Suitable for alloyed and non alloyed steel up to a tensile strength of 900 nmm non ferrous metals cast iron hard plastics high elasticity due to low heat shaping manufacturing process low risk of breakage especially when drilling with diameters smaller than 6 mm spiral flute with oxide coating for rapid chip removal long lifetimes due to tough core thickness and distinct hardness within the area of application 13 piece metal drill bit set hss r din 338 1 5