Steels undergo numerous heat treatments to achieve targeted mechanical properties. The 300M steel is thus used for the manufacture of hardened and tempered landing gear. The martensitic hardening and tempering heat treatment is applied to the parts just before the final machining finishing phases. To better control the final geometry of the parts and optimize production lines, Safran Landing Systems is using numerical simulation to predict distortions induced by the hardening heat treatment.
As the trial and error principle is not economically viable nowadays, the objective is to predict its distortions by means of simulation software. For this purpose, the precise determination of heat transfer as a function of location, temperature and cooling rate is essential. Within the framework of a research partnership, several studies are carried out to provide all the necessary inputs to the industrial software. The one that follows in this thesis focuses on the determination of thermomechanical properties of 300M steel as a function of temperature and cooling rates. Several methodologies are used to determine these properties. The use of the DIL 805 A/D dilatometer gives us the length variation of the steel. A thermogravimetric analyzer is used to measure the heat flow of the 300M steel in tandem with its mass. Also, a laser flash allows us to find the thermal diffusivity. Finally, the characterization of the steel by means of microstructures and hardness tests has been carried out.
The experimental results were processed to obtain the desired thermal properties. Thus, numerical models were developed for density, coefficient of thermal expansion, specific heat, latent heat, thermal diffusivity and thermal conductivity as a function of temperature and heating and cooling rate. These identified models were then compared with the existing literature and the 300M steel was characterized as a function of the cooling rate.
| Date | 17 Aug 2020 |
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| Original language | French |
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| Awarding Institution | - École de technologie supérieure
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| Supervisor | Mohammad Jahazi (Supervisor) |
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Alcaras, R. (Author),
Jahazi (Supervisor),
17 Aug 2020Student thesis: Master's thesis › Master in Engineering: Mechanical Engineering