A U-bolt is a U-shaped fastener bolt used to secure pipes to various surfaces and supporting structures.

U-bolt is often used in the following construction: metallurgy, petroleum, chemical industry, vehicles, ships, electric power, Bridges and other mechanical hydraulic system of oil, water, gas as the medium of the pipeline fixation. Surface galvanized processing and other processes, made of "U" font style.

U-bolt has simple structure, elegant appearance, durable, convenient disassembly and assembly.

Pipe clamp surface treatment is galvanized, other surface treatment methods can be selected as required.

First, black stainless steel screws

Stainless steel screw black reason:

Black stainless steel screws are usually caused by too much heat from cold heading or rubbing teeth. Usually in the cross groove part. In the production process, the heat can be timely dispersed through the supply of lubricating oil, and the speed of the machine can also be appropriately lowered to avoid problems. Of course, stainless steel screw black in addition to technical reasons, there may be stainless steel screw itself material problems will also cause stainless steel screw surface black.

Stainless steel screw black solution process flow

Oil removal - water - cross tank cleaning agent - water - neutralization - water - drying; Heat the stainless steel screw cross slot cleaning agent to 70 degrees, and then put the stainless steel screw products after oil removal into the cross slot cleaning agent, soak for 5-15 minutes, over water, neutralize, and blow dry.

Two, stainless steel screw loose problem

The main reasons for the loosening of stainless steel screws:

Spontaneous bolt loosening - Shock, vibration, dynamic load

Relaxation - settlement, creep, relaxation

To prevent spontaneous loosening, the sliding between the connecting parts needs to be eliminated, or at least reduced to below the critical level. This can be achieved by increasing axial tension, increasing friction between clamping components or reducing cyclic load - for example, shock, vibration or cyclic heat load.

Stainless steel screw loose solution:

One, the use of special materials, such as engineering resin materials, which have better resilience. Attach it to the stainless steel screw denture. Make it mechanically rub with the nut or material product. Produce vibration and resistance. Completely solve screw loose problem.

Two, simply speaking is in stainless steel screw thread coated with a layer of glue, the so-called glue. This kind of glue is called breakfast glue. This adhesive has high adhesion, non-toxic and other good properties. This glue is applied to stainless steel screws. After drying, it has strong adhesion. Can make the stainless steel screw thread in the nut thread combination, or in the product thread hole joint, produce excessive tightening effect. Play a super anti - loose role.

1. Replace fine teeth with thicker ones

There are many important connectors on the machine, such as the drive shaft, and most of the bolts are fine thread. If parts are missing during maintenance, some maintenance personnel will use coarse teeth bolts instead, which should be avoided.

Because the fine tooth bolt has large inner diameter, small pitch and outer Angle, high strength, good self-locking performance, and strong ability to withstand impact, vibration and load exchange. Once the coarse bolt is used instead, it is easy to loose, take off, disassemble, and even cause mechanical accidents.

2, the pore is not fit

The bolts that bear the lateral load and shear force on the machine, such as the drive shaft bolts and flywheel bolts, should be fitted with the bolt holes for the transition fit, the assembly should be strong and reliable, and can withstand the side force. Some people do not pay attention to check in the assembly process, and still continue to install when there is a large gap between the bolt and the bolt hole, which is easy to loose or cut off the bolt accident.

3. Thickened nuts to increase connection reliability

Some people mistakenly believe that thickened nuts increase the number of turns on the thread and improve the reliability of the connection. But in fact, the thicker the nut, the more uneven the load distribution between the threads of each ring, the more easy to loosen the coupling.

4, a mother more pads

After the installation is completed, sometimes the bolt is too long, so someone will install extra spring washer on the bolt. In this case, the uneven force of the spring washer in the firm process will be broken, so that the preload of the bolt decreases, and may produce eccentric load, reducing the reliability of the bolt connection.

A screwed bolt is acted upon by two forces, one downward and one upward. The bolt rotates down the thread, creating a downward axial force in contact with the thread.

At the same time, there is an upward force corresponding to the downward axial force, which is generated by the upward distribution of the nut in contact with the plane below. A tightened bolt should ensure that the upper and lower forces are balanced against each other. Because of the function of bolts, the material of bolt manufacturing has two requirements, one is rigid, the other is toughness, both of which are indispensable.

But all ductile materials have one thing in common, that is, there is a limit to the stress. In mechanics, this limit is represented by a stress-strain curve. There is no need to go too far. We just need to know that in the process of screwing the bolt, as a kind of elastic parts, its elasticity will take effect.

As the bolt is tightened gradually, the elastic action of the bolt will approach a limit. Once this limit is broken, the bolt will enter the yield stage from the elastic stage.

Once the bolt enters the yield stage, it will deform. This deformation is irreversible, that is to say, the bolt will fail. In real life, when we constantly tighten the bolt, there will be trip phenomenon is caused by this reason, and once out, it is impossible to screw on again, because the bolt has been deformed, it can be seen that the tighter the bolt is not the better.