High-silicon solution-strengthening ferrite spheroidal graphite iron casting and manufacturing method thereof

Abstract

The invention relates to a high-silicon solution-strengthening ferrite spheroidal graphite iron casting, and further relates to a manufacturing method of the high-silicon solution-strengthening ferrite spheroidal graphite iron casting. The high-silicon solution-strengthening ferrite spheroidal graphite iron casting comprises the components of, by weight, 3.25%-3.35% of C, 3.70%-3.80% of Si, 0.15%of Mn or the less, 0.03% of P or the less, 0.012% of S or the less, 0.035%-0.05% of Mg, 0.004%-0.015% of Re, 0.004%-0.006% of Sb and the balance iron. The manufacturing method comprises the steps of raw material batching, smelting in a cupola, molten iron desulphurization, smelting in an electric furnace, sampling analysis and blending, tapping, spheroidization and primary inoculation treatment, slag removal, and pouring. The high-silicon solution-strengthening ferrite spheroidal graphite iron casting and the manufacturing method thereof have the advantage that the defects of shrinkage porosity and cavity generated when the QT500-14 spheroidal graphite iron casting with the wall thickness being larger than 60 mm is manufactured by high-silicon solution-strengthening ferrite spheroidal graphite cast iron can be effectively overcome.

Description

technical field [0001] The invention relates to a ductile iron cast, in particular to a high-silicon solid-solution strengthened ferrite nodular iron cast and a manufacturing method thereof. Background technique [0002] Ductile iron is widely used in castings such as hubs, bases, bearing housings, and main shafts of wind turbines. With the continuous development of the industry, the demand for using QT500-14 ductile iron on wind turbines is increasing. QT500-14 ductile iron The characteristics of the material are high tensile strength and yield strength, but low elongation and notched impact toughness, and high brittleness. At present, the GB / T1348-2009 national standard for ductile iron only has technical requirements for the QT500-7A grade, and there is no technical regulation for the QT500-14 grade; although the European standard for DIN EN1563:2005-10 ductile iron has a wall thickness ≤ 60mm QT500- 14 There are technical regulations for ductile iron, but there are no t...

AI Technical Summary

Problems solved by technology

In order to obtain higher comprehensive performance indicators, the current common method is to use high-silicon solid-solution strengthening process to manufacture ductile iron castings. The impact of silicon low carbon tends to increase shrinkage porosity, especially for castings with wall thickness > 60mm

Yang Sen mentioned in the article "Prevention Measures for High-Strength Cast Ductile Iron Crankshaft Shrinkage Porosity" (Modern Cast Iron, Issue 06, 2015) that it can be solved by optimizing the cold iron process layout, reducing the pouring temperature, adjusting the chemical composition and increasing the inoculation. Shrinkage and porosity defects inside the crankshaft, but this process is suitable for thin-walled castings and requires strict control of the entire set of casting process parameters such as smelting, spheroidizing, and pouring; while wind turbine castings are thick-walled castings, therefore, while meeting the strength index , how to solve the shrinkage problem will be the biggest problem faced by QT500-14 ductile iron