Partial annealing of tempered 1075 (C45-->C40)

Hi
I've got an application where the blue tempered 1075 is just a little too brittle. Are there any references for how to bring down the temper just a bit,
say from C45 to C40?
Thanks,
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Blue is about as soft as it'll go. About all that's left is gray. Polish the part to shiny, then heat it REAL gently until colors start to appear. First straw, then brown, red. purple, blue. As the blue starts to fade into gray, quench. One way to do this is a more or less controlled manner is to heat up a piece of steel that's maybe 10 times as heavy as your part to just barely glowing in a dimmly lit shop. That way you know you have about 900 degrees to start with. Wait till the glow just disappears and bring your part close to the heated plate. Depending on the ratio of sizes and thicknesses of the heated plate to the part to be tempered further, the part could heat up very fast. Maybe try a sample.
Pete Stanaitis --------------
P Oster wrote:

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Pete,
One other followup detail is that I'm trying to make the steel suitable for bending, and in this case the outer edges of the part see the most stress. Even annealing just the outer "skin" of the part will suit.
Is 900 F , the minimum temp for any annealing to occur ?
Thanks for the info.
P Oster

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I would call that a hot tempering....to really anneal, it has to be brought above the critical temp (around 1500F) and cooled slowly back through it. I would say anything above 600F should soften it enough to bend rather than break.
Tim
-- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games: http://webpages.charter.net/dawill/tmoranwms
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brought
than
High-carbon steel (was the subject 1075?) doesn't bend very well cold, even fully annealed. Its elongation, and thus its bendability, is less than that of low-carbon steel, and it requires a lot of force to bend it.
If you want to work a real bend into that stuff, it's easier to hot-work it or hot-forge it. 900 - 1200 degress F is listed at the source below for general hot-working. Hot forging is done at 1700 - 2200 F. I'd just go for bright red and hammer it, but I haven't worked very much high-carbon steel hot. I have had a bunch of failures trying to work it cold, after annealing, making woodworking tools back before I knew anything about steel.
Here are some properties for it. This isn't very complete, but it will give you an idea:
http://www.suppliersonline.com/propertypages/1075.asp
Ed Huntress
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Oh man, I was working a blade blank a while ago, had left it in the forge to cool and WOW was it soft the next day. Like annealed copper...well, not quite, but it was great. Especially important since we don't have a bench grinder(!) and I have to hand file(!!) the blank to shape before hardening. Of course all I needed to do was smooth out hammer marks and straighen the blade. YMMV.
Tim
P.S. I've managed to do pretty tight bends in music wire without breaking it..
-- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games: http://webpages.charter.net/dawill/tmoranwms
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On Fri, 7 May 2004 23:52:47 -0500, "Tim Williams"

You want a bench belt sander? I just snarffed up 3 of them yesterday. You will have to install your own motor and sanding belts. Ive got two of them that are either 2 or 3" by 42 and one thats 1x 42. (Ill have to double check).
Ill sell YOU only one of them for $25 plus the shipping and if its the 1" one, toss in some new belts.
They are direct drive..the motor pulley is the bottom sanding belt pully. I can take a picture if you like.
They are shop worn, but never used. The motors were removed and the units stuck on a shelf.
Gunner
That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there.         - George Orwell
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Thanks for the offer, might actually be useful come to think of it. We already have a belt/disk sander combo, uh 3" wide belt maybe 36" long plus 6" disk, but we never have any belts for it. Go figure! Disk is also spinning on the shaft for some unknown reason, gotta take the guards off and check it out some day.. sigh.
Tim
-- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games: http://webpages.charter.net/dawill/tmoranwms
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On Sat, 8 May 2004 23:36:07 -0500, "Tim Williams"

Best place bar none that Ive found for belts and disks is:
http://www.barbkat.com /
She sells through the net and via ebay. Honest, really good belts, EXCELLENT priceing etc etc. Ive many shops now buying abrasives from her at my recommendation and quite happy to do so.
Gunner
That rifle hanging on the wall of the working-class flat or labourer's cottage is the symbol of democracy. It is our job to see that it stays there.         - George Orwell
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Nice, thanks!
Tim
-- "I have misplaced my pants." - Homer Simpson | Electronics, - - - - - - - - - - - - - - - - - - - - - - --+ Metalcasting and Games: http://webpages.charter.net/dawill/tmoranwms
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