The standard values of 4.8 and 8.8 are based on the characteristics of the data, the better the performance.
1. Class 4.8 bolts are made of raw round steel. The specification and model is not accurate enough to resist bending deformation when connecting, but it is convenient to install and has low production cost, so it is mostly used for tension connection or temporary fixing during installation.
2. The shank of 8.8 grade bolt is machined by numerical control, the surface is smooth and the specification is accurate.
3. The production and installation is complex, the price is high, and it is seldom used.
General bolts can be divided into A grade, B grade and C grade according to the manufacturing precision. Class A and B are special bolts, and class C are random bolts.
For connecting bolts used in steel frame structures, ordinary class C bolts are generally used unless otherwise stated. There are differences in processing methods of different grades. The general corresponding processing methods are as follows: the bolt rods of An and B bolts are machined by numerical control, with smooth surface, accurate specifications and complete grades of raw and auxiliary materials. For grade 8.8, the production and installation is complex, the price is high, and rarely used. Grade 2 C bolts are made of unprocessed round steel, the specifications and models are not accurate, and the characteristic grade of raw and auxiliary materials is 4.6 or 4.8. The bending connection has large deformation, but the installation is convenient and the production cost is low. It is mostly used for stretching connection or temporary fixing during installation.
Post time: Jan-06-2023