The identification methods of high strength bolt are mainly seen in five aspects:
1. Look at the mark. Generally, there is a mark on the packing box of the bolt. It can be divided into three levels: 8.8, 10.9 and 12.9. Generally, there is no grade mark on the hexagonal plane of hexagon bolt, which is an ordinary grade. Generally, high strength bolt has strength indication. For example: 8.8; but now there are too many fake and shoddy, we should also pay attention to the purchase channel and purchase acceptance.
2. Generally, the grade of inner hexagon bolt is high, because the inner hexagon hole of inner hexagon bolt can be used only after heat treatment. The material that can improve the hardness after treatment is quenched and tempered steel, and the mechanical strength of quenched and tempered steel is high;
3. Non galvanized high-strength bolts are generally black. The black outer layer is an oxidation layer formed by artificial processing, which is called blackening in industry. It is a protective layer formed by corrosion of strong alkaline substance on metal surface, which can resist oxidation. There is also a process called hair blue, the role and principle of the same. Therefore, high strength bolts generally will not rust!
4. The simplest experience judgment: throw it underground and listen to the sound. The high-intensity sound is brittle. The bright sound is made of steel strip. Through the scratch test with saw blade and other hard tools, the surface hardness of high-strength bolts is higher than that of ordinary bolts.
5. The problem of quenching and tempering is that the general high-strength material without quenching and tempering is grade 8.8. Maybe some businessmen will not adjust and temper it. When grade 12.9 or 10.9 is sold to customers, the way to distinguish is to see that in the sun, the hair that is not tempered is dark, the hair that has been tempered is colored, and the hair that has been burnt will be colored. This is the most basic common sense.
8.8 Heavy Hex Bolt And Nut Galvanized DIN 931 8.8 Grade Heavy Hex Bolt And Nut Galvanized Grade: 8.8/ 10.9/ 12.9 Ect Color: Oxidation blackening,Zinc plating, Surface treatment: HDG, PTFE coated, plain, black, galvanized, yellow zinc plated Packing: 25kg carton then pallet or according to the customer’s need Application: Machinery industry High strength bolts Length: […]
DIN931 Black Heavy Hex Bolt Material: Stainless steel 303/304/316/316L,Carbon Steel,Alloy Steel Brass,Bronze,Aluminum. Surface: Bronze, Zinc, Rainbow, Plain, Nickle, Passivated, Electrophoresis, Dacromet, Chrome plated. Head Type: Pan,Binding,Cheese,Truss,Flat,Oval,Round,Fillister, (Trim) Hexagon (Socket Cap), Lotus, Square. Drive Type: Slotted(Socket), Square, Pz, Philips, Triangle, H, Torx(Pin), Rri-Wing, Lr, Sing Way. Heat Treatment: Tempering,Hardening,Stress Relieving,etc. Available Sizes: M1.6,M2,M2.5,M3,M3.5,M4,M5,M6,M8,M10-M20 Standard: GB,JIS,ANSI,DIN,BS,ISO,Sample is […]