What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
At present, the standard parts on the market mainly include carbon steel, stainless steel and copper. A carbon steel. We distinguish low carbon steel, medium carbon steel and high carbon steel and alloy steel by the content of carbon in carbon steel material. 1 Low carbon steel C%≤0.25% is usually called A3 steel in China. Foreign countries are basically called 1008, 1015, 1018, 1022, etc. Mainly used for grade 4.8 bolts, grade 4 nuts, small screws and other products without hardness requirements. (Note: 1022 material is mainly used for drill tail screws.) 2 Medium carbon steel 0.25% 3 High carbon steel C%>0.45%. 4 Alloy steel is basically not used in the market: alloying elements are added to ordinary carbon steel to increase some special properties of steel: such as 35, 40 chromium molybdenum, SCM435, 10B38. Fangsheng screws mainly use SCM435 chromium molybdenum alloy steel, the main components are C, Si, Mn, P, S, Cr, Mo. Two stainless steel. Performance grade: 45, 50, 60, 70, 80 1 Mainly divided into austenite (18% Cr, 8% Ni) with good heat resistance, good corrosion resistance and good weldability. A1, A2, A4 2 Martensite, 13%Cr have poor corrosion resistance, high strength and good wear resistance. C1, C2, C4 ferritic stainless steels. 18%Cr has better upsetting and corrosion resistance than martensite. The imported materials on the market are mainly Japan. According to the level, it is mainly divided into SUS302, SUS304 and SUS316. Three coppers. Commonly used materials are brass...zinc-copper alloys. The market mainly uses H62, H65, H68 copper as standard parts.
The positioning pin is a pin designed to accurately position the two adjacent parts of the mold in a mold composed of two or more parts. It can be seen that the positioning pin plays a positioning role, and the mold must be accurately synchronized when it is closed. product, and the positioning pin can make the upper and lower molds play a role in accurate positioning. In the mold design and manufacture of Yueluo, the positioning pin is one of the most common parts. Since it is only used for positioning between parts, few people will pay too much attention to it. In the cold stamping process of Yueluo, the dimensional accuracy of the blanking parts depends on the size of the working part of the punch and the concave die, and the dimensional difference between them constitutes the blanking die gap. Gap is an important process parameter for die design, and its size has a great influence on the quality of the section of the blanking part, the blanking force, and the life of the die. If the gap is too large, punching burrs will appear in punching; if the gap is too small, secondary cracks will occur in the section and extrusion burrs will appear, which will make the quality of the section after punching unsatisfactory, and a reasonable gap will not only help the punching section. The improvement of quality also contributes to the improvement of the lifespan of the 5-pack.
rivet is a nail-shaped object used to join two parts or components with a through hole and a cap on one end. In riveting, the riveted parts are connected by their own deformation or interference. There are many types of rivets, and they are informal, commonly used are R-type rivets, fan rivets, blind rivets, blind rivets, tree rivets, semi-circular head, flat head, semi-hollow rivets, solid rivets, countersunk head rivets, blind rivets, hollow rivets Rivets, these usually use their own deformation to connect the riveted parts. Generally less than 8 mm with cold riveting, larger than this size with hot riveting. But there are exceptions. For example, the nameplate on some locks is riveted by the interference between the rivet and the lock body hole.
screw is a common threaded connection part, which is mainly used to fix a part on the connection body. When it is necessary to connect, use the screw to pass through the hole on the connected parts, and screw the external thread on the screw into the connecting body to tighten it; The coupling part is separated from the coupling body. Existing common tools for screw disassembly and assembly are generally adjustable wrenches, open-end wrenches, Torx wrenches, socket wrenches, Allen wrenches, flat-blade screwdrivers, cross-shaped screwdrivers, etc., and a screw can only be disassembled with one or one type of tool. Assembly work; when the types of tools are not complete, the screw disassembly and assembly work is difficult to complete, and the screw disassembly and assembly work is greatly limited by the tools.
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