JPH046233A - Continuous casting mold material made of cu alloy having high cooling power and its manufacture - Google Patents

Abstract

PURPOSE:To manufacture a continuous casting mold material made of a Cu alloy having high cooling power by subjecting Cu alloy stock having a specified compsn. constituted of Cr, Zr, Ti, Si, Fe, Ni, Co and Cu to solution treatment and thereafter executing specified aging treatment. CONSTITUTION:Cu alloy stock contg., by weight, 0.1 to 1% Cr, 0.01 to 0.15% Zr, 0.005 to 0.1% Ti, 0.003 to 0.1% Si, 0.005 to <0.1% of one or more kinds among Fe, Ni and Co and the balance Cu with inevitable impurities is subjected to solution treatment. After that, this stock is subjected to primary aging treatment at a prescribed temp. in the range of 425 to 475 deg.C. Next, this stock is subjected to secondary aging treatment at a prescribed temp. in the range of 525 to 575 deg.C. In this way, the alloy components are satisfactorily precipitated to reduce the content of solid soln. in the matrix and to improve its thermal conductivity. Thus, the continuous casting mold material made of a Cu alloy provided with high high temp. strength and high temp. elongation as well as >=70% (IACS%) electrical conductivity and having high cooling power can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a continuous casting mold material made of a Cu alloy that has excellent cooling ability, strength, and thermal fatigue resistance, and its production.

[Conventional technology]

The same applicant had previously filed Japanese Patent Application No. 61-271103 (Japanese Unexamined Patent Publication No. 63-125632) with Cr: 0.1-2.5%, Zr: 0.01
~0.5%, Ti:0.01~0.7%, S+
: 0.003 to 0.1%, FeNi
and one or more of Co: 0.1-1
．． An application has been filed for a Cu alloy for continuous casting molds, which has a composition (the above weight %, below % shows weight %) containing 2% of Cu and unavoidable impurities.

[Problem that the invention seeks to solve]

On the other hand, in recent years, there has been a remarkable improvement in productivity in continuous steel casting technology, with casting speeds of 1 to 2 m/sin significantly increasing to 3 to 4 m/sin. The surface temperature of the inner surface of the mold that comes into contact with the mold also increases, and depending on the casting conditions, it may reach 500°C or more.

However, many continuous casting mold materials made of Cu alloys, including the above-mentioned conventional continuous casting mold materials made of Cu alloys,
Although it has high high temperature strength to withstand large thermal stress and high high temperature elongation to withstand severe thermal fatigue environment, thermal conductivity is insufficient and electrical conductivity is 40-65% (IA
Therefore, when casting under the above-mentioned severe conditions, the mold tends to be easily deformed and cracked, and the service life is reached in a relatively short period of time.

[Means to solve the problem]

Therefore, from the above-mentioned viewpoints, the inventors of the present invention have developed a mold that has high electrical conductivity, that is, good thermal conductivity, and cooling performance, while having the high high-humidity strength and high-temperature elongation required for continuous casting molds. As a result of research to develop a continuous casting mold material made of a Cu alloy with a high content of Cr: O, 1-1%, Zr: 0.01-0.
15%, Ti: 0.005-0.1%, S
i: 0.003 to 1%, contains one or more of Fe, Ni, and Co (iron group metals) or 2Ff1 or more: 0.005 to less than 0.1%, and the rest is Cu
It is made of a Cu alloy having a composition consisting of When the second aging treatment is performed, most of the C and Z dissolved in the matrix in the first aging treatment become
It precipitates finely in the matrix in the form of u3Zr, and also
In aging treatment, TM and iron group metals (
Since the fine precipitates in the form of Fe, Nj, Co) The resulting continuous casting mold material made of Cu alloy is formed as described above, iJ't! ! This ensures high thermal conductivity with electrical conductivity of 70% or more (IAC 5%), and the structure in which the fine precipitates are uniformly and abundantly dispersed ensures high high temperature strength and high temperature elongation, making it excellent for practical use. The research results showed that the new product exhibited excellent performance over a long period of time.

This invention was made based on the above research results, and includes (a) Cr: 0.1-1%, Zr: C1
, (11~[1,15%, Tf:0.QO5~0.
1%, Sj: 0.003-0.1%, Fe, N
One or more of j and Co: 0.0
After solution treatment, a first aging treatment at a predetermined temperature within the range of 425 to 475 ° C. , the second at a predetermined temperature within the range of 525-575°C.
A method for manufacturing continuous casting mold material made of Cu alloy with high cooling capacity, which involves performing aging treatment to sufficiently precipitate, reducing the content of alloy components dissolved in solid solution in the matrix, and improving thermal conductivity. .

(b) and Cr:0 produced by the above method
．． I ~1%, Zr: 0.01~0.15%, T
i: (1,005~[1,1%, S i:
[1,003 to 0.1%, one or more of Fe, Ni, and Co: [1,005 to less than 0.1%, and the remainder is Cu and inevitable impurities] and 70% (IAcs%
) Continuous casting mold material made of Cu alloy with high cooling ability and having an electrical conductivity of more than 100%.

It has the following characteristics.

Next, in the continuous casting mold material of the present invention, the reason why the composition of the Cu alloy, the electric conductivity, and the aging treatment temperature are limited as described above will be explained.

A. Ingredient composition (a) Cr Most of the Cr dissolved in the matrix during the solution treatment is actively and finely precipitated within the crystal grains of the matrix during the first aging treatment, increasing the strength within the grains. As a result, the strength at room temperature and high temperature is improved, but the content is 0.1
If the content is less than 1%, it is impossible to secure the desired high strength, while if the content exceeds 1%, the relative proportion of C dissolved in the matrix increases even after two aging treatments, and this causes Since it becomes difficult to suppress the improvement in electrical conductivity and ensure electrical conductivity of 70% (IACS%) or more, the content is set at 0.1 to 1%.

(b) Zr Similarly, most of the Zr dissolved in the matrix during the solution treatment is deposited at the grain boundaries of the matrix during the first aging treatment (: u 3Z
r precipitates finely in the form of an intermetallic compound, which suppresses grain boundary slippage at high temperatures, improving grain boundary strength, resulting in embrittlement due to intergranular fracture at high temperatures ( However, if its content is less than 00%, the desired effect will not be obtained, while if its aRm exceeds 0.15%. As with Cr, the proportion of solid solution in the matrix increases, making it difficult to secure the desired high electrical conductivity, so the content is reduced from 0.01 to 0.15.
%.

(c) Similar to Ti and iron group metals, these components also form a solid solution in the substrate during solution treatment, hardly precipitate during the first aging treatment, and (F) occur during the second aging treatment.
c, Ni, Co) Ti, mainly precipitates finely and actively within the crystal grains of the substrate in the form of an intermetallic compound of y (Fe, Ni, Co) In addition to significantly improving the strength at room temperature and high temperature when it is included with Cu3Zr, it also improves the high temperature strength and elongation when it coexists with Cu3Zr precipitated at the grain boundaries. If the content is less than 0.005%, the desired effect of improving the above-mentioned action cannot be obtained.On the other hand, if the content exceeds 0.1% for Ti and 0.1% or more for iron group metals, Cr As in the case of Zr and Zr components, the proportion of solid solution in the matrix increases and it becomes difficult to secure an electrical conductivity of 70% (IACS%) or more. T i:
0.005-0.1%, iron group metal: 0.005-0.1
It was set as less than %.

(d) Si The Si component includes the above (Fe, Ni, Co) Ti
It has the effect of precipitating the intermetallic compound in a fine state, thereby further promoting the precipitation strengthening effect of the intermetallic compound, but if its content is less than o or ooa%, the desired effect is not obtained. However, if it exceeds 0.1%, coarse crystallites of Si will appear during casting, and these will not disappear even in solution treatment and will reduce high temperature strength and elongation. 0.003~0
．． It was set at 1%.

B. Electrical conductivity In continuous casting where the casting speed is, for example, 3 to 4 m/1n, the electrical conductivity of the conventional continuous casting mold material made of Cu alloy, which is about 40 to 6596 (I AC 5%), cannot be heated. Because the conductivity is not sufficient and a satisfactory cooling capacity cannot be obtained, the mold is likely to deform and crack, resulting in a short service life, or if the electrical conductivity of the mold material is When the lAC is 3% and 70% or more, it has high thermal conductivity and exhibits excellent cooling ability, so there is no deformation or cracking in the mold, and high-speed continuous casting can be performed stably over a long period of time. Therefore, the electrical conductivity of the mold was set at 70% (IAC 3%) or higher.

C1 Aging Treatment Temperature In this invention, as mentioned above, the alloy components are completely dissolved in solid solution by solution treatment, and in the next step of aging treatment, as much of the alloy components as solid solution are precipitated in the base material, and this precipitation improves high-temperature strength. and high-temperature elongation, while ensuring a high electrical conductivity of 70% (IAC 3%) or more due to the base material having a significantly low metal content. In other words, it is generally known that electrical conductivity is determined by the alloy base.
The lower the solid solution content in the matrix, the higher the electrical conductivity. Therefore, if sufficient precipitation is performed during aging treatment, high electrical conductivity, high temperature strength, and high temperature elongation can be obtained. It becomes like this.

From this point of view, when we investigated the types of precipitates and the temperature at which they tend to precipitate in the Cu alloy of the present invention having the above composition, we found that the precipitates were Cr and Cu3Zr.

and (Fe, Ni, Co) Ti account for most, y Cr and Cu 3Z' are in the temperature range of 425-475 °C, and (Fe, Ni, Co) Ti is 52
It has been found that each aging process actively precipitates in the temperature range of 5 to 575°C, so even if the aging treatment temperature deviates from the above range to the lower or higher range, sufficient precipitation will not occur. can't do it.

〔Example〕 Next, the present invention will be specifically explained using examples.

Using a normal vacuum melting furnace, each first
5 kg of each Cu alloy molten metal having the composition shown in the table was melted, cast in a mold, side-faced, and then hot forged and hot rolled under normal conditions. Width = 100 m x thickness Sa: 5
A Cu alloy material was prepared as a hot-rolled plate material of No. 11!1 and then cut into a predetermined length. After holding the material at a temperature of 980°C for 30 minutes, it was subjected to a solution treatment of water quenching, and then the material was subjected to a solution treatment as shown in Table 1. Methods 1 to 27 of the present invention and Comparative methods 1 to 23 were carried out by carrying out the first and second aging treatments at a temperature maintained for one hour, respectively, and the continuous casting mold material of the present invention and the comparative continuous casting mold material were obtained. 1 to 27 were manufactured.

In addition, Comparative Methods 1 to 23 all have one of the constituent requirements of the present invention (marked with * in Table 1) outside the scope of the present invention.

In addition, for the purpose of comparison, the component composition of the Cu alloy material and 1
Conventional methods 1 to 3 were carried out under the same conditions except that the aging treatment performed only once was changed to the conditions shown in Table 1 to produce conventional continuous casting mold materials 1 to 3.

Next, the electrical conductivity of the various continuous casting mold materials obtained as a result was measured, and the materials were subjected to room temperature and high temperature tensile tests, and heat resistance tests.

In the high temperature tensile test, the tensile properties were measured after being held at 500°C for 10 minutes, and in the heat resistance test, the mold material was heated to 450'C+n.
1 at each temperature of lO℃ (n: an integer from ○ to 15)
After holding for a time, the mold material was heated under air cooling conditions, and the hardness of the mold material after heating was determined as e+, and the heating temperature at which the hardness corresponded to 90% of the hardness before heating was defined as the heat resistance temperature. These results are shown in Table 2.

〔Effect of the invention〕

From the results shown in Tables 1 and 2, it can be seen that methods 1 to 1 of the present invention
Continuous casting mold materials 1 to 27 of the present invention manufactured in Step 27 are all conventional continuous casting mold materials 1 manufactured by Conventional methods 1 to 3.
-Exhibits excellent room temperature and high temperature tensile properties equivalent to 3,
And higher than this, both are 70% (IAC 3%)
In contrast to the above electrical conductivity, as seen in the comparative continuous casting molds manufactured by comparative methods 1 to 23, it was found that either the component composition of the Cu alloy or the aging treatment temperature However, it is clear that even if the method is outside the scope of the present invention, at least one of the above-mentioned characteristics will be inferior.

As mentioned above, according to the method of the present invention, it has the high temperature strength and high temperature elongation required for continuous casting molds, and
% (IAC 3%) or higher, and therefore, a continuous casting mold made of this mold material can be used under conditions of high casting speed. Since it exhibits excellent thermal conductivity and high cooling ability, it provides industrially useful effects such as exhibiting excellent performance over a long period of time without causing deformation or cracking.

Claims (2)

[Claims] (1) Cr: 0.1-1%, Zr: 0.01-0.15
%, Ti: 0.005~0.1%, Si: 0.003~
0.1%, one or more of Fe, Ni, and Co: 0.005 to less than 0.1%, and the remainder is Cu and unavoidable impurities (wt%). Consisting of Cu alloy with 70% (
A continuous casting mold material made of a Cu alloy with a high cooling ability, characterized by having an electrical conductivity of IACS%) or higher. (2) Cr: 0.1-1%, Zr: 0.01-0.15
%, Ti: 0.005~0.1%, Si: 0.003~
0.1%, one or more of Fe, Ni, and Co: 0.005 to less than 0.1%, and the remainder is Cu and unavoidable impurities (wt%). After the solution treatment, the Cu alloy material having A method for manufacturing a continuous casting mold material made of a Cu alloy having a high cooling ability, which is characterized by performing precipitation to reduce the content of alloy components dissolved in the matrix to improve thermal conductivity.