JPS58107463A - Mold material for precipitation hardening type continuous casting - Google Patents

Abstract

PURPOSE:To provide the titled mold material low in conductivity and equipped with more excellent high strength and high temp. tenacity compared to a Cr-Cu alloy which is a conventional precipitation hardening type material, obtained by applying solution heat-treatment and ageing heat-treatment to a copper alloy material containing Cr, Zn, Al and Fe. CONSTITUTION:A copper alloy material containing 0.3-1.5wt% Cr, 0.03-0.6wt% An, 0.01-2.0wt% Al and 0.1-1.0wt% Fe and the remainder comprising Cu is prepared. In the next step, solid heat-treatment and ageing heat-treatment are applied to said copper alloy material to obtain the titled mold material showing low conductivity of 60-30% IACS, having more excellent high temp. strength and high temp. elongation compared to a conventional Cr-Cu alloy and high in tenacity. This mold material is most suitable for the continuous casting mold material 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 of steel or the like 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 improve the quality of ingots and to continuously cast high-grade steel.

However, the mold material used in the conventional continuous casting method for steel etc. 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 steel and other materials using an electromagnetic stirring device, it has been possible to achieve high-temperature strength and high-temperature elongation, which are the characteristics required for conventional mold materials, and to achieve an electrical conductivity of 60 to 50% depending on the usage conditions. Low electrical conductivity cast material with engineering AC8 may be required.

In view of these circumstances, the inventors of the present invention set the electrical conductivity to 6.
We have developed a high-toughness mold material that is characterized by a low AO8 of 0 to 50% and also has superior high-temperature strength and elongation compared to the conventional precipitation hardening material, aluminum copper. Through intensive research, we were able to complete the present invention.

The mold material of the present invention has a weight ratio of Cr s O,! i~1.
596. ZrN), 05-0.6%, Aj:C, 01
~2.096. A copper alloy material composed of Fs t O, 1 to 1.0%, and the balance Cu, and this copper alloy material is subjected to solution heat treatment and aging to have an electrical conductivity of 60 to 50! AC8 has a low electrical conductivity and has high toughness with excellent high temperature strength and high temperature elongation compared to term steel, which is a conventional precipitation hardening material.

Among the compositional components of the material of the present invention, Cr is added for the purpose of increasing high-temperature strength, and if it is less than 1 s%, the effect is small, and if it is more than 1.5%, the effect of increasing high-temperature strength is small relative to the amount added. On the contrary, the molten metal oxidizes violently and deteriorates the castability.

Zr is added to refine recrystallized grains, increase high-temperature strength, and improve high-temperature elongation, but if it is less than 0.0!1%, the effect will be small, and if it is more than 0.6%, it will be less effective compared to the amount added. In addition, the improvement in effectiveness is small, and the oxidation of the molten metal becomes severe, resulting in poor castability.

A/ is added for the purpose of reducing electrical conductivity and improving high-temperature elongation, but in order to achieve the desired electrical conductivity of 60 to 50% lAC3, the amount added is 0.01%. If the addition amount is less than 20%, the effect will be small, and if the addition amount is more than 20%, the electrical conductivity will be at the desired lower limit.
This is not preferable because it becomes 8 or less.

Fs is added for the purpose of improving high-temperature elongation, refining crystal grains, and lowering electrical conductivity, but when the amount added is 0.
If the amount is less than 1%, the above effect will be small, and if it is more than 1.0%, the hardness will be significantly lowered, which is not preferable.

Steel alloy materials with the above composition that are solution-treated and aged after forging exhibit a low electrical conductivity of 60-50% lAC8, and also have high strength and strength superior to conventional glue shim copper.
It showed high temperature toughness.

Therefore, the material of the present invention is most suitable as a mold material for continuous casting of a single hemorrhoid equipped with an electromagnetic stirring device.

Next, examples of copper alloy materials having the composition of the present invention will be given,
At the same time, conventional precipitation hardening materials such as shim copper and shim copper were used as comparative examples, and the electrical conductivity of each material was forged under the same conditions, solution treated, and aged.
) was tested.

The results are shown in the table below.

Table Chemical composition and electrical conductivity Also, the test results of high temperature tensile strength, high temperature yield strength, and high temperature elongation from room temperature to 500°C of the above examples and comparative examples are as follows:
As shown in Figures 1 to 3, O As is clear from the above table and Figures 1 to 3,
The copper alloy material of the present invention not only has a lower electrical conductivity than conventional laminated PM copper to the desired low electric conductivity of 60 to 30%lAC3, but also has a high temperature range from room temperature to 500°C, which is higher than that of laminated shim copper. Furthermore, it can be seen that it is a highly tough material with high strength and high elongation.

[Brief explanation of the drawing]

1 to 5 are diagrams showing the test results of high temperature tensile strength, high temperature yield strength, and high temperature elongation from room temperature to so o °C of Examples and Comparative Examples, respectively. Test: ff1 degree (°C); M temperature (0 test result?i%false jiC) ■2 times

Claims (1)

[Claims] Weight ratio: Or: 0. ! l~1.5%, Zr: 0.
05~0.6%, Aj:Q, 01~2.0%, Fe
: A copper alloy material composed of 0.1 to 1.0% Cu and the remainder Cu, which is heat-treated by solution treatment and aging to achieve an electrical conductivity of 60 to 50% and a low AC8. Mold material for precipitation hardening continuous casting with high electrical conductivity, high strength, and high temperature toughness.