Is there enough material to bandsaw off? If so, you could use a die grinder to grind a place for the bandsaw blade to start and cut through, then keep the blade in the unhardened stock. If milling is the only option, conventional milling (not climb milling), often lets you get under the worst of the hardened scale. It's going to beat up your tooling no matter what so using inserted tooling is probably going to be cheaper than burning up high dollar end mills.
All in all, your shaper may be the cheapest way to go.
I have an old ceramics kiln that I use to anneal flame cut steel. So far the normal cool down in the sealed kiln is slow enough. It's probably more of a normalization that a true anneal but it's good enough.
Have you tried a indexable facemill? I never use an endmill for squaring blocks - only facemills. With hardened stuff, I find carbide works well as long as you slow it down. You're good if you've got one that takes cheap inserts.
I was thinking along the lines of Karl with the disc grinder, but .09" is a lot of material and it's very labour intensive to hog material for a long time.
My Tempil Basic Guide to Ferrous Metalurgy shows a normalizing temp of about
1600 F. for steel with 30 points of carbon. 4130 normalizes in still air, very still air, don't let the cat wag his tail near the cooling piece and don't fart. A full anneal can be had by very slow cooling in the furnace. The stuff will cut like butter then and will need to be re-hardened after machining. Good luck.
Actually..no..I dont have such a facemill. I havent been able to scrounge up one and a supply of inserts. A fair and dimenishing number of carbide facemills that are cemented..and no way to resharpen them. And with material like this...I dont want to use any more up.
Yup. Thanks for the advise
"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."
Annealing 4130 (and most of the other low alloy steels) may be annealed at 1550 F for a time long enough to allow thorough heating of the section size. It should then be cooled in the furnace at a rate of less than 50 F per hour down to 900 F, followed by air cooling from 900 F. ==========================================================
and put 3460 in the search box to go to that page, then click the link at the top for additional info. This gives composition and physical properties for most common steels, and heat treating data on the tool steels (but not 4014, big sigh ;-)). Then put
3464 in the search box and repeat to get data on stainless steels. Again, they give annealing data for most alloys but not for 17-4 and
17-5 PH, again, big sigh. Anyway, a useful grab for the future. Hold times at temperature seem to be 1 hour per inch of thickness. This assumes good heat circulation and if you stack your plates directly on each other they will look like one really thick plate. Put some little spacers in between each plate so the air can circulate.
-- Regards, Carl Ijames carl.ijames at verizon.net
You have to use aids to avoid big attacks of 'Can't Remember Sh*t' like that. Do you have any programmable timers or an old Lux wind-up kitchen timer around? Or use a good old (loud) alarm clock that will not quit till you turn it off...
If you figure it's going to need looking at in an hour, set the alarm for an hour. And set up a second alarm at two hours in case you miss the first. If you figure it needs looking at before you go to bed, put something big and heavy on the bed - when you go to move it, you'll remember.
(And tell the wife/roommate/kids why you are setting the alarm, so they know not to just turn off the alarm without finding you.)
And in the end... It was already scrap material when you started. So what did you lose, except some electricity running the kiln? ;-)
If they did warp into interesting shapes, you can always weld them into a sculpture, let your muse loose.
I think next time..Ill fire the oven up without anything in it..fiddle around until its the proper temperature..THEN load it. It will sag of course..then slowly return to the proper temp..and I can go from there
Still pissed me off.
"The importance of morality is that people behave themselves even if nobody's watching. There are not enough cops and laws to replace personal morality as a means to produce a civilized society. Indeed, the police and criminal justice system are the last desperate line of defense for a civilized society. Unfortunately, too many of us see police, laws and the criminal justice system as society's first line of defense." --Walter Williams