Bending steel is cracking at outer bend:

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Hi guys,
i am new to bending and recently went for the swagg brake for my HF press.
1018 cold finished steel 1.125 by 1/4" thick and 14" long.
Bend to 90 and inspect bend to find cracking along the entire outer edge of bend.
What am I doing wrong?
thanks,
Jon
 
Cold finished bar already has a fair amount of stress in it, unless it has been stress relieved. Unlikely in off-the-shelf materials. If you have a oxy-fuel torch, heat it up low red for a couple of minutes, then after it cools, try it.

Otherwise, about the only other thing I can think of is that you are trying too tight a radius.
 
Just a carpenter here so I am asking more than saying:)) isn't it just the scale that the flaking cracking is coming from? If it is just the scale cracking is that a problem?
I have some construction grade plates that have a surprising heavy coating of scale on them. I have been looking at them and wondering what I will use them for.

Thanks
Rich
 
I agree with heating red hot. Cool SLOWLY. Plus,you are probably bending the inner corner too tight into a sharp bend. This causes the metal on the outside of the bend to stretch a lot,pulling it apart. It makes for a weak bend even if it doesn't crack on you.

Any way you can contrive to bend the inside with a radius instead of a sharp bend?
 
Jon,

1-try breaking the corners on the outside of the bend.
2-air bend only, no bottoming!
3-female die opening needs to be 8-10 times the metal thickness, so 2-2.5 inches--bigger is better. Male die should have ~3/16 in radius.
This should result in an inside radius of .31-.39 in.

Even following the above guidelines, I've run across some cf that can't be bent a full 90º without cracking. It is then time for the hot wrench!

regards
Bob
 
Radius the edges of the bar(all 4 sides) and bending slowly usually works for me
 
ome said:
Hi guys,
i am new to bending and recently went for the swagg brake for my HF press.
1018 cold finished steel 1.125 by 1/4" thick and 14" long.
Bend to 90 and inspect bend to find cracking along the entire outer edge of bend.
What am I doing wrong?
thanks,
Jon
Click to expand...
Hi Jon,
suggest you heat CDS before bending or if you wish to bend cold use hot rolled steel instead of CDS. Good luck
 
I had the front seat sliding mechanism on my Ford Taurus break. Some "Engineer" had designed the 1/8" thick steel to have a SHARP bend in it. It broke just like a mitered picture frame. I was really angry that Ford was letting stuff like that get by. I found out they were recalling Escorts for the same problem. I got the dealer to have it welded. While I was waiting,I looked at the new Taurus's and saw their seat tracks were bent on a curve. So I traded the car in on a new one. That was such basic safety equipment.

Eventually,I got to where I'll never buy another ford,for the incredible problems I had with my last one,a 1999 Windstar van.
 
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What is the largest radius that you can bend to? This kind of steel would be fine with 1/4" cold. That means that a 1/2" bar will fit in the curve on the inside of the bend. If you need a sharp 90 degree bend, you will have to do it hot, and you will also have to upset the bend. This is almost certainly NOT what you want.
 
Depends what you're using the metal for.
You can also stress relieve it with a bandsaw cut, bend it in, weld and finish the outside radius. Depth of cut would be slightly less than half. Depending on the application, welding, cutting, or heating for a bend will sacrifice some strength.
 
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