Rare-earth-free spheroidized core-spun yarn and application thereof in spheroidal graphite casting

Abstract

The invention discloses a rare-earth-free spheroidized core-spun yarn and application thereof in spheroidal graphite casting, wherein the core-spun yarn is prepared from steel sheet coated core powder, and the core powder consists of the following components in percentage by mass: 28-32% of Mg, 43-46% of Si, 2-4% of Ca, 8-10% of Ba, and the balance of Fe and impurities, wherein MgO is less than orequal to 1.5%. Application of the rare-earth-free spheroidized core-spun yarn in the spheroidal graphite casting comprises the following steps: batching, smelting, sand-mixing, core-making, modeling,casting, process inspecting, sand dropping and quality inspecting, wherein the casting step comprises inoculating, spheroidizing and casting forming, and the spheroidized core-spun yarn is applied tothe spheroidizing step. According to the technical scheme provided by the invention, the rare-earth-free spheroidized core-spun yarn is free of rare-earth element accumulation, is less in cementite forming element amount, is small in cementite tendency, has a cementite isolation rate lower than or equal to 0.5%, improves spheroidizing quality, saves core-spun yarn feeding-in amount, realizes rare-earth-free pure magnesium spheroidizing, and reduces production cost.

Description

technical field [0001] The invention relates to the technical field of iron and steel castings, in particular to a rare earth-free spheroidized cored wire and its application in spheroidal graphite castings. Background technique [0002] Ductile iron is a high-strength cast iron material developed in the 1950s. Spheroidal graphite is obtained through spheroidization and inoculation treatment, which effectively improves the mechanical properties of cast iron, especially the plasticity and toughness, and thus obtains carbon Due to the high strength of steel, nodular cast iron is based on the excellent properties close to steel, and has been successfully used to cast some parts with complex stress, high strength, toughness and wear resistance. [0003] After continuous development, nodular cast iron has been widely used for spheroidizing with rare earth magnesium alloy materials. Using nodular cast iron to cast castings, although the rare earth-containing magnesium alloy mater...

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Problems solved by technology

[0004] The purpose of the present invention is to propose a rare earth-free spheroidized cored wire and its application in nodular castings, aiming to solve the tendency of cementite in nodular castings caused by the accumulation of rare earth elements in the casting process of ball grinding castings, which is hard and brittle. Problems with processing, easy breakage and high isolation rate

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