SAPH440 steel plate is a commonly used automotive structural parts material, mainly for the following reasons:

1. High strength: The SAPH440 steel plate has a high yield strength and tensile strength, making it able to withstand most of the loads and stresses required for automotive components. This high strength characteristic helps to improve the overall stiffness and safety performance of the vehicle.

2. Good impact toughness: SAPH440 steel plate has good impact toughness, which can absorb and disperse energy in a collision accident, reducing the injury of the accident to the vehicle occupants.

3. Excellent formability: SAPH440 steel sheet is easy to process and form, and complex automotive structural parts can be manufactured by cold bending, hot bending and other ways. This makes the production process more flexible and can meet the design needs of different models.

4. Corrosion resistance: SAPH440 steel plate after anti-rust treatment and coating, has good corrosion resistance. This is very important for the long-term use of the car in harsh environmental conditions, which can extend the service life of the vehicle.

In summary, SAPH440 steel plate has become a commonly used automotive structural parts material due to its high strength, good impact toughness, excellent formability and corrosion resistance.