CN112394026B - Rapid evaluation method for performance of weather-resistant steel rust layer for transmission tower in rural atmospheric environment - Google Patents

Abstract

The invention discloses a method for quickly evaluating the performance of a weathering steel rust layer for a power transmission tower in a rural atmospheric environment, which belongs to the technical field of the performance evaluation of the weathering steel rust layer.

Description

Rapid performance evaluation of weathering steel rust layer for transmission towers in rural atmospheric environment method

technical field

The invention relates to the technical field of weathering steel rust layer performance evaluation, in particular to a rapid performance evaluation method for weathering steel rust layer performance for power transmission towers in a rural atmospheric environment.

Background technique

Transmission towers often use hot-dip galvanizing for anti-corrosion. Hot-dip galvanizing requires special rust removal, pickling, and galvanizing processes. The investment is large, and the pollution in this process is serious. Usually zinc liquid needs to be heated to about 450℃, which will release harmful gas and endanger human health, especially Cr6 ⁺ in galvanized passivation solution has great harm to human body and environment, which is very unfavorable to environmental protection, and Cr6 ⁺ polluted Governance has become a worldwide problem, and it has always been restricted by the environmental protection department.

Weathering steel is atmospheric corrosion-resistant steel, which is a low-alloy steel between ordinary steel and stainless steel. By adding a small amount of alloying elements to the steel, it forms a protective layer on the surface of the metal matrix to slow down the development of corrosion to the depth of the material, thereby improving the corrosion resistance of the steel. It can avoid the current pickling, hot-dip galvanizing and other processes, and some weathering steels can also be used directly, and the longer the use time, the more prominent the corrosion resistance.

The use of weathering steel for transmission towers can remove the traditional hot-dip galvanizing process and reduce pollution to the atmosphere and soil environment; weathering steel transmission towers have no hot-dip galvanizing processing costs, and can also reduce post-corrosion maintenance costs, helping to reduce project costs. .

In order to promote the rapid formation of a stable rust layer when the weathering steel bridge is exposed and prevent the problem of early rust sagging, surface stabilization treatment technology is often used at present, that is, the surface of the weathering steel is treated before it is used to form a breathable and water-permeable. film. The properties of this film are a decisive factor in the corrosion resistance of weathering steels.

At present, the detection methods of weathering steel rust layer mainly include visual inspection method, adhesive tape adhesion test method, ultrasonic test and so on. These methods all measure the surface properties before service, and cannot evaluate the performance of the rust layer during long-term service, and cannot target the characteristics of different atmospheric environments.

To evaluate the long-term service performance of the rust layer, it is necessary to use accelerated environmental simulation tests. There is currently no unified method. The most commonly used method is to refer to TB/T 2375 "Cyclic immersion corrosion test method for weathering steel for railways". The test solution was NaHSO ₄ with a concentration of 0.01 mol/L, and the evaluation method was the weight loss method. Most of the existing papers and patents use periodic infiltration corrosion tests, and different test solutions are used for different service environments, and then the evaluation is carried out through the analysis of weight loss method, corrosion morphology, XRD corrosion products and other methods. The disadvantage of this method is that the test period is long: according to TB/T2375, the "periodic infiltration test + weight loss method" is adopted, and the test period can be agreed to be 50, 75, 100 hours, and the test material is a bare material without surface stabilization treatment, 100 hours The weekly immersion test reflects the generation speed of the rust layer on the surface of the weathering steel, and cannot reflect the performance of the rust layer during long-term service. The performance of the rust layer during long-term service requires a longer test.

The typical atmospheric environment is divided into rural atmospheric environment, coastal atmospheric environment and industrial atmospheric environment. This patent proposes a rapid test and evaluation method for evaluating the durability of the weathering steel rust layer for power transmission towers in a rural atmospheric environment.

SUMMARY OF THE INVENTION

The purpose of the invention is to provide a rapid evaluation method for the performance of the weathering steel rust layer for power transmission towers in a rural atmospheric environment, so as to solve the above technical problems.

In order to achieve the above purpose, the invention provides the following technical solutions: a method for evaluating the durability of weathering steel rust layers for power transmission towers in a rural atmospheric environment, comprising the following steps:

Step 1: Sampling of test samples: select three groups of weathering steel samples to be tested, of which two groups of weathering steel samples are stabilized;

Step 2: Simulated corrosion test: One group of stabilized weathering steel samples is subjected to a water bath test, wherein the simulated solution is deionized water, the pH of the simulated solution is 7, the temperature is 50°C, and the water bath test time is 8 hours ;

Step 3: Record the test data: record the adhesion test result F2 of the weathering steel samples after the stabilization treatment and simulated corrosion after the water bath, and record the adhesion of another group of weathering steel samples that have been stabilized but not subjected to simulated corrosion. Test results F1, and record the measured reference adhesion F0 of another group of weathering steel samples that have not been stabilized and simulated corrosion;

Step 5: Corrosion resistance evaluation: evaluation value K value; of which:

K=F1/F0+F2/F1;

Compare the K value of each style, the larger the K value, the better the service performance in the rural atmospheric environment.

Preferably, in the third step, the adhesion test method is to use a weight with a diameter of φ10mm, fix the bottom surface of the weight on the rust layer on the surface of the sample through adhesive, and use a tension machine to apply force to the weight The tensile force produced by pulling the rust layer off the sample.

Preferably, in the fifth step, according to the characteristics of the sample, the qualified reference value K0 is drawn up, and when the sample K≥K0, it means that the performance of the rust layer of the sample is excellent.

Compared with the prior art, the beneficial effects of the invention are:

The invention provides a method for rapidly evaluating the performance of the weathering steel rust layer of a power transmission tower in a rural atmospheric environment, and a corrosion simulation test is carried out according to the service characteristics of the simulated rural atmospheric corrosion environment. Due to the good service environment in the rural atmospheric environment, the long-term weekly immersion test consumes a lot of manpower and material resources, and a rapid evaluation method is urgently needed. The water bath equipment is used instead of the weekly immersion equipment. Compared with the weekly immersion equipment, the price of the water bath equipment is lower and the test is more stable. In view of the fact that the protective performance of the rust layer in the rural atmospheric environment is mainly reduced, the adhesion of the rust layer is reduced under humidity and strong sunlight. The rust layer fell off under the rain, so the evaluation method was changed to determine its performance by detecting the change of adhesion, which can effectively shorten the test time.

Description of drawings

In order to illustrate the technical solutions of the embodiments of the invention more clearly, the following briefly introduces the accompanying drawings used in the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the invention, which are not suitable for ordinary people in the art. As far as technical personnel are concerned, other drawings can also be obtained based on these drawings without any creative effort.

Fig. 1 is the flow chart of the performance test evaluation of the weathering steel rust layer of the present invention.

Detailed ways

The technical solutions in the embodiments of the invention will be clearly and completely described below with reference to the drawings in the embodiments of the invention. Obviously, the described embodiments are only a part of the embodiments of the invention, not all of the embodiments. Based on the embodiments in the invention, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the invention.

Referring to Figure 1, the invention provides a technical solution: a method for evaluating the durability of weathering steel rust layers for power transmission towers in a rural atmospheric environment, comprising the following steps:

Step 1: Sampling of test samples: select three groups of weathering steel samples to be tested, of which two groups of weathering steel samples are stabilized;

Step 2: Simulated corrosion test: One group of stabilized weathering steel samples is subjected to a water bath test, wherein the simulated solution is deionized water, the pH of the simulated solution is 7, the temperature is 50°C, and the water bath test time is 8 hours ;

Step 3: Record the test data: record the adhesion test result F2 of the weathering steel samples after the stabilization treatment and simulated corrosion after the water bath, and record the adhesion of another group of weathering steel samples that have been stabilized but not subjected to simulated corrosion. Test results F1, and record the measured reference adhesion F0 of another group of weathering steel samples that have not been stabilized and simulated corrosion;

Step 5: Corrosion resistance evaluation: evaluation value K value; of which:

K=F1/F0+F2/F1;

Compare the K value of each style, the larger the K value, the better the service performance in the rural atmospheric environment.

Further, in the third step, the adhesion test method is to use a weight with a diameter of φ10mm, fix the bottom surface of the weight on the rust layer on the surface of the sample through adhesive, and use a tension machine to apply force to the weight. The tensile force produced by pulling the rust layer off the sample.

Further, in the fifth step, according to the characteristics of the sample, the qualified reference value K0 is drawn up, and when the sample K≥K0, it means that the performance of the rust layer of the sample is excellent.

Example 1:

The weathering steel samples with the same chemical composition and three different stabilization treatment processes (the sample is Q420NTH) are respectively A sample, B sample and C sample, which are evaluated by this patented method, and the test data are recorded in Table 1. , in which the bare sample was exposed to the air for one month, and the measured adhesion F0 was 2Mpa;

Table 1: Comparison table of test results of 3 different weathering steel samples with the same chemical composition and different stabilization treatments

Through this method, sample A and sample B have better service performance in rural atmospheric environment, while sample C has poor performance.

Comparing the weight loss test results of the three kinds of samples hanging on site for 1 year, the results are consistent, so it can be concluded that the evaluation method of the present invention is consistent with the most accurate field hanging test results.

Example 2:

Three weathering steel samples with different chemical compositions in the same stabilization treatment process (the sample is Q420NTH), respectively A sample, B sample, and C sample, are evaluated by this patent method, and the test data are recorded in Table 2. , in which the bare sample is exposed to the air for one month, and the measured adhesion F0 is 2Mpa;

Table 2: Comparison table of test results of 3 different weathering steel samples with the same stabilization treatment process and different chemical compositions

By this method, sample A is better than test C is better than sample B;

Comparing the weight loss test results of the three kinds of samples hanging on site for 1 year, the results are consistent, so it can be concluded that the evaluation method of the present invention is consistent with the most accurate field hanging test results.

Example 3:

The weathering steel samples (samples are Q420NTH) of three different manufacturers with the same stabilization treatment process are respectively A sample, B sample and C sample, which are evaluated by this patented method, and the test data are recorded in Table 3. , F0 adopts the average value of the three manufacturers;

Table 3: Comparison table of test results of 3 different weathering steel samples with the same stabilization treatment process and different manufacturers

By this method, the performance of sample A, sample C is better, and the performance of sample B is poor;

Comparing the weight loss test results of three kinds of samples hanging on site for 1 year, the results are consistent, so it can be concluded that the evaluation method of the present invention is consistent with the field hanging test method with the most accurate test results.

Embodiment 4:

According to the characteristics of the sample and the corrosion test results of the on-site hanging sample for 1 year, the evaluation method of the present invention is used to formulate the qualified reference value K0. When testing the sample, the F1, F2 and K values are calculated according to the experimental method and the evaluation method of the present invention. When the sample K≥K0, it indicates that the sample has excellent performance of the show layer.

Based on the above three examples, it can be concluded that the test results show that the evaluation method of the present invention is consistent with the results of the traditional evaluation method, and can effectively evaluate the durability performance of weathering steel in rural atmospheric environment.

In the description of the invention, it is to be understood that the terms "coaxial", "bottom", "one end", "top", "middle", "the other end", "upper", "one side", "top" The orientation or positional relationship indicated by , "inside", "front", "center", "both ends", etc. are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the invention and simplifying the description, rather than indicating Or imply that the device or element referred to must have a particular orientation, be constructed and operate in a particular orientation, and therefore should not be construed as limiting the invention.

In the invention, unless otherwise expressly specified and limited, terms such as "installation", "arrangement", "connection", "fixation" and "screw connection" should be understood in a broad sense, for example, it may be a fixed connection or a It can be a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between the two elements, Unless otherwise clearly defined, those of ordinary skill in the art can understand the specific meanings of the above terms in the invention according to specific situations.

Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principle and spirit of the invention , the scope of the invention is defined by the appended claims and their equivalents.

Claims (2)

1. A method for evaluating the durability of a weather-resistant steel rust layer for a transmission tower in a rural atmospheric environment is characterized by comprising the following steps:

the method comprises the following steps: sampling a test sample: selecting three groups of weathering steel samples to be tested, wherein two groups of weathering steel samples are subjected to stabilization treatment;

step two: simulation of corrosion test: performing a water bath test on one group of stabilized weathering steel samples, wherein the simulation solution is deionized water, the pH =7 of the simulation solution, the temperature is 50 ℃, and the water bath test time is 8 hours;

step three: recording test data: recording an adhesion test result F2 of the weathering steel sample subjected to the stabilization treatment and the simulated corrosion after water bath, recording an adhesion test result F1 of another group of weathering steel samples subjected to the stabilization treatment and not subjected to the simulated corrosion, and recording a calculation reference adhesion F0 of another group of weathering steel samples not subjected to the stabilization treatment and the simulated corrosion;

step five: and (3) corrosion resistance evaluation: evaluating the value K; wherein:

K＝F1/F0+F2/F1；

comparing and comparing K values of all the patterns, wherein the larger the K value is, the better the service performance is under the atmospheric environment of the country;

and step five, drawing up a qualified reference value K0 according to the characteristics of the sample, and when the sample K is more than or equal to K0, indicating that the performance of the sample rust layer is excellent.

2. The method for evaluating the durability of the weathering steel rust layer for the transmission tower in the rural atmospheric environment according to claim 1, characterized in that: in the third step, the adhesion force test mode is that a weight with the diameter of phi 10mm is used, the bottom surface of the weight is fixed on the rust layer on the surface of the sample through adhesive, and a tensile machine is used for applying force to the weight to pull the rust layer from the sample to generate tensile force.

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