Tool Steel Square Bar 1018 has a good combination of all the typical traits of steel - strength, some ductility, and comparative ease of machining. Chemically, it is very similar to A36 Hot Rolled steel, but the cold rolling process creates a better surface finish and better properties. The bar is precision ground to a maximum surface finish of 40 Ra on both the thickness and width. Also, the bar is mechanically straightened with a flatness aim of 0.005" per foot.