[TheForge] Re: triangle bells/rebar

[Devon Headen]

>The modulus of elasticity for carbon steels is virtually the same at  
>30,000,000 psi. Hard or soft, strong or weak, tempered or quenched or  
>annealed. Up to the point that it bends permanently, a spring or blade  
>made of A36 will deflect virtually the same as a spring made of  
>quenched and tempered 5160 (under the same load). As Jim said, the  
>stronger material will allow you to bend it farther to a higher stress  
>level before it will bend permanently and not "spring" back to it's  
>original shape. The stress level that it bends permanently at is called  
>the yield stress. Yield stress varies dramatically for different steels  
>and different materials. A-36 steel has a yield stress of 36,000 pounds  
>per square inch. A572 grade 50 has a yield stress of 50,000 pounds per  
>square inch. Quenched and tempered 440C stainless has a yield stress of  
>270,000 psi. (grin) Alloy content and heat treatment DRAMATICALLY  
>affect yield stress. But not moment of inertia of the shape or modulus  
>of elasticity of the material.

That's very interesting. Like I said, I just started doing this a couple've months ago, so I'm not all that knowledgable, so humor me. Do you know if there is any difference in density of different steels? It seems like there would have to be some.

On rebar. I've tried rebar from several different sources around here, and all of it I've come across is pretty much crap. It forges rather well hot, but as soon as it gets cold it really likes to break at stress points. I make a tool rack out of some rebar. Worked fine the first two times I slid the hammer in. On #3, the metal snapped right in two.