JPS58107460A - Mold material for precipitation hardening type continuous casting - Google Patents

Abstract

PURPOSE:To provide the titled mold material having low conductivity and equipped with high strength and high temp. tenacity, obtained by applying solution heat-treatment and ageing heat-treatment to a copper alloy material prepared by adding a small amount of one kind or more of Al, Fe or Si to a base Cu alloy containing Cr ane Zr. CONSTITUTION:A copper alloy material is prepared by adding 5wt% or less one kind or more Al, Fe, Si, Ni, Sn, Zn and Mn to a base alloy containing 0.3- 1.5wt% Cr, 0.03-1.5wt% Zr and the remainder comprising Cu. In the next step, solution heat-treatment and ageing heat-treatment are applied to said copper alloy material to obtain the titled mold material equipped with high strength and high temp. tenacity and showing low conductivity of 70-15sec IACS without losing excellent high temp. characteristics of the aforementioned base alloy. This mold material is suitable for the mold material used in continuous casting of steel provided with an electromagnetic stirring apparatus.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel copper alloy material having various properties suitable as a material for a mold used in continuous casting, such as those equipped with an electromagnetic stirring device.

Recently, the electromagnetic stirring method has been widely adopted as a continuous casting method for steel.
This makes it possible to learn about the quality of ingots and to continuously cast high-grade irons.

However, the mold material used in the conventional continuous casting method for steel parts has a high electrical conductivity of 100 to 80%, so when an electromagnetic stirring device is installed, the high electrical conductivity causes eddy current loss. This causes a large attenuation of the magnetic force, which has the drawback of reducing the stirring effect on the molten steel in the mold.

For this reason, in the continuous casting of ropes and the like using electromagnetic stirrers, it has been possible to achieve high-temperature strength and high-temperature elongation, which are the characteristics required for conventional mold materials, and also to have an electrical conductivity of 70 to 15% depending on the usage conditions. A low electrical conductivity molding material of engineering AC8 may be required.

In view of these concerns, the present inventors have developed electrical conductivity t- of chromium-zirconium steel, which is a conventionally known precipitation hardening material, without impairing its excellent properties of high-temperature strength and high-temperature elongation. We conducted intensive research to reduce the mechanical strength by 70 to 15% to 8Kt, and were able to complete the mold material of the present invention.

The mold material of the present invention has a weight ratio of Cr: 0.5 to 1.5.
%, Zr: 0.05 to 0.6%, and the balance is Cu, with AI, Fe, Si, N
A copper alloy material made by adding one or more of I, Sn, Zn, and Mn in a total amount of 5% or less.This material is heat-treated by aging and heat treatment to have an electrical conductivity of 70 to 70.
It has the low electrical conductivity of 15% ACS, yet has high strength and high temperature toughness.

The basic alloy of the material of the present invention is Or: 03-1.5%,
Zr:0.0! The composition is 1 to 0.6% Cu, and the balance is Cu. Of these, Cr is added to increase high-temperature strength, and below 0.3%, the effect is small, and above 1.5%, it is added. Considering the amount, the effect of increasing high-temperature strength is small, and on the contrary, the bath water oxidizes violently, resulting in rapid castability.

Zr is added to refine the recrystallized grains, increase high-temperature strength, and improve high-temperature elongation, but the effect is small below 0.1%, and the effect is small when above 0.6%, considering the amount added. Not only is there little improvement in effectiveness, but the oxidation of the bath water becomes severe and castability becomes extremely poor.

The basic alloy with the above composition is a highly tough precipitation-hardened mold material with excellent high-temperature strength and high-temperature elongation, but its electrical conductivity is as high as 80% or more, so continuous casting of steel etc. using an electromagnetic stirring device is required. It is not preferred as a mold material.

The present invention uses Ad and Fe for the above-mentioned basic alloy composition.

By adding one or more of Si, Ni, Sn, Zn, and Mn in a total amount of 5% or less, the excellent high-temperature strength and high-temperature elongation properties of the basic alloy can be further improved, and the electrical conductivity can be improved. Desired low height 70-1596
It was possible to obtain a precipitation hardening type continuous casting mold material whose air AC was reduced to 8).

Figure 1 shows additive elements Aj, Fe, Si, Ni, S
This figure shows the relationship between the amount of n, Zn, and Mn added and the electrical conductivity. As shown in Figure 1, Aj, Fe,
Si, Ni, Sn.

It can be seen that the addition of both Zn and Mn lowers the electrical conductivity.

However, for AJ, Fe, Ni, Sn, and Zn, if the amount added is 5.0% or more, the electrical conductivity will hardly decrease and will not become small, but instead will cause high-temperature brittleness, and the excellent high-temperature properties of the basic alloy will be reduced. It will damage the characteristics. Furthermore, it can be seen that in the case of 'SL and Mn, the electrical conductivity is as low as about 15% AC3 even when the addition amount is 1 to 2%.

Further, in the case of the present invention, An, Fe, Si, N
i, Sn, Zn.

It is also possible to add one kind or two or more kinds of Mn coexisting in the material. When they are allowed to coexist, it is preferable that the total amount added is 5% or less, as is clear from FIG.

In this way, the copper alloy material of the present invention has the basic alloy 4CAj
, Fe, 81. N1. This material is made by adding one or more of Sn, Zn, and Mn in a total amount of 5% or less, and this material is subjected to K1 conversion treatment and aging treatment after forging.
It had high strength and high temperature toughness without impairing the excellent high temperature properties of the above basic alloy, and exhibited a low electrical conductivity of 70 to 15% engineering AC8.

This material is most suitable as a mold material for continuous casting of steel or the like equipped with an electromagnetic stirring device.

Next, we will introduce an example of a chromium-zirconium steel alloy (Or 0.80%-Zr 0.20%), which is a conventional precipitation hardening material.
Examples 1 to 16 of copper alloy materials having the composition of the present invention, in which the comparative example was made into a five-piece alloy, were forged under the same conditions, and then subjected to catalytic treatment. Electric conductivity (%IAC8) of the aged treated product
was tested. The results were as shown in the table.

Table Chemical composition and electrical conductivity Also, the test results of high temperature tensile strength, high mO, 2% yield strength, high temperature elongation, and high temperature hardness from room temperature to 500 °C of the above comparative examples and Examples 1 to 16 are shown in Table 1. Figures 2 to 5
It was as shown in the figure.

As is clear from the above table and Figures 2 to 5,
The alloy material of the present invention has an electrical conductivity of 70 to 15% compared to a conventional chromium-zirconium steel alloy (comparative example).
It can be seen that it is a material with high strength and high elongation at high temperatures from room temperature to 10° C., and has high toughness that fully takes advantage of the characteristics of the basic alloy.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the relationship between the amount of additive elements added and electrical conductivity. Figures 2 to 5 are comparative examples and examples 1 to 16, respectively.
High temperature tensile strength from room temperature to 500℃. A diagram showing the test results of high temperature 0.2% yield strength, high temperature elongation, and high temperature hardness. : Drinking force Ot ('/Ri纂1 round test temperature (°υ Temperature / l ('C) 40th test temperature (C)

Claims (1)

[Claims] Weight ratio: Cr: 0.5-1.3% TZr: 0
Aj + Fe * S1 + N1 + Sn, Zn,
A copper alloy material made by adding one or more types of Mn in a total amount of 5% or less, and this steel alloy material is subjected to solution heat treatment and aging to achieve an electrical conductivity as low as 70 to 15% and AC8. A precipitation hardening continuous casting mold material with high electrical conductivity, high strength, and high temperature toughness.