Tor:

Don't know if this is much help, but I offer the following:

First digit is alloy type: 1 indicates 99.00 or greater purity of aluminum

Last two digits, for 1000 series indicates the nearest hundreth of aluminum purity. (1130 would be 99.30% pure)

Second digit indicates "special control" of an impurity.  Whether that major impurity is iron or silicon, or something else I do not know.

A few web-sites to consider might be:

www.naad.org

www.aluminum.org

A book I use for reference is "Structure and Properties of Engineering Alloys" by William F. Smith

Machinery's Handbook also has some good information also.

Scott

Thank you for quick response.
But the second digit info is the one Im looking.
Still, your info on the last two digits has helped me a lot.

Thanks again.

The following is the compositional differences between
1100 and 1200:


1100
.95Si+Fe, .05-.2Cu, .05Mn, .10Zn, .05others

1200
1.0Si+Fe, .05Cu, .05Mn, .10Zn, .05Ti, .05others

Vince