Patent ID: 6315844
Filing Date: 2001-11-13
Classification: C21D,C22C,E01B

Abstract:
A process for manufacturing a high strength track section of steel comprising the steps of:providing a quantity of steel having a chemical composition of 0.3 to 0.6% C, 0.8 to 1.5% Si, 0.7 to 1.0% Mn, 0.9 to 1.4% Cr, 0.6 to 1.0% Mo, remainder iron and usual smelting-related impurities;heating said steel to about 750.degree. C.;cooling said steel to below about 450.degree. C. to produce a bainitic basic structure with a tensile strength of approximately 1100 N/mm.sup.2 ;heating said steel to a temperature T.sub.4 where 400.degree. C.<T.sub.4 <550.degree. C.;cooling said steel in a controlled way to produce a steel having a tensile strength of at least 1200 N/mm.sup.2 ;heating said steel to a temperature T.sub.1 where 750.degree. C.<T.sub.1 <920.degree. C.;cooling said steel in an accelerated form to a temperature T.sub.2 where 250.degree. C.<T.sub.2 <400.degree. C. in a medium selected from the group consisting of a polymer/water mixture, a molten salt, and a powder;heating said steel to a temperature T.sub.3 >T.sub.2 where 400.degree. C.<T.sub.3 <560.degree. C.;holding said steel at a temperature T.sub.3 for a time t.sub.1 where 60 minutes<t.sub.1 <150 minutes; and,cooling the steel to room temperature.