High-nickel austenitic nodular cast iron material for automobile turbine housing and preparation method for high-nickel austenitic nodular cast iron material

Abstract

The invention discloses a high-nickel austenitic nodular cast iron material for an automobile turbine housing and a preparation method for the high-nickel austenitic nodular cast iron material. The high-nickel austenitic nodular cast iron material comprises the following components in percentage by weight: 1.70 to 1.90 percent of carbon, 4.90 to 5.50 percent of silicon, 0.50 to 0.80 percent of manganese, less than 0.05 percent of phosphorus, less than 0.02 percent of sulfur, 0.06 to 0.09 percent of magnesium, 34.0 to 36.0 percent of nickel, 1.75 to 2.00 percent of chromium and the balance of iron. The preparation method comprises the following steps of sequentially throwing silicon carbide, cast iron, a recycled material, waste steel and pure nickel into melting equipment for melting; adding ferro-manganese, ferrochromium, ferrosilicon and a low-sulfur carburant after the materials in the melting equipment are molten; extracting the molten materials for spectral analysis; raising the temperature of the melting equipment to 1,560 to 1,620 DEG C for nodularizing treatment after the molten materials are qualified; pouring the heated materials into a nodularizing ladle for wire feeding nodularizing treatment; pouring the nodularized materials into a casting ladle for secondary inoculation, removing oxidizing slag, and performing standing and cooling; cooling and casting material liquid, and performing sand shakeout cleaning; performing heat treatment on a casting after the sand shakeout cleaning, and annealing the casting to obtain a finished product. The high-nickel austenitic nodular cast iron material is high in casting and machining performance and low in cost, and process conditions are reasonable, easy to control and favorable for casting production.

Description

Technical field [0001] The invention relates to a high-nickel austenitic ductile iron material for automobile turbine shells and a preparation method thereof. Background technique [0002] With the rapid development of turbocharging technology, its energy-saving and environmentally-friendly features have been widely accepted by many automakers. As one of its main components, the turbine shell has higher and higher requirements for high temperature resistance and corrosion resistance. The austenitic ductile iron material has good high-temperature mechanical properties and corrosion resistance. It is a good material for the production of turbine shells, but the casting performance of high-nickel austenite material is very poor. It is used in the production of complex structures and uneven wall thickness. In the case of turbine shell castings, the thin-walled parts are prone to micro-shrinkage porosity, and the thick and large parts are prone to defects such as shrinkage holes. At t...

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Problems solved by technology

[0002] With the rapid development of turbocharging technology, its energy-saving and environmental protection features are widely accepted by many automobile manufacturers. As one of its main components, the turbine shell has higher and higher performance requirements in terms of high temperature resistance and corrosion resistance. High nickel The austenitic ductile iron material has good high-temperature mechanical properties and corrosion resistance, and is a good material for the production of turbine casings, but the casting performance of the high-nickel austenitic material is poor. For turbine casing castings, micro-shrinkage porosity is prone to occur in thin-walled parts, and shrinkage cavities and other defects are prone to appear in thick and large parts. At the same time, the tendency of the material to form carbides will affect the machining performance and increase the cost of tool use in the machining process. Therefore, its composition needs to be adjusted

[0003] At present, the production process of high-nickel austenitic nodular iron material mainly includes molten iron smelting, spheroidizing treatment, inoculation treatment, pouring, cooling, sand cleaning, heat treatment and other processes. Due to the high alloy content of high-nickel nodular iron material, in The temperature requirement in the smelting process is relatively high, it is difficult to control the spheroidization and inoculation links, and casting defects such as poor spheroidization are prone to occur, which brings hidden dangers to the mass production of castings, so it needs to be improved

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