JPS5956944A - Production of cast iron casting - Google Patents

Abstract

PURPOSE:To stabilize the quality performance of a product and to facilitate the automation of casting by charging the molten iron which is subjected to an adjustment of a component compsn. and an inocculation treatment into an ingot mold to form an ingot, melting the same in an ultra-high speed melting furnace and charging the melt into a desired casting mold. CONSTITUTION:An inoculating agent, for example, Ca-Si-Ba-Al, is added to the melt produced by melting pig iron for casting and subjecting the ame to a component adjustment of C, Si, etc. to inoculate the melt and such melt is charged in an ingot mold, whereby an ingot is produced. Since ingot is melted at a high speed in an ultra-high speed melting furnace of >=10KW/kg power density, then the melt is charged in a desired casting mold, whereby a cast iron casting having a good inoculation effect is obtd. The need for the operation of adding an inoculant with a conventional mold is thus eliminated, moreover,the stable quality performance is assured and the control thereof is made easy. Many of the inoculating agents adapted to the above-mentioned method are of a commercially marketed class.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a cast iron 'I'J' snout. In particular, in this book'), Akira adjusted the composition of component A11 [-7] and then inoculated the foundry ingot (hereinafter referred to as master alloy) into an ultra-high-speed melting process (after...). The present invention relates to a method for manufacturing stable, high-quality cast iron castings by manufacturing.

In the past, most cast irons other than PC 10 were inoculated to improve mechanical properties by improving the graphite structure and preventing chilling. In particular, in the case of ordinary cast iron with FC, 2!r or more, inoculation is essential because c + S] is low and it is easy to whiten.In the case of Fuada ductile Hayabusa 1 iron, inoculation is essential.

Inoculation is indispensable because CO2 is used, which is easily converted to white iron.

In recent years, with the development of industry, machines have become larger and on the other hand, resource saving,
There is a need to reduce the weight of bait by saving energy, and there is an urgent need to improve Toga. Furthermore, I have recently been involved in manufacturing cast iron,
An ultra-high-speed finger-melting method has been developed to automate casting with the aim of improving bath water properties and yield, and reducing costs. However, since the cast iron ρ1g inoculated using this melting method has a uniform contact When tapping hot water, a contact agent is added to the water gutter or an inoculant is added to the ladle, but it is known that the inoculating effect gradually disappears as time passes after addition.

The duration of this effect depends on the type of inoculation and molten metal temperature.

Although it differs depending on the shape of the ladle, etc., it takes about R~20 minutes, which is a short time, and the disadvantage is that the quality of the inoculated iron castings tends to vary and is difficult to control.

The present invention aims to improve the drawbacks of the above-mentioned conventional manufacturing method for regular iron castings, such as the variation in the inoculation effect that occurs when an inoculant is added, the difficulty in automating casting due to the inoculation work, and the difficulty in automating casting. The object of the present invention is to provide a method for producing cast iron products that can achieve the above object 1] by providing the method described in the claims.

Next, the present invention will be explained in detail.

Nishitetsu castings usually have a large flaky graphite structure with poor mechanical interstitial structure, but by applying appropriate contact to this structure, the shape of the graphite can be made fine and the tip can be rounded. It is possible to make the graphite curved, thick and short, and to make the distribution of graphite uniform, thereby improving the mechanical properties. In addition, ordinary iron castings are classified into cast iron castings such as graphite-shaped flaky graphite, fungal graphite, caterpillar-shaped graphite, and spheroidal graphite9. The most important thing in inoculation is the gradual disappearance of the inoculation effect over time after the addition of the inoculant, and in the casting process, product variations occur as the casting time elapses. In order to improve the dispersion of cast iron castings caused by the properties of the above-mentioned inoculant, the present inventors made an ingot for castings after adjusting the chemical composition after 11 nights of research, and then melted it using an ultra-high-speed melting method. Having newly found that the inoculation effect remains sufficiently in cast products cast after melting, we came up with the idea that the conventional work of adding inoculants can be omitted and stable quality can be ensured.

Next, the present invention will be explained as 11 with respect to experimental data.

Figure 1 shows various inoculants (ca RI Ba AZ
The tensile strengths of samples obtained by ultra-high-speed melting and normal melting of mask-alloys equivalent to F'0.25 inoculated with +Ca:Si[-"Si, Si) are compared.

According to Fig. 1, when melting and casting an inoculated foundry ingot, normal melting (total melting time, 70 minutes, from burn-through to /<
The inoculation effect is low at up to /so"C, but the inoculation effect is low, but ultra-fast dissolution (total dissolution time 6 minutes, from melting to /l/-30°C)
It can be seen that the effect of C'2 inoculation persists at 7 minutes).

riil notes: (r, / Ultra-high-speed melting of master alloy as shown in the figure) JJ, jy manufacturing with a screw provides stable quality and excellent mechanical properties, a! I iron castings can be produced.

Next, the manufacturing method of m'j chichi castings of the present invention will be explained.

After adjusting the molten pig iron composition, a 411i welding agent is added to the molten metal, which is then poured into a rectangular mold to produce a master alloy. , the shape of the 5-go mask alloy is 1 (+- It is preferable to match the shape of the melting furnace in order to improve the force efficiency).

Examples of suitable inoculants include Fe-Si, C! a
-Si, C! a-S], -Ba-Fe,
Ca-Si-Ba-Al-Fe.

Oa-Si-1-Mn-Fe, C!
a-Si-Al-Til"e, Ca
31AIJi(n, Ba, Fe,
Ca Bj-At-RIDM-)1'e
, Ca-Si-Al-Mn-Ba,
−Z rFe + Ca S iA IM
g ” e + caS ]-Al-Mn-Z
An inoculant consisting of at least 7 types selected from r -Fe and graphite can be selected as needed. Many of these are commercially available, and if necessary, Cu, Sn It is also possible to use an inoculant further containing the following.

Next, the composition of the commonly used inoculants mentioned above is as shown in the table below.

Next, the above master alloy is heated to a power density of 10 KW/l<(
: Melt l-1 in one or more ultrafast melting furnaces By casting this into a desired mold, cast iron (#, J) having an inoculating effect can be produced.

Next, the present invention will be explained with reference to examples.

Example] - Pig iron having the component composition shown in Table 1 was melted in the air using a β3KW high frequency electric furnace in a No. 70 graphite crucible with a full alumina lining, with a melting amount g ky per time,
As shown in Table 2, adjust C+ 83L/) using f, iron melt, and Fe-8ii, fl'c 15,
FC YuS.

The various inoculants shown in Table 3 were added to the molten metal of the material equivalent to FC33 and the material at /'130"C at a rate of 0.7%, converted to 81st grade, to give 4SψX /'7.
Pour the master alloy into a mold with a weight of 3 kg.
) -6 Manufactured.

Table 1 Chemical composition Eu of pig iron Table 2 Target composition (%) of mask-alloy Table 3
Next, each of these master alloys was melted into one super-fast melting time (total 8 minutes melting time, 1 minute at 1ttso 0C"! from burn-through) and fast melting) [11 agent composition (%)]
lIi! (Total dissolution time 20 minutes, from melting ///so”c
g minutes) in the trench, and then poured into the chill test mold, tensile test mold, and mold. The chill depth and tensile strength of these samples were measured. Figures 2 to 7 show the chill depth, and Figures 3 to 7 show the results of the tensile test. Figures 2 to 7
According to the figure, when re-dissolving the mask-alloy, the inoculation effect is sufficiently sustained by ultra-high-speed dissolution, and the inoculation effect of the inoculant is stronger than that of Fe-Si, graphite, and carbon.
a-81゜0a-81-Ba,, C! a-8i-BF
l, -AI is excellent, especially Oa -Si -B
The effect of a-AA is large. In addition, regarding the relationship between the inoculation effect and the cg (carbon equivalent) value, the sustainability of the inoculation effect is greater in CF and el with high values, while the effect immediately after inoculation is small with high C1B values, and in FC, 2O-FC, ? It can be seen that the inoculation effect is particularly good in the evening CF2 value.

As can be seen from the examples above, by producing cast iron castings by the production method of the present invention, cast iron castings with excellent mechanical properties and less variation in quality can be obtained. Furthermore, by dissolving the master alloy at an ultra-high speed, the inoculation work can be omitted, so even materials that require inoculation can be easily automated, which is a great advantage.

ψ f in the drawing? ri simple d; θ bright Figure 1 is 1. Figure 1 shows the relationship between melting rate and tensile strength when mask-alloy equivalent to RO 25 is cast. Figure 1 shows the relationship between melting rate and clear chill depth in FCis. 1 Figure 3 shows the relationship between melting rate and clear chill depth in FCis. , Figure 7 is a diagram showing the relationship between dissolution rate and clear chill depth in F'03S, Figure 6 is a diagram showing the relationship between dissolution rate and clear chill depth in F'03S, and Figure 6 is a diagram showing the relationship between dissolution rate and clear chill depth in F'03S.
(A figure showing the relationship between the dissolution rate and tensile strength in 'C1,!; Figure 4 is a figure showing the relationship between the dissolution rate and tensile strength in FCl-, Figure 7 is a figure showing the relationship between the dissolution rate and tensile strength in It is a figure showing the relationship of tensile strength.

Patent Examiner: Iwate Steel Co., Ltd. Representative Patent Attorney Mura 1) Politics Chart 5 Procedural Amendment (Method) March 2, 1930, Director General of the License Agency, Mr. Kazuo Wakasugi] Indication of the case 1939-1939 i Samurai Word'I Request 1 Otsu 7 Gu No. 3 2
Title of the invention Method for manufacturing cast iron castings 3 Relationship with the person making the amendment - 11) Patent applicant 4 Agent - 104 8. Contents of the amendment The amendments are made as shown in the attached sheet.

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Claims (1)

[Claims] 1. ω1 Monokawa iron source is decomposed from bamboo, and then the component composition is adjusted.F
G S ], Ca S 1+ Ga-8I
Ba-FG, Ca, -8i-Ba-AI-F'e
, C! a-8i -fi, l -Mn -FO, Ca
-IEi-△l -Tj, -F'e. CFl, S], -AI Mn
Ba, Fe C! a B],
-Ai -REM -Fa, Ca
-Si-A/! -Mn -BaZr 'F
e, Ca SL AI M(q Fe
, Ca-8; -A4- Mn -Zr -Fe
, After inoculation treatment by adding an inoculant consisting of at least /a selected from graphite, cast into a sea cucumber mold with a 6J, 10 KW/l<9 or more” A method for manufacturing cast iron castings, which features high-speed melting and casting.