An iron-based alloy composition including: boron (B): 1. 6-2.4 wt. %; carbon (C): 2.2-3.0 wt. %; chromium (Cr): 3.5-5.0 wt. %; manganese (Mn): below 0.8 wt. %; molybdenum (Mo): 16.0-19.5 wt. %; nickel (Ni): 1.0-2.0 wt. %; silicon (Si): 0.2-2.0 wt. %; vanadium (V): 10.8-13.2 wt. %; and balanced with iron (Fe). Further, an item including a substrate portion and a hardfacing coating bonded to the substrate portion, wherein the hardfacing coating is made by an overlay welding process using the iron-based alloy composition.

A method for the production of cast iron starting from pre-reduced iron ore (DRI) with an electric arc furnace includes the steps of preparing a charge of pre-reduced iron ore DRI having a metallization higher than 90% and containing over 2.8% by weight of carbon, wherein at least 80% of the carbon is combined with the iron to form iron carbide Fe.sub.3C; charging the charge of pre-reduced iron ore into the electric arc furnace; and melting the DRI charge to form liquid cast iron having at least 80% by weight of actual carbon content deriving from the carbon in the charge of pre-reduced iron ore, the melting step being in a reducing atmosphere and in a melting chamber of the electric arc furnace subjected to a positive internal pressure generated by the gases produced by reduction reactions that develop during melting.

A method for the production of cast iron starting from pre-reduced iron ore (DRI) with an electric arc furnace includes the steps of preparing a charge of pre-reduced iron ore DRI having a metallization higher than 90% and containing over 2.8% by weight of carbon, wherein at least 80% of the carbon is combined with the iron to form iron carbide Fe.sub.3C; charging the charge of pre-reduced iron ore into the electric arc furnace; and melting the DRI charge to form liquid cast iron having at least 80% by weight of actual carbon content deriving from the carbon in the charge of pre-reduced iron ore, the melting step being in a reducing atmosphere and in a melting chamber of the electric arc furnace subjected to a positive internal pressure generated by the gases produced by reduction reactions that develop during melting.

One aspect of the disclosure provides an iron-based hardfacing layer which includes hard or wear resistant phases resulting at least in part from dissolution of silicon and/or boron carbide particles into a liquid iron-based metal during the fabrication process. In an embodiment, the hardfacing layer is formed by a fusion welding process in which carbide particles are added to the molten weld pool. In an example, the filler metal supplied to the welding process is a mild steel. In an embodiment, the hardness as measured at the surface of the hardfacing ranges from 40 to 65 HRC. In an example, the iron-based hardfacing layer also includes tungsten carbide particles.

One aspect of the disclosure provides an iron-based hardfacing layer which includes hard or wear resistant phases resulting at least in part from dissolution of silicon and/or boron carbide particles into a liquid iron-based metal during the fabrication process. In an embodiment, the hardfacing layer is formed by a fusion welding process in which carbide particles are added to the molten weld pool. In an example, the filler metal supplied to the welding process is a mild steel. In an embodiment, the hardness as measured at the surface of the hardfacing ranges from 40 to 65 HRC. In an example, the iron-based hardfacing layer also includes tungsten carbide particles.

A nanocrystal production method includes a light irradiation step of applying light to a surface of a metal material immersed in water to form nanocrystals on the surface. In this nanocrystal production method, the metal material contains iron, the nanocrystal contains at least one of iron oxide and iron hydroxide, and in the spectrum of the light, a wavelength at which the intensity is maximum is not less than 360 nm and less than 620 nm.

An outer layer of a rolling roll having a chemical composition comprising by mass 1.3-2.8% of C, 0.3-1.8% of Si, 0.3-2.5% of Mn, 0-6.5% of Ni, 1-10% of Cr, 0.9-6% of Mo, 0-8% of W, 0.5-6% of V, 0-3% of Nb, and 0% or more and less than 0.01% of B, the balance being Fe and inevitable impurities, and meeting the formulae (1): 1000117752C+14Si11Mn+6.8Cr+1W+0.65Mo+12V+15Nb1115, and (2): 5Cr+Mo+0.5W+V+1.2Nb15, wherein C, Si, Mn, Cr, W, Mo, V and Nb represent % by mass of these elements, and a structure containing eutectic carbide without graphite.

An outer layer of a rolling roll having a chemical composition comprising by mass 1.3-2.8% of C, 0.3-1.8% of Si, 0.3-2.5% of Mn, 0-6.5% of Ni, 1-10% of Cr, 0.9-6% of Mo, 0-8% of W, 0.5-6% of V, 0-3% of Nb, and 0% or more and less than 0.01% of B, the balance being Fe and inevitable impurities, and meeting the formulae (1): 1000117752C+14Si11Mn+6.8Cr+1W+0.65Mo+12V+15Nb1115, and (2): 5Cr+Mo+0.5W+V+1.2Nb15, wherein C, Si, Mn, Cr, W, Mo, V and Nb represent % by mass of these elements, and a structure containing eutectic carbide without graphite.

The present invention refers to a gray cast iron alloy with chemical composition especially developed to promote high hot mechanical strength and good thermal conductivity, with antimony and nitrogen contents, wherein the antimony content ranges from 0.05 to 0, 12% by weight, and the nitrogen content ranges from 0.008 to 0.013% by weight, based on the total weight of the gray cast iron alloy.

An outer layer of a rolling roll having a chemical composition comprising by mass 1.3-2.8% of C, 0.3-1.8% of Si, 0.3-2.5% of Mn, 0-6.5% of Ni, 1-10% of Cr, 0.9-6% of Mo, 0-8% of W, 0.5-6% of V, 0-3% of Nb, and 0% or more and less than 0.01% of B, the balance being Fe and inevitable impurities, and meeting the formulae (1): 1000117752C+14Si11Mn+6.8Cr+1W+0.65Mo+12V+15Nb1115, and (2): 5Cr+Mo+0.5W+V+1.2Nb15, wherein C, Si, Mn, Cr, W, Mo, V and Nb represent % by mass of these elements, and a structure containing eutectic carbide without graphite.