In the manufacture of fasteners, the correct selection of fastener materials is an important part, because the performance of fasteners is closely related to its materials. If the material is improperly or incorrectly selected, the performance may not meet the requirements, the service life may be shortened, or even accidents or processing difficulties may occur, and the manufacturing cost will be high. Therefore, the selection of fastener materials is a very important link. Cold heading steel is a steel for fasteners with high interchangeability produced by cold heading forming process. Because it is formed by metal plastic processing at room temperature, each part has a large amount of deformation and a high deformation speed. Therefore, the performance requirements of cold heading steel raw materials are very strict. On the basis of long-term production practice and user research, combined with GB/T6478-2001 Technical Conditions for Cold Heading and Cold Extrusion Steel GB/T699-1999 High-Quality Carbon Structural Steel and target JISG3507-1991 Cold Heading Characteristics of Carbon Steel Wire Rod for Steel, taking the material requirements of grade 8.8 and grade 9.8 bolts and screws as an example, the determination of various chemical elements. If the C content is too high, the cold formability will be reduced; if it is too low, the mechanical properties of the parts cannot be met, so it is set at 0.25% - 0.55%. Mn can improve the permeability of steel, but adding too much will strengthen the matrix structure and affect the cold forming performance; when the part is quenched and tempered, it has the tendency to promote the growth of austenite grains, so it should be appropriately improved on the basis of international standards. 0.45 % - 0.80 %. Si can strengthen the ferrite and reduce the cold formability. SP is an impurity element, and their existence will cause segregation along the grain boundary, resulting in the embrittlement of the grain boundary and damage to the mechanical properties of the steel. It should be reduced as much as possible. B. The maximum value of boron content is 0.005%, because although boron element can significantly improve the permeability of steel, it will also increase the brittleness of steel. Excessive boron content is very unfavorable for workpieces such as bolts, screws and studs that require good comprehensive mechanical properties.
Most of the existing belts control the length of the belt by fixing the other end of the belt by the buckle, and the period that is often buckled by the buckle will be deformed and damaged after long-term use, and the user may change the position from standing to sitting or after meals. The circumference of the belt can be adjusted, and micro-adjustment is not necessarily possible when adjusting the tightness of the pin buckle type or buckle plate type belt buckle. In order to solve this problem, it is necessary to design a belt that is relatively suitable for the waist of a person.
The spring screw is a tool that uses the physical and mathematical principles of the oblique circular rotation of the object and the frictional force to fasten the machine parts step by step; the screw is a common invention in people's production and life for thousands of years. According to the application field, Screws have a wide range of applications.
Applications Automotive industry -- cars, trucks, buses, compressors, construction machinery, wind power equipment, fasteners, fasteners, agricultural machinery, foundry industry, drilling equipment, shipbuilding industry, military mining equipment, oil drilling rigs (onshore or offshore), public utilities, rail transit drives System metallurgical equipment rock hammer
The common riveting techniques of non-blind rivets are divided into cold riveting and hot riveting. Cold riveting is a riveting method that uses a rivet rod to partially pressurize the rivet, and continuously swings around the center or the rivet is forced to expand until the rivet is formed. The common cold riveting methods are the pendulum riveting method and the radial riveting method. The pendulum rolling riveting method is easy to understand, and the rivet head only swings and rolls in the circumferential direction.
We have many years of experience in the production and sales of screws, nuts, flat washers, etc. The main products are: flat head hexagon socket screws, pillar heightened columns, external hexagon titanium screws, GB849 washers and other products, we can provide you with suitable fastener solutions for you Program.