Metals and metal alloys are highly preferred building materials in mechanical design in construction works. Metals, in particular, are widely used in force bearing structures. In this respect, it is important to know the mechanical properties of metal materials. The behavior of metal materials under mechanical loads is called mechanical properties. Mechanical properties, on the other hand, are mainly due to the interatomic bond strength of the metal. However, the effect of the internal structure of the metal material is also high. By changing the internal structures of the metals, the same material is given different mechanical properties. Mechanical properties of metals are determined by different test methods for different loading conditions.
The tensile properties of metals vary according to the force per unit area of an applied force. If the force is perpendicular and causes the metal to elongate or shorten, this is called normal stress. However, if the force is within the section and causes an angle change in the metal, this is called shear stress. The forces applied to metal materials can always cause normal or shear stresses.
The most important characteristics of building materials are the extent to which these materials can be deformed and how durable they are. The test method used to determine the deformation and strength properties of metal materials is tensile testing. The power applied during the test is increased until the material breaks. At this time, changes in the metal material are continuously recorded. Another test is compression tests. If the material is subjected to a load in the form of compression, the deformation and strength characteristics of the material under the stress load are determined. The tests here are similar to the tensile tests.
In the hardness tests, it is determined how much resistance a metal material has against a hard object dipped in the surface. The hardness values of metal materials are directly related to the strength of the materials and are of great importance. As a non-destructive test method, these tests are performed by different methods (such as Brinell, Vickers or Rockwell hardness measurement method) according to the shape of the penetrating tip and the force applied.
Notch impact tests are applied to measure the dynamic toughness of the material under conditions that direct metal materials to behave brittle. These conditions are three-axis loading, low temperature forcing and sudden impact.
Fatigue damage is also encountered in metal materials. This damage is caused by the breakage of metal materials after a certain period of time under the effect of lower repetitive stresses compared to the tensile strength. This is demonstrated by fatigue tests.
Today, the usage areas and properties of metal materials used in the building sector are carried out by authorized test and inspection institutions, in accordance with the relevant legal regulations and standards published by domestic and foreign organizations. Here are a few standards that are based on these tests:
· TS EN ISO 8491 Metallic materials - Pipe (full cross section) - Bending test
· TS EN ISO 6892-1 Metallic materials - Tensile test - Part 1: Test method at ambient temperature
· TS EN ISO 6892-2 ... Section 2: High temperature test method
· TS EN ISO 6892-3 ... Part 3: Low temperature test method
· TS EN ISO 6507-1 Metallic materials - Vickers hardness test - Part 1: Test method
· TS EN ISO 6507-4 ... Section 4: Charts and hardness values