The high-strength stud is used for the fixing and linking function of the connecting machine. Both ends of the stud have threads, and the middle screw has thick and thin ones. It is called straight rod/shrink rod, also called double-head screw. Generally used in mining machinery, bridges, automobiles, motorcycles, boiler steel structures, pylons, long-span steel structures and large buildings. Bolts refer specifically to screws with larger diameters or without heads, such as stud bolts. In general, it is not called "stud" but "stud". The most common form of stud is threaded at both ends and polished rod in the middle. The most typical use: anchor bolts, or places similar to anchor bolts, when thicker connections cannot be achieved with ordinary bolts. High strength stud bolts are mainly used in construction, transportation, hardware, construction sites and other fields. Grades: 12.9, 10.9 and 8.8