I'm asking as it seems its about .5mm at my local steel stock holders.
Just bought some steel, they used two strips. The blackened has rounded edges and is 2.85mm whilst the bright has square edges and is 3.3mm.
Bit miffed to get home and notice the difference. Luckily the bloke cutting mis read the instructions and i've got too much bright (so enough to
do what i wanted just out of that - but i have to do lots of my own cutting).
I don't know but if its for the yacht you might need stainless (the winds just changed btw)
Black is hot rolled, Bright is cold rolled.
as said above and sometimes black not exactly very accurate especially the box section......
lots of cheap and nasty Chinese steel out there with crap in it you won't see until you try to gas cut it or weld it.
bright usually comes in shorter lengths than black....don't know why just always has.
Mark
yup as mentioned above, hot rolled and cold rolled, its the hot metal reacting with the air a forming a black scale, also bright has/may have some
post rolling operations to make it exactly the size needed, whereas black doesnt have that (hence rounded edges etc) - black should be cheaper...?
[Edited on 1/11/08 by hellbent345]
On a practical note, the black steel will be easier to bend without cracking - the bright will probably need to be red-hot to achieve the same result.
Isn't bright steel sometimes refered to as enginering steel because of the sharp edges and yes it desn't like to be bent cold.
Tony
Strictly speaking "Bright" only refers to the surface finish not the the grade of steel or manufacturing method although in practice bright steel is always cold formed.
I've always known 'bright' as BDMS - bright drawn mild steel - referring to the way hot steel is drawn through dies to get the correct shape. The action work-hardens the steel, which is why it can crack when bent.
quote:
Originally posted by David Jenkins
On a practical note, the black steel will be easier to bend without cracking - the bright will probably need to be red-hot to achieve the same result.