The door reinforcement beams are made from ultra high-strength steel (UHSS).

The front bumper reinforcement beam and the rear bumper reinforcement beam are made from aluminum alloy.

The front pillar upper stiffener, the front inner upper pillar, the center pillar upper stiffener, the front side frame extension, the side sill reinforcement, the front floor center tunnel, rear frame upper stiffener A, rear frame upper stiffener B, and rear frame A are made from ultra high-strength steel (UHSS) (1500 MPa).

Ultra high-strength steel (UHSS) (1500 MPa) sheet: This is an ultra high-strength material manufacturing procedure. A heated steel sheet is press-formed in the metal mold and then quenched to create ultra high-strength steel.

If the ultra high-strength steel is heated, the strength of the steel is reduced. If the 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 if they are damaged; they must be replaced if they are damaged.