It is a common error in assuming that Stainless Steel Self Drilling Screws will drill into steel. However, that is not the case. To provide corrosion resistance, stainless steel self-drill screws are made from AISI-304 or AISI-316 grades. These cannot be hardened and therefore the drill point can only drill into softer materials like Aluminium. For fixing onto steel structures, Bi-Metal self-drilling screws have been developed. These screws have a carbon steel tempered drill point welded onto a stainless steel shank. This design enables the dual advantages of 1) self-drilling through hard metal sheet up to 12mm and 2) corrosion resistance on the stainless shank 3) drilling, tapping and fastening in one shot. Besides, the induction heat treatment on drilling point, which avoid sensitization of the stainless steel material on the shank.
