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cant straighten a curved keeps curving back


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ok i know im new but ive got 2 pices os spring from an old truck 2 times ive tried the annealing process but after i leave em in a 15 gallon bucket of vermiculite overnight they curve and warp so what am i doing wrong or am i ive got em as straight as i could both times but when i go get em the next day they do the curving suff again im heating to nomagnet state and a little above in dim light they are almost orange they arent curving as much as they where but this last time they didnt miss it by much
and what is the best way to get em straight

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when you hammer the steel to get it straight, it natural gets stress in the steel from the hammering, cycle the blade to relax this, and to "reset" the steel this process is called normalizing. After you heat, air cool, and heat heat again, it will remain straight . you may have to straighten a few minor times but after a few cycles it should be better

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Have you tried hammering into a reversed-curve, opposite to the natural bend just to see what happens?

Have you tried using a Jig to restrain it during cooling?

Have you tried heating, then water-quench, followed by reheat and anneal by slow cooling?

Wonder if higher temp might work?

Seems almost like Shape-Memory-Alloy, but that is most unlikely.

Shape memory alloy - Wikipedia, the free encyclopedia

Titanium exhibits "shape-memory" but old truck springs aren't Titanium.

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what ive tried is to straighten then anneal so far i havent tried normalizing is that my problem ?
i havent tried a jig and spring steel in water ? i thought that water wasnt a good thing for spring steel thought it was oil only
i dont have a anvil and no anvil doesnt help at all i been trying to use block but busted 5 so far lol got get something for a anvil

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Fdisk, are they thin pieces?

I've been making a pair of 5160 (spring steel) blades recently, and they (1/8th inch thick) like to warp too. The first one stayed straight after being annealed but warped considerably upon hardening. I normalized it 2 times in a row (heat to critical, air cool), then annealed and it was fine. And it was still straight after hardening. Learning from that, the second blade went much more smoothly with 2 normalizings, annealing, then later hardening and tempering... everything went smoothly. Normalizing is the key!

Also, its good to make sure the piece is evenly supported and that both sides cool at the same rate.

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Another thing would be to try and make sure that it is packed evenly into whatever you use to insulate and try to ensure there is no uneven heat source to ensure even cooling. I'm not a bladesmith though. Thinking out loud now but what do people think would happen if you packed the thinner part better than the thicker part or, say left if on the forge and had the thinner edge towards the bottom where it's retaining more heat, to try and equilibrate the heat retention issues of the different sizes of metal? Would probably take a lot of experimenting and practice to keep it from increasing the warping though.....

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I am not trying to slow down your learning but there are a few things that stick out in your thread: Metal working is a step process. Some folks on here have said it is like trying to run before youlearn to crawl. I think that is an extreme example but it does make a point. Straightening, heat treating and forgeing I believe can be learned by anyone that has the desire. And to do these things you need some basics. There is a portion on the opening page called getting started Good place to begin, There are also some basic tools youi need. There is also info on here for things that may be used as anvils. A lot of the items we need have substitutes that will allow youir growth in this field. You do not need to spend a lot of money and get all the "right" stuff to begin. Start with projects that are basic. Some of the early bps are great projects for those of all skill and experience levels. When you step past basics one of the most often things we see is frustration from failure. It is not a good day in the shop to have things repeatedly fail and not know why. It is not that you are doing things wrong, it is that you have not figured out what is the correct way. The advice above will help, but I believe overall that you will be more skilled in less time if you get into basics as a start. Stick with mild steel and grow into this craft. There is alot ov knowledge in the bps on this site and links to other sources. Work and study,,then work some more. And have some fun.....

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Both pices are 15 inches long 1/4 thick and about 2 inches wide also when i put it in the bucket to cool i placed it closed to 1 side then i later added the other pice beside it and it did seem to bend more that time
and rich i agree with you i may be bitting of more than i can chew but im a pretty persistant person and i have already made 2 forges witch are working pretty good i belive i didnt think metal could be heated that fast and i am used to stock removal but
new to hammer forging thought i would mess around with it while im scrounging for parts to make a anvil it may sound like im trying to take big steps but im realy just trying out stuff not big deal if my first attemp fails i just figured i could make a curved pice off spring close to straight lol
funny thing is my first attemp was more straight than my second but im seeing my mistakes also i musta learned a little so no water on spring steel i had no clue of that 2 weeks ago

also i was a firefighter for 12 years and everytime we had a structure fire about 2 hours later i would feel a little sick to my stomack kind bloted feeling now ive only fired up my forge 2 times first time was with some bs kingston charcoal dint make feel bad at all second time was with cowboy bran hardwood charcoal same smell as a house fire and after about 2 hours i started feeling a little sick what is this im not depriving myself of 02 or anything its just the smell have any of you ever had this to happen ?

Edited by Fdisk
forgot something
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Btw you guys are great i love this forum and im in no hurry just getting my feet wet once i learned i could heat metal to critcal state i just couldnt resist hammering a little i was amazed at how pliable a pice of steel is when heated and i have a boat load of leaf springs for free so thats why i started with spring steel my uncle has a junk yard and he said anytime i want a spring come get it and with all the help files ive read reread and will reread again along with helpfull folks like yall im sure ill get the hang of it in time

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As you noticed, putting both pieces in the vermiculite together doesn't work well, the sides facing each other will cool more slowly, while the outside faces will cool and shrink faster, warping them outwards. I find most smithing operations benefit from consistency and evenness. Heat your metal evenly, cool it evenly.

Study up on heat treating, definitely don't quench air or oil hardening steel in water, and patiently keep practicing. You made it this far (which means you're probly already hooked :) ), just gotta keep at it!

And of course, be safe. It's not fun anymore when you're on fire.

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Granted, water will cause cracking (or worse) to 5160 spring steel 90% of the time, so that was a bad initial suggestion on my part. My point was to Quench it rapidly (Normalize) as opposed to slow-cooling it in vermiculite. Then, you could re-heat/anneal and continue processing.

IF it IS 5160 (or some similar grade of spring-steel from an old truck spring,) it should be forged, then Normalized (heated to Critical-Temperature then cooled in still air or oil-quenchant,) followed by annealing, grinding, hardening, tempering and final-grinding.

Here is a good link on the subject:

5160 Blade Forging Ed Caffrey article

Edited by DerekC
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Granted, water will cause cracking (or worse) to 5160 spring steel 90% of the time, so that was a bad initial suggestion on my part. My point was to Quench it rapidly (Normalize) as opposed to slow-cooling it in vermiculite. Then, you could re-heat/anneal and continue processing.

IF it IS 5160 (or some similar grade of spring-steel from an old truck spring,) it should be forged, then Normalized (heated to Critical-Temperature then cooled in still air or oil-quenchant,) followed by annealing, grinding, hardening, tempering and final-grinding.



Derek, You should take a back seat to this, as you have 3 strikes already, #2 YOU do not quench at all to normalice, not rapidly, also
#3 NOT OIL cool for normalizing, the OIL is a quench for hardening,
It is hard enough to learn things with out false and incorrect information being thrown about.

Also fDisk remove the galv, before it kills y ou. Please. Edited by mod07
typo
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ok i used my forge with the galvanized tube and when it is at its hotest i can place my hand on it its a little warm but not hot but as soon as i can ima make another with no galvanizing and the normalization seems to be my problem so far from what i had read i thought i needed to anneal first the normalize but i guess that part isnt as important as to what is first till i need to work the steel

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Hi Fdisk. It does not sound like fume fever to me. I made a similar Lively style forge, and the galvanized sheet does not get hot enough to release fumes. It doesn't even get hot enough to boil water. But, I did get some zinc fumes from a galvanized pipe that I used for a ground forge. I was careful not to breathe them. The worst I had was when I was pouring brass. I was working in a real shop with a high ceiling and hood. The foundry master made me wear leathers and spats, and choreograph the moves dry, but he laughed at me when I said that I was afraid of getting fume fever. As soon as the brass stream broke out of under the cover flux, it would flare up and produce a big cloud of zinc fume. If I ducked my head away, I'd mess up and get voids in the casting. Somehow the pour had to be very smooth. Oddly enough I got a lot of metal taste in my mouth, but never got fume fever. Guess the old guy knew what he was talking about.

As for getting sick from the charcoal fumes, yes, I have seen this happen. It depends on the brand and source of the charcoal. I have noticed that incompletely coaled charcoal can get some people sick. I got a couple of ladies sick during a demo with some bad charcoal, but I didn't get sick myself. Strange. The smoke did smell funny. I also do BBQ and smoking, and some of that lump charcoal can make people who eat the meat sick. Just switch brands.

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Fdisk:

Your problem isn't heat treating, (normalizing, annealing,) etc. your problem is lack of basic forging skills.

You are trying to straighten a piece of arched spring steel by hammering it on an anvil. This will change the thickness and cross section unevenly, you don't have the skill to do so evenly as yet. Straightening flat stock on an anvil face is harder than it looks. Apprenticeman was only half kidding when he said your anvil is too flat.

Even us old dogs tend to forget how hard straightening was when we were learning so here're a couple tricks.

#1. Straighten over the hardy hole. With the arch up apply easy blows over the hardy hole. This will bend the steel with minimal alteration to the thickness.

#2. Use a wooden block to straighten on. A nice sized (say 6-8" dia) end grain piece of not too hard wood like poplar works nicely. Again, it will BEND your arched spring stock straight without altering the cross section.

#3. Use a wooden mallet and your anvil. Again this will minimize alteration of the cross section, bending it straight.

Your problem is uneven alteration of the cross section as you attempt to FORGE it straight. You want to BEND it straight, not FORGE it straight.

Forget about the heat treating for now. Spring steel is pretty forgiving of mis-handled heat treatment as long as you don't push it. Don't quench it in water from any heat, just lay it in the dirt and let it cool down till you can hold it again. At the end of the day poke it in a bucket of perlite, wood ash or warmed lime for the morrow.

You are attempting things so far ahead of yourself you are NOT going to succeed unless you are VERY persistent and immune to frustration. Look at it this way. What advice would YOU give a guy that wanted to go into a burning building who didn't even know how to buckle his turnouts?

Of course this is nowhere near as serious, it's just the analogy that came to mind I figured would really stand out for you. Nothing you're probably going to do at the forge is likely to get anyone hurt.

Unless maybe you do quench the wrong piece of steel and it shatters, minutes, hours or days later when some innocent picks it up to take a look.

Frosty

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