Method for producing workpieces from lightweight steel having material properties that are adjustable across the wall thickness

A Method for producing a workpiece having properties which are adjustable across a wall thickness or strip thickness of the workpiece, said workpiece being made of an austenitic lightweight steel which has an alloy composition comprising by weight percent

• 0.2% to 1% carbon,
• 0.05% to <15% aluminum,
• 0.05% to 6.0% silicon,
• 9% to <30% manganese,
• and at least one element selected from the group consisting of chromium, copper, boron, titanium, zirconium, vanadium and niobium, chromium≦6.5%;
• titanium+zirconium≦0.7%;
• niobium+vanadium≦0.5%, boron≦1%, the remainder iron including common steel companion elements,
• said method comprising the steps of:
• subjecting the workpiece to a decarburizing annealing treatment under an oxidizing atmosphere thereby causing a ferritic or meta-stable austenitic structure to form in a surface proximate region of the workpiece;
• and
• subjecting the workpiece to an accelerated cooling and/or a cold forming for generating an increased hardness in the surface proximate region and a property gradient of the workpiece, wherein a layer thickness and properties of the austenitic structure are adjustable via variation of at least one annealing parameter selected from the group consisting of temperature and holding time and via variation of at least one of a gas composition and a partial pressure of the atmosphere.