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Main process elements for heat treatment of large steel castings
- Nov 21, 2018 -

Main process elements for heat treatment of large steel castings

 

The heat treatment of large steel casting slag and slag tanks is generally composed of three stages of heating, heat preservation and cooling. The determination of process parameters is based on ensuring product quality and energy saving.

1. Heating is the most energy-intensive process in the heat treatment process. The main technical elements in the heating process are the selection of the appropriate heating method, heating rate and charging method.

2. The austenitizing holding temperature of the insulated steel castings should be determined according to the chemical composition and the required properties of the cast steel. The heat treatment time of the steel castings should be determined in two aspects: the singularity is that the surface of the casting is consistent with the temperature of the core; The second is the homogenization of the structure, so the residence time of the insulation depends on the thermal conductivity of the cast steel. The section thickness of the casting is usually the main basis for estimating the holding time.

3. After cooling, the steel castings can be cooled at different rates to complete the transformation of the steel phase to obtain the required metallographic structure and achieve the specified performance specifications. In general, increasing the cooling rate is advantageous for obtaining a good tissue state and refining the salvation, thereby improving the performance of the steel, but it is easy to cause a large stress on the casting to cause deformation or cracking of the structurally complicated casting. Heat treatment cooling media for steel castings are commonly used in air, oil, water, brine and molten salt.

 

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