ES439398A1 - High elastic-limit weldable cast steels - Google Patents

Abstract

Procedure for the preparation of a molded, weldable steel, with a high elastic limit, by melting the mixture of constituents, by adding to the molten mixture of deoxidizers and by casting this mixture at a temperature of 1600º-1690ºC, with subsequent heat treatment cycle, characterized in that a steel is prepared that has a carbon content of 0.09 to 0.15% by weight, manganese of 1.30 to 1.80% by weight, molybdenum of 0.15 to 0, 35% by weight, silicon from 0.10 to 0.40% by weight, vanadium from 0.03 to 0.06% by weight, niobium or tantalum from 0.005 to 0.05% by weight, aluminum from 0.015 to 0.050 % by weight, titanium from 0.002 to 0.040% by weight, nickel from 0.10 to 0.30% by weight, chromium from 0.10 to 0.25% by weight, sulfur less than or equal to 0.020% by weight and phosphorus less than or equal to 0.030% by weight, the complement being up to 100% by weight essentially iron, the steel of which also has a very fine-grained microstructure, consisting of bainite with a small content of e carbon and ferrite hardened by the presence of fine precipitates of complex carbon nitrides, mainly molybdenum, vanadium and niobium or tantalum, carrying out a cycle of thermal treatments that include a homogenization treatment at a temperature between 900ºC and 1050ºC with times of raising and maintaining the temperature for several hours, a water quenching at room temperature after heating for one hour to a temperature approximately between 875 and 950ºC with a temperature rise time of several hours, and tempering at a temperature between 550ºC and 580ºC with elevation and temperature maintenance times of several hours. (Machine-translation by Google Translate, not legally binding)