Heat treatment line with a method of dynamical adjustment for manufacturing a thermally treated steel sheet

A heat treatment line comprising:

• a heating section;
• a soaking section;
• and
• a cooling section including a cooling system,
• the heat treatment line implementing a method of dynamical adjustment for manufacturing a thermally treated steel sheet having a chemical steel composition and a microstructure mtarget comprising from 0 to 100% of at least one phase chosen among:
• ferrite, martensite, bainite, pearlite, cementite and austenite, wherein a predefined thermal treatment TT, comprising at least a heating, a soaking and a cooling steps, is performed, such method comprising:
• A. a control step wherein at least one detector detects any deviation happening during TT,
• B. a calculation step performed when a deviation is detected during TT such that a new thermal path TPtarget is determined to reach mtarget taking the deviation into account, such calculation step comprising:
• 1) a calculation sub-step wherein through variation of the cooling power, new cooling paths CPx are calculated based on TT, the initial microstructure mi of the steel sheet to reach mtarget, the heating path, the soaking path comprising Tsoaking and Tcooling, the cooling step of TT being recalculated using said CPx in order to obtain new thermal paths TPx, having the cooling step replaced by one CPx in order to obtain a thermal path TPx, each TPx corresponding to a microstructure mx,
• 2) a selection step wherein one TPtarget to reach mtarget is selected, TPtarget being chosen among the calculated thermal paths TPx and being selected such that mx is the closest to mtarget and
• C. a new thermal treatment step wherein TPtarget is performed online on the steel sheet.