JPH0832938B2 - Cu alloy continuous casting mold - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a Cu alloy continuous casting mold having excellent high temperature properties, particularly high temperature strength, high temperature hardness, and thermal fatigue resistance.

[Conventional technology]

In general, in general continuous casting molds, especially in continuous casting molds that are exposed to severe thermal fatigue environment where locally large thermal stress such as water-cooled rotating roll for rapid solidification of molten metal repeatedly acts, local thermal stress is Thermal conductivity to soften,
High temperature strength to withstand large thermal stress, high temperature elongation to withstand harsh thermal fatigue environment, and surface roughness due to abrasion during casting (When surface roughness occurs, the surface condition of the product is significantly deteriorated. Since high temperature characteristics such as high temperature hardness are required to prevent the mold from significantly shortening the service life), Cu-Cr alloys that have these characteristics have been conventionally used for its production. And Cu
-Zr-based alloys and further Cu-Cr-Zr-based alloys are widely used.

[Problems to be solved by the invention]

On the other hand, with the progress and development of continuous casting technology in recent years, casting molds tend to be used in more and more harsh environments. Especially, improvement in productivity and contact with molten metal due to the advent of electromagnetic stirring technology. The surface temperature of the mold is gradually rising from the conventional 300 to 400 ° C to 400 to 500 ° C.

Furthermore, recently, since various excellent properties have been exhibited, it has been performed to cast rapidly alloyed ribbons by casting various alloys such as silicon steel by a roll method. Even in a water-cooled rotary roll mold used for, it is usually exposed to a high temperature of 500 ° C, and since the molten metal is constantly poured into one place, thermal stress always acts locally, and the roll mold is cooled rapidly. With frequent rotations (e.g. surface speed: 2-40 m / sec), localized heating and cooling becomes more frequent, and thus when the casting enters a stabilized state, as in a normal continuous casting mold, Compared to the case where the magnitude and distribution of the thermal stress acting on the mold is kept almost constant until the casting is completed, the water-cooled rotary roll mold constantly undergoes a much larger local repeated thermal stress. Becomes a door, it becomes extremely severe thermal fatigue occurs (thermal cycle fatigue) that is exposed to the environment.

Continuous casting mold under such severe working environment,
When manufactured with the above conventional Cu alloy, among the high temperature characteristics, especially high temperature strength and high temperature hardness are insufficient, it is not possible to fully satisfy this, especially in the production of water-cooled rotary roll mold Currently, it cannot be applied.

[Means for solving problems]

Therefore, the inventors of the present invention, from the above viewpoint, conduct research to develop a material having excellent high-temperature characteristics, which can be used for manufacturing not only ordinary continuous casting molds but also water-cooled rotary roll molds. As a result, the continuous casting mold, in important% (hereinafter,% indicates weight%), Ni: 1.3-5%, Ti: 0.2-2%, Cr: 0.1-1.5%, Zr: 0.01-0.5%, P: 0.001 to 0.2%, Fe and / or Co: 0.01 to 0.5%, and, if necessary, Sn: 0.05 to 0.5%, with the balance being Cu and inevitable impurities. When composed of a Cu alloy, the resulting Cu alloy continuous casting mold is excellent in high-temperature properties, in particular, high-temperature strength, high-temperature hardness, and thermal fatigue resistance. Therefore, for example, a locally large thermal stress is repeatedly exerted under severe conditions. Excellent even when used as a water-cooled rotary roll mold that is exposed to a heat fatigue environment We have obtained the knowledge that the performance will be exhibited over a long period of time.

The present invention has been made based on the above findings, and the reason why the component composition of the Cu alloy constituting the continuous casting mold is limited as described above will be described below.

(A) Ni and Ti These components form an intermetallic compound of Ni _x Ti _y that is finely precipitated in the crystal grains (matrix), thereby dramatically improving the high temperature strength and high temperature hardness of the mold. Has the effect of causing the content of Ni: less than 1.3% and Ti0.2
If it is less than%, the desired effect on the above-mentioned action cannot be obtained. On the other hand, even if the contents thereof exceed Ni: 5% and Ti: 2%, respectively, the above-mentioned action is saturated and further improvement effect cannot be obtained. Not only that, but the thermal conductivity will decrease sharply, so the content of Ni: 1.3-5%, Ti: 0.2-2, respectively.
Defined as%.

(B) Cr The Cr component itself finely precipitates in the crystal grains to improve the strength of the mold, and in the presence of Ni and Ti, further improves the high temperature strength and high temperature hardness of the mold. However, if the content is less than 0.1%, the desired effect on the above-mentioned action cannot be obtained, while if the content exceeds 1.5%, no further improvement effect appears due to the action, and rather coarse Cr In addition to the crystallized product of (1), the ductility is remarkably reduced, and the melting and casting becomes difficult, so the content is set to 0.
It was set at 1 to 1.5%.

(C) Zr Zr component forms an intermetallic compound of Cu ₃ Zr which is finely precipitated mainly in the grain boundaries by combining with Cu, thereby suppressing the slip of the grain boundaries at high temperature and increasing the strength of the grain boundaries. It has the effect of improving the thermal fatigue resistance by increasing the temperature, thereby preventing embrittlement (decrease in ductility) due to grain boundary fracture at high temperatures,
If the content is less than 0.01%, the desired improving effect on the action cannot be obtained, while even if the content exceeds 0.5%, no further improving effect can be obtained by the action, and conversely the ductility is reduced. In addition, the melting and casting become difficult, so the content was set to 0.01 to 0.5%.

(D) The P P component has the effect of improving the heat resistance and strength of the mold, but if its content is less than 0.001%, the desired effect is not obtained on the other hand, while its content is 0.2%. Although it is expected that the strength will be improved if the content exceeds the above range, on the other hand, the ductility and thermal conductivity will be remarkably reduced, so the content should be 0.00
It was set at 1 to 0.2%.

(E) Fe and Co These components form an intermetallic compound of (Fe, Co) _x Ti _y which is finely precipitated in the crystal grains by combining with Ti, and thus the strength and thermal conductivity of the template are obtained. However, if the content is less than 0.01%, the desired improving effect on the action cannot be obtained, while if the content exceeds 0.5%, the effect cannot be further improved. On the contrary, since the thermal conductivity suddenly decreases, the content should be 0.01-
It was set at 0.5%.

(F) Sn Since the Sn component has the effect of improving high temperature strength,
It is contained as necessary, but if the content is less than 0.05%, the desired high temperature strength improving effect cannot be obtained, while if the content exceeds 0.5%, the ductility tends to decrease, so that Its content was defined as 0.05% to 0.5%.

〔Example〕

Next, the Cu alloy continuous casting mold of the present invention will be specifically described by way of Examples.

Using a normal vacuum melting furnace, in a graphite crucible, 5 kg each of various Cu alloy melts each having the component composition shown in Tables 1 to 3 were melted, cast into a mold, and then chamfered, Hot forging and hot rolling are performed to obtain a plate material having a width of 100 mm and a height of 5 mm, and by cutting this into an appropriate length, the Cu alloy continuous casting mold plate material of the present invention (hereinafter, the present invention plate material 1-21, comparative Cu alloy continuous casting mold plate material (hereinafter,
Comparative mold plate materials) 1 to 12 and conventional Cu alloy continuous casting mold plate materials (hereinafter referred to as conventional mold plate materials) 1 to 3 were manufactured.

It should be noted that the temperature of any of these mold plate materials: 980 ℃ 30
After holding for a minute, a water-cooled quenching treatment is applied, and subsequently,
The present invention template plates 1 to 21 and the comparative template plates 1 to 12 were kept at a temperature of 525 ° C. for 2 hours, and the conventional template plates 1 were kept at a temperature of 450 ° C. for 1 hour. Further, the conventional mold plate materials 2 and 3 were each subjected to an aging treatment at a temperature of 475 ° C. for 2 hours.

In addition, all of the comparative template plates 1 to 12 have a composition in which any one of the constituent components (marked with * in Table 1) is out of the range of the present invention.

Then, for these various mold plate materials, Vickers hardness at room temperature and 500 ℃, and to measure the electrical conductivity for the purpose of evaluating the thermal conductivity, further room temperature tensile test, temperature: after holding for 10 minutes at 500 ℃ A high temperature tensile test for measuring tensile properties, a heat resistance test, and a thermal cycle fatigue test were performed, and the respective results are shown in Tables 4 to 6.

The heat resistance test is conducted by heating to each temperature in the temperature range of 450 to 700 ° C at intervals of 10 ° C.
After holding for a period of time, air-cooling to room temperature is set as one cycle, and the hardness is measured in each cycle. Based on this measurement result, the heating temperature at which the hardness becomes 90% of the original hardness is the heat-resistant temperature. did.

Further, the thermal cycle fatigue test uses the thermal fatigue test apparatus shown in the schematic cross-sectional view in FIG. 1 to fix and support the test piece 1 in which the notch is formed in the central portion on the test piece holder 2.
With the holder 2 attached to four holder support rods 4 extending radially from the rotary shaft 3 at equal angular intervals of 90 °, the flame 6 of the propane gas burner 5 is applied to the test piece 1 for 40 seconds, and its center Part is heated to the maximum temperature of 500 ° C ± 25 ° C, and then the rotary shaft 3 is automatically rotated 90 ° in the direction of the arrow, and the heated test piece 1 is immediately heated to 7 ° C. Simultaneously with the rapid cooling, the next test piece 1 is moved to the burner heating position and heated for 40 seconds in the same manner as above, and the series of heating and cooling operations is performed for each test piece 1 for 1000 cycles. The number of additional cycles when cracking and deformation occurred in one piece was checked. The results are shown in Tables 4-6.

〔The invention's effect〕

From the results shown in Tables 4 to 6, the present invention template plate materials 1 to
21 is superior in room temperature and high temperature strength, room temperature and high temperature hardness, heat resistance, and heat fatigue resistance to all in comparison with the conventional mold plate materials 1 to 3, and is also excellent in heat conductivity. On the other hand, as seen in the comparative template plate materials 1 to 12, when the content of any one of the constituent components is out of the scope of the present invention, at least one of the above characteristics is inferior. It is clear that

As described above, the Cu alloy continuous casting mold of the present invention,
While maintaining good balance of high-temperature strength, high-temperature hardness, high-temperature ductility, and heat resistance, it has excellent heat fatigue resistance, so not only ordinary continuous casting molds but also rapidly solidified ribbon production It exhibits excellent performance over a long period of time even in practical use as a water-cooled rotary roll mold for use, and a continuous casting mold that is required to be thinner due to the introduction of electromagnetic stirring technology.

[Brief description of drawings]

 FIG. 1 is a schematic sectional view showing a thermal fatigue test apparatus. 1 ... Test piece, 2 ... Test holder, 3 ... Rotating shaft, 4 ... Holder support rod, 5 ... Propane gas burner, 6 ... Flame, 7 ... Water.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuhiko Tabei 1230 Kamihidani, Okegawa City, Saitama Prefecture, Okegawa Daiichi Works, Mitsubishi Metal Co., Ltd. (56) Reference JP 62-50428 (JP, A) JP SHO 62-182238 (JP, A) JP-A-62-182239 (JP, A)

Claims (2)

[Claims] 1. Ni: 1.3 to 5%, Ti: 0.2 to 2%, Cr: 0.1 to 1.5%, Zr: 0.01 to 0.5%, P: 0.001 to 0.2%, Fe and / or Co: 0.01 to 0.5% Cu, characterized in that it is composed of a Cu alloy having a composition (containing at least wt%) of Cu and the balance of Cu and inevitable impurities.
Alloy continuous casting mold. 2. Ni: 1.3-5%, Ti: 0.2-2%, Cr: 0.1-1.5%, Zr: 0.01-0.5%, P: 0.001-0.2%, Fe and / or Co: 0.01-0.5% , Cu, and Sn: 0.05 to 0.5%, and the rest is composed of a Cu alloy having a composition of Cu and inevitable impurities (above wt%).
Alloy continuous casting mold.