Currently, a screw generally includes a shank body, a threaded portion formed on the outer edge of the shank body, and a conical head formed at the rear end of the shank body. When the current thread is in use, since the thread part is cylindrical, the thread part and the workpiece are vertical, so it is relatively laborious when in use, and it is difficult to locate, lock and unlock.
Convex washers are mainly punched out of iron plates. The shape is generally a flat washer with a hole in the middle. Flat washers are usually thin pieces of various shapes to reduce friction, prevent leakage, isolate, prevent loosening or Dispersing pressure, the rationality of its design structure and the safety during use are very important.
Type 1 nut refers to an ordinary hexagonal nut with a nominal height of m ≥ 0.8D. Its type and size should meet the requirements of GB/T6170; while the height of type 2 nut is higher than that of type 1 nut, its type and size should comply with GB/T6170. T6175. There are two purposes to increase the type 2 nut: one is to obtain a relatively inexpensive nut that does not require heat treatment by increasing the height of the nut. Because D≤M16 grade 8 type 1 nuts do not need heat treatment, among grade 8 nuts, only the specifications of D>M16~39 use type 2 nuts. Obviously, type 1 nuts that do not need heat treatment cannot reach grade 9 nuts. Mechanical property requirements. Another purpose of specifying Type 2 nuts is to obtain a more ductile grade 12 nut. As the height of the nut increases, the guaranteed stress index can be achieved at a lower quenching and tempering hardness, so the toughness of the nut is increased. Classified by tooth spacing: standard teeth, regular teeth, fine teeth, very fine teeth and cross teeth. Classification by material: stainless steel hexagon nuts and carbon steel hexagon nuts, copper hexagon nuts, iron hexagon nuts. Classification by thickness: hexagonal thick nuts and hexagonal thin nuts. Classification by usage: hot melt copper nut, hot pressed copper nut, embedded copper nut and ultrasonic copper nut
Heat treatment broadcast quenching and tempering HB220-270, nitriding HRC>65 foreign use titanium carbide coating method to improve the corrosion resistance of the screw surface, but according to reports, its wear resistance is not good enough. A series of measures have been taken abroad to improve the wear resistance and corrosion resistance of the screw. One way is to use highly wear-resistant and corrosion-resistant alloy steel. Such as 34CrAlNi, 31CrMo12 and so on. There is also a method of spraying Xaloy alloy on the surface of the screw. This Xaloy alloy has high wear and corrosion resistance.
screw is a tool that uses the physical and mathematical principles of the circular rotation and friction of an object to fasten the mechanism of the object step by step. When using screws to fasten objects and parts, it is often necessary to use screws with spring washers and flat washers to lock and fix the relative position, so as to improve the stability of the fastening connection and make the screws less prone to loosening. However, in the prior art, the method of manually inserting the spring washer and the flat washer in sequence is generally used, which not only increases the workload of the staff, but also makes the installation efficiency relatively low. On the other hand, the traditional screw with a gasket only has the function of fixing, Without the function of sealing, it cannot be applied to special equipment such as oil tanks and airtight cabins. Therefore, it is necessary to design a screw that can reduce the workload and have its own sealing structure.
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