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Fix cracks in billet posible ?


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Wanted to continue my work on a springsteel billet and noticed cracks at the first blow.

Is there a way to fix this mess?

 

crack1.JPG

 

crack2.JPG

 

Last thing i remember is quenching that part in cold veggie oil to test the hardness, yes was hard..

My understanding is that springsteel should be able to handle a wee bit of cold oil..

Edited by Karim
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It seems the steel was way too hot for any kind of quench. It exploded.

In my opinion you ruined the whole piece beyond any fixing trick. At least for this cracked part.

 

Cut it and use the rest.

Quench tests are good to do, but use small samples

 

You learned something today :)

 

Stéph

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Looks quite nicely crazed.

It might have been the quench, might have been something else. Might be worth checking the rest of the billet for hairline cracks, whatever's left of it.

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There can be quite a few factors that caused the cracks. Stephane brought up a good point about over heating and quenching. I do find it hard to believe veggie oil (especially cold) could cause cracks that drastic though. Since you aren't specific on what steel your using my guess is that you're using a "mystery steel" that already had cracks/fractures in it from before, which is common in leaf springs, old mower blades, etc. , and the quench exaggerated the cracks.

Edited by Austin_Lyles
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It could be the steel itself and just exploded during the quench. This one leaf spring I tried using was just stock full of cracks, had to ditch practically the whole thing.

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This billet was forged from a big ass part of the leaf not just cut out. I had to draw it out from ab 2cm/3cm to this size, so moved almost al the material. Thinking of that the steel should have been fine b4 i messed whit it. Or is this still possible to have fractures even after moving all the metal? :wacko:

Next time small part for heat treating...

As fixing (experiment) the only thing i can come up whit is heating to forgeweld and removing all the steel again, cutting restacking during the process.

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It is possible for small cracks to survive all that forging, since they move with the rest of the steel. They show up whwn quenched because of the contraction. And while in theory they might weld back together, in practice that rarely happens. I would scrap it and start over.

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The cracks are probably not bad luck, but caused by forging too hot (overheating the steel during forging process). Spring steels can be a bit more fussy to forging temperature than simple carbon steels. Some steels 'cottage cheese' when you get them to hot which can be interesting !

 

If you overheated a few times, and then quenched without any normalisation cycles the grain the steel may have been moohasive when you did the oil quench, which would not have helped with it remaining homogeneous ! It would be interesting to break a bit of the billet and have a look.

 

If the steels in a billet are very different you can also get problems with heat treatment when they have different contraction (or expansion!) rates on quench, and the billet will tear itself apart.

 

Both Owen Bush and Mick Maxen (whose skills I am in awe of) told me in my very early days of pattern welding, when I was messing with 'unknown' steels, that known steel was very cheap in the overall scheme of things. They were 100% right. I still think I learnt a lot more about patternwelding from having to ponder what when wrong when welding the back of a filing cabinet to a landy leaf spring than I would have done if I just got a load of compatible 15n20 & 20c from the outset though ! :D

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I don't think arc welding would do you any good anyway when the steel is as comprehensively buggered as yours is.

Was the springsteel new or reclaimed? I had a few run ins with reclaimed spring steel when I first started out. I don't know if it was the composition or fatigue or what but crazing, cracking, crumbling and a stubborn refusal to weld are some of the properties I fondly remember.

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Looks like bad overheating. How hot did you get this? Stress fractures, from fatigue, in my experience simply run across the bar in one or two places , not all over the place like this piece. I forge spring stock all the time and never had anything look like this.

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Looks like bad overheating. How hot did you get this? Stress fractures, from fatigue, in my experience simply run across the bar in one or two places , not all over the place like this piece. I forge spring stock all the time and never had anything look like this.

Was red hot in daylight, waited one min then quenched. But at least i earned a bonus for " how bad can i crack it ! " :lol:

 

John:

Would you like me to try and smash of a piece of that iron (still hard and thick) or grind true as u prob will not see any grain structure then?

 

And yes so true, if i was doing this as profession i would stick to known steels 100%, only i like exploring and consider springsteel/railroadsteel the best low costs steels to use if they will harden n are forge-weld-enabled, this in combination whit high carbon steels for a edge.

 

Dan:

Used/reclaimed springsteel if that means the same ... Alan also stated no welding and yes for this billet, no hope haha

As far as fatigue in metal my theory would be to realign the molecules whit heating and normalizing, local repairs will introduce new fatigue cracks.

Edited by Karim
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Ha! You gave it away: "red hot in daylight." This is often white hot in dim light. Never try to forge in open daylight, nless you have trained your eye to compensate. There is a reason we smiths like to work in dimly lit burrows, it's better for the steel.

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Alas, Karim, only experience with what is too hot or too cold is the only thing that can teach as far as this limited communication can go. :( Can you work after dark? That will show you much about the nature of your heat and steel. And mineral coal is not so bad if you can get it, it's no so bad for setting the shed on fire. ;)

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Ha! You gave it away: "red hot in daylight." This is often white hot in dim light. Never try to forge in open daylight, nless you have trained your eye to compensate. There is a reason we smiths like to work in dimly lit burrows, it's better for the steel.

I very rarely can work in a dimly lit forge. I used to have a big piece of pipe stood on end that I could hold hot steel inside to see the true color. Then my wife made it into a planter......

My next forge stand will have an enclosed area under the forge much like a lot of brick & mortar forges have for the same purpose.

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You said Cold Veg oil....how cold was it? Room temp or fridge cold?

was from the store and we are having a warm period ab 26c (above room temp)

 

I sometimes walk into my shed whit the iron clamped in thongs to see if its red or white, best can do for now .. red i use to forge, red/black (tactually red in the shed) i use to hammer in shape, white i use to set welds.

 

Alan:

no working after dark now, try to keep the neighbours happy by being considerate ab time and forging hours spend. The last smith in the village left us years ago so i have to find out myself, whit help and thanks to pointers on this forum, considering some holidays in Holland your welcome ;)

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A word on how I prepare reclaimed leaf springs, I usually cut off 6-8 inches from the mounting points(ends and middle) then I split item in half long ways and inspect the cuts looking for any cracks, I usually end up scrapping around 25% of each leaf. I also have the misfortune of having an outside forge, I get past lighting issues by having it on the north side of a shed and underneath a large oak.

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Yeah, you don't need true darkness, but shade is good. When I replaced the fluorescent tubes in my shop a couple of years ago I went from soft white, 3500K color temperature to daylight 6500K because I could see my non-forging work much better that way. It took me a few weeks to be able to forge weld again afterwards because things looked cooler than they were in the fire compared to the old.lights.

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If you are forge welding don't wear sunglasses. It can damage your eyes after long term exposure. They don't block the IR light that is emitted at those temps, and actually causes more of it to enter your eyes because your pupils are dilated.

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