Abstract
	The paper deals with classification of steel sheets on the base of strength and structural characteristics in automotive industry. Experimental works were aimed to obtain the best strengthening parameters as are work hardening and solid solution ferrite hardening from interstitial carbon atoms during paint-baking of auto body. Hardening process from interstitial atoms is realized as two-step process. First step is BH (bake hardening) effect made by interaction of interstitial atoms with dislocations. The Cottrels atmosphere is obtained. Second step of BH effect is produced by precipitation hardening from microalloyed elements.
	WH (work hardening) effect is obtained by cold plastic deformations during sheet deep drawing. Experimental works referred to the achievement such plastic material properties after cold rolling, annealing and skin-pass rolling, which classify the material ZStE 220 BH after this treatment to drawing categories on the level DQ - DDQ. The optimal treatment conditions, which are result from experimental works, for maximization of sum (WH+BH) effects are following: summary cold rolling deformation ?cold = 65 %, annealing temperature Tanneal = 700°C at the maximum sum (WH+BH) = 86 MPa.