A production line for hot steel strips, being fed from two casting lines ( a, b ) for thin slabs of thickness ≤ 100 mm, only one of which ( a ) is aligned with a finishing rolling mill (g), comprises also two pairs of rotatable heating furnaces with mandrel (A1, A2; B1, B2), each respectively on either line, with an intermediate bypass section ( d ) between the furnaces of the first pair (A1, A2) to allow the endless rolling in a finishing rolling mill ( g ) located downstream. The furnaces (B1, B2) of the second pair of furnaces on the line ( b ) can be transferred along a path ( k ) from said line to the rolling line and vice versa for producing single strips. Furthermore an induction furnace ( f ) is provided upstream of the finishing rolling mill ( g ). Also the corresponding production process is described.