Aging treatment: leave the casting in the open air for several months or even longer, allowing the casting to deform naturally and slowly to eliminate stress;
Graphitization annealing: Heat the casting to 900-960°C and keep it for 1-4 hours, and then cool it in the furnace to eliminate the white structure, reduce the hardness and improve its processing performance;
Normalizing: divided into high temperature normalizing and low temperature normalizing. The high-temperature normalizing temperature generally does not exceed 950-980°C, and the low-temperature normalizing temperature is generally heated to 820-860°C. Artificial aging treatment is required after normalizing to eliminate the internal stress generated during normalizing;
Annealing: including casting stress relief annealing, cooling annealing and high temperature annealing. Stress relief annealing is mainly used for ductile iron parts that will not undergo other heat treatments. The casting is heated to 520-550°C at a slow heating rate (60-100°C/h), and then heated in the furnace at a slow rate (20°C) after being kept for a period of time. -30℃/h), cool to 150-200℃, come out of the furnace and air-cool. At this time, the stress of the casting is basically eliminated;
Quenching: Heat the casting to 30-50°C above the final temperature of the A layer, and then quench in oil to obtain a martensite structure to improve the mechanical properties of the casting;
Tempering: In order to appropriately reduce the residual stress after quenching, tempering should generally be performed after quenching.
Aging treatment: leave the casting in the open air for several months or even longer, allowing the casting to deform naturally and slowly to eliminate stress;
Graphitization annealing: Heat the casting to 900-960°C and keep it for 1-4 hours, and then cool it in the furnace to eliminate the white structure, reduce the hardness and improve its processing performance;
Normalizing: divided into high temperature normalizing and low temperature normalizing. The high-temperature normalizing temperature generally does not exceed 950-980°C, and the low-temperature normalizing temperature is generally heated to 820-860°C. Artificial aging treatment is required after normalizing to eliminate the internal stress generated during normalizing;
Annealing: including casting stress relief annealing, cooling annealing and high temperature annealing. Stress relief annealing is mainly used for ductile iron parts that will not undergo other heat treatments. The casting is heated to 520-550°C at a slow heating rate (60-100°C/h), and then heated in the furnace at a slow rate (20°C) after being kept for a period of time. -30℃/h), cool to 150-200℃, come out of the furnace and air-cool. At this time, the stress of the casting is basically eliminated;
Quenching: Heat the casting to 30-50°C above the final temperature of the A layer, and then quench in oil to obtain a martensite structure to improve the mechanical properties of the casting;
Tempering: In order to appropriately reduce the residual stress after quenching, tempering should generally be performed after quenching.
