Tensile Strength Test

Everything breaks at some point – the important thing is to know when that will happen.

TÜV Rheinland has one of the largest tensile and compression testers available in the private industry, with a load capable of up to 1.2 million pounds. Our complete machine shop is able to test tensile bars quickly and accurately. No job is too complex.

With tensile strength test services from TÜV Rheinland, you can be sure of:

• Quick and inexpensive results with a small margin of error
• Experienced test engineers and quality services
• A lead against the competition with a neutral audit seal
• Reduced risk of company liability with documented safety standards
• Proof of how high your high-quality standards are
• TÜV Rheinland’s exclusive, one-stop service
• Compliance with local government and legal requirements

Our approach is as follows:

• Samples are provided and then prepared to a known size (tensile bar). For different types of materials, there are known property ranges of tensile yield and elongation.
• As the samples are pulled, these properties are measured to find out if the material samples tested fall into the appropriate range predetermined by the standard.
• As the material is continually pulled apart until it breaks, you obtain a good, complete tensile profile – a curve shows how the product reacted to the forces being applied. The point of failure is of most interest and is typically called the “ultimate strength,” or UTS on the chart.

Metals, including steel, have a linear stress-strain relationship up to the yield point. In some steels, the stress falls after the yield point. This is due to the interaction of carbon atoms and dislocations in the stressed steel. Cold-worked and alloy steels do not show this effect.

For most metals, the yield point is not sharply defined. Below the yield strength, all deformation is recoverable and the material returns to its initial shape when the load is removed. This recoverable deformation is known as elastic deformation. For stresses above the yield point, the deformation is not recoverable and the material will not return to its initial shape.

Ultimate tensile strength (UTS or SU) is indicated by the maxima of a stress-strain curve and, in general, indicates when necking will occur. As it is an intensive property, its value does not depend on the size of the test specimen. Rather, it depends on the preparation of the specimen and the temperature of the test environment and material.

The standard way of measuring tensile strength is to use a small bar with uniform width (other than at the edges, where the thickness increases) and to “pull” at each end until the bar fails. In the process, other mechanical properties can be culled. The material can vary widely – from metals to plastics, even wood.

Three definitions of tensile strength:

• Yield strength – the stress at which material strain changes from elastic deformation to plastic deformation, causing it to deform permanently.
• Ultimate strength – the maximum stress a material can withstand when subjected to tension, compression, or shearing. It is the maximum stress on the stress-strain curve.
• Breaking strength – the stress coordinate on the stress-strain curve at the point of rupture.

Testing for tensile properties determines what the product’s projected life span may be and the part’s load-bearing capacity. In addition, the product can be verified that it meets the requirements of the standards it is projected to meet, verifying that it has the correct heat treating or annealing.

TÜV Rheinland’s test engineers have many years of experience and are capable of fabricating the appropriate fixtures to pull large complex parts. The width capacity is 5 feet and the height is 15 feet, which provides a large range of testing products in their as-built state.

If you are interested in TÜV Rheinland’s tensile strength test services, you may also be interested in these services:

• Product testing
• Welding

Our services cover products made from metal, plastic, wood, and other materials.