JP2750820B2 - Method for measuring manganese content in cast iron - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for measuring manganese content in cast iron. More specifically, the present invention relates to a method for measuring the manganese content in cast iron by subjecting a molten cast iron to thermal analysis.

[0002]

2. Description of the Related Art When scrap is used as a raw material in the production of cast iron, manganese is mixed. If manganese is present in the cast iron as described above, the cast iron tends to be turned into white pig iron, which causes chill generation and shrinkage defects. Therefore, it is usually specified that the content of manganese in cast iron be 1% or less.

[0003]

However, conventionally,
In the production process of cast iron, there was no means to quickly measure the manganese content, so there was no choice but to strictly select the type of scrap to be used. Therefore,
The test piece was manufactured by solidifying the molten cast iron, and this was analyzed by emission spectrometry.

[0004]

According to the present invention, as a means for solving the problem, according to the present invention, a molten metal injected in front of a furnace is placed in a cup-shaped sampling container equipped with a thermocouple generally used for thermal analysis of molten cast iron. Add more than 1% of inoculant to the weight of the melt,
The eutectic temperature of the cast iron is determined by an automatic thermal analyzer connected to a thermocouple, and the manganese content in the molten metal is determined by comparing the eutectic temperature with the manganese content obtained in advance.

As an inoculant, silicone-based materials such as F
e-50% Si; Fe-75% Si; silicon containing a special element, for example, Ca-Si; Fe-Si-Ca;
Fe-Si-Sr; Fe-Si-Ba; Fe-Si-
Ce; Al-Ca-Si; RE-Si and the like are preferable,
Graphite materials are unsuitable.

The amount of the inoculant to be added depends on the type of the inoculant, but in the case of a silicon type generally used as an inoculant, as shown in FIG. The amount indicates a constant eutectic temperature.

[0007] The amount of the inoculant at which the inoculation temperature becomes constant also differs depending on the properties of the target molten metal. By adding 1% or more to the weight of the molten metal, a constant eutectic temperature is exhibited.

As shown in the example of FIG. 2, the relationship between the eutectic temperature and the manganese content obtained by the method of the present invention is such that the eutectic temperature decreases linearly as the manganese content increases.

[0009]

The austenite and eutectic reactions of cast iron
There are cementite type and austenitic / graphite type. In the former technique utilizing the eutectic reaction, tellurium has been conventionally used. Since the eutectic temperature is not influenced by the properties of melting and is greatly affected by the components of the molten metal, particularly the silicon content, it has been practically used as a silicon analysis method.

[0010] The latter eutectic reaction is greatly affected by the manganese content when sufficient graphitization can be performed during eutectic solidification of the molten metal.
It can be used as a manganese analysis method. But,
Normally, it cannot be sufficiently graphitized, so that it is greatly affected by the properties of the molten metal, and a molten metal having a strong tendency to form white iron has a lower eutectic temperature.

Therefore, according to the present invention, at least 1% of the inoculant based on the weight of the molten metal is previously placed in a sample collection container for thermal analysis so that sufficient graphitization can be performed during eutectic solidification of the molten metal. By doing so, the cast iron melt poured into this container can be sufficiently graphitized, whereby the manganese content in the melt can be analyzed.

[0012]

According to the present invention, when manganese is present in cast iron, it tends to form white pig iron, which causes chills and shrinkage defects. Manganese in cast iron is mixed from the raw material scrap, but there is no conventional method for quickly measuring the manganese content in the molten cast iron. I was doing it.

According to the method of the present invention, the manganese content in the cast iron can be measured very simply and easily in front of the furnace. It is.

[Brief description of the drawings]

FIG. 1 is a diagram showing the relationship between the eutectic temperature of cast iron and the amount of inoculant added.

FIG. 2 is a diagram showing a relationship between a eutectic temperature and a manganese content.

Continued on the front page (72) Inventor Yasushi Kubota 32 Akaike, Toyota-cho, Iwata-gun, Shizuoka Prefecture Within Japan Sublance Probe Engineering Co., Ltd.

Claims (3)

(57) [Claims] 1. A sample collection container for thermal analysis of molten cast iron,
Adding at least 1% of an inoculant to the weight of the molten metal to be injected into the container, injecting the molten metal into the sampling container and measuring the eutectic temperature thereof, and A method for measuring manganese content in cast iron, comprising comparing the measured eutectic temperature of cast iron with the relationship between manganese content. 2. The method according to claim 1, wherein the inoculant is Fe-50% Si or F.
2. The method of claim 1, wherein the method is one of e-75% Si. 3. The method according to claim 1, wherein the inoculant is Ca—Si;
Ca; Fe-Si-Sr; Fe-Si-Ba; Fe-S
The method of claim 1 wherein the method is selected from the silicon-based class consisting of i-Ce; Al-Ca-Si and RE-Si.