A casting method for thin-walled castings

Abstract

The invention provides a casting method of a thin section casting. The casting method comprises the following steps that metal furnace charge is melted to molten iron in a cupola furnace, when the temperature of the molten iron reaches 1520-1550 DEG C, the molten iron flows out from an iron outlet in the cupola furnace and enters an iron outlet groove, nucleating agent A is firstly added into the iron outlet groove, and the molten iron and the nucleating agent A are flushed into a casting ladle through the iron outlet groove for the first breeding and then are injected into a casting mold cavity to form the casting in a pouring mode. The casting method is characterized in that when molten iron is injected into the mold cavity, nucleating agent B is firstly added into the mold cavity for carrying out in-cavity breeding on the molten iron in the mold cavity, and the nucleating agent B comprises, by weight of molten iron discharging from the furnace, 0.2%-0.4% of silicon iron nucleating agent containing 75% of silicon iron, 0.1%-0.5% of silicon barium nucleating agent and 0.1%-0.5% of silicon zirconium nucleating agent. According to the casting method, the nucleating agent is directly placed in a mould, iron liquid solidifying conditions are improved, graphitization decay time is effectively prolonged, breeding effect can be improved to the largest extent, a hard material phenomenon of the thin section casting is solved, a bad white cast tissue phenomenon which occurs partially is avoided, production cost is lowered, and a production period is shortened. The nucleating agent is mixed type nucleating agent, the addition of the silicon zirconium nucleating agent is helpful for improving inherent quality of the casting, and the performance uniformity of different portions of the casting is guaranteed.

Description

technical field [0001] The invention relates to a method for casting castings, in particular to a method for casting thin-walled castings. Background technique [0002] The casting method of thin-walled castings in the prior art is as follows: in the cupola, the metal charge is melted into molten iron, and the casting solution with a tapping temperature of 1450°C-1500°C is injected into the ladle through the tapping chute, The inoculant is first added to the ladle, and the molten iron is inoculated twice in the tap trough and the ladle successively. After the two inoculation treatments, the molten iron is injected into the cavity of the casting and cast to form a casting. The inoculant used for the two inoculation treatments is Ferrosilicon inoculant, containing 75% ferrosilicon. This casting method is widely used in thick castings, which can improve the uniformity of the section and improve the mechanical properties of the castings. For thin-walled castings, especially ca...

AI Technical Summary

Problems solved by technology

For thin-walled castings, especially castings with a thickness of 6-9mm in the processing part, material hardness is prone to occur during the casting process with this method, and white structure may also appear locally. The current solution is to anneal 100% of the casting, so that It not only increases the production cost, but also prolongs the production cycle

At the same time, the inoculant is mainly ferrosilicon inoculant containing 75% ferrosilicon. Although 75% ferrosilicon can reduce whitening, improve graphitization, and improve the hardness and strength of castings, it can reduce the performance difference of different parts of castings. The effect is not significant

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