Customized Hexagonal bolt,Customized Hexagonal Socket Head Bolt,Customized Special Carriage Bolt

When we first tighten a bolt in a bolt group, the connected part is compressed to produce elastic deformation. After the adjacent bolt is tightened, the pre tightening force of the initially tightened bolt is reduced due to the elastic deformation of the connected part. This phenomenon is called elastic interaction. This phenomenon is the most significant in high-strength bolt connections. Experiments show that it is affected by elastic interaction.

The pretightening force of bolts may be reduced by 35% at most. Such a large reduction in the pretightening force of bolts is unacceptable in many applications. In order to reduce the impact of elastic interaction, generally, the bolts of bolt groups should be tightened several times in a certain sequence. The tightening method can be carried out according to the previous bolt tightening method.

1. when two nuts with one thick nut and one thin nut are used for locking, the thin nut should be placed below. Most people use it upside down. However, in order to prevent wrong use, it is now recommended to use two identical nuts.

1. when placing the washer, do you place it at will? In fact, the side without mark should contact the nut.

As for the nut, is it screwed to the bolt at will? The side with the mark on the nut needs to be exposed, so as to facilitate the tracking and inspection of the nut.

1. it is better not to use spring washer for bolt connection of grade 8.8 and above that needs pre tightening. The experiment shows that the anti loosening effect of spring washer in pre tightening bolt is relatively poor, which will also cause rapid reduction of pre tightening force, and the gain is not worth the loss.

1. the contact surface of bolt connection shall not be painted. Paint will increase the stress relaxation of bolts, that is, the prestress of bolts will be reduced over time.

1. the structure is connected with bolts. When bolts are selected, the size of bolts shall not be less than M12.

1. when tightening high-strength pre tightening bolt with torque method, if the washer contacting the nut rotates with the nut when tightening the nut, the connection is invalid, because the bolt manufacturer guarantees the friction resistance between the nut and the washer when producing the bolt group, and the friction coefficient between the washer and the connector is unknown. Therefore, the corresponding relationship between tightening torque and pre tightening force is also unknown. Therefore, the bolt set needs to be replaced.

1. when the bolts are tightened, they cannot be tightened to the final torque at one time, unless all bolts at the unified connection are tightened at the same time.

1. when the bolt is tightened, the speed of tightening the nut shall not be too fast, which will affect the friction coefficient between the screw threads.

1. when tightening bolts, it is not necessary to re lubricate high-strength bolts, because bolt manufacturers are responsible for lubricating high-strength bolt components, and they ensure the torque coefficient of bolts.

1. in bolt connection, after the nut is tightened, the exposed length of the screw should be about 2 to 3 threads.

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