Bolt, High strength bolts, Screw
Standard fastener products include 12 categories, such as bolts, studs, nuts, screws, wooden screws, Self Tapping Screws, washers, rivets, pins, baffles, fasteners, and connecting pairs (such as welding nails, irregular nails). At present, on an international scale, the "Fasteners" (ISO/TC2) of the Second Technical Committee of the International Organization for Standardization only includes bolts, nuts, screws, and self tapping screws (including self drilling self tapping screws and self extrusion screws), and has developed and released international standards for 9 types of products, including flat washers, core rivets, pins, fasteners, and welding nails. Among them, products such as bolts, nuts, screws, self extruded screws, self tapping screws, self drilling self tapping screws, and flat washers have specified mechanical properties (grades), but no material grade is specified.A screw is a tool that utilizes the physical and mathematical principles of the oblique circular rotation and friction of an object to gradually tighten the mechanical components of the object. Screws are a common term for fasteners, commonly used in everyday language. Screws are essential industrial necessities in daily life, such as tiny screws used in cameras, glasses, clocks, electronics, etc; General screws for television, electrical products, musical instruments, furniture, etc; As for engineering, construction, and bridges, large screws and nuts are used; Transportation equipment, airplanes, trams, cars, etc. are used with both large and small screws. Screws bear important tasks in industry, and as long as there is industry on Earth, the function of screws will always be important. The screw has been a common invention in people's production and life for thousands of years, and according to its application field, it is the first great invention of humanity. 
