grain in metal

If grain has a direction in a given piece of wrought metal, it's because it was forged or cold-worked in the direction of the grain axis. If you're looking at a piece of rolled steel or other metal, in other words, the grain direction is lengthwise: parallel to the axis on which it was rolled.

Cast parts may have some local grain direction, which will be perpendicular to the face of the part, where grain-gorwth was propagated by chilling and crystalization. Within one casting, that can mean there are many origin points of grain-growth direction, and they can oppose or intersect each other. But the grain in castings is relatively unimportant, except that it can identify a potential line of failure if the part is overstressed.

In forgings, the effect tends to be the opposite. The grain line follows the direction in which the metal was worked, and it follows curves or bends that are forged into the metal. The grain in this case adds strength, or reduces the *loss* of strength that occurs when grain direction runs perpendicular to the line or plane of stress -- particularly tension.

Oops...I reread that, and it looks like mud. Good luck.

Ed Huntress

Aluminum sheet that's been grained has simply been run through a giant belt sander. The "grain" in this case is just a surface finish.

perpendicular

Not to me! Sort of the same way my crippled mind thinks. I agree fully with your comments, Ed, for what it's worth.

Harold

perpendicular

perpendicular

Not the same thing, Jim. He's talking about the grain structure of the object, not the finish on the surface, although I'm willing to suggest that in most cases, if the full sheet has been so finished that the graining would parallel to the grain structure of the base material.

Harold

Aluminum sheet that's been grained has simply been run through a giant belt sander. The "grain" in this case is just a surface finish. ^^^^^^^^^^^^^ Not the same thing, Jim. (clip) ^^^^^^^^^^^^^ What about the grain in bread. I think it's random.

I have formed tons of aluminum sheet and it definitely has a directional grain. Form a ninety in the wrong direction and the plate cracks. Randy

Not if you buy forged bread. It's only cast bread that's random.

Rolled bread is something we don't want to think about. It's what you get when your groceries fall out of the bag, you don't notice, and you run over them with your car.

"Rolls" are just not the same thing.

Ed Huntress

Maybe we're both suffering the same malady, Harold. Too many zinc fumes, maybe.

Ed Huntress

In bending steel plate the minimum bend radius is the smallest if the bend is across the grain. If bending parallel with the grain, a larger bend radius is required. When rolling steel the plate is frequently turned 90 degrees until it gets too wide. After that it is rolled to the required thickness which is than the grain direction. HTH.

Does 12 Grain bread have more strength that 7 grain?

Tony

Oh, contraire! We grind our own. Always the same grain, although certainly randomly placed!

Harold

Nah, not a chance. I've yet to see any zinc fumes coming off my monitor. These days that's about the only thing I'm up to. Damned winter.

Harold

I'm inclined to say only when made with cheese. Makes it more binding.

Harold

A good question; I suppose it depends upon heat-treatment. You can refine the grain by chewing and swallowing the bread. Checking out the results, though, is a little messy. See Gunner's post on "Top Gun."

Ed Huntress

Thanks Ed, your explanation was quite lucid. And thanks to all the rest of you also for the excellent treatise on grain direction in bread. Quite amusing - Bob S.

Have you ever tried to change the grain on aluminum and then anodize it. The natural grain will come back and then you have 2 different grain.

Glenn Houst>I have formed tons of aluminum sheet and it definitely has a directional