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Strengthening a steel part useful in a car, comprises a step of carburizing or carbonitriding and a step of nitriding that are performed in a same furnace, where nitriding step is carried out next to step of carburizing or carbonitriding
Strengthening a steel part useful in a car, comprises a step of carburizing or carbonitriding and a step of nitriding that are performed in a same furnace, where nitriding step is carried out next to step of carburizing or carbonitriding
The method comprises a step of carburizing or carbonitriding and a step of nitriding that are performed in a same furnace. The nitriding step is carried out next to the step of carburizing or carbonitriding. The step of carburizing or carbonitriding is carried by a step of increasing a temperature at an atmospheric pressure or a reduced pressure to a temperature above a temperature of the grade of steel chosen for the part. The step of carbonitriding or cementing is carried out above the temperature of the grade of steel chosen for the part with the atmospheric pressure or reduced pressure. The method comprises a step of carburizing or carbonitriding and a step of nitriding that are performed in a same furnace. The nitriding step is carried out next to the step of carburizing or carbonitriding. The step of carburizing or carbonitriding is carried by a step of increasing a temperature at an atmospheric pressure or a reduced pressure to a temperature above a temperature of the grade of steel chosen for the part. The step of carbonitriding or cementing is carried out above the temperature of the grade of steel chosen for the part with the atmospheric pressure or reduced pressure. The method further comprises: hardening the part between the step of carbonitriding or cementing and the step of nitriding, where the temperature at the end of the hardening step depends on the nature of treated steel and is determined by exploitation of curves; and cooling using a liquid or gas coolant, where the liquid is pressurized or not. A fluid of hardening is gas under pressure. The step of nitriding is carried out in gas phase with atmospheric pressure or reduced pressure and at a temperature of 450-600[deg] C. The temperature of the step of nitriding is selected to allow the bainite formation. The step of nitriding is followed by a step of cooling at an ambient room temperature.
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