If ultra high-strength steel is heated, the strength of the steel is reduced. If ultra high-strength steel is damaged, for example, in a collision, and the reinforcement beams or the ultra high-strength steel (UHSS) (1500 MPa) sheet are bent, the beams of the ultra high-strength steel (UHSS) (1500 MPa) sheet may crack when attempting to straighten them. If a door beam is damaged, the whole door assembly must be replaced.

For this reason, the door, bumper reinforcement beams, and the ultra high-strength steel (UHSS) (1500 MPa) sheet should NEVER be repaired; they must be replaced if they are damaged.