KR20130120181A

KR20130120181A - Initial melting for manufacturing cgi castiron and method for manufacturing non-inoculating type cgi castiron using the same

Info

Publication number: KR20130120181A
Application number: KR1020120043240A
Authority: KR
Inventors: 남승현; 마대웅; 김진국; 박정래; 윤영철
Original assignee: 현대중공업 주식회사
Priority date: 2012-04-25
Filing date: 2012-04-25
Publication date: 2013-11-04

Abstract

Disclosed is a raw water for producing CGI cast iron and a method for producing an inoculated CGI cast iron using the same.
Non-inoculated CGI cast iron manufacturing method according to the present invention in weight%, carbon (C): 3.5-3.7%, silicon (Si) 1.4-1.6%, manganese (Mn): 0.3-0.5%, phosphorus (P): 0.15 ~ 0.25%, sulfur (S): 0.2 ~ 0.4%, copper (Cu): 1.35 ~ 1.45%, boron (B): 0.015 ~ 0.025%, and prepare a raw water consisting of the remaining iron (Fe) and unavoidable impurities Doing; Adding 1.0 to 1.5 parts by weight of a spheroidizing agent comprising silicon (Si) and magnesium (Mg) based on 100 parts by weight of the wontang; And casting and cooling the wontang to which the spheroidizing agent is added.

Description

Cinnamic iron for manufacturing cast iron and non-inoculated CCI cast iron manufacturing method using the same

The present invention relates to a technology for producing CGI (Compacted Graphite Iron) cast iron used in a cylinder liner of an engine, and more particularly, to a raw water capable of producing CGI cast iron even by non-inoculation and a method of manufacturing a non-inoculated CGI cast iron using the same. will be.

BACKGROUND With the development of engine technology, various engines have high power output.

In order to configure such a high power engine, a cylinder liner capable of maintaining high strength is required.

Conventional cylinder liners have been produced using flake graphite cast iron, spherical graphite cast iron and the like. The flaky graphite cast iron has a long structure and good connectivity, and has a good ability to damp vibrations, but has a weak strength, making it difficult to apply in high-power engines. In addition, in the case of spheroidal graphite cast iron, there is a problem that it is difficult to be applied as a cylinder liner that is excellent in strength but lacks in heat conduction and vibration damping ability, and thus is required to attenuate impact because it is located on the inner surface of the cylinder.

Recently, in order to solve the problems of the flake graphite cast iron and the spheroidal graphite cast iron, many studies have been made on the high strength, high ductility of the compacted graphite iron (CGI).

Background art related to the present invention is Republic of Korea Patent Publication No. 10-2009-0093291 (2009. 09. 02. Publication), the document discloses CGI cast iron.

It is an object of the present invention to provide a raw water which can produce CGI cast iron even in the non-inoculated form.

Another object of the present invention to provide a method for producing CGI cast iron in a non-inoculated form using the above-mentioned wontang.

Wontang according to an embodiment of the present invention for achieving the above object by weight, carbon (C): 3.5-3.7%, silicon (Si) 1.4-1.6%, manganese (Mn): 0.3-0.5%, phosphorus ( P): 0.15 ~ 0.25%, Sulfur (S): 0.2 ~ 0.4%, Copper (Cu): 1.35 ~ 1.45%, Boron (B): 0.015 ~ 0.025%, with remaining iron (Fe) and unavoidable impurities Is done.

CGI cast iron manufacturing method according to an embodiment of the present invention for achieving the other object by weight, carbon (C): 3.5 ~ 3.7%, silicon (Si) 1.4 ~ 1.6%, manganese (Mn): 0.3 ~ 0.5 %, Phosphorus (P): 0.15 ~ 0.25%, sulfur (S): 0.2 ~ 0.4%, copper (Cu): 1.35 ~ 1.45%, boron (B): 0.015 ~ 0.025%, and remaining iron (Fe) Preparing a raw water consisting of an unavoidable impurity; Adding 1.0 to 1.5 parts by weight of a spheroidizing agent comprising silicon (Si) and magnesium (Mg) based on 100 parts by weight of the wontang; And casting and cooling the wontang to which the spheroidizing agent is added.

At this time, the spheroidizing agent in weight%, silicon (Si): 44-47%, aluminum (Al): 0.1-0.3%, magnesium (Mg): 2.3-2.7%, calcium (Ca): 0.2-0.6% and One containing the remaining iron and inevitable impurities can be used.

CGI cast iron manufacturing method using the wontang according to the present invention by increasing the silicon content of the wontang, it is possible to produce a CGI cast iron that satisfies the target properties without the additional inoculation treatment to add silicon.

1 is an embodiment showing a CGI cast iron manufacturing method according to an embodiment of the present invention.
Figure 2 shows the microstructure of the CGI cast iron according to Example 1.
Figure 3 shows the microstructure of the CGI cast iron according to Example 2.
Figure 4 shows the microstructure of the CGI cast iron according to Comparative Example 1.
Figure 5 shows the microstructure of the CGI cast iron according to Comparative Example 1.

Advantages and features of the present invention and methods for achieving them will be apparent with reference to the embodiments described below in detail with the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the raw water for producing CGI cast iron according to a preferred embodiment of the present invention and a non-inoculated CGI cast iron manufacturing method using the same.

Hot water for CGI cast iron manufacturing

Crude cast iron for manufacturing CGI cast iron according to an embodiment of the present invention in weight%, carbon (C): 3.5-3.7%, silicon 1.4-1.6%, manganese: 0.3-0.5%, phosphorus (P): 0.15-0.25%, sulfur (S): 0.2 to 0.4%, copper (Cu): 1.35 to 1.45% and boron (B): 0.015 to 0.025%.

The rest other than the above components are made of iron (Fe) and impurities which are inevitably included in a manufacturing process of a wontang.

Hereinafter, the role and content of each component included in the raw water for producing CGI cast iron according to the present invention will be described.

Carbon (C)

Carbon (C) is added in order to maximize the process graphite amount determination ratio.

The carbon is preferably included in 3.5 to 3.7% by weight of the total weight of the wontang. If the content of carbon is less than 3.5% by weight, the effect of addition thereof is insufficient. On the contrary, when the content of carbon exceeds 3.7% by weight, graphite spheroidization shrinkage and flow failure may occur.

Silicon (Si)

Silicon (Si) is added to improve the amount of CGI graphite crystallization.

The silicon is preferably contained in 1.4 to 1.6% by weight of the total weight of the wontang. If the content of silicon is less than 1.4% by weight, the effect of addition thereof is insufficient, and graphite fragmentation may occur. On the contrary, graphite spheroidization shrinkage defects may occur when the content of silicon exceeds 1.6% by weight.

Manganese (Mn)

Manganese (Mn) assists in CGI graphite formation.

The manganese is preferably included in 0.3 ~ 0.5% by weight of the total weight of the wontang. If the content of manganese is less than 0.3% by weight, flaky graphite is generated. In contrast, when the content of manganese exceeds 0.5% by weight, spherical graphite is generated.

Phosphorus (P)

Phosphorus (P) contributes to improving the wear resistance of CGI cast iron by forming phosphide.

The phosphorus is preferably included in 0.15 to 0.25% by weight of the total weight of the wontang. If the content of phosphorus is less than 0.15% by weight, phosphide formation is insufficient. Conversely, if the content of phosphorus exceeds 0.15% by weight, brittleness can be increased.

Sulfur (S)

Sulfur (S) assists in CGI graphite formation.

The sulfur is preferably contained in 0.2 to 0.4% by weight of the total weight of the wontang. When the content of sulfur is less than 0.2% by weight, spherical graphite is generated. In contrast, when the content of sulfur exceeds 0.4% by weight, flaky graphite is generated.

Copper (Cu)

Copper (Cu) contributes to the pearlite stabilization.

The copper is preferably contained in 1.35 ~ 1.45% by weight of the total weight of the wontang. If the content of copper is less than 1.35% by weight, the effect of addition thereof is insufficient. On the contrary, when the content of copper exceeds 1.45% by weight, there is a problem in that brittleness increases.

Boron (B)

Boron (B) improves the hardness of the phosphide and contributes to improving the wear resistance of CGI cast iron.

The boron is preferably added in 0.015 to 0.025% by weight of the total weight of the wontang. When the addition amount of boron is less than 0.015% by weight, the addition effect is insufficient. On the contrary, when the addition amount of boron exceeds 0.025% by weight, there is a problem that brittleness increases due to excessive hardness increase.

CGI Cast Iron Manufacturing Method

Usually, in the CGI cast iron manufacturing method, after adding a spheroidizing agent, an additional inoculation process is performed in order to add a silicone component.

However, the CGI cast iron manufacturing method according to the present invention provides a method for omitting the above additional inoculation treatment, which can be achieved by the composition of the hot spring and spheroidizing agent and the like.

1 is an embodiment showing a CGI cast iron manufacturing method according to an embodiment of the present invention.

Referring to FIG. 1, the illustrated CGI cast iron gymnastic method includes a round garden preparation step S110, a spheroidizing agent adding step S120, and a casting / cooling step S130.

In the preparation step (S110) of the above composition, that is, by weight%, carbon (C): 3.5-3.7%, silicon 1.4-1.6%, manganese: 0.3-0.5%, phosphorus (P): 0.15-0.25%, sulfur (S): 0.2 to 0.4%, copper (Cu): 1.35 to 1.45%, boron (B): 0.015 to 0.025%, and a raw water consisting of the remaining iron (Fe) and inevitable impurities.

Next, in the step of adding a spheroidizing agent (S120), a spheroidizing agent including silicon and magnesium is added to the raw water having the above composition.

It is preferable that the spheroidizing agent containing silicon and magnesium is added in 1.0-1.5 weight part with respect to 100 weight part of round baths which have the composition mentioned above. When the amount of the spheroidizing agent added is less than 1.0 part by weight relative to 100 parts by weight of the wontang, the spheroidization efficiency is insufficient. On the contrary, when the amount of the spheroidizing agent exceeds 1.5 parts by weight relative to 100 parts by weight of the wontang, there is a problem that the workability is lowered without further spheroidizing effect.

Meanwhile, the spheroidizing agent used in the present invention is a weight%, silicon (Si): 44-47%, aluminum (Al): 0.1-0.3%, magnesium (Mg): 2.3-2.7% and calcium (Ca): 0.2 Contains ~ 0.6%.

In addition, the said spherical agent by weight%, carbon (C): 0.15% or less, manganese (Mn): 0.3% or less, phosphorus (P): 0.01% or less, sulfur (S): 0.005% or less, and chromium (Cr) ): One or more of 0.03% or less may be further included.

The remainder of the above components consist of iron and impurities which are inevitably added in the preparation of the spheroidizing agent.

Silicon (Si) assists in the diffusion of the other ingredients in the spheroidizing agent and serves to supplement the silicon content in the final CGI cast iron. The content of the silicon is preferably 44 to 47% by weight of the total weight of the spheroidizing agent. When the addition amount of silicone is less than 44 weight%, the addition effect is inadequate. On the contrary, when the amount of silicon added exceeds 47% by weight, it may cause nucleation of crystals upon cooling of the hot water.

Aluminum (Al) contributes to spheroidizing the shape of graphite. The content of aluminum is preferably 0.1 to 0.3% by weight of the total weight of the spheroidizing agent. If the content of aluminum is less than 0.1% by weight, the effect of addition is insufficient. Conversely, when the content of aluminum exceeds 0.3% by weight, the brittleness of CGI cast iron can be increased.

Magnesium (Mg) induces nucleation of CGI graphite. The magnesium content is preferably 2.3 to 2.7% by weight of the total weight of the spheroidizing agent. If the content of magnesium is less than 2.3% by weight, sufficient CGI graphite nucleation is difficult to achieve. On the contrary, when the content of magnesium exceeds 2.7% by weight, it may inhibit the stability of the wontang.

Calcium (Ca) plays a role in assisting graphite spheroidization. The content of calcium is preferably 0.2 to 0.6% by weight of the total weight of the spheroidizing agent. When the content of calcium is less than 0.2% by weight, the effect of addition thereof is insufficient. Conversely, when the content of calcium exceeds 0.6% by weight, the stability of the wontang can be inhibited.

In addition, the spheroidizing agent used in the present invention may further include one or more of carbon (C), manganese (Mn), phosphorus (P), sulfur (S), and chromium (Cr). These materials can be added for various purposes, such as controlling the final content of CGI cast iron, improving oxidation resistance. If included, the content is 0.15% by weight or less based on the total weight of the spheroidizing agent, manganese (Mn): 0.3% by weight or less, phosphorus (P): 0.01% or less, sulfur (S): 0.005% Hereinafter, chromium (Cr): may be 0.3% by weight, but is not necessarily limited thereto.

Next, in the casting / cooling step (S130) is cooled after casting the sprinkler is added for a certain time.

Example

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. It is to be understood, however, that the same is by way of illustration and example only and is not to be construed in a limiting sense.

Details that are not described herein will be omitted since the description can be inferred by those skilled in the art.

1. Manufacture of CGI Cast Iron

(One) Example One

By weight, carbon (C): 3.6%, silicon (Si) 1.5%, manganese (Mn): 0.4%, phosphorus (P): 0.2%, sulfur (S): 0.3%, copper (Cu): 1.4% , Boron (B): to prepare a raw water consisting of 0.02% and the remaining iron (Fe) and inevitable impurities,

By weight%, a spheroidizing agent comprising silicon (Si): 45.5%, aluminum (Al): 0.15%, magnesium (Mg): 2.5%, calcium (Ca): 0.4%, and the remaining iron and unavoidable impurities was prepared.

Thereafter, 1.5 parts by weight of the spheroidizing agent was added to 100 parts by weight of the wontang, followed by casting for 30 minutes, followed by air cooling to 25 ° C.

(2) Example 2

By weight, carbon (C): 3.6%, silicon (Si) 1.55%, manganese (Mn): 0.35%, phosphorus (P): 0.2%, sulfur (S): 0.3%, copper (Cu): 1.4% , Boron (B): to prepare a raw water consisting of 0.02% and the remaining iron (Fe) and inevitable impurities,

By weight, silicon (Si): 46.7%, aluminum (Al): 0.28%, magnesium (Mg): 2.14%, calcium (Ca): 0.29%, carbon (C): 0.11%, manganese (Mn): 0.22 %, Sulfur (S): 0.002%, chromium (Cr): 0.02%, and a spheroidizing agent including the remaining iron and inevitable impurities.

Thereafter, 1.2 parts by weight of the spheroidizing agent was added to 100 parts by weight of the wontang, followed by casting for 30 minutes, followed by air cooling to 25 ° C.

(3) Comparative Example 1

By weight, carbon (C): 3.6%, silicon (Si): 1.1%, manganese (Mn): 0.4%, phosphorus (P): 0.2%, sulfur (S): 0.3%, copper (Cu): 1.4 %, Boron (B): 0.02% and the rest of the iron (Fe) and unavoidable impurity

(4) Comparative Example 2

Thereafter, 1.5 parts by weight of the spheroidizing agent was added to 100 parts by weight of the wontang, and then inoculated with 0.4 parts by weight of a Ca-Si alloy consisting of 30% by weight of calcium (Ca) and 70% by weight of silicon (Si). After casting for minutes, it was air cooled to 25 ° C.

Table 1 shows the mechanical properties of the CGI cast iron produced by the method according to Examples 1 and 2 and Comparative Examples 1 and 2, Figures 2 to 5 is a method according to Examples 1 and 2 and Comparative Examples 1 and 2 The microstructure of the prepared CGI cast iron is shown.

[Table 1]

Referring to Table 1, in the case of the CGI cast iron according to Examples 1 and 2, the tensile strength of about 450 ~ 500MPa, the hardness of about 210 ~ 240HB while showing an elongation of 1% or more.

However, in the case of the CGI cast iron according to Comparative Example 1, which has a relatively low content of silicon in the Wontang, as shown in FIG. 4 (Comparative Example 1), flake graphite is crystallized to have similar hardness, but different hardness and elongation. It was very reduced compared to the case.

In addition, although the composition of Comparative Example 1 and Wontang, but CGI cast iron according to Comparative Example 2 additionally inoculated with Ca-Si, exhibited similar physical properties as Examples 1 and 2, the microstructure (Fig. 5) also performed It was similar to the microstructure of CGI cast iron according to Example 1 (FIG. 2) and the microstructure of CGI cast iron according to Example 2 (FIG. 3).

However, in the case of Comparative Example 2, Ca-Si additional inoculation was made, it can be seen that the process is added to the CGI cast iron according to Examples 1-2.

As described above, in the method for producing CGI cast iron according to the present invention, a separate inoculation treatment may be omitted due to the silicon content of the raw water and the silicon content of the spheroidizing agent. Therefore, the CGI cast iron manufacturing method according to the present invention can simplify the manufacturing process, and can also reduce the manufacturing cost.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It is to be understood that the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims

By weight%, carbon (C): 3.5 ~ 3.7%, silicon (Si) 1.4 ~ 1.6%, manganese (Mn): 0.3 ~ 0.5%, phosphorus (P): 0.15 ~ 0.25%, sulfur (S): 0.2 ~ Raw material for producing cast iron of CGI (Compacted Graphite Iron) comprising 0.4%, copper (Cu): 1.35 to 1.45%, boron (B): 0.015 to 0.025%, and consisting of the remaining iron (Fe) and unavoidable impurities.

By weight%, carbon (C): 3.5 ~ 3.7%, silicon (Si) 1.4 ~ 1.6%, manganese (Mn): 0.3 ~ 0.5%, phosphorus (P): 0.15 ~ 0.25%, sulfur (S): 0.2 ~ 0.4%, copper (Cu): 1.35 ~ 1.45%, boron (B): 0.015 ~ 0.025%, comprising: preparing a raw water consisting of the remaining iron (Fe) and inevitable impurities;
Adding 1.0 to 1.5 parts by weight of a spheroidizing agent comprising silicon (Si) and magnesium (Mg) based on 100 parts by weight of the wontang; And
Casting and cooling the wontang to which the spheroidizing agent is added; CGI cast iron manufacturing method comprising a.

3. The method of claim 2,
The spheroidizing agent is in weight percent, silicon (Si): 44-47%, aluminum (Al): 0.1-0.3%, magnesium (Mg): 2.3-2.7%, calcium (Ca): 0.2-0.6% and the remaining iron And CGI cast iron manufacturing method comprising an inevitable impurity.

The method of claim 3,
The spheroid is weight%, carbon (C): 0.15% or less, manganese (Mn): 0.3% or less, phosphorus (P): 0.01% or less, sulfur (S): 0.005% or less and chromium (Cr): 0.03 CGI cast iron manufacturing method, characterized in that one or more of the% or less is further included.