What kind of steel is used for round small size screws?

Update:18-01-2019
Summary:

The rechargeable automatic clip-on screwdriver uses a r […]

The rechargeable automatic clip-on screwdriver uses a rechargeable battery as a power source to enable workers to work anywhere and improve efficiency. The whole is controlled by a motor turntable screw, and the screws are distributed on a turntable similar to a clip.

    The rotation of the turntable is realized by the feeding of the screw, thereby realizing the automatic supply of the screw. The realization of the screwdriver function is completed by two motors, and the motor respectively controls its corresponding working area and reciprocates. Through continuous improvement of the screwdriver, it greatly saves working time, improves work efficiency, and achieves the goal of "win-win". The screws that hold the speaker horn break during transport. Suitable tools for failing screw stainless steel screws, stainless steel chemical anchors and maintenance workers using scanning electron microscopy, metallographic microscope, ICP and hardness tester. First, the structure (see picture): This screwdriver is a two-part set of the screw clamping part and the ordinary screwdriver. The chemical composition and comprehensive performance of the raw material SWRCH22A steel for the production of hexagonal flanged self-tapping screws were tested. The microstructure of the fractured screws was analyzed by scanning electron microscopy and optical microscopy.
Round small size screws and hexagonal small size stainless steel U-bolts are widely used in the inlaying process of metal panels, control boxes and power cabinets. The special structure of the structure, when assembling, just put the small size screw into the hole of the metal plate.

    It is realized by the “up and riveting” operation. Generally, the plate hole is pre-opened on the thin plate, and the small-sized screw is placed in the hole of the plate, and the inner toothless portion is raised from the inside to the outside with the jig, so that the small-sized screw and the thin plate are tightly riveted. Small-size screws are generally not hardened to ensure their toughness. When the fixture is raised, the components can be tightened and the components are not cracked. Therefore, when producing, it is important to choose a good material. The small size screws are riveted to the sheet to form an effective fixed internal thread on the sheet. The small-sized screws are divided into two types: quick-cut steel small-size screws Z NZ type and stainless steel small-size screws ZSNZS type; from the shape, they are divided into cylindrical small-size screws Z ZS; hexagonal small-size screws NZ NZS stainless steel screws four Species, respectively, applied to different use environments. When using the screw column, it must be according to the thickness of the plate used, the exact size range, the hardness of the low carbon steel plate must be less than 70 RB, and the hardness of the stainless steel plate must be less than 80 RB. The surface of the free-cutting iron is processed, and the stainless steel maintains the original color. The user can order the product according to the model specifications in the table, or can be customized according to the needs. The hole size of the plate must be processed to a tolerance of 0-+0.075mm. It is recommended to punch. The installation must be carried out by means of "up and riveting" work, and it must not be knocked in. When the stainless steel chemical anchor material is stainless steel, the tail number is indicated by "S". Due to the special toughness of the steel, the special fixture is used to rise from the inside to the outside, so that the small-sized screws are tightly tightened in the hole of the plate, the components are assembled firmly, and it is not easy to fall off, and the assembly process is simple. 2. In order to further ensure that the small-size screws do not slide, many manufacturers adopt the method of increasing the teeth; 3. The raw materials are free-cutting iron or free-cutting stainless steel; the high-strength nuts are tightened with special wrenches to make the bolts huge. The controlled pre-tension, through the nut and the backing plate, also produces the same amount of pre-stress on the connected parts.

    Under the pre-pressure, a large friction force will be generated along the surface of the connected member. Obviously, as long as the axial force is less than the frictional force, the member will not slip and the connection will not be damaged. This is the high-strength nut connection. s reason.
   The results show that the fracture of the screw is caused by the expansion of the quenching crack caused by improper heat treatment, and provides effective improvement measures to solve the problem of screw fracture. The finite element numerical simulation technology is used to optimize the mold design and forming process of precision micro-screws.