JPH02212366A - Melting-resistant metallic member - Google Patents

Abstract

PURPOSE:To obtain the melting-resistant metallic member having excellent corrosion resistance, mechanical strength and thermal shock resistance and easy to sinter, at the time of sintering ZrB2-BN series ceramics, by using MoSi2 and/or ZrSi2 as a sintering auxiliary. CONSTITUTION:Respective materials of A) ZnB2, B) BN and C) a sintering auxiliary of MoSi2 and/or ZrSi2 having >=95% purity and <=10mum, preferably <=5mum average grain size are used and are mixed in the proportion of 45 to 90 pts.wt., preferably 55 to 85 pts. A, 5 to 30 pts., preferably 10 to 30 pts. B and 5 to 25 pts., preferably 5 to 15 pts. C. The mixture is sintered at 1800 to 2000 deg.C, preferably at 1850 to 1950 deg.C usually for about several hours in vacuum or in a reducing atmosphere by the method of atmospheric, hot press, HIP sintering, etc., by which the melting-resistant metallic member can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a molten metal member used for processing highly corrosive molten metal such as molten steel.

[Conventional technology]

Various ceramic materials have been studied as molten metal resistant members, and BN or 51aN4-AtN-BN-based materials are mainly used for floors. For example, Japanese Patent Publication No. Sho 63-58793 discloses the application of a ZrB2-BN composite sintered body to a refractory for molten metal distribution. However, mechanical strength, heat resistance, and corrosion resistance vary depending on the composition, and it is difficult to necessarily use a member with well-balanced physical properties. For example, if the addition mt of BN is increased to improve heat resistance 11, the corrosion resistance and mechanical strength will drop sharply, and the sintering method is also limited to the hot press method, and the firing conditions are a temperature of 2000°C or higher, a pressure 5DDkg/a
Normally, it is difficult to say that it must be greater than or equal to n”.
However, there were problems in that the shape and size of the molded product were limited.

[Problem to be solved by the invention]

In order to solve the above-mentioned problems, the present inventors have discovered that it is possible to obtain a molten metal member having unprecedented corrosion resistance, mechanical strength, and thermal shock resistance, and have completed the present invention. It has arrived.

[Means to solve the problem]

That is, the present invention provides Zr8245-90)jji part, B
N2 Ma 5-30mji section as well as MoSi2 and/or 1! "m
5iz This is a melt-resistant metal member obtained by sintering a mixture consisting of 5 to 25 heavy metals.

The present invention will be explained in more detail below.

Molten-resistant metal parts include nozzles for pouring hot water, for example, nozzles for horizontal continuous casting, and in order to smoothly pull out the slab, refractories or break rings for connecting between the tundish and the mold play an important role. The required characteristics of this refractory material include thermal shock resistance, high corrosion resistance, high lubricity, and machinability. For these Yasugi*p, Zr
B2-BN Thread Performance Association Furthermore, the firing temperature is lower than conventional ones, and it can be produced not only by the pot press method but also by the pressureless sintering method.

The blending composition of the raw materials is 1 part zrB245~90'', BN
5-30! Namihi Kurabe Mo8i2 and/or ZrSi2
5-2511Lii part. Preferably ZrB25
5-85N neck, BNlo ~30 heavy lid, Mo8i2
and/or ZrSi 25° to 15Jkit part. B
If N is too small, thermal shock resistance cannot be expected, and if it is too large, corrosion resistance will decrease. If Mo812 and/or Zr812 is too small, the sinterability will not improve, and if it is too large! Impairs the original properties of hB2.

As a raw material for ZrB2, BN, MoSi2 and/or ZrSi2 used in the present invention, 1 gold
The silicide is MoSi2.11\Si. is used.

The raw materials may be mixed either dry or wet, usually using a ball mill or the like, and an organic binder may be added if necessary.

For molding, commonly used methods such as mold pressing, arp, slip casting, injection molding, etc. can be applied.

The firing method is carried out in a vacuum or a reducing atmosphere, and atmospheric pressure sintering, hot press sintering, H-P sintering, etc. are used, and are not particularly limited. Firing temperature is 1800-210
In the range of 0°C, 1850 to 1950°C is preferable from the viewpoint of sinterability and economical efficiency. The firing time ranges from several tens of minutes to several tens of hours at the highest retention rate, and is appropriately selected depending on the size, shape, and size, but is usually about several hours.

Examples will be described in detail below.

〔Example〕

ZrB2, BN, MoSi with average particle size 2-3/jFW
2. After mixing and pulverizing ZrSi2 raw material powder in a predetermined ratio in a ball mill, normal pressure sintering and hot press sintering are performed, and the resulting sintered body is 3 am x 4 tm.
A 36 mm x 36 mm test piece was prepared and its bending strength, thermal shock resistance and corrosion resistance against SUS 304 were examined. The results are shown in Table-1.

In addition, in the pressureless sintering method, mold press-CIP molding (2, 7
ton/cm2+3 min) K rows were kneaded and then fired.

(11 Bending strength: Based on JIS R1601.

(2) Heat resistance (# * Self-temperature difference...The test piece was kept at a predetermined temperature in an electric furnace for 1 hour, then dropped into water and quenched. The curve of the obtained quenched test piece was measured in a high-pressure test. The m-degree difference in which the strength decreased was defined as the temperature difference between the two heat resistances.

(A steel piece of 312US 304 was placed in a crucible and heated in a high-frequency induction furnace at 1600°C. The test piece was immersed in this bath water and taken out after 1 hr to evaluate the corrosion rate.

A: No reaction B: Low reactivity C: High reactivity In the comparative example of Margin Experiment/I61.2, the bending strength was low, and similarly in Experiment 1 I63 OBN without heat resistance (11J Hayabusa temperature difference was 200°C).

In the example experiment/i64.5.6.7, the effect of the amount of BN added was investigated, and the bending strength was 14 to 35 kg, and the cod heat shock resistance temperature difference was 450 to 800°C, which was a well-balanced performance. I showed money.

In Experiment/I68.9, the amount of EN added was large and the strength of the song was extremely low.

Experiment 410 uses sintering aid f MoSi2 f Zr5j2
When changed to , the physical properties were almost the same. Experiment/161
As shown in Fig. 8, excellent effects were obtained even when Mo812 and ZrSi2f were used together.

Experiment 411.12.16.14 added 6*tz of sintering aid
However, the bending strength is 13 to 23 Yu/1lI2,
The thermal shock resistance temperature difference was good at 650 to 750°C.

Experiment/1615.16.17 was conducted by hot press sintering, but Experimental Scrap 16 without Mo5i2 addition could only obtain a low curve strength. Experimental rot 17 is SiC'
was used as a sintering aid, the bending strength was low, and the corrosion resistance was poor.

〔Effect of the invention〕

The melt-resistant metal member of the present invention not only has excellent mechanical strength, thermal shock resistance, and corrosion resistance, but also has the advantage of being easier to sinter than conventional members.

Patent applicant Denki Kagaku Kogyo Co., Ltd.

Claims (1)

[Claims] 1. A melt-resistant metal member obtained by sintering a mixture consisting of 245 to 90 parts by weight of ZrB, 5 to 30 parts by weight of BN, and 25 to 25 parts by weight of MoSi_2 and/or ZrSi.