MANUFACTURING METHOD OF SHAPED PART HAVING AT LEAST TWO STRUCTURAL AREAS OF VARIOUS DUCTILITY Russian patent published in 2012 - IPC C21D9/46 C21D1/673 

FIELD: metallurgy.

SUBSTANCE: sheet billet (7) cut of steel strip (4) of high-strength boron-containing steel having aluminium-silicon coating is first heated uniformly in zone 1 (8) of furnace (11) with temperature zones (8, 9, 10) to temperature approximately of 830° to 950°, and kept at this temperature level during certain period of time (t). Then, area (12) of the first type of sheet billet (7) in zone 2 (9) of furnace (11) is cooled approximately to temperature of 550° to 700° and kept at this decreased temperature level during certain period of time (t₁). At the same time, area (13) of the second type of sheet billet (7) in zone 3 (10) of furnace (11) is kept at temperature level approximately of 830° to 950° during period of time (t₂). After this heat treatment is completed, sheet billet (7) is deformed during hot plastic forming and shaped part (1) is obtained. Steel sheet has aluminium-silicon coating pre-applied as per diffusion alloying technology.

EFFECT: preventing scale formation.

12 cl, 3 dwg