A sample rack for high temperature oxidation corrosion test and preparation method thereof

Abstract

The present invention discloses a sample holder for high temperature oxidation corrosion test and a preparation method thereof, comprising a quartz boat body with openings at both ends, a plurality of hanging rods arranged side by side along the width direction on the top of the quartz boat body, a plurality of anti-slip rings arranged on the hanging rods along the length direction thereof, and a pull ring arranged at each end of the quartz boat body. The sample holder of the present invention is made of quartz, and the preparation process is combined with welding and annealing treatment technology, which can increase its strength so that it can be used for high temperature oxidation / corrosion tests, and can increase the number of samples placed at one time, thereby improving the test efficiency, avoiding mutual influence between samples, and reducing experimental errors.

Description

Technical Field

[0001] The invention belongs to the technical field of material oxidation corrosion, and in particular to a sample rack for high-temperature oxidation corrosion test and a preparation method thereof. Background Art

[0002] Among the failure reasons of the "four tubes" of high-parameter power station boilers, flue gas corrosion caused by coal powder combustion on the outside of the furnace tubes and high-temperature steam oxidation corrosion inside the furnace tubes play an important role and are also one of the essential reasons for boiler explosion accidents. Flue gas corrosion of the heating surface includes high-temperature corrosion and low-temperature corrosion. The sulfur in the flue gas forms a composite sulfate with the liquid ash and iron oxide on the walls of the superheater and reheater tubes. The strong reducing atmosphere in the area near the burner allows sulfur to exist alone in an atomic state, causing high-temperature corrosion of the water-cooled walls of the superheater and reheater and the area near the burner. The surface feed water temperature of the economizer is low, and the SO3 water vapor in the flue gas combines to form sulfuric acid vapor, which condenses on the metal surface with a temperature lower than the flue gas dew point and causes low-temperature corrosion.

[0003] Steam oxidation is a special form of corrosion, and the degree of corrosion is directly related to the parameters of the steam medium (temperature and pressure). In particular, the inner wall of the superheater, reheater, steam pipe and other components of the power station boiler often suffers from severe oxidation and shedding during operation. There are two forms of damage caused by oxide peeling. First, the oxide peeling rate is the highest during the startup and shutdown of the unit. In vertical superheaters and reheaters, the shedding often completely blocks the bottom elbows, especially the curved parts with large curvature. Under normal circumstances, this blockage may not be cleaned up when the unit is put into operation, resulting in short-term overheating and damage when the unit is loaded. Secondly, the most common problem caused by oxide peeling is the wear of solid particles in the turbine, which causes serious damage. Commonly corroded parts include the turbine valve stem, the first-stage nozzle unit and the medium-pressure turbine diaphragm.

[0004] The high steam parameters and high efficiency development of thermal power plant units make the service conditions of boiler tubes more complex and demanding, and the performance of the materials used under higher requirements also needs to be further verified and improved. Considering the power generation efficiency of power plants, it is not feasible to carry out actual test experiments in power plants. Therefore, in order to study and solve the problems of flue gas corrosion and water vapor oxidation, a large number of laboratory tests and analysis work need to be carried out. At present, many scientific research institutes at home and abroad have developed steam oxidation test devices, but there is no special sample rack for high-temperature oxidation corrosion test. The sample rack used will pollute the test samples after oxidation or corrosion, and cannot be used for a long time. Summary of the invention

[0005] In order to solve the problems existing in the prior art, the present invention provides a sample rack for high temperature oxidation corrosion test and a preparation method thereof, which can increase the number of samples placed at one time, thereby improving the test efficiency, avoiding mutual influence between samples, and reducing experimental errors.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a sample rack for high-temperature oxidation corrosion test, comprising a quartz boat body with openings at both ends, a plurality of hanging rods arranged side by side along the width direction on the top of the quartz boat body, a plurality of anti-slip rings arranged on the hanging rods along the length direction thereof, and a pull ring is respectively arranged at both ends of the quartz boat body.

[0007] Furthermore, the quartz boat body is semi-cylindrical, and the wall thickness is 2-5 mm.

[0008] Furthermore, the hanging rods are evenly distributed on the top of the quartz boat body, and the multiple hanging rods are parallel to each other.

[0009] Furthermore, the anti-slip ring is welded to the hanging rod, and the hanging rod is welded to the top of the quartz boat body.

[0010] Furthermore, the anti-slip rings on the plurality of hanging rods are located on the same straight line along the length direction of the quartz boat body.

[0011] Furthermore, the pull rings are arranged on both sides of the bottom of the quartz boat body.

[0012] The present invention also provides a method for preparing a sample rack for high temperature oxidation corrosion test, the specific steps of which are:

[0013] S1 obtains blanks of quartz rods and two specifications of hollow quartz tubes and cuts them;

[0014] S2: the cut blank is cleaned, dried and annealed to obtain a quartz boat body 1, a hanging rod 2 and a non-slip ring 3;

[0015] S3: install and weld the anti-slip ring 3 on the hanging rod 2, and then weld the hanging rod 2 to the top of the quartz boat body 1 to obtain a precursor;

[0016] S4 cleans, dries and anneals the precursor to obtain a sample holder.

[0017] Furthermore, the hollow quartz tube includes a large-sized quartz tube and a small-sized quartz tube, wherein the large-sized quartz tube is the quartz boat body, and the small-sized quartz tube is a non-slip ring, and the inner diameter is consistent with the quartz rod; the quartz rod is a hanging rod, and the length of the quartz rod is consistent with the diameter of the quartz boat body.

[0018] Furthermore, the welding adopts hydrogen-oxygen flame welding technology.

[0019] Furthermore, the annealing process is 1000° C. to 1150° C., kept warm for 4 h to 6 h, and cooled with the furnace.

[0020] Compared with the prior art, the present invention has at least the following beneficial effects:

[0021] The present invention provides a sample rack for high temperature oxidation corrosion test. By opening holes at both ends of the sample rack, the corrosion environment can flow dynamically, so that the test environment is closer to the actual service environment. A plurality of hanging rods are arranged on the sample rack of the present invention, and anti-slip rings are distributed on the hanging rods, which can increase the number of samples placed at one time, thereby greatly improving the test efficiency. The anti-slip rings can avoid mutual influence between samples and reduce experimental errors.

[0022] The sample holder of the present invention is made of quartz, and the preparation process is combined with welding and annealing technology to increase its strength so that it can be used for high-temperature oxidation / corrosion tests. The sample holder will not oxidize or corrode in various corrosive environments between room temperature and 1100°C, will not contaminate the test samples, and can be used for a long time at higher temperatures, saving costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention.

[0024] In the attached drawings: 1-quartz boat body, 2-hanging rod, 3-anti-slip ring, 4-pull ring. DETAILED DESCRIPTION

[0025] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0026] See also Figure 1 The present invention provides a sample rack for high temperature oxidation corrosion test, comprising a quartz boat body 1, a hanging rod 2, a non-slip ring 3 and a pull ring 4, wherein: both ends of the quartz boat body 1 are open, a plurality of hanging rods 2 are arranged on the top of the quartz boat body 1 along the width direction for hanging samples, a plurality of non-slip rings 3 are arranged on the hanging rod 2 along the length direction thereof for preventing the samples from moving back and forth and avoiding mutual influence between the samples, and a pull ring 4 is respectively arranged at both ends of the quartz boat body 1.

[0027] Preferably, the quartz boat body is semi-cylindrical, with openings at both ends of the cylinder and a wall thickness of 2 to 5 mm.

[0028] Preferably, the number of the hanging rods 2 is not less than 3, and the hanging rods 2 are evenly distributed at the two ends and the middle of the top of the quartz boat body, and the distance between the two hanging rods 2 arranged at the two ends of the quartz boat body 1 does not exceed 15 cm.

[0029] Preferably, the plurality of hanging rods 2 are parallel to each other and are connected to the quartz boat body 1 by welding.

[0030] Preferably, the anti-slip rings 3 on the plurality of hanging rods 2 are located on the same straight line along the length direction of the quartz boat body 1 .

[0031] Preferably, the pull rings 4 are arranged on both sides of the bottom of the quartz boat body 1 .

[0032] During the test, the sample is passed through the spiral NiCr wire and then placed on the hanging rod 2. The same string of samples is placed in the middle of the anti-slip ring 3 located in the same straight line to ensure that the samples do not affect each other. The test can be carried out after placing it in the high-temperature oxidation device. If the oxidation device channel is long, tools can be used to hang it on the pull ring 4 for movement.

[0033] The preparation process of the sample holder of the present invention is: cutting blanks - cleaning - annealing - welding - cleaning - annealing. Specifically,

[0034] 1) The blanks are hollow quartz tubes and quartz rods of two specifications, which are cut to the required size by a cutting machine. The large-sized quartz tube is the quartz boat body 1, and the quartz rod is the hanging rod 2, the length of which is consistent with the diameter of the quartz boat body 1; the anti-slip ring 3 is a small-sized quartz tube, and the inner diameter is consistent with the quartz rod;

[0035] 2) The cut blanks are placed in high-purity water for cleaning and cooling, and after drying, placed in a heat treatment furnace for annealing;

[0036] 3) The annealed anti-slip ring 3 is installed on the hanging rod 2 and welded by hydrogen-oxygen flame welding technology, and then the hanging rod 2 is welded to the top of the quartz boat body 1 to obtain a sample rack;

[0037] 4) Clean the sample rack, dry it, and then perform annealing heat treatment to eliminate welding thermal stress. Use high-purity water for cleaning.

[0038] Preferably, the annealing process is 1000-1150° C., kept warm for 4-6 hours, and cooled with the furnace.

Claims

1. A method for preparing a sample holder for high temperature oxidation corrosion test, characterized in that: The sample holder for high temperature oxidation corrosion test comprises a quartz boat body (1) with openings at both ends, a plurality of hanging rods (2) arranged side by side along the width direction on the top of the quartz boat body (1), a plurality of anti-slip rings (3) arranged on the hanging rods (2) along the length direction thereof, and a pull ring (4) is respectively arranged at both ends of the quartz boat body (1); The specific steps for preparing the sample rack for high temperature oxidation corrosion test are: S1 obtains blanks of quartz rods and two specifications of hollow quartz tubes and cuts them; S2: cleaning, drying and annealing the cut blanks to obtain a quartz boat body (1), a hanging rod (2) and a non-slip ring (3); S3: installing and welding the anti-slip ring (3) on the hanging rod (2), and then welding the hanging rod (2) to the top of the quartz boat body (1), thereby obtaining a precursor; S4 cleans, dries and anneals the precursor to obtain a sample holder.

2. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The quartz boat body (1) is semi-cylindrical and has a wall thickness of 2 to 5 mm.

3. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The hanging rods (2) are evenly distributed on the top of the quartz boat body (1), and the multiple hanging rods (2) are parallel to each other.

4. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The anti-slip ring (3) is welded to the hanging rod (2), and the hanging rod (2) is welded to the top of the quartz boat body.

5. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The anti-slip rings (3) on the multiple hanging rods (2) are located on the same straight line along the length direction of the quartz boat body (1).

6. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The pull rings (4) are arranged on both sides of the bottom of the quartz boat body (1).

7. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The hollow quartz tube comprises a large-sized quartz tube and a small-sized quartz tube, wherein the large-sized quartz tube is a quartz boat body (1), and the small-sized quartz tube is a non-slip ring (3), the inner diameter of which is consistent with that of a quartz rod; the quartz rod is a hanging rod (2), the length of which is consistent with the diameter of the quartz boat body (1).

8. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The welding adopts hydrogen-oxygen flame welding technology.

9. The method for preparing a sample holder for high temperature oxidation corrosion test according to claim 1, characterized in that: The annealing process is 1000 ℃ ~ 1150 ℃, keeping temperature for 4 h ~ 6 h, and cooling with the furnace.

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