COLD-ROLLED FIXING SCREW COMPRISING A SELF-TAPPING THREAD

摘要

Fixing screw formed by cold rolling consists of a material made from steel having a ferritic structure and further components having a higher carbon content compared with the carbon in the ferrite. The mixed structure has a carbon content of maximum 0.42 wt. % and a maximum grain size corresponding to at least 2000 grains/mm2, preferably 3000 grains/mm2, with inherent stresses maintained by he cold rolling.