Any production of aluminum products must conduct quality control of the products, following the chosen standards. Each major region has its standards, but there are universal indicators that are checked in any case. This is the chemical composition, micro and macrostructure of the metal, and the geometry of the manufactured products. Testing methods reveal the quality of the surface of a metal product.
Testing methods are usually applied by factories in combination, as this approach allows for an objective picture of the condition of the aluminum product.
Non-destructive testing (NDT) of aluminum products
Description: A detailed description of types of non-destructive testing, such as visual inspection, ultrasonic testing, and radiographic analysis.
The name of the method immediately defines its essence. Non-destructive testing does not disrupt the structure of the product and does not cause any damage to it. Here you can find hidden defects and other issues. There are three main methodologies:
- Visual inspection of surface defects. Loupes, microscopes, and cameras are used.
- Radiography. Based on the method of X-ray radiation, which transmits images through a special detector. One can find voids, inclusions, cracks, and other inhomogeneities.
- Ultrasonic testing uses ultrasonic waves to detect defects. Hollows or cracks reflect signals along their boundaries and return them to the device.
This category also includes magnetic control.
Destructive quality control methods
When conducting destructive testing of an aluminum product, the goal is to determine the load limit that the item can withstand without deformation. In this category, there are static loads where the force on the experienced sample is easily measured. The tensile test, like the compression test, is performed using the appropriate equipment. The result of the testing in the first case is tensile strength, yield strength, and failure strain. In the second case, it is the limit of elasticity, the limit of plasticity, and the limit of proportionality.
By testing the product for bending, one can determine the strength of the material, calculate the stress and deformation of bending, and assess the bending resistance. There is a 2-point bend, a 3-point bend, and a 4-point bend. The impact viscosity is also important, and it is tested under conditions of varying temperature and rapid loading.
Mechanical testing of aluminum products
Such mechanical tests are characterized by compressive, shear, and rapid tensile forces. Methods are divided into the following categories: Static testing is conducted under constant or gradually increasing load.
- During dynamic testing, strength characteristics increase very rapidly.
- The hardness of the aluminum product is determined through cyclic changes in loads.
- Sometimes it is possible to conduct a technological test when the equipment allows for the simulation of specific operational scenarios.
Spectral analysis of aluminum alloy composition
X-ray fluorescence for aluminum products is a non-destructive procedure. The analyzer identifies metals and elements in an object by detecting their energy signatures. The method allows, through spectral analysis, to assess the quality and safety of the material. An alternative called optical emission spectroscopy involves obtaining an enlarged image using the luminescence of excited atoms and molecules of the sample.
Metallographic analysis of aluminum products
The purpose of such analysis is to study the structure of aluminum at both macro and micro levels. Metallography allows us to see the shape, size, and arrangement of crystals, as well as to find pores, voids, cavities, and other inclusions. There is a difference between the macroscopic and microscopic methods:
- Macroscopic structural analysis involves studying with the naked eye or with the aid of a magnifying device up to 30 times. Here, cracks or defects in the material can be seen.
- Microstructural analysis requires the use of an optical or electron microscope. Here, the dynamics of the change in the internal structure of the alloy can be seen after heating or mechanical loading.
It helps to determine the structure of the material of specialized software.
Corrosion testing of aluminum alloys
The task during testing is to determine the material's resources in an aggressive environment. Corrosion tests are most often conducted through cyclic corrosion chambers or salt spray.
The difference is as follows:
- Salt fog consists of a concentrated solution of sodium chloride that is sprayed throughout the test chamber space. A sufficiently aggressive environment where corrosion processes activate quickly.
- Cyclical tests combine salt mist and other external conditions present in the world. It's about moisturizing, drying, and controlled humidity.
In addition to the salt chamber, aluminum products are also tested in an alkaline or acidic mist.
Application of computer tomography for quality control
Not every non-destructive testing method can be applied to aluminum products. Sometimes complex geometry does not allow for the detection of internal defects. Computed tomography is identified as an accurate, reliable, and stable process for verification and control. Here, a combination of modern equipment and specialized software is used, which is responsible for building a three-dimensional model.
3D visualization is based on the tomographic image of the part, and sometimes this process takes several hours. The program will quickly identify suspicious areas where the geometry differs from what is specified in the project.
Problems and challenges in quality control of aluminum products.
The challenges of quality control in aluminum products encompass several issues. This is too large a set of individual tests, for which appropriate laboratory conditions and expensive equipment are often required. Not all tests have the same measurement accuracy, as it depends on the context and parameters of the chosen part. For the production of aluminum products, it is important to seek ways to establish the automation of testing.
Conclusion: Optimization of the Quality Control Process
In any enterprise, it is important to establish regular quality control. Knowing the quality standards and understanding how to identify various defects makes it easy to notice them early in the production process. With early resolution of issues with the products, the manufacturer will practically adhere to the quality guarantee. Optimization of control occurs based on the analysis of which non-destructive and destructive methods will be effective. Making a complete list of possible tests for aluminum products is often irrational and pointless. This will only lower the productivity of the enterprise.
