Here's the problem:
1/4" 1018 flat bar, cold bent on a press using a 1/4" radius punch in a V die, and getting cracks on the heel.
What I know so far: The material is silicon killed coarse grain, cold finished. The coasre grain makes the material more likely to be brittle. 1018 can be case hardened to RC45 in thin (less than 1/2") sections.
My proposed solution is to either hot bend the material or order the material in a better grade, annealed. The problem doesn't occur every time, indicating that there are likely variations in the grade of material we receive, or inconsistency in the material properties (???) from one stick to another in the same heat.
Thoughts?
Is there any way you could utilize a radius of at least 3/8" instead of 1/4"?
If not, IMHO it should not take much heat to resolve the issue since it doesn't happen all the time. A rod oven, if large enough for your parts, might even do it at 250°F, up to 400° may be better. Nothing high enough to change basic properties, just ease the stress load.
Have a Great Day, Brent
I agree with Dualie, 2T or 2.5T would be a mininum bend radius for 1018....or you may have to order it with a number 2 temper(half hard) or number 3 temper(quarter hard) in it if you cannot change the radius.
Take look at the MTR and determine the elongation. Then do the elongation calc for the radius applicable. That will tell you where you stand. Then you can make an informed decision instead of guessing.
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