Vehicle door of armor steel

A vehicle door, comprising:

• a window frame;
• a lower surface portion formed jointly with the window frame in one piece from a hot formed and press hardened sheet metal plate, at least the lower surface portion having a Brinell hardness of 500 to 600 HB and a yield strength of 1,200 to 1,450 MPa, wherein at least one of the lower surface portion and the window frame has a wall thickness of at least 6 mm;
• a curved zone defined by a radius of curvature sized to be 1 to 3 times the wall thickness;
• and
• a connection zone for a door hinge,
• wherein the sheet metal plate is made of a steel alloy which comprises, in weight-%:
• Carbon
• 0.33-0.38
• Silicon
• 0.2-0.7
• Manganese
• 0.7-1.2
• Phosphorus
• max. 0.03
• Sulfur
• max. 0.02
• Boron
• 0.002-0.005
• Chromium
• 0.6-1.0
• Copper
• max. 0.12
• Nitrogen
• max. 0.005
• Titanium
• 0.015-0.025
• Nickel
• 1.5-2.0
• Molybdenum
• 0.2-0.5
• Tin
• max. 0.04, and
• as optional components
• Aluminum
• 0.006-0.06
• Niobium
• 0.02-0.05
• with a balance being iron and incidental impurities.