts (abrasive type & size, mfrs or model numbers) would you recommend for grinding this material? Should I be looking at different abrasive types for hogging off lots of metal vs finishing/polishing maybe?

Question 2:
Any "gotchas" I should be aware of regarding grinding hard D2 in particular or grinding in general? I figure safety-wise that a painter's mask & safety goggles are the minimum required.

Question 3:
Should I just spring for a 1x42 Delta or Jet benchtop belt sander as an upgrade in fuctionality over the clamped hand belt sander and consider it a starting investment for a new hobby? (I know the answer to that one is, "Of course!!!") ;) :D Like I need another hobby. :rolleyes:

Thanks in advance for your recommendations.

(edited to add) Forgot to mention that I've also got a regular benchtop grinder (with wheels, not a belt) I can use for extremely rough stock removal.
 
I'd use the grinding wheel for all the grinding I could. That hardened steel will just eat up your belts! Like you said, keep cooling it in water, and do your FINAL finishing on the belt. This is what worked best for me in the past.
 
<www.bucorp.com/coldworksteels/aza_bohler_item.asp?iItem_Id=40>

The site above is the information sheet on D2 for Bohler/Uddeholm North America. Click on the D2 data sheet link for heat treat, including annealing, hardening, stress relief and tempering.

The annealing process is fairly long and controlled for D2, but grinding hardened D2 will not be any picnic either. If you do grind it hardened you will probably need to retemper it after. D2 requires at least two tempers for two hours each.
 
Guys, thanks for the input. Especially thank you Steve for that link & the advice to temper it twice. :)

Quick follow-up question on tempering temps chart from that link:
For approximately 58-60 RC finished hardness, will the tempering temperature need to be 360 degrees Fahrenheit to satisfy their statement "lowest tempering temperature 360 degrees F" and still be at upper-50's RC hardness when I'm done? Or can I temper it at about 300 to place the RC at 60'ish? Whatever temp I use, I figure I'll just temper it in the oven over-night to give it plenty of extra time.

Thanks in advance, -- Greg --
 
Greg,
For the 58-60 range, assuming a mid range hardening at 1850F, try tempering at 500F. Without doing the hardening yourself its hard to tell for sure-the range is from 1810 to 1920 with 500 degree tempers ranging from 57 to a little under 60. Tempering at 360 will give you a 59-62 hardness range depending on the hardening temp.

When I use D2, I harden at ~1875, freeze with dry ice overnight and triple temper at 400 for about 60 HRC. Twice is the minimum called for by specs.

Edit: I wouldn't temper it overnight. I haven't done this with D2, but had to reheat treat some A2 last year that I tempered for seven hours while having "a" beer.
 
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Originally posted by shgeo
...I tempered for seven hours while having "a" beer.
----------------

Steve, I see you drink extra-large beers too. ;) :D Thanks for the more specific temperature info.
 
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