| 摘要 |
The invention relates to a cold-rolled fixing screw consisting of a low-alloy carbon steel with a high degree of deformation according to the ratios of external diameter to core diameter of > 1.2 and pitch to external diameter of > 0.23, with a self-tapping thread for screwing into materials, in particular plastics. The screw material of said steel screw with a ferritic structure contains additional constituents with a substantially higher carbon content than the carbon that is contained in the ferrite. Said mixed structure has a maximum carbon content of 0.42 weight percent and a maximum grain size that corresponds to at least 2000 grains/mm2, preferably at least 3000 grains/mm2, with a residual stress that is impressed and maintained by the cold rolling process. |
