New thread (newbie)

Charly the Bastard posted this reply to my earlier questions.

"Auto petro products usually have metallic soaps to reduce foaming, and these can contaminate the work at quench temps. 5160, which is what most leaf springs are made of, will go to Rockwell 61-63 full hard. Draw in oven at

375 F for two hours and allow to cool in still air to ambient; Rockwell 55-57 final hardness."

"Cool in still air". Is this the same as allowing to cool in a bucket of wood ash ? Does one have to use the kitchen oven to get the 375 for 2 hours? Isn't 375 sort of hard to get and maintain in a forge ? I take it that this 'draw and cool' is after the oil quench and is the last heat related act..

Reply to
charles
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I use an electric toaster oven with an oven thermometer inside. It works quite well for small pieces.

Eide

Reply to
Eide

Nope, cool in still air means cool in still air. Cool in ash takes longer as the ash acts as a refractory. Yeah, the draw is after the quench and the cleanup with a wire brush. You'd be surprized at just how accurate a 'kitchen oven' is these days. I use a computer controled oven myself, but you can get good repeatable results in the kitchen. Preheat the oven, put in the part, after two hours take it out and set it on a rack to cool. At 375, it should have a golden brown oxide color.

Charly

Reply to
Charly the Bastard

Ok, now heres a question. I did a couple of large blades (5160 new material) in my oven a while back at between 350 and 400F for 1 hour soaks, two times. I used a K type meter to watch the temp in the gas oven and it swings back and forth 20 to 40 degrees either way and I set for the middle. I got that golden brown color each time. Really liked it and have been thinking on doing a blade and leaving the color... Anyway I just did another blade from the exact same material and used the same treatment to temper it. Used a thermocouple to monitor the temp. Virtually the same process on exactly the same material and got almost no color on the metal. What gives? In retrospect I'm wondering if I might have opened the oven door more times the first time around and just leaving it alone might have cut out the available oxygen - thus much less coloration? Seems like something was different but can't put my finger on it. This last blade seem springier than the one before with - roughly - similar geometry. The new one is flat ground and the one before is convex.

GA

Reply to
Greyangel

I don't know. :/

Sounds like they ended up with different tempering. :/

The "oxide coating color" of course depends on surface texture and a number of other things like oil on the surface, but somehow that doesn't seem like enough to explain this big of a difference.

A few months ago I re-drew the temper on a few blades I had around here some were O1 and some were 1095 and they all got the same golden color at 425F for an hour. They were all pretty much the same shiny finish to start with tho ("polished" on the fine grit deburring wheel).

My reason for drawing the temper so far was just an experiment. Retained austenite transforms to secondary martensite or secondary bainite at 400-450F. The hardess tested out to reflect what the books say they should have been also.

When I draw at 325f or 350F my blades stay white, if they were polished first, which is hardly ever.

GA, do me a favor sometime and heat treat some 5160 but only draw the temper in boiling water for an hour and see how strong it is. :)

Alvin in AZ

Reply to
alvinj

Well, the fire doesn't get into the box on a gas oven, neither do combustion gasses, just the heat. I've had color variance too, usually it traces back to a particular stick of stock. Batch variance, it's an imprefekt wurld. It's the tap of the diamond that matters, and that is consistant no matter the color intensity.

On the shape difference; a little convex can make a big difference in the 'feel', compound curves are inherently stiffer to a bending force. Don't get me wrong, stiff can be a Good thing. Think about the development of plate body armor. Plate started out with simple curves and thickness, and finished highly fluted and much thinner. Why? Because compound curves are harder to deform from their shape, so you need less mass to provide the same level of protection. My bet on the difference is shape, not heat treatment.

The oxide is really thin, mere molecules deep. Leave it if you want, but it does wear off quickly.

Charly

Reply to
Charly the Bastard

protection. My

The shape difference makes sense on the springyness. As for the color... Same batch of material. It starts life as a 22 foot bar and they cut it in three to ship. I'm for Alvins theory on the finish of the blade at the time of temper at this point. Possibly I tempered at a higher temp the last blades too. I'd been experimenting with small stuff for strength and knew exactly what I was doing at the time. Now the details are kind of hazy... ;-) I like the diamond idea though. I'm thinking on finding a machine shop that can do hardness testing for me. Any idea how common it is for a small time local machine shop to have that equipment and what range of cost they are likely to ask?

GA

Reply to
Greyangel

By the third temper I had it shined up pretty good so no oil and no significant oxide. I'm about convinced that I did the previous batch at around 450. I was going for toughness since the blades were both "fighting" blades. This one never went more than 420 and that was just breifly while I was adjusting the oven temp. Oh yeah, I reread my last post and overstated the swing of the oven. Thirty to fourty degree was total range not plus/minus from center. I was shooting for 375ish and got from 360 to 400 in constant transition

Kind of unrelated but I did something this time that I didn't do before that might have an effect on the steel. I pulled it from the quench as soon as the color was gone from the blade for a couple seconds, then put it back for several more seconds and swirled it around a bit and pulled it out again while it was still pretty hot to the touch. I file tested at that point and the file bit when I put some good force into it but skated if used lightly. Kind of worried me till I picked it up again after it sat and cooled for a while and it had that "hard feel" to it that I was expecting. What kind of formation can you expect if you quench it over the nose curve and then let it air cool from, say, 600 degrees?

Speaking of which, I went looking for a temper graph for 5160 but didn't find anything. You got one or a reference?

Got a geometry in mind? I got some quarter by 3/8ths sticks that I cut off the tang of this last blade to play with. Does it matter if they are just kind of square?

GA

Reply to
Greyangel

Yeah... my wife thinks so ;-)

Reply to
Greyangel

That sounds like the explaination to me.

Oh heck. :/ You need to move up to the high quality stuff like I use... a "Toastmaster System III Toaster Oven"! It doesn't swing nearly that much (course it won't hold no sword tho;) and the dial mark was so far off, I used MEK or something and removed the mark and drew in my own. ;) (but still go by the thermometer)

Actually, now that I think about it, I use it in the house, it won't work worth anything outside with the slightest breeze. Is that what's going on?

I want to give this one more time than I have time for right now. Snap judgment sounds like you got the same products you would have gotten anyway, they were just postponed. If you got some bainite it wasn't much and it won't hurt anything anyway? :)

With 5160 you have at least 100 seconds to get down to 450F -after- having only 4 seconds to get it under 900F (glowing) and still get martensite and no bainite. To get to 600F you have 50 seconds.

I've got a book titled "Bainite In Steels" (Institute of Materials

1992, not ASM).

You betcha! :)

I made some photo copies of 8660, 5160, 9260 and L6/4370 and several others while I had the Heat Treater's Guide "checked out" from the UofA. :)

Been meaning to mention that to you guys actually.

The only real disappointment in the heat treater's guide is the fact that it doesn't address tortional impact testing -at all- and the heat treater's trouble shooting section is really lame.

It's not "an authored book(?)" it's an edited collection of free information bound up (real pretty) for $274 (used price on amazon!).

Funny but it didn't "check out" (the librarian screwed up) and when the alarm went off, he hurryedly;) and embarassedly;) killed the theft device and got me on my way. Later looking at the slip and checking it out on the internet... the UofA still thought it was on the shelf. :)

If it had been what I thought was a really-good-book that might have been a quandry(?) for me to solve. ;)

The librarians know me now and are glad to see me, even. ;) I talked to them about what happened when I brought it back.

Funny how that used-to-wouldh've been the "expected" thing to do for "a man" but not now, huh? :/

Sounds perfect, having more than one sounds really cool too. :) Do whatever it is that you need to do to get a feel for how strong one is when simply drawn in boiling water for an hour.

Hmmm... 1/2 hour in the freezer for one of them? ;)

Strength prob'ly won't be detectable but hardness will increase in the cold treated one. Done any cold treating yet?

That extra hardness generated by the cold treatment remains through the normal tempering treatment/s with no loss in "toughness". -ASM Tool Steels [paraphrased but true]

In other words, you gain 1/2 to 1+1/2 points hrc (to even 2+1/2 hrc points with something like A2 or D2) and they remain, as-in, -added to- the hardness otherwise expected... with no loss in "toughness"!

Need proof anyone? :)

Hmmm... you know, if a blacksmith doesn't understand how soft

-retained austenite- is ...who the heck does? ;)

Alvin in AZ

Reply to
alvinj

snippage

I picked one up at a shop auction for about half the cost of a new unit. But even a new one isn't That Bad. I get catalogs listing new desktop units for around $600. All things considered, that's quite reasonable for durable tooling. There used to be a local spring fab shop that I bought stock from; they'd thump a blade for a buck, but that was one of those goodbuddy things. When they closed, I got my own out of necessity. High tech where it counts. The oven and the tester give me +/- one point consistency. I think that's 'close enough' for everyday, swords aren't rocket science after all.

Charly

Reply to
Charly the Bastard

I think it was you got me looking at heat treating ovens. If you're doing blades for a living then an oven and a hardness tester should be standard shop equipment. I'll muddle along with my one car garage full of basic tools for a while yet. I still got the day job :-)

GA

Reply to
Greyangel

Yeah, I got one of those toaster ovens. They work pretty well. The last shortsword I did just fit in the gas oven lying flat from corner to courner and I said to myself "self - thats the biggest blade you can make". This time I figured if I couldn't stuff it in the oven then I would go for a quick bluing in the forge. The blade went into the oven from the far bottom corner to the top close corner after I cut an inch off the tang (made purposely long to facilitate handling while heat treating - I drill a hole in the end of the tang and bolt another piece of steel to it). So this last blade is the longest one I can make at this time....

:-) Do you know how many of your posts I skip over till later - when I have the time they require (and deserve) to respond?

Now this is the kind of thing I've been wondering about. I knew there would be some secondary critical curves to work with but haven't seen the information for it. Somewhere in "the book" that I haven't got to yet? What happens when you get below 900 and slow the cooling for more than 50 seconds? What if you get to 600 and stick the blade in a pile of ash to slow cool?

Can you send me a copy of the TT and temper graphs for 5160 and L6??? You got my email address right?

Is there info in there that would not be in the ASM book? At that price I'd be looking for an "all in one" manual - and that's just a wish list at this stage ;-)

It's a strange thing... I know human nature doesn't change much but in this respect things definately have changed. When I was about four or five a soda machine dumped a bunch of change and I was told "it's not yours to take". Now days most folks would brag about the machine giving them a bunch of free cash. And it is getting worse. People are starting to act like the only restraints that count are the enforced legal restraints. If you can't be caught then it's ok... They've put up a bunch of traffic cameras at some of the intersections in town here. Run a red light and get a ticket by photo proxy. Do you know what happens in the non-monitored intersections now?

Haven't tried it yet... I'll do that when I can get to this. Supposed to go forge weld a stack at a friends house today and I still got to clean up the metal... And here I am at the keyboard ;-).

GA

Reply to
Greyangel

Cool, thanks. :)

Page 180 Fig.7-4 is for 1080 instead of 5160. You have 1 second to get 1080 below 900F because there is no Cr (or Mo or hi-Mn) to slow everything down like there is in 5160.

1060 on the other hand, requires even higher speed than 1080 so the 4 seconds the 1% of Cr is giving you in 5160 is more than just 4 times the time.

Page 218 Fig.7-36(b) Sounds/looks like what you did? :)

Page 183 Fig.7-5(a) doesn't-mistakenly-show an Mf [martensite finish] line which is cool for an old book, instead shows an M90[%] line. :) It really is a good book and much better than my school book. The teacher has made up for that by handing out "topic keys" that so far total almost 2" thick. (the stuff left out of the book in his opinion) Funny thing, almost all that stuff is in MT&P. :) (and then some!:)

Page 218 Fig.7-36(abc) again. The Mf line is actually well below zero (for plain carbon steel and lower for alloy steels) so hardly ever does anyone actually do (a) or (b). So what most everybody except for me, when I leave my stuff in the feezer for a couple hours (and Ed Fowler for another guy;) are really doing instead of (a) is in reality more like (c).

MT&P strikes again, see--> Page 214 section-7.7 ;)

I have newer+more expensive books that never even mention that!

Also something I confirmed here just lately is instead of 0.83% carbon being eutectoid it's been retroactively changed to 0.77%. Weird but true. :/

In theory-> Fig.7-36(d) :)

Funny, but in two weeks (after thanksgiving break) we are going to take 11 samples of 1/8" cold rolled 1095 and do 11 different heat treatments to them one including a salt pot and lower bainite formation then test them, including clamping them in a vise and hammering the crap out of them. :)

The last sample (all austenitized one way or another) we'll leave in the furnace and simply turn it off and let the whole works cool down "furnace anneal style", that's one extreme. The other extreme we'll

-water quench with no tempering- another sample. And there will be

9 others in between. :)

For sure... just haven't figured out the best way to go about it yet. :)

They used large print and large graphs, the book is huge but low on info IMO.

Like the metallurgy teacher is fond of saying "all this information used-to be given away by the steel manufactures" and has several old examples with company names on the books, with an address included to get your own "free copy".

LOL! Funny how clueless those in power can be huh? Or ...are they being "dumb like a fox"? :/

Cool. Whenever the mood strikes you, will be fine. :)

BTDT(sorta) but today it's windy as anything here. :/

Alvin in AZ

Reply to
alvinj

As you've seen in another post you have to be careful agreeing with me... when I back-pedal, I'll back-over you. :/ I'm not used to people agreeing with me. In high school I was a libertarian (but didn't know what to call it back then) and almost my whole family is democrats with many of them being do-gooder-bureaucrats. I've never bothered looking in the rear veiw mirror when I changed my mind. ;)

-The shit hit the fan with a "home invation"!- a about a year ago and one of them do-gooder-bureaucrats is now seeing the light. Too bad that's what it takes huh? :/ Others not -directly effected- or too brain damaged from the home invation to think straight :/ ...are still oblivious and simply think I'm nuts and wrong-headed "as always". :/

Why can't people, as smart as these, learn by others mistakes? :/

Why does it have to happen to them directly for them to see what's going on?

Alvin in AZ (ex-C-Span junky, had to quit, the doctor said it was killing me)

Reply to
alvinj

Don't feel bad, I worked my ass off for almost a decade to pay off the tooling. And it's still evolving. Now I need a MiG welder and a pipe bender and an english wheel and an edge roller and I need to make fixtures and jigs and... it never ends. Can I interest you in some cable billet?

Charly

Reply to
Charly the Bastard

Maybe. :) How thin can you go on that stuff?

Alvin in AZ

Reply to
alvinj

The dieset makes .300 thick, but I can whip up shims to make it thinner. It will probably go down to about .075 before it gets flimsy. It's 1

1/2" 7X19 draw wire from a rig. I figure at least 1080 from the spark. I gots lots, and can make up to 24" long. It squeezes down just under 1 3/4" wide at .300 thick. I usually get $50 a foot, plus $10 a foot per fold, which I think is fair for stock considering the labor in it. If you cut into it and find a bad spot, send it back and I'll send you another, shoot till you win. Tell me what you're after.

Charly

Reply to
Charly the Bastard

About 1/8" thick... at least 1" wide... at least 4" long.

A blade blank for a Buck 110 or Schrade LB-7. ;)

Only "need" one so far, just to check the stuff out.

The important part is the thickness.

Maybe it's just that I'm not that good but I find it really difficult to get a wide surface flat and parallel and at a certain number-thickness (.125" +.002" or -.001"). The tricky part is to have only +/-.0005" from one portion of the tang-area to another.

Seems to me, it's up to me, to get that kind of accuracy but if the piece is -way off size to start with- it just isn't worth the trouble. BTDT too many times where the piece had to be scrapped and a new one started.

Since I'm whinnin' "it's too difficult" I won't kick you around if you tell me the same thing back, after all you-are working with a hammer. ;) I'm working with files and can't get it right unless it was pretty stinkin close to start with.

Alvin in AZ

Reply to
alvinj

Same here. :)

I had and used two Taylor thermometers one coiled bi-metal and one mercury. They read the same, so finally settled on the mercury one and bolted it to the rack.

What are you using to austenitize the steel? Are you using "the magnet method"? Are you quenching in "quenching oil" or what? Eide, where you at?

How to draw the temper on my pocket knife springs to ~650F was a puzzle for a while until I realized "stuff begins to glow at 750F in the dark".

So, at night I placed the fresh quenched and sanded pocket knife springs on the "burner coil" of the electric stove, turned on the stove, turned out all the lights and when the coil barily started to glow, I shut off the stove and turned on the lights and whatched the "colors run". :) (later realized, if the dial is set just-right, the stove will turn itself off, as soon as it begins to glow;)

Works like a champ and after they get that pretty "old watch spring" blue color pick them off the stove, cool them down, sand them white again and give them a second draw.

I had one, made from O1, break on me so I went to drawing them twice. I re-drew one-half of that broken spring again and it tested-ok the second time. YMMV

Anybody on here read that crazy method in the Brownell's catalog about burning oil away with the fresh-quenched-spring in it? Not saying it won't work (don't know, but figure it does) it's just who wants to mess with that? (even if you lived out in the middle of nowhere with no neighbors, BTDT, and still didn't like the idea)

Alvin in AZ

Reply to
alvinj

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