Almost all industries use aluminum alloy. It is used everywhere, from the manufacture of dishes, and to the manufacture of spare parts for cars.
It starts with the fact that there are severalvarious alloys in which aluminum is used. However, this one is considered the most popular among others. Silumin is the next step after aluminum. It is obtained by means of a silicon alloy added to this chemical element. The combination of these two elements provides the resulting alloy with increased hardness, as well as increased resistance to wear of parts obtained from the alloy.
The content of silicon in such alloys ranges from4 to 22%. Also worth mentioning is that some more elements can be added. They include copper, zinc, titanium, iron or calcium. It is also known that silumin contains 5 to 14% silicium.
It is important that silumin is all the alloys that wereare obtained on the basis of silicon and aluminum, but it is necessary to understand that not all final materials have the same properties. It is necessary to know that as the percentage of silicon content increases, the final strength of the material rises, but its fragility also increases. The main advantages that can be distinguished from this alloy are:
All these advantages together and were able to ensure the high popularity of this material.
The drawback of this material is only one - it's hisincreased brittleness. If to speak about mechanical influence silumin is capable to sustain high loads, however if, for example, to drop a product from this alloy, it, most likely, will burst. It is also worth noting that the melting point of silumin is not too high - only 580 degrees Celsius.
Since silumin is an alloy of aluminum and silicon, andalso just one of its varieties, a special marking was developed that allows you to quickly and easily determine the percentage of components, as well as what kind of chemical elements were used in making the alloy. In order to mark the silumin alloy, alphabetic and numeric designations are used. For example, AK12 or AK9TS7. The first letter always indicates the aluminum content in the alloy, and the second one on the silicon content. The figures show what percentage of this chemical element is in silumin. In this case it is 12%. Since other elements can be added, their letter is also indicated. The second example shows the marking of aluminum - A, silicon - K 9% and zinc - C 7%.
It is also important to note that the alloy hasincreased fluidity in the molten state, as well as good weldability. If we take into account that the melting point of silumin is only 580 degrees Celsius, then this can be attributed to the list of material advantages.
Most often it is said that silumin is an alloyaluminum and silicon. However, this is not a true statement. This name is used for alloys in which the content of an element such as silicon is in the region of 12-13%. Such a group of alloys is usually called eutectic, normal, or ordinary silumin. However, there is another classification of this material.
The first group of silumin from aluminum iseutectic. Their strength parameters are rather small, but the advantage of this type is different. It has excellent casting parameters. Materials from such an alloy are used in the casting of thin products, which in the future will be used in the environment of increased vibration or under the influence of shock loads.
It is also important to note that when casting this groupalloys, such requirements as the elongation of the microstructure can be presented to it. To fulfill this requirement, it is necessary to modify the silumin with sodium during the casting operation in the mold or in the mold.
It is also important to note that high resistance toEffects on the alloy of an aggressive environment are only those that are characterized by high purity of the composition. In other words, in such materials there should be a minimum content of various impurities, such as iron and others.
There are several groups to which silumin is divided. This division is carried out using this material for various purposes.
The eutectic silumin, which is markedAK12, that is, only 12% of the silicon content, as well as not hardened by heat treatment and does not form shrinkage strength, it is recommended to use for the manufacture of hermetic parts of devices or aggregates of low loading.
As an example of a pre-eutectic siluminyou can take the alloy AK9h. For its manufacture, quenching is already applied at a temperature of 530 degrees with an exposure time of 2 to 6 hours. After this, the material is cooled in hot water and the aging process is activated at a temperature of 175 degrees, which lasts for 15 hours. The use of silumin of this group is carried out for the production of loaded and large-sized parts.
The third group of alloys is a high-alloyhypereutectic silumin, the marking of which is AK21M2. The membership of this material is a piston group of alloys. This material is intended for work in an environment with elevated temperatures, since it is distinguished by increased heat resistance, high coefficient of wear resistance.
Since it may happen that there will be cracks orthe same faults on the details of this alloy, that is, the possibility of carrying out repairs. Most often for carrying out this type of work a special substance is used - epoxy adhesive. However, in the event that the part should be operated in an environment with increased loads, it is best to use welding. However, it is necessary to take into account the composition of the alloy, since not all of them are able to withstand the temperature of the welding machine, some of them can simply melt.
Repair silumin at home with the help ofArgon arc welding is considered the most simple method. However, all recognize that the best solution for repairing parts will still appeal to professionals, but independent welding is also quite real. It is important to note that the work of argon-arc welding should be carried out in an environment of inert gases.
Most often to achieve this goal, they usedirectly argon gas, but in some cases it is possible to use a mixture of argon and helium. It is also important to note that after welding work on the repair of silumin parts, all welds must be processed. After this procedure, the seams will be almost invisible.</ p>>