JPS63199857A - High temperature durable flame spray coating material - 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 relates to equipment members that have excellent corrosion resistance, wear resistance, and build-up prevention properties at high temperatures and are used in high-temperature equipment industries such as the steel industry. It is something.

(Prior Art) In the steel industry, hearth rolls are used in continuous annealing furnaces for cold-rolled steel sheets, plated steel sheets, etc., for example. These hearth rolls are rolls for conveying the steel plate when annealing the steel plate to a temperature of 700° C. or higher, and come into contact with the steel plate at a high temperature. At this time, the scale layer (iron oxide) on the surface of the steel sheet and the iron from the softened steel sheet adhere to the surface of the hearth roll, forming build-ups, and eventually causing scratches on the steel sheet.

In addition, in heat treatment furnaces for thick plates, pipes, wire rods, etc., the conveying equipment inside the furnace and the products come into contact at high temperatures, so materials that do not easily cause build-up are required, just like hearth rolls.
Furthermore, since wear occurs in places where there is sliding or high friction, wear resistance in hot conditions is also essential. In addition, high-temperature gas, dust, fume, etc. pass through the gas collection skirt and hood at the top of the LD-OG converter at high speed, and sometimes slag and metal particles adhere to the gas collection skirt and hood, so the inner surfaces of the skirt and hood are made of metal. Problems include oxidation of the metal, abrasion due to dust, and peeling due to rapid temperature fluctuations.

For this reason, heat-resistant steel, ceramic spray-coated members, etc. have conventionally been used as this type of material. for example,
Special Publication No. 57-29549 and Special Publication No. 5B-17
As described in Japanese Patent No. 775, the surface of the hearth roll is thermally sprayed with ceramics or heat-resistant alloys such as zirconia or alumina.

(Problem to be solved by the invention) However, even improvements in heat-resistant alloys have little effect on preventing build-up caused by adhesive deposits, and ceramic sprayed coating layers of zirconia and alumina do not adhere to the base metal. Due to the difference in the coefficient of thermal expansion, the film itself peels off when subjected to multiple temperature fluctuations, so it is not fully satisfactory in terms of high-temperature wear resistance and prevention of build-up.

Further, the above-mentioned UtO, cermet-based thermal spray coating can be obtained by applying 50 vol. of Ah03 as shown in Japanese Patent Publication No. 58-17775. %, it has excellent wear resistance, but in various environments, it is not chemically inert, so it easily reacts with iron oxides, and unfortunately it does not have an excellent effect on preventing build-up. do not have.

The present inventors have developed various coating materials and coating methods that have excellent high-temperature abrasion resistance required for equipment members such as transportation equipment used in these oxidizing or reducing atmospheres and are highly effective in preventing build-up. As a result of research, we have discovered a thermal spray coating layer that has excellent adhesion to substrates such as hearth rolls, does not peel off, and has excellent high-temperature strength and build-up prevention, and has completed the present invention.

That is, the present invention has been made for the purpose of providing a thermal spray coated member having a coating layer with excellent high temperature wear resistance and a large build-up prevention effect when used in an oxidizing or reducing atmosphere. It is something that

(Means for solving the problem) The present invention includes 51 to 95 vol,% of AIto,
The remainder is Co, Ni, Crs Mo, Fe, jV
The object of the present invention is to provide a high-temperature resistant thermal spray coated member characterized by being coated with one or more selected from among , Y, and St-based gold metals.

The present invention will be described in detail below.

The base of equipment members such as hearth rolls is made of heat-resistant cast steel, for example. These substrates contain IV, O, 51 to 95
A cermet coating containing vol.% is applied by thermal spraying.

The reason why M2O is used as a ceramic component in the present invention is because it is considered to have excellent corrosion resistance, wear resistance, and build-up resistance among ceramics.

However, Al, O, which transforms from α-type to T-type during thermal spraying, returns to α-type^l12o in the operating temperature range of about 800 to 1100°C, so M2O3 alone does not undergo volume expansion. It peels off easily and does not have sufficient durability. Therefore, in the present invention, Co, Nil Crs M
It is a cermet-based material containing metals such as ol Fe, jV, and Y, and the thermal spraying method involves colliding with the object to be thermally sprayed and mechanically biting into it to adhere.
High melting point materials such as N2O3 and Co, Ni, Cr,
A method in which metal materials such as jV and Y are applied at a high speed of 500 m/sec or more is preferred.

Therefore, for the coating of the present invention, for example, explosive thermal spraying is preferable, but other thermal spraying methods such as plasma arc thermal spraying, flame thermal spraying, and high-velocity plasma spraying can also be applied.

M2O3 was added to 51 vol. % or more, the thermal spray coating exhibits sufficient chemical inertness to impart build-up resistance. % or more, the strength of the thermal sprayed coating could not be obtained and sufficient peeling resistance was not exhibited.
By reducing the amount to a level of µm, it becomes possible to form a thermal spray coating with excellent peeling resistance.

In this case, if the M2O content exceeds 95%, the amount of matrix metal to be blended decreases, and sufficient durability (peeling resistance) cannot be obtained. For this reason, in the present invention, the Al2O3 content is set to 51 to 95 vo
Particularly preferred is 1 Uz (h 70-85 vol.), with the remainder being matrix metal.

%, the balance is a mixed structure consisting of matrix metal. This is because by limiting the Alt's content to 70 to 85 vol.%, a peel-resistant coating with significantly superior build-up resistance can be obtained.

(Example) Example 1 The present inventors conducted an experiment using the test apparatus shown in FIG. 1 in order to investigate the build-up property of iron oxide.

A half-moon-shaped roll 6 with a radius of 3511 m was manufactured from 5CH22 (25Cr-2ONi-0,4C), and a 30 fl x 5011 roll was coated on both sides with each thermal spray coating shown in Table 1.
A SUS plate 4 of size X5** is used as a sample.

Build-up raw material 5 (iron oxide powder such as Fe3Q4) is sprinkled between the half-moon roll 6 and the two thermal spray samples 40, and 2
A build-up reproduction device in which a half-moon roll 6 reciprocated over a sheet of thermal sprayed sample 4 was used for the evaluation test.

These devices are installed at the bottom of the pot-shaped furnace 2, and the N2-5%
A reciprocating motion is performed for 4 hours at a constant temperature of 850° C. in a reducing atmosphere of H2 to generate build-up.

In the above reproduction test, as shown in Figure 2, the surface that comes into direct contact with the half-moon roll is surface A, the surface behind it is surface B, and
The opposite surface was designated as C, and the build-up occurrence status after the test was compared using the build-up resistance index shown in Table 2 and the sum of the evaluation scores for each surface. In addition, the build-up resistance of the sprayed samples was evaluated based on the average value of the adhesion area ratio of Fe3O4, which is a build-up source. The results of the build-up resistance test are shown in Table 3. A/t O
s to 70°85 vol. It has been found that the present invention containing %% has superior build-up properties compared to others. As mentioned above, <Al2O3 is 51 vol. This is because when the composition exceeds %, inert properties exhibiting sufficient build-up resistance become noticeable.

Table 1 Thermal Sprayed Coating Composition Example 2 Furthermore, in order to accurately evaluate the occurrence of build-up in a continuous annealing furnace, the following experiment was conducted.

Made of 5tlS310S, diameter 260mm, body length 35mm.
Two test rolls 15 and 16 of 0 dragon were made, and NtCh 70 vat as described above (Table 1 ■■) was applied to the surface of the rolls.

A 5US310S stainless steel roll was used as a comparison material.

An endless thin steel plate 14 was wound around these two rolls, and a rotating contact test was conducted.

FIG. 3 shows a schematic diagram of the evaluation device used in the test. still,
In the figure, 12 and 17 are drive motors, 18 is a balance weight, and 13 is a silicon carbide heating element. Figure 4 shows the atmosphere and temperature pattern tested. Further, detailed test conditions are shown below.

Zhang crab 0.15 kg/ *yaz Rotation speed: tlhl roll 80 r, p, m, tlh
20 - 40 r, p, m (Slip occurred on both rolls) Temperature: 2,850° C. Experiment time: 20 minutes Regarding the test rolls, the build-up occurrence status after the test was evaluated based on the number of build-ups occurring and the adhesion area ratio. The results are shown in Table 4, and it was found that the product of the present invention had better build-up resistance than the comparative stainless steel roll in both the number of build-ups and the adhesion area ratio.

It was also found that the wear resistance was improved by adding Al2O.

Example 3 Next, the following experiment was conducted to examine the high temperature wear resistance of the coating material of the present invention.

As shown in Figure 5 (using 5US310S as the material, diameter 1
A test roll 21 having a length of 20 cranes and a body length of 100 dragons was prepared, and its surface was coated by thermal spraying with various materials shown in Table 5. This was heated to 850° C. by a heating element 22 and rotated in contact with a 75 x 500 x 10 (Dragon) 5S4L steel plate 20 under its own weight using an end fulcrum 19 in an oxidizing atmosphere and a reducing atmosphere to investigate its high-temperature wear resistance.

Table 6 shows the experimental results, and from this, lV2O.

The cermet coatings of the present invention containing A/, O, and ZrO
.

It was found that the abrasion resistance was superior to that of (1) which consisted of each of the following alone. This is possible with lV2O3 coating or ZrO
This is due to the effect that the metal compensates for the brittleness of the 2nd coating.

In addition, in the cermet coating, Al2O, 60vO
! The cermet coating of the present invention containing 1% or more is superior, and this is due to the high hardness of the A1201 grains.

As a result of the above, it is expected that the coating of the present invention exhibits better wear resistance than conventional coatings made of ceramics or the like.

Example 4 Next, the peeling resistance of the sprayed coating was evaluated by a thermal shock test.

Various raw materials were thermally sprayed onto a 5US304 substrate measuring 30 x 50 x 5 mm, heated in an electric furnace at 1000°C for 15 minutes, and then dropped into water for rapid cooling to perform a thermal shock test.

The heating and quenching was repeated until the sample peeled off, and the evaluation was based on the number of repetitions. Note that the test atmosphere was air.

The test materials and thermal shock test results are shown in Table 7. From this, it was found that the coatings ① to ② of the present invention were significantly superior in peeling resistance compared to the comparative materials ① and ②. This is because the metal portion in the coating acts as a buffer for the difference in thermal expansion between the metal substrate and the ceramic, improving thermal shock resistance.

(Effects of the Invention) As shown in the above-mentioned examples, the thermal spray coating member according to the present invention has excellent build-up resistance and peeling resistance, and is useful for extending the life of equipment used in high-temperature equipment and for steel plate products. This greatly contributes to higher quality.

[Brief explanation of the drawing]

Figures 1 and 2 are explanatory diagrams of the build-up test equipment, Figure 3 is a schematic diagram of the 20-ru type build-up simulator, and Figure 4 is the atmosphere and temperature tested in the 20-ru build-up simulator. FIG. 5, which shows the pattern, is an explanatory diagram of the high-temperature abrasion test device. 1: Atmospheric gas introduction tube, 2: Furnace, 3 Nidra, 4: Thermal spray sample, 5: Build-up raw material, 6: Roll, 7: Pressure rod, 8: Weighted material, 9: Counter balance, 10:
Seal plate, 11: Reducer, 12: Magnetic 1 motor, 13:
Silicon carbide heating element, 14: Endless cold thin steel plate, 15: m
l roll, 16: 11h20-ru, 17: Nagi 2 motor, 18: balance weight, 19: fulcrum, 20: steel plate,
21: Roll, 22: Heating element. Figure 1 Figure 3 / 77 Parakunsk L Ite Figure 4 FIFM (graduate) Main exam singing 1

Claims (2)

[Claims] (1) Al_2O_3 in 51 to 95 vol. %, and the remainder is one or more selected from Co, Ni, Cr, Mo, Fe, Al, Y, and Si-based metals. . (2) 70 to 85 vol. of Al_2O_3. % and the remainder is one or more selected from Co, Ni, Cr, Mo, Fe, Al, Y, and Si-based metals as claimed in claim 1. Element.