Method for casting as-cast high-tenacity cast iron bearing cover of locomotive

Abstract

The invention relates to a method for casting an as-cast high-tenacity cast iron bearing cover of a locomotive. The method comprises the following steps: sand mulling, molding, core making, mould assembly, charging smelting, tapping spheroidization inoculation treatment, casting, cooling, unboxing and casting cleaning. The step of charging smelting comprises charging arrangement and smelting, as well as the smelting of a medium-frequency induction furnace, wherein the charging comprises 35-45 percent of pig iron, 25-35 percent of returning iron and 25-35 percent of waste steel according to weight percentage. The tapping spheroidization inoculation treatment comprises spheroidization treatment and secondary silicon-barium inoculation. Stream inoculation of tertiary sulfur-oxygen nucleating agent is conducted during the casting. The bearing cover of the locomotive produced by the method has a tensile strength higher than or equal to 400 MPa, a specific elongation more than or equal to 18 percent, a hardness HBS ranging from 130 to 180 and a low temperature (-20 DEG C) impact value higher than or equal to 12 J / cm; the spheroidization rate the metallurgical structure of casting body is higher than or equal to 85 percent, and the ferrite content is higher than or equal to 95 percent; the thickness difference of casting walls is less than or equal to + / - 1 mm; and the detection result of the casting ultrasonic and magnetic powder inspection reaches the second grade standard of the state.

Description

technical field [0001] The invention relates to the field of casting, in particular to a method for casting a locomotive as-cast high-toughness nodular iron bearing cover with low-temperature impact performance. Background technique [0002] Due to the spherical shape of graphite, nodular cast iron material not only has high mechanical properties such as high tensile strength and elongation, but also has good mechanical properties at room temperature under dynamic load-impact toughness and fatigue strength, so it is widely used in various construction machinery. For the ductile iron materials used in construction machinery such as airplanes, trains, automobiles, and wind power generators that often work in cold regions, there is also a requirement for low-temperature impact resistance. [0003] Ductile iron parts of locomotive bearing caps are generally required to be high toughness ductile iron parts with low temperature impact performance. The mechanical properties of th...

AI Technical Summary

Problems solved by technology

The disadvantage of this traditional production process is that the production cycle is long and increases the production energy consumption of the product

At the same time, due to the deformation defects of the product after high-temperature treatment, it is difficult to ensure the dimensional accuracy and produce waste products; moreover, when the product is heat-treated, more scale is produced, and a shot blasting cleaning process is added to remove the scale, etc.

Therefore, there are a series of problems and defects in the traditional production process

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