0. Introduction AISI 300 Series based bi-metal self-drilling and self-tapping screws: The solution to manufacture the most ideal self-drilling and self-tapping screw, is to: • Combining the main part of a screw made out of AISI 300 series Stainless Steel. • Having a drill-point and the first tapping threads in hardened Carbon Steel. • The hardened Carbon Steel part (drill point and first threads) will do the drilling and tapping which is then followed by the stainless steel part going into the application and forms the permanent fixing.   it is possible to make construction solutions using suitable real stainless steel for all outdoor use in tough environments; coastal and industrial area     Bi-metal  self-drilling screws meld 304 stainless steel and alloy steel to leverage their differing strengths. A self-drilling, bi-metal screw capable of tapping threads into the sturdiest of substrates while also achieving maximum rust protection   1. Feature : DD Fasteners provide the corrosion resistance of 300 series stainless steel and the efficiency of drill screws.   High strength, ductility, and reliability Immune to hydrogen assisted stress corrosion cracking (HASCC) Higher corrosion resistance compared with carbon steel and 410 series stainless steel fasteners DD Fasteners Ruspert coating creates greater galvanic compatibility in dissimilar metal applications, including connections involving aluminum 18-8 stainless compatible with pressure treated lumber   2. General Applications and Uses: Steel-to-steel connections Aluminum-to-steel connections Aluminum-to-aluminum connections Wood-to-steel connections