Tensile Test

The tensile test is used to determine the yield strength (Rp0.2 or Rp1.0), tensile strength (Rm), elongation at break (A) and, in some cases, the reduction in area (Z). In this type of test, a sample is pulled apart at a uniform and shock-free speed until it breaks. The tensile test is carried out at room temperature (20°C), whereas the hot tensile test is carried out at a predefined temperature (up to 1000°C, for example). This test belongs to the category of destructive material testing.

Table of contents

• Performing the tensile test in accordance with DIN standards
• Characteristic values of the tensile test
• Necking in the tensile test
• Purpose and application of the tensile test

Performing the tensile test in accordance with DIN standards

The tensile test is performed in accordance with various standards, with DIN EN ISO 6892-1 being the most common standard for tensile testing. The test is usually performed at room temperature (approx. 20 °C). In some cases, however, the tensile test can also be performed at different temperatures in order to examine the material behaviour under different conditions.

In addition to temperature, the test speed and sample geometry are also regulated by the standard. A typical tensile testing machine contains a clamping device to fix the sample in place and a device to apply the tensile force. The sample is then stretched step by step while the applied tensile force is measured.

Characteristic values of the tensile test

The tensile test provides several important characteristic values, including:

• Tensile strength: The tensile strength of a material is the maximum tensile stress it can withstand before failing. This value is crucial for evaluating the strength of a material and determining its suitability for various applications. The higher the tensile strength, the more resistant the material is to tensile forces.
• Yield strength: The yield strength of a material is the stress at which it exhibits permanent deformation and loses its elasticity. This point marks the transition from elastic behaviour, in which the material returns to its original state after the load is removed, to plastic behaviour, in which permanent deformation occurs. The yield strength is an important parameter for assessing the usability and safety of components.
• Elongation: The elongation of a material is the relative lengthening of the sample during the tensile test, measured in percent. It indicates how much the material deforms under tensile load. Higher elongation indicates a material's ability to deform before it fails. Elongation is important for evaluating the ductility and ductility of a material.
• Cross-sectional reduction: Cross-sectional reduction is the constriction or narrowing of the sample cross-section at the fracture point, expressed as a percentage. This parameter shows how the material narrows locally when it is under tensile stress and stretches to the breaking point. Cross-sectional reduction can provide insights into the behaviour of the material during failure development and is important in materials testing.

Necking during tensile testing

Necking is a characteristic feature of tensile testing. It occurs due to the local narrowing of the material when it is under tensile stress. This effect is particularly noticeable in ductile materials such as metals. Necking indicates that the material is about to fail. It is often referred to as the ‘neck’ and is an important indicator of material deformation and strength.

Purpose and application of the tensile test

The tensile test is used to characterise the mechanical properties of a material and to ensure that it meets the requirements of various applications. Tensile strength is important for assessing the strength of a material, while the yield point provides information about its elasticity. This test method is used in materials development, quality control and manufacturing to ensure the safety and reliability of products. It helps engineers and materials scientists select materials that can withstand the specific requirements and stresses in various industries.

Tensile testing is a crucial tool in materials testing and plays a key role in ensuring the quality and safety of products across various industries. By evaluating the tensile strength and yield strength of a material, manufacturers can ensure that their products meet the required standards and can withstand the stresses they will be subjected to during use. This process also makes it possible to compare materials in terms of their mechanical properties and make the right choice for specific applications.