What the other guys said!

I talked to the metalugist at North Star Steel in St. Paul about
the issue. When they run the common Grade 40 and Grade 60 rebar,
the only thing they have to hit is 40,000psi and 60,000psi
respectively. Easiest way to get the 60,000 number is to let the
carbon content float up to the .4 to .6% range. And this stuff
will be unweldable, might be good for jackhammer bits!

You can buy weldable rebar, it should have 'weldable' impressed
in the side every few feet. Keep in mind that SOME of the common
rebar is weldable, just that you cannot be sure when you buy a
bundle. And just because you get it from a commercial supplier
does not mean you will be getting different stock than Home Depot.

BTW: The steel process is something to watch! 30 cars in, 60,000
pounds of molten steel out 4 hours later. Alloy ingredients show
up in a wheelbarrow. Pour steel into continuous molds (copper
with water cooling) 60' high. Cut the 4-1/2" square stock into
20' billets, send to the rolling mill. Cutting torch does not
need a preheat flame, picture a pure O2 blast hitting white hot
steel. Big boys have big toys!!!

Tim Williams wrote:

In case anyone was wondering, rebar is indeed any composition. Tonight I
was forging on some and out of curiosity, cheezily heat treated one end
(brought it to orange heat, quenched, reheated for a little longer than it
took the water to boil off to sorta temper). Took a strike with the hammer
and sure enough it broke. Spark test reveals something like 1040 but it
must have some other alloying elements since it bears some resemblence to
higher alloy steel (wrench stock for instance).

So yes, it's real crappy material. On the other hand. It can be hardened.
What a scary thought, toolbits forged from rebar. Hmmmm. But still........

Tim

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