Common specifications for large hexagonal bolts can refer to: SH3404, HG20613, HG20634, etc. Its classification can be divided into two categories: ordinary holes and hinge holes, according to the form of force applied to the connection. The bolts used to fix the holes are consistent with the size of the holes and are used when subjected to lateral forces. Hexagonal head, round mouth, square head, sinker, etc. At this stage, large hexagon bolts in the market are mainly made of carbon steel, stainless steel and copper. (1) Carbon steel. We can distinguish low carbon steel, medium carbon steel, high carbon steel and carbon steel by the carbon content in carbon steel. 1. Low carbon steel C%<0.25% is generally called A3 steel in China. Most overseas call them 1008, 1015, 1018, 1022 and so on. It is mainly used for products without strength requirements such as grade 4.8 bolts, grade 4 nuts, and small screws (note: drill tail bolts are usually 1022 materials). 2. Medium carbon steel 0.25% 0.45%. At this stage, it is basically not used in the market. 3. Carbon steel: Alloying elements are introduced into general carbon steel to increase certain characteristics of the steel, such as 35, 40 chromium molybdenum, SCM435, 10B38. The p-xylene screw is usually made of SCM435 chrome-molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo. (1) Stainless steel plate. Property level: 45, 50, 60, 70, 80 martensite (18%Cr, 8%Ni) has good temperature resistance, corrosion resistance and forgeability. A1, A2, A4 austenite and 13%Cr have poor corrosion resistance, high toughness and good wear resistance. C1, C2, C4430 stainless steel. 18%Cr upset forging has better corrosion resistance than austenite. At this stage, the most important imported materials in the market are Japanese products. In terms of grades, they are SUS302, SUS304 and SUS316. (2) Copper. A common material is copper-zinc-copper alloy. In the market, H62, H65 and H68 copper key as standard parts. Tablet PC components for new carbon steel products: 14.8-grade hexagonal screws 1008K10101015K26.8-grade hexagonal screws, serial numbers are optional.