Rivet joints are made from special parts. Such a fixed bond is difficult to separate. The rivets themselves are made of plastic material.
Structure
Rivet joints consist of three elements:
- two parts of connected parts;
- rivet.
The last element is placed in special holes that are located on the edges of the parts to be joined.
The rivet holds in the necessary position of the part. In this case, the fixing element has the following structure:
- body;
- kernel;
- embedded head - serves to form the future product;
- closing head - is formed in the process of connecting two elements.
A large number of rivets are used to fasten large parts. In this case, the finished joint will be called a rivet seam.
Fields of application
Prior to the appearance of high-quality welding, rivet joining of parts was widespread. Currently, it is used in some areas of technology. Rivet joints of parts are used in the construction of aircraft, ships, submarines, as well as for various high-precision devices. In addition, rivets are used when connecting building elements, such as an I-beam, channel, corner.
They help withstand variable vibration loads. Rivet joints are used to combine various types of material. For example, for fastening cast iron products with aluminum sheet.
Rivet joints. Advantages and disadvantages of the bonding method
Among the positive aspects are:
- simple technological execution;
- ability to combine dissimilar metals;
- high reliability of the connection;
- counteracts vibration and shock loads.
However, like every compound, there are negative aspects, among which are the following:
- to create a rivet bond, it is necessary to spend a large amount of metal;
- requires significant labor costs;
- high price;
- riveted joints can be destroyed due to the wrong diameter of the holes that are on the edges of the products;
- during operation, the tightness of the connection decreases.
There are a lot of types of rivet joints, since each of them is used in a certain industry.
Rivet joints: classification
This type of connection is divided according to this principle:
1. Functional purpose. Among the compounds, three main types are distinguished: durable ones are used to hold large loads; dense, which provide tightness; combined - perform both functions.
2. Technological design of the seam. The joint seam can be overlapped and butt.
The latter type is performed using one or more overlays.
3. The number of slices. This indicator shows the number of slices passing through one rivet under load. According to this principle, rivet joints are single and multi-shear. Their number is not limited.
4. The number of rivet rows. They can be one, two, three, etc. The number is not limited.
As mentioned earlier, rivet joints are used in various industries. Therefore, there are various types of rivets. In addition to the above indicators, these types are classified according to the shape of the embedded heads:
- semicircular;
- secret;
- half-secret;
- cylindrical.
Kernel
In its form, the following types are distinguished:
- solid;
- hollow (have a through hole);
- semi-hollow - the rod is divided into two parts: one is solid, and the other is hollow.
The basic information about fasteners and components is contained in the regulatory documentation.
GOST 10303-68 characterizing rivet joints includes the basic sizes of rivets. Here, its diameter, the length of the body and the rod, as well as the type of head are registered.
Production material
The main materials for the manufacture of rivet joints are low carbon steels, non-ferrous metals, as well as some alloys. Despite this, strict requirements are imposed on each material:
- To facilitate installation of the product, the material should be ductile.
- Materials should have the same temperature expansion index. If this requirement is not met, an additional voltage will occur with temperature differences. The rivet joints will eventually collapse.
- Materials must be uniform. This is done so that the galvanic current does not destroy the connection. For example, to fasten steel parts, steel rivets are used, copper elements - copper, etc.
Loads
Acceptable were determined as a result of numerous tests and experiments. In addition, they were carefully studied by specialists.
There are several types of loads: shear, tensile, and crushing stresses. For each
type of metal, these indicators differ from each other.
When using two elements of low carbon steel, the allowable tensile load should not exceed 150 MPa, and the shear stress should not exceed 100 MPa.
It is worth noting that these indicators were developed not only for connecting elements, but also for rivets.
For them, there are permissible loads. For example, for carbon steel products, shear stress should not exceed 100 MPa. On crushing, it is not more than 300 MPa.
Permissible loads for elements depend on the method of making holes in the products.
If there is a lot of stress, the holes must be made by drilling.
In case of temporary exposure to the product, the permissible loads are reduced by 20%. In some cases, for example with a cold rivet, this figure is reduced by 30%.
Rivet production guidelines
These rules for the manufacture of compounds have been developed by highly qualified specialists. They were identified as a result of many years of testing in the laboratory, as well as during the operation of the compound. So, among them there are:
1. Connecting parts and rivets should be made of strong uniform material.
2. Rivets should provide a small amount of attenuation between parts. For this, as a rule, I use a chess way of fixing.
3. Bending of the main structural elements should be avoided. To do this, rivets are placed along the axis that passes through the center of the connected elements.
4. On one rivet connection, elements that have different diameters cannot be used.
5. To avoid turning the parts to be joined, the number of rivets should be at least two.
6. The number of elements on one side should be no more than three. With an increase in this indicator, the strength of the product will decrease.
7. With a butt joint , more rivets must be used compared to an overlap joint.
8. It is necessary to ensure tightness. For this purpose, special glue or paint, which is obtained by flame spraying, is applied at the rivets.
9. After fixing the parts, check.
10. The number of rivets depends on the design of the rivet joint.
Such a connection is not very common in our time. It was almost completely replaced by welding.
However, it is used in the manufacture of aircraft, ships, and also some devices. The main advantages are high strength of the finished joint and easy installation. However, to use it, it is necessary to spend a significant amount of metal. Therefore, this type of connection is expensive and time consuming.
Conclusion
There are a large number of riveted joints.
The main types and sizes of rivets are indicated in the regulatory documentation. The type of item depends on the industry used. Installing them requires accurate execution. The slightest deviation in the diameter of the hole can lead to the destruction of the entire product.
In their manufacture, it is necessary to adhere to some rules that were drawn up by specialists based on many years of calculations and experiments.
So, we examined the features of this type of compounds.