grain in steel plate?

Well, it is like a forged piece, cold or hot rolled steel. You do have cristals that are initialy unoriented. As soon as you "massage" the steel, the crystals get longer and longer (like whiskers). Yes, there is a difference in strenght. You know of forged steel. But more, it makes a difference in keeping the edge in a knife or so. Warpage? Yes. The outer skin is compressed. If you either cut it away or heat it up during welding (or remove when cutting) it will relief the stress and the part will bend. Hot rolled steel isn't that much prone to warpage.

HTH, Nick

yes to all.

Gunner

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Theodore Dalrymple,

I havn't seen any call for a particular orientation in steel but I have seen it in alumiun quite often

I thought AL was grainless, at least if it isn't forged. OTOH, a "grained" finish is often specified on fabricated AL parts. It's just a surface sanding that looks like grain.

The first chunk of steel approx. 1.5" X 8" X 10" that I tested my planer that I just brought back to life showed me. I could not figure out what I was doing wrong for the longest time. Everything I tried gave about the same results, like shave/cutting string cheese against the grain. Sure looked like it was ripping the steel to me, and after weeks of pounding my head I turned the work 90's and it cut beautifully.

Grant,

Although machinists almost never talk about grain, smiths talk about it all the time as a dominant concern. You can find more information in those circles. It really is a big deal for parts operating near their limits.

All steel has some grain direction. It is extremely important if you are rolling or forming the material. Imagine rolling a plate the wrong way into a pressure vessel. If the plate is low alloy and you form a standard ninety degree bend it will open up..... or in some cases split. You might try taking a 1/4 by three flat bar, cut a square piece in your ironworker then form it the wrong way. Flat bar has a very pronounced grain compared to mild steel plate. In a properly run plate shop as material is cut, all the crops are marked with grain direction. If you do a weld test on plate with grain running the wrong way it can be interesting when you bend test. Randy

GWE

Nope! Aluminum has grain, and the surface of which you speak is generally not from sanding, but rolling. That's not to say that you can't find sanded material.

While it all has grain of sorts, the alloy and heat treat (if it's a heat treatable alloy) makes a huge difference as to how it responds. For example, using some 6061-T6, try making some strips, maybe 1" wide, from

1/8" thick material, running the "grain" on one sample parallel to the long side, then one with the grain at right angles to the long side. Bend these strips in a fairly tight 90, say a 1/8" radius. The one that has the grain running parallel to the long side will bend nicely, while the one that has the grain at right angles to the long side (parallel with the bend) will break.

There are occasions when it's difficult to discern the grain in aluminum, but the material is generally marked parallel to the grain, so that can be used as a method of determining which way it runs.

Harold

I don't doubt you. OTOH, I've called out grain on AL electronics sheetmetal many times and I've watched the tinbender apply it with a giant belt sander.

Come to think of it, you're right. I do remember grain being an issue on minimum radius bends in AL sheet.

What about something like cast tooling plate? Would it have a grain, or perhaps a crystaline structure that would act like a grain?

So what is the right way to bend a 90 degree vee in plate? Bend it so the bend axis is parallel to the grain, or perpendicular?

GWE

Interesting subject----How is grain affected on a bend if the piece is heated to cherry red first? As in bending across grain but heating to cherry red. Or heating after a bend..

ED

To remove all grain "direction" you would have to heat the steel to near molten. If you heated the steel to red you would reduce the problems of opening up the grain when bending the wrong way. At elevated temperatures grain can be persuaded to be non directional but this is at high temps and long soaking times. The grain growth would result in a weakened material. I have bent "J" bolts out of one inch diameter 4130 alloy. You had to have a very bright red to successfully bend the bolts without tearing the grain. If bent at a dull red the bar tore open much like a wooden tree branch. I have personal experience in this unfortunate matter :')) Randy

ED

Grain makes a big difference if you need to bend or fold the metal. Less chance of cracking if the bend is perpendicular to the grain.

David