Low-temperature-resistant nodular iron casting and preparation method thereof

Abstract

The invention relates to a low-temperature-resistant nodular iron casting. The low-temperature-resistant nodular iron casting comprises the following components in percentage by weight: 3.6% to 3.7% of C, 1.9% to 2.0% of Si, less than 0.015% of Mn, less than 0.015% of P, less than 0.012% of S, 0.04% to 0.055% of Mg, 0.01% to 0.02% of Re, and the balance iron. A preparation method of the low-temperature-resistant nodular iron casting comprises the following steps: 1, preparing raw materials; 2, smelting; 3, sampling, analyzing and blending; 4, adding a pretreating agent; 5, tapping iron, nodulizing and inoculating; 6, deslagging; 7, casting. The low-temperature-resistant nodular iron casting and the preparation method thereof have the advantages that the nodular iron casting contains little Mn and P and is free of thermal treatment; the average impact energy of the nodular iron casting is not less than 10J under the temperature of -40 DEG C, -50 DEG C and -60 DEG C.

Description

technical field [0001] The invention relates to a ductile iron casting and a preparation method thereof, in particular to a low temperature resistant ductile iron casting and a preparation method thereof. Background technique [0002] The market demand for low-temperature-resistant and high-toughness ductile iron castings is growing rapidly. It is mainly used in equipment in alpine regions, such as gearboxes, hubs, bases, etc. for wind power equipment, or railway and subway accessories, etc. At present, on the website of the State Intellectual Property Office, the invention patent with the authorized announcement number "CN102534090B" discloses a preparation method of -60°C low-temperature impact ductile iron. The average value of the impact energy under the environment can be greater than 10J. However, this preparation method also has the following problems: 1. Since pig iron, steel scrap and recycled material are used as raw materials in this preparation method, and these...

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Problems solved by technology

However, this preparation method also has the following problems: 1. Since pig iron, steel scrap and recycled material are used as raw materials in this preparation method, and these materials all contain Mn and P elements, the There are more Mn and P elements in ductile iron castings, and Mn can increase the tendency of segregation and promote the formation of carbides and pearlite in the matrix, which is very unfavorable to toughness, especially to the impact energy of low temperature resistant nodular cast iron. Serious damage; And P will reduce the toughness and plasticity of ductile iron castings, thereby greatly reducing the low temperature impact performance of ductile iron castings; Improve the production cost of ductile iron castings; 3. The impact toughness of low temperature resistant ductile iron castings is affected by many factors. To master the impact performance of ductile iron castings, it is not comprehensive to only know the impact data at a single specific temperature. If the temperature In the transition region of plastic-brittle transition temperature, a slight change in temperature can cause a large change in impact toughness, which will cause large performance fluctuations