Abstract: Railroad rail steels having a pearlitic structure and containing 0.720 to 0.860 wt % carbon; 1.000 to 1.280 wt % manganese; 0.450 to 1.000 wt % silicon; 0.010 to 0.100 wt % copper; 0.150 to 0.280 wt % chromium; 0.0010 to 0.0500 wt % aluminum; 0.050 to 0.120 wt % nickel; 0.100 to 0.260 wt % molybdenum; 0.100 to 0.210 wt % vanadium; 0.0010 to 0.0065 wt % nitrogen; 0.0010 to 0.0080 wt % phosphorus; 0.0010 to 0.0040 wt % sulfur; and 0.0100 to 0.0350 wt % niobium with the remainder of said steel being iron, can be used to make railway rails that are particularly resistant to rolling contact fatigue and, hence, shelling.

Abstract: The invention relates to medium carbon steels and low alloy steels having a concentration of a machinability enhancing agent (“MEA”), i.e. tin and/or antimony, at its ferrite grain boundaries which enhances the steel's machinability and to processes for producing such steels. The invention encompasses medium carbon steels and low alloy steels characterized by having MEA bulk contents of from about 0.02 to about 0.09 weight percent, by having the sum of the MEA bulk content and the copper bulk content being no greater than about 0.10 weight percent, and by having a microstructure at the time of machining having a concentration of MEA at ferrite grain boundaries in an amount at least about five times the MEA bulk content of the steel.

Abstract: The invention relates to free-machining steels which do not rely on lead as a means of enhancing machinability. Instead, the steels of the invention employ concentrations of tin, arsenic, and/or antimony at ferrite grain boundaries to replicate a role of lead, which the inventors have discovered, in enhancing machinability. This role is to cause an embrittlement at the localized cutting zone temperatures by changing the fracture mode from transgranular to intergranular at those temperatures. The invention's use of concentrations of tin, arsenic, and/or antimony at the ferrite grain boundaries of the steel permits the machinability-enhancing effect to be obtained while employing bulk contents of tin, arsenic, and/or antimony below the levels at which hot tearing becomes problematic.

Abstract: A steel of particular utility in forging applications has a composition, in weight percent, of from about 0.05 to about 0.35 percent carbon, from about 0.5 to about 2.0 percent manganese, from about 0.5 to about 1.75 percent molybdenum, from about 0.3 to about 1.0 percent chromium, from about 0.01 to about 0.1 percent niobium, from about 0.003 to about 0.06 percent sulfur, from about 0.003 to about 0.015 percent nitrogen, from about 0.2 to about 1.0 percent silicon, balance iron plus conventional impurities. The steel may be worked in the austenite region to produce a well-conditioned austenite structure, cooled to transform the microstructure to a mixture of ferrite and bainite, and then cold forged to a final form. The steel may also be hot forged without first producing the well conditioned austenite. Heat treating of the final product is not required.