COOLED AND ANNEALED BAINITE STEEL PART, AND A METHOD OF MANUFACTURING IT.

摘要

The invention provides a method of fabricating a steel part, the method comprising the steps of: preparing and casting a steel having the following composition in percentage by weight: 0.06%<=C<=0.25%; 0.5%<=Mn<=2%; traces<=Si<=3%; traces<=Ni<=4.5%; traces<=Al<=3%; traces<=Cr<=1.2%; traces<=Mo<=0.30%; traces<=V<=2%; traces<=Cu<=3.5%; and satisfying at least one of the following conditions: 0.5%<=Cu<=3.5%; 0.5.%<=V<=2%: 2<=Ni<=4.5% and 1%<=Al<=2%; the remainder being iron and impurities resulting from preparation; hot deforming the cast steel at least once at a temperature in the range 1100 DEG C. to 1300 DEG C. in order to obtain a blank of the part; controlled cooling of the blank for the part in still air or forced air; and heating the steel to perform precipitation annealing before or after machining the part from said blank. The invention also provides a part obtained by the method.