MANUFACTURING METHOD OF STRUCTURAL ELEMENT MADE FROM STEEL CAPABLE OF SELF-HARDENING OUTDOORS AND STRUCTURAL ELEMENT MANUFACTURED BY THIS METHOD Russian patent published in 2015 - IPC C21D8/02 C22C38/38 C22C38/32 

FIELD: metallurgy.

SUBSTANCE: invention refers to a manufacturing method of structural elements made from steel capable of self-hardening outdoors. Steel has the following composition, wt %: C ≤ 0.20, Al ≤ 0.08, Si ≤ 1.00, Mn 1.20 to ≤ 2.50, P ≤ 0.020, S ≤ 0.015, N ≤ 0.0150, Cr 0.30 to ≤ 1.5, Mo 0.10 to ≤ 0.80, Ti 0.010 to ≤ 0.050, V 0.03 to ≤ 0.20, B 0.0015 to ≤ 0.0060, iron and inevitable impurities are the rest. A workpiece from hot-rolled or cold-rolled sheet steel or a steel pipe is heated to a temperature of ϑ_workpiece = from 800 to 1050°C, and it is plastically deformed in a die to a structural element. When the part is removed from the die it is cooled outdoors. After removal from the die, the structural element temperature ϑ_removal is above 200°C and below 800°C, and during cooling outdoors it is hardened.

EFFECT: achieving required mechanical properties of a plastically deformed element without final roasting.

9 cl, 2 dwg