What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
The technical process of nickel-phosphorus plating for high-strength bolts consists of three parts: The first part is the pre-treatment process, including the precision and appearance inspection of high-strength bolts before plating, manual degreasing, immersion degreasing, pickling, electro-activation and flash nickel plating and other processes; the second part is the electroless nickel plating treatment process; the third part is the post-treatment process, including the processes of hydrogen-displacing heat treatment, polishing and finished product inspection. As follows: Bolt chemical composition inspection → bolt pre-plating accuracy, visual inspection → manual degreasing → visual inspection → immersion degreasing → hot water washing → cold water washing → pickling → cold water washing → electric activation → cold water washing → flash nickel plating → cold water washing → Deionized water washing → Electroless nickel plating → Deionized water washing → Cold water washing → Hydrogen removal → Polishing → Finished product inspection.
2. Low cycle fatigue Low cycle fatigue means that the fatigue stress is close to or exceeds the yield limit of the material. The material has a certain amount of plastic deformation in each strain cycle. The life is generally in the range of 102 to several times 104, and the fatigue curve is generally used. ε-N curve representation. The finite element calculation results show that after the bolt is screwed into the lock nut, the stress at the root of the threaded piece is large, and part of the surface area is in a yield state, while the strain in the central area of the root of the threaded piece is small, and the strain situation is more complicated. The area with high strain at the root of the thread piece experiences reciprocating loading, which is prone to low cycle fatigue, which reduces the pressure of the thread piece and reduces the screw-out torque.
In order to achieve this technical purpose, the plan of Guangdong Yueluo Hardware Industry Co., Ltd. is: a new type of open rivet, including a rivet body and a mandrel, the rivet body and one end of the mandrel are fixedly connected, and the lower end of the rivet body is provided with There is a round table, the top of the mandrel is provided with a nail head pit, the mandrel is provided with a stop groove, the lower side of the stop groove is provided with a mandrel breakpoint, and the mandrel is set on the mandrel. There is a stop ring, the stop ring is located on the lower side of the round table, and the lower side of the stop ring is provided with an assembly warp.
The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to overcome the deficiencies in the existing technology and provide a square nut fastener for cable tray installation, which has a simple and reasonable structure, and is extremely convenient and flexible to operate; it does not occupy C-shaped steel after installation. The space at the bottom increases the diversity of installation, and can be applied to square nuts of different thicknesses, and the installation is firm
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