Speeds and Feeds for ASTM A-500 Grade B Steel

Hey all- So I machine 99% aluminum. I recently have been machining some structural tubing. I am just curious if anyone knows what you would look up for speeds and feeds in the machinist handbook for this grade of steel? i seem to be wearing out tools like crazy. i used the #'s for a 1018 steel and am not sure if it's even close to correct. the problem is there is no catagory in the machinist handbook for A-500. i was just curious if anyone does a lot of this type of machining and can throw out some speeds and feeds. or what is comparable to look up in the machinist handbook that i can use. Thanks!
Nate

I mainly just use a 4 flute Iscar solid carbide end mill. for most operations.