Patent ID: 10023926

Abstract:
The invention relates to a method for the production of martensitic cast steel of high strength and excellent abrasion- and impact-wear resistance, intended for large parts used as anti-wear cladding in crushing and grinding mining operations, having a chemical composition, expressed in percentage by weight, of between 0.35˜0.55% C, 0.60˜1.30% Si, 0.60˜1.40% Mn, 4.5˜6.50% Cr, 0.0˜0.60% Ni, 0.30˜0.60% Mo, 0.0˜0.70% Cu, 0.010˜0.10% Al, 0.0˜0.10% Ti, 0.0˜0.10% Zr, 0.0˜0.050% Nb, less than 0.035% P, less than 0.035% S, less than 0.030% N, optionally 0.0005˜0.005% B, optionally 0.015˜0.080% rare earths, and the rest being iron. The method for the production of cast steel includes smelting, pouring and heat treatment. The smelting can be performed in an electric arc furnace with acidic or basic refractory or an electric induction furnace. Smelting in an electric arc furnace as a normal operation includes melting, oxygen insufflation, blocking, refining and deoxidation. Smelting in an electric induction furnace includes melting, refining, control of nitrogen in solution and deoxidation. The heat treatment comprises hardening in forced or still air depending on the thickness of the parts, followed by a tempering heat treatment. The cast steel of the invention demonstrates excellent resistance to abrasion-/impact-wear and a suitable chemical composition balance, with the addition of microalloying agents in order to obtain high hardenability and full curing in large cast parts, typically up to 14 inches thick, with Brinell hardness preferably around 630 BHN depending on the heat treatment conditions applied.