JPS6054139B2 - Manufacturing method for spheroidal graphite iron castings - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to a method for manufacturing spheroidal graphite iron castings by performing spheroidization treatment in a mold, and in particular, a method for producing spheroidal graphite iron castings by providing a plurality of weirs in the mold, This invention relates to a manufacturing method in which a reaction chamber is provided in the middle of the weir to homogenize and facilitate the spheroidization treatment of the molten metal, and to easily obtain homogeneous spheroidal graphite cast iron even in large castings.

<Prior Art> As is well known, the spheroidization of graphite during the production of iron castings is widely known as a means of obtaining excellent properties of the material of cast iron castings. For example, graphite spheroidization treatment using magnesium and silicon is widely known. It has been widely adopted.

Generally, spheroidization inoculation, including spheroidization treatment using magnesium and silicon, was performed outside the mold during the molten metal treatment process.

<Problems to be Solved by the Invention> However, performing the graphite nodularization treatment outside the mold has the disadvantage that the graphite nodularization treatment may be unstable depending on the various conditions during casting, and in some cases In the past, there were problems in that graphite spheroidization could not be achieved sufficiently due to segregation, resulting in non-uniformity of the material.

To deal with this, a method has recently been devised and adopted in which the above-mentioned spheroidizing inoculation treatment is carried out in a reaction chamber through a weir provided integrally within the mold during casting.

Therefore, the spheroidization inoculation treatment using a reaction chamber provided in the mold is a method that simply provides a single weir with a reaction chamber, and according to this type of method, the instability of graphite spheroidization is considerably reduced. This has been improved and has the advantage of reducing the non-uniformity of the casting material.

However, although the method of simply providing a single weir exhibits the above characteristics when casting small castings, it is difficult to use a reaction chamber when casting large castings or castings with complex shapes. Not only does it have to be extremely large, making it impractical in terms of casting methods and casting costs, but it also requires a significant increase in the amount of spheroidizing agents and inoculants such as magnesium and silicon. If this is not done, there is a disadvantage that it is not possible to achieve a uniform five-quality material, and furthermore, there are disadvantages such as a so-called poor yield.

The purpose of this invention is to solve various problems in the production of spheroidal graphite iron castings based on the above-mentioned prior art, and to eliminate the above-mentioned drawbacks, solve the difficulties, and eliminate the disadvantages. The purpose of this invention is to provide an excellent method for producing spheroidal graphite iron castings that reduces the amount of curing agents, inoculants, etc., reduces costs, and improves workability, thereby benefiting the field of cast iron use in the iron and steel industry. . In order to solve the above-mentioned problems, the structure of the present invention, which is based on the above-mentioned claims, is to solve the above-mentioned problems by directing the molten metal poured from the sprue through the runner. After passing through, the water is divided into multiple processing lines, poured into each weir in parallel, and then supplied from each weir to each reaction chamber to achieve stable graphite spheroidization in each reaction chamber and homogenize the spheroidal graphite. At the same time, technical measures were taken to homogenize the properties of large or geometrically complex castings and eliminate segregation.

<Embodiment> Next, one embodiment of the present invention will be described below with reference to the drawings.

In the figure, when a cast iron sprue melted in a cupola, low frequency furnace, etc. is poured directly into the sprue 1, the molten cast iron flows through the runner 2, which has a circular flow shape in plan view, in a divided manner to the left and right, and passes through multiple runners. For example, the water is divided into four weirs 3, 3, 3, 3 as a preliminary step and flows into reaction chambers 4, 4, 4, 4 connected in series to the weirs 3, 3, 3, 3.

Thus, the molten cast iron is preliminarily poured into each reaction chamber 4. Reception room 4
After reacting with a predetermined spheroidizing agent and inoculant that had been put into the spheroidizing agent and undergoing spheroidizing and inoculating treatment, it flows into the desired product mold 5, solidifies, and is molded.

At that time, the molten cast iron flows through the four previous weirs 3, 3, . 3,3
Since the flow is divided into two, enters each reaction chamber 4, and then flows into the corresponding product mold body 5, it passes through a runner which is extremely effective in terms of casting plans, and the product mold 5 with a large or complicated shape. The molten metal flows throughout the area with an average amount, and the spheroidal graphite is distributed homogeneously.

Effects of the Invention> As described above, according to the present invention, after molten cast iron is introduced from the sprue, the molten metal is distributed in parallel to a plurality of weirs as a preliminary step, and then graphite spheres are formed in the corresponding reaction chambers. As a result, the graphite is spheroidized extremely homogeneously and without any unevenness, and the flow of the casting metal is evenly distributed according to the casting plan, making it easier to cast large or complex castings. The excellent effect is that the cooling is even and the properties are uniform.

The spheroidization rate is affected by the distance after passing through the reaction chamber, but when manufacturing complex and large castings, comparing the case where a single weir is installed and the case where multiple weirs are installed in parallel to supply the molten metal, Naturally, the maximum distance of the flow is longer for a single unit, and therefore, the longer the distance the molten metal flows, the greater the temperature drop during hot water supply.

Therefore, when a single weir is provided, molten metal must be supplied at a higher temperature than when multiple weirs are provided.

Regarding the relationship between hot water supply temperature and spheroidization rate, as is known to those skilled in the art, as the hot water supply temperature increases, the spheroidization rate worsens in areas near the weir.

However, in this invention, as mentioned above, by supplying hot water through a plurality of weirs, the hot water temperature can be increased, and the hot water can be supplied at a low temperature, thus increasing the spheroidization rate of the entire product. This has the effect that it is not necessary to increase the amount of the spheronizing agent added in order to obtain a spheroidization rate higher than a typical value.

[Brief explanation of the drawing]

The drawings are explanatory diagrams of one embodiment of the present invention, with FIG. 1 being a plan view and FIG. 2 being a partially sectional side view thereof. 3...cough, 4...reaction chamber.

Claims (1)

[Claims] 1. In a method for manufacturing spheroidal graphite iron castings by in-mold spheroidization inoculation treatment, the above-mentioned in-mold spheroidization inoculation treatment involves passing the molten metal through a plurality of weirs provided in the mold, and then injecting the molten metal into each of the weirs. A method for producing spheroidal graphite iron castings, characterized in that the process is carried out in a reaction chamber.