JPS6158867A - Flame spray material for furnace wall maintenance - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention aims to remove local damage to furnace walls such as joint cuts, cracks, and peeling of bricks that occur during the use of kilns and molten metal containers using plasma. The present invention relates to thermal spraying materials used for repairs by thermal spraying.

(Conventional technology and its problems) Conventionally, in kilns such as heating furnaces and coke ovens, and in molten metal containers such as tundishes, ladles, and secondary processing furnaces, local damage occurred to the furnace walls during use. In some cases, it was common to repair the area by spraying fireproof material on it and reuse it.

And, this 1 (% as the spraying material used for 5 cases)
An aggregate of 3101% AL=o= etc., mixed with water as a binder and an inorganic binder such as water glass, phosphate, clay, etc., was used.

However, when such sprayed materials are used, adhesion is poor due to the harmful effects of added water contained in the binder, and as a result, the number of repairs is increased, making it difficult to effectively extend the life of the reactor. I couldn't figure it out.

Recently, technology has been adopted to spray fire-resistant materials on the above-mentioned auxiliary parts, but these are mainly used as fire-resistant materials (hereinafter referred to as "sprayed materials"). 910h
Affi, o3/f? Since an oxide with a high melting point is used, RF
There was a problem in that if this thermal spray material was thermally sprayed at a high temperature for complete tC melting, the damaged part of the reactor wall would be easily damaged by thermal shock. For this reason, in the normal case, a low melting point oxide JJ is included in the thermal spray material as disclosed in 11ν 1983-99208:
They were blended together to form a repair body with a low melting temperature.

This thermal spray material has good workability and a large biasing force, which eliminates the drawback of the conventional material that it easily peels off.

(c) Means for Solving the Problems) The present inventor conducted various experiments in addition to the addition of low-melting point oxides with the aim of solving the problems mentioned above, and as a result, the oxide-based refractory One or more alloys containing metallic silicon or/and silicon components are blended into the aggregate,
In addition, the thermal spray material containing 1 to 20 vt% of particles whose particle size is adjusted to 100 to 50 μm has appropriate viscosity, high weldability with the formation of a metallic phase and an amorphous phase, and a high weldability after application. It has been found that the fire resistance is sufficient to withstand over-use conditions.

The reason for adding an alloy containing gold 3 silicon or #'i/ and a silicon component to the oxide-based refractory aggregate according to the present invention is as follows.

In other words, the melting point of the alloy of metal silicon and aluminum is below 1500°C, and the unique point of the oxide-based refractory framework, which is the main component (
For example, 13j, 1F (i/), 1? from 31 (h: 1710'C). '; Inside the spraying material 11: j5 no 111°zA particles is Zri Sl:, '1: Now the applied cell can be removed, and furthermore, the spraying q3'mouth 17'''?::i 1
□The three bodies are oxidized from the surface phase (5to1r4), and the adhesion between the refractory aggregates and gas '1'
+71'l: ``: A thermal spray that has been well-hardened and amorphized ((because it also has the function of imparting toughness to the material.!
[5102 for the base material brick whose main component is ν, sho,
When using an oxide-based thermal spray material as the main component, 810! Considering that the material transforms into a tridymite phase depending on the furnace temperature (800 to 1200°C), it is desirable that the thermal spray material has a main component of Sin and gold, and that the transition to tridymite can be easily prevented. . That is, it is desirable to provide a thermal spray material with a composition that can coexist with the 9-tridymite phase as much as possible. In addition, from the viewpoint of workability, it is better to have the melting temperature of the thermal spray material as low as possible, and the material t-
You have to choose.

In order to satisfy these conditions, the composition and content of the metallic silicon and/or silicon alloy are determined.

That is, the grain size of a mixture of one or more types of metallic silicon and/or an alloy containing a silicon component is 100 to 50 μm, and the content is 1 to 20 μm.
It is expressed as wt%.

If the content of these metal elements is less than 1 wt.
If the adhesion of the sprayed repair object deteriorates, the effect of the repair cannot be expected, and if it exceeds 1 or 2 Qwt, the melting point of the entire sprayed material will be low, and the This is because there is a high possibility that the repair layer will melt, and in such a situation, the bonding strength of the repair layer that has bonded the cracks cannot be said to be sufficient.

In addition, in the case of fine particles less than 50 μm,
As described in No. 6364, most of the gold powder was oxidized and burned by the plasma fire during J injection, and no metallic phase was formed to bind the aggregate particles, and the desired purpose was not achieved. n
do not have. This is because, in the case of coarse particles exceeding 100 μI11, an independent metal phase is likely to be formed within the sprayed layer, resulting in a decrease in the bonding strength of the sprayed layer. In particular, if the metal phase is unevenly distributed within the sprayed layer, the repair effect will be insufficient as described above.

Previous: 8 The alloying elements in the metal powder include 5i-Or system, S
lc & system and 5i-A! system etc. is appropriate. As a ferroalloy, the 1θ content must be 5 vtl or less. In particular, bricks whose main component is 5in2,
This is because it is easily eroded by Pa. Similarly, the Mn content needs to be adjusted to 5wt5 or less, since 14nO after liquefaction tends to leave a liquid phase even in a low temperature range of 1000° C. or less, resulting in a decrease in strength. Furthermore, 0 is oxidized and sprayed 1i
Since it is easy to generate air r(il) in J and it is necessary to remove as much as possible, its content must be kept below tO,1vt,-.

Among them, in order to obtain the above-mentioned characteristic molecule: M, it is desirable to set the components of the oxide-based refractory aggregate as follows.

Sunaichi, SiO2 formulation j: jt 70-95 v
rt%to, At! 01 formulation Ql-t5-30 W
tl Tossuru? -t;+%14tL, yes. 5102 is blended because it improves wear resistance and is stable against gas phases such as 00 gas.

Also, Aha! Although it is a substance with a9i point (Sin, relatively high), it is blended because the viscosity of the melt is low.

If the StO content exceeds 95wt-, that is, the AAlOs content is less than 5wt%, the melt formed during thermal spraying will be highly viscous, and even with the addition of Kita metal powder as mentioned above, there will be significant unevenness. A thermal spray layer is easily formed. Also, AM! O
If Toru exceeds 30wt-, that is, s10 costume is 70w
This is because, if the material is less than t-, a mullite phase is likely to be formed within the layer, although the sprayed layer surface forms a smooth and dense repair layer. In other words, although the sprayed layer itself containing the mullite phase has high initial strength, its thermal expansion characteristics are completely different from that of the amorphous phase or the silica phase modified by this phase, so sifting occurs due to temperature fluctuations during the operation process, causing the repair layer to deteriorate. This is the cause of shortening the lifespan of the product.

In addition, as the oxide-based refractory aggregate having the above-mentioned components, 0.
A particle size of 5 to 0.05 mm is preferable. Ideally, a range of 200 μm=100 μm is appropriate, but a wide particle size distribution is advantageous in terms of cost.

(Execution t2) Examples of the present invention will be described below. The thermal spraying material according to the present invention is made by arbitrarily selecting powders such as Zenkoku Silicon, Cuero/Licon, calcium silicon, silicomanganese, and silinichrome for refractory materials such as silica sand, quartz, calcined silica, Rokuite, and Noriki Flower. was equipped.

For the primary gas Ar flow 100, the secondary gas NJ! 1
A plasma jet was generated using Tab gas at a flow rate ratio of t-5 to t-10, and sprayed onto silica bricks or waxite bricks preheated to 100°C. Base material shape is medium 3Q x 10
The strength of all samples was measured by stacking thermal sprayed bodies with a thickness of 15 to 20 on one end face of a medium 30 mm. That is, as shown in the drawing, the sample (υ) is fixed, and the sample (11 is Full effect, rJ(
The shear stress when the thermal sprayed material (1) peels off from the base brick (2) was calculated. Note that +51 in the figure is the pedestal for the sample (11).

Note that the sample +11iiQ degree during bending was also measured in an atmosphere of 1000°C.

The measurement results are shown in the table below. The apparent porosity in the table is calculated using J-Ko S-1220 for each sample after the bending test.
This is the north result measured in accordance with 5.

As is clear from the table below, the thermal spray material according to the present invention is
When compared to conventional thermal spray materials, the porosity is significantly improved and the adhesion is quickly improved.

(Efficacy of the invention! 7!:) As stated above, the thermal spray material according to the present invention has a remarkable improvement in porosity and adhesion, as is clear from the experimental results, compared to conventional thermal spray materials. It also has good properties, and even when sprayed onto damaged parts of the reactor wall, it will not cause peeling [iL].

[Brief explanation of the drawing]

The drawing shows a method for measuring the adhesive strength between the thermal sprayed material of the present invention and the conventional thermal sprayed material.

Claims (1)

[Claims] (1) One or more types of oxide-based refractory aggregate mixed with metal silicon or/and an alloy containing a silicon component, and whose particle size is adjusted to 100 to 50 μm. A thermal spray material for furnace wall repair characterized by containing 20 wt%.