Hot tensile testing at the Defontaine Group laboratory
The Defontaine Group’s materials laboratory has recently taken another important step in strengthening its in-house testing capabilities. Our customers require hot tensile tests to validate the quality of the welded parts we produce. It has also become strategic to be able to carry out these tests directly in-house without having to subcontract them to qualified testing laboratories. The aim is twofold:
To reduce lead times: while a test carried out by a subcontractor takes around 4 weeks, the Defontaine Group laboratory is able to complete it in just 2 weeks.
To optimise responsiveness & test management: by carrying out the entire process in-house – from the preparation of test specimens to the analysis of results, The Defontaine Group avoids the hazards associated with transport, loss of samples or intermediate delays. This organisation guarantees greater control and responsiveness at every stage.
Installed at the beginning of January 2025, the hot tensile testing machine is currently in the final stages of testing and parameterisation to guarantee reliable results that meet our customers’ strict requirements
Hot tensile testing: a key technology for the aerospace industry
When we talk about materials testing, we often think of standard conditions at room temperature. However, in the demanding field of aeronautics, the parts used in flight have to withstand high temperatures. This is where hot tensile testing comes in, a mechanical test that is essential for simulating the real conditions under which materials are used.
What is a hot tensile test?
Tensile testing consists of applying a uniaxial force to a test specimen until it breaks, in order to study its behaviour: yield strength, maximum resistance, elongation, necking (= reduction in surface area), etc. Hot tensile testing uses the same principle, but at high temperatures (e.g. 650°C, 780°C, etc.) to reproduce the conditions under which materials are used in extreme environments (reactors, engines, turbines, etc.).
It is therefore a crucial test for the aeronautical sector, where materials are subjected to significant mechanical stress in a severe thermal environment (e.g. engine operation, etc.). By carrying out tests under these conditions, we obtain data that is much more representative of reality than tests at ambient temperature.
Hot tensile test procedure:
- Preparation of the test specimen:
The specimen is carefully inspected, measured and identified. Two thermocouples are attached to its ends to monitor and control the temperature. - Installation:
The test specimen is inserted into the tension rods, the thermocouples are connected and the oven is closed. - Temperature rise:
The target temperature is reached gradually. A stabilisation time of at least 30 minutes is allowed to ensure thermal homogeneity of the test piece. - Test run:
The software runs the test, and the specimen is stressed until it breaks. The extensometer measures the deformations up to the elastic limit, then is removed so as not to be damaged when the specimen breaks. - End of test and analysis of results:
After cooling, the specimen is measured again to obtain the final data. The results (curves, mechanical characteristics, etc.) are then exported for analysis of the various parameters (yield strength, stress, etc.).
With hot tensile testing, our customers in the aerospace industry can be sure that their materials will stand up effectively in real-life conditions. Thanks to hot tensile testing, we can guarantee that welded metal or special metal alloy parts will be able to withstand mechanical stresses in flight, without loss of performance or breakage.
In short, hot tensile testing is a benchmark test for controlling the characteristics of high-performance materials for aerospace. Thanks to this hot tensile testing machine, our laboratory is able to offer its industrial partners precise and reliable data, directly derived from real conditions close to use. Hot tensile testing represents an important lever for meeting growing market demands with agility, and illustrates the Defontaine Group’s constant desire to improve by investing in high-performance tools
More information on the Defontaine group’s materials laboratory: https://www.defontaine.com/en/service-laboratories/
