What is the meaning of the screw and the 4 and 8?
Strength grade 4.8, nominal tensile strength of 400MPA products, yield strength 320 (nominal 80%). For details, please refer to GB3098.1 or ISO898-1. There are all indicators
He means that the tensile strength of the screw minimum 400MPa, the minimum yield strength of 320MPa (tensile strength of 80%). Please refer to the national standard GB3098.1 or ISO international standard ISO898-1 the requirements.
Screw should be written on the 4.8 bar, 4.8 on behalf of the strength level
