Casting method for large wind power casting and casting produced through casting method

Abstract

The invention discloses a casting method for a large wind power casting. The casting method comprises the following steps of (a) smelting furnace burden into molten iron, and (b) carrying out spheroidizing treatment and inoculation treatment on the molten iron and then carrying out casting, mold filling and solidifying so as to obtain the casting, wherein in the step a, the content of C in the molten iron is controlled to be 3.65-3.90wt%, the content of Si is controlled to be 0.8-1.2wt%, the content of Mn is controlled to be 0.05-0.20wt%, the content of P is controlled to be less than or equalto 0.035wt%, the content of S is controlled to be 0.006-0.015wt%, in the step b, the spheroidizing treatment specifically comprises the following steps of firstly, adding spheroidizing agents accounting for 1.00-1.20wt% of the molten iron into a spheroidizing chamber, then covering the spheroidizing agents with covering agents accounting for 0.4-0.7wt% of the molten iron and finally, pouring themolten iron into the spheroidizing chamber for spheroidizing and inoculation treatment, and in the step b, the inoculation treatment is carried out specifically in three steps. According to the casting method, the density and the roundness of graphite balls can be improved by using a large number of covering agents and a repeated inoculation mode. The invention further discloses the wind power casting. The wind power casting cast by the method has the advantages of being relatively high in strength and impact absorbing energy and excellent in mechanical performance.

Description

technical field [0001] The invention belongs to the technical field of casting technology, and in particular relates to a casting method of a large-scale wind power casting and a casting made by it. Background technique [0002] QT400-18AL-1 material is a standard grade of ductile iron material that has just been established in the domestic wind power industry in the past one or two years. This material requires castings to have the same tensile properties as QT400-18AL material specified in GB / T 1348-2009. Test the impact energy at -30±2°C, and the test value should meet the requirement that the average impact energy is greater than 10J, and the single impact energy is greater than 7J (60mm<wall thickness<200mm). According to the brittle transition curve of the QT400-18AL material, the brittle transition temperature of the large-scale casting samples generally starts above -10°C and ends at around -60°C, so the -20°C impact test is changed to -30°C impact Test, its v...

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Problems solved by technology

[0004] For QT400-18AL-1 material, although some measures have been taken in the existing casting process to delay the decline of spheroidization and inoculation, the effect is not obvious, resulting in low spheroidization rate of castings, graphite sphere density and roundness. The flatness is not high, and the performance of the casting is not stable, so it is urgent to develop a new solution to provide assistance for the production of large castings of QT400-18AL-1 material, and also provide a method for the production of other large and super large ferritic ductile iron castings Means to improve performance and provide a basis for new material development

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