A rivet is one of the tools used to connect two or more pieces. Non-riveted nails are generally made of two parts, the cap and the cylindrical rod. When two or more pieces want to be joined together, a hole the diameter of a rivet nail cylinder is made on the pieces so that the nail cylinder passes through it and the cap protrudes. Then, by machine or manually, the rest of the cylinder is shaped into a cap to completely fasten the parts between the two caps.
In some cases, the rivet nail is heated to red before riveting, and after riveting, the screw shrinks with decreasing temperature, reducing the length of the rod; But the cap that is in contact with the parts prevents this reduction in length and instead compresses the middle parts. Following this, the connection becomes stronger.
In cases where it is necessary to connect the production parts permanently and not to separate them, the rivet can be trusted and used. This feature is due to the fact that rivets can withstand both axial and shear stresses. Bearing these two types of pressure prevents the connection from loosening.
Rivets resistance to axial and shear stresses
Axial stress along the axis of the axis occurs when the force is perpendicular to the cross section of the body. Tensile or compressive stresses are of this type. The shear stress is applied in parallel with the cross section of the body and may change the shape of the body due to the pressure exerted by moving the cross section involved. In contrast, other connection tools, such as screws, only withstand axial stresses, so after a while they may lose their connection to the surfaces and fall between the surfaces.
Types of connections made with rivets
There are two types of rivet connections; One is the joint, where the ends of the two parts to be joined are in contact with each other, and the other is the edge-to-edge connection where the two parts of the parts to be connected are in contact. They are caught and mounted on top of each other to be fastened together. This connection can be partial or complete.
The connections mentioned above require strong and inseparable connections on large scales and hard materials. Rivets are used for such connections, such as the connection of steel bridges, or the fuselage or various types of tanks.
When do we need a rivet connection?
The quality of the connection and its lifespan are important categories for making new metal tools in various industries. The use of a rivet is the most logical option when it is necessary to connect the two parts so that they do not break due to impacts and the two parts do not separate, or the parts cannot be easily separated.
Also, in cases where we want the manufactured device to have a long life, or it is supposed to bear very heavy weights, or it is not possible for the product to be inspected and repaired several times, we can Use rivets to connect. In addition, rivets can be used to connect parts that only have access to one side.
The rivet response for such situations has made it a unique and reliable connection option that can be used in the automotive industry, home appliances, ventilation equipment and a variety of other industries.
Criteria for rivet connection lifespan
As mentioned, rivets create inseparable connections that cannot be easily disassembled without a special tool. But in the meantime, the quality of the rivet work also depends on the alloy and the material from which the rivet is made. Some substandard raw materials or materials that are unsuitable for their intended purpose can break the connection and loosen the parts due to corrosion and change in the size and shape of the rivet. Rivets are often made of steel, galvanized steel, stainless steel, aluminum and copper.
Also, the distance of the screws, the length of the rivet cylinder and the diameter of the hole made on the desired parts also affect the quality of the connection. If the diameter of the hole created for the rivet is less than enough, the rivet will not easily enter the hole and will damage the desired surface. Even if the hole is larger than required, the strength of the connection will decrease and it may even break and disappear. The diameter of the hole created should be a very small and calculated amount larger than the diameter of the rivet so that both the rivet can easily enter the hole and the body of the rivet comes into contact with the parts during riveting and compression and the strength of the connection Increase.