Low-cost seawater-corrosion-resistant nodular cast iron and preparation method thereof

Abstract

The invention relates to a low-cost seawater-corrosion-resistant nodular cast iron and a preparation method thereof, and belongs to the technical field of casting alloys. The nodular cast iron comprises the following chemical components: 3.5-3.9% of C, 2.3-2.9% of Si, 0.5-2.0% of Zn, less than 0.3% of Mn, less than 0.025% of S, less than 0.06% of P, 0.03-0.05% of Mg residues, 0.02-0.04%of Re residues and the balance of Fe. Low-price industrial waste steel is adopted as the main raw material for producing the nodular cast iron, zinc-containing core-spun yarn is added before discharging, precious metal such as nickel in the corrosion-resistant nodular cast iron is replaced with zinc, the production cost is low, and energy conservation and environmental protection are achieved. The preparation method comprises the following steps: (1) adding raw materials into a medium-frequency electric furnace to be smelted into molten iron, adding the zinc-containing core-spun yarn before discharging, and then performing discharging; (2) carrying out purification treatment during spheroidizing and inoculation treatment of molten iron; and (3) performing pouring to obtain the nodular cast iron. The spheroidization level of the prepared nodular cast iron is 1-2 level, the spheroidization rate is larger than or equal to 90%, the ferrite content is larger than or equal to 90%, the tensile strength is larger than or equal to 450 MPa, the elongation is larger than or equal to 10%, and the nodular cast iron can normally work in the marine environment and has remarkable beneficial effects.

Description

technical field [0001] The invention relates to nodular cast iron technology, in particular to a low-cost seawater corrosion-resistant nodular cast iron and a preparation method thereof. Background technique [0002] Ductile iron has the essence of iron and the properties of steel, and is a new type of engineering material with high plasticity, strength, corrosion resistance and wear resistance. my country is the country with the largest output of ductile iron, and its annual output accounts for more than one-third of the world's total annual output. The ductile iron castings produced must not only meet the needs of the domestic market, but also be exported abroad to meet the needs of the international market. [0003] At present, the production of ductile iron mainly uses pig iron. Domestic pig iron mainly comes from iron ore smelting. Iron ore is a non-renewable resource, and the amount available is getting smaller and smaller. The cost of using pig iron directly is increa...

AI Technical Summary

Problems solved by technology

Usually, expensive nickel, chromium and other alloying elements are added to ductile iron, so that the production cost remains high. Therefore, a raw material with low production cost, abundant mining output and easy access is needed to produce seawater corrosion-resistant nodular cast iron.

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