A weathering steel surface rust layer stabilizing treatment liquid and a treatment method

Abstract

The application provides a weathering steel surface rust layer stabilizing treatment liquid and a treatment method, and the composition of the treatment liquid is as follows: Cu(NO3)2: 0.5-1.0%, FeCl3: 0.5-1.0%, NaHSO3: 0.1-0.5%, Na2MoO4: 0.05-0.15%, Fe3O4: 0.5-2.0%, and the rest is deionized water; (5*NaHSO3+FeCl3) / Na2MoO4=20-25. Compared with the prior art, the weathering steel surface rust layer stabilizing treatment method provided by the application can promote the weathering steel surface to quickly form a dense and stable alpha-FeOOH, improve the atmospheric corrosion resistance, and the corrosion rate of the rust layer after reaching stability is less than or equal to 75% of the weathering steel without treatment. The treated weathering steel can be used in a climate environment (industrial atmosphere, rural atmosphere). Moreover, the treatment construction of the application is convenient, economical and environmentally friendly.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of steel materials and its corrosion protection technology, and particularly relates to a rust layer stabilizing treatment liquid for weathering steel surface and a treatment method. BACKGROUND

[0002] Weathering steel has excellent atmospheric corrosion resistance, good strength and toughness, and welding performance, and is widely used in outdoor equipment and components manufacturing such as railway vehicles, containers, bridges, buildings, etc. However, due to the addition of alloy elements such as Cu, Cr, Ni, etc., the manufacturing cost of weathering steel is significantly higher than that of ordinary carbon steel. Although the paint-free application can greatly reduce the later use and maintenance cost of weathering steel, it takes a long time to form a stable and dense protective rust layer, usually more than 3 years. On the one hand, the corrosion rate of the material is fast before the formation of a dense protective rust layer, which can easily lead to corrosion failure; on the other hand, the phenomenon of rust liquid flowing and scattering often occurs, which pollutes the surrounding environment and affects the appearance. Therefore, weathering steel is still used mainly after galvanizing or painting for corrosion protection, which limits its further popularization and application.

[0003] In order to promote the paint-free application of weathering steel, domestic steel enterprises and research institutions have carried out long-term research work on the surface rust layer stabilization treatment of weathering steel, but so far there is no mature and widely used surface rust layer stabilization treatment technology.

[0004] The patent CN 108660447 A published on October 16, 2018 discloses a pretreatment liquid and a pretreatment method for stabilizing the rust layer on the surface of weathering steel. The chemical components and their mass fractions in the pretreatment liquid disclosed in the patent are as follows: 0.5-2% Cr(SO4)3, 0.3-1.2% FeSO4, 0.1-0.6% CuSO4, 0.3-1.2% NaHSO3 and 0.2-1.0% NiSO4, and the balance is H2O. The pretreatment liquid is sprayed onto the surface of weathering steel, and after one spraying, it is naturally dried. The dried weathering steel surface is sprayed with water three times, and before each spraying, the weathering steel surface is naturally dried. Although the pretreatment method for stabilizing the rust layer on the surface of weathering steel described in the patent is simple to operate, the pretreatment liquid contains chromium salt which pollutes the environment. Moreover, the implementation effect only shows that a uniform and dense rust layer is obtained without rust liquid flowing phenomenon, and does not mention the time required for the rust layer to reach stabilization, which is a key indicator.

[0005] CN107794523 A published on March 13, 2018 discloses a kind of weathering steel plate fast rusting method, and rusting process flow is: steel plate surface cleaning, homogenization, pre-oxidation, oxidation and subsequent processing.Steel plate surface cleaning: using sandpaper, angle grinder or shot blasting to steel plate surface is handled, so that steel plate surface is rust-free, oil-free, no other adhering material.Homogenization: using brushing, roll coating or spraying method, nickel salt solution (4kg nickel sulfate is dissolved in 100 liters 0.05 moL / L phosphoric acid solution, 3kg OP-10 non-ionic surfactant is added, and conductivity ≤20 μs / cm water is diluted 10 times) is attached to steel plate surface.Oxidation: using brushing, roll coating or spraying method, oxidation liquid (2.4% NaCl, 2.4% CuSO4, 3.2% FeSO4 and 3.2% NaHSO3 four kinds of aqueous solution are prepared, then four kinds of solution are mixed according to the proportion of volume ratio 1:1:1:1, stirring, standing 8 hours for use) is attached to steel plate surface, and the generated thin corrosion product layer is promoted to grow fast.Subsequent processing: using brushing, roll coating or spraying method, one or two of water, sodium chloride or sodium bisulfite solution is attached to steel plate surface, and the corrosion product layer generated after surface oxidation treatment is not perfect in quality.The construction process described in the patent is complex, not suitable for on-site construction, and the implementation effect does not explain the key indicator of the time required for the rust layer to reach stabilization.

[0006] CN 106835092 A published on June 13, 2017 discloses a kind of steel plate surface generation stable rust layer processing method, and the mass percentage of surface treatment solution is CuSO4: 0.5% ~ 5%, FeSO4: 1% ~ 5%, NaHSO3: 0.1% ~ 3%, NaCl: 0.1% ~ 3%, Fe2O3: 0.05% ~ 3%, Cr2 (SO4) 3: 0.05% ~ 3%, and the rest is water and unavoidable impurities.The treatment liquid contains chromium salt that pollutes the environment, and the implementation effect is verified by periodic immersion accelerated corrosion test, and the actual use effect needs to be further verified in atmospheric environment.

[0007] Therefore, it is necessary to provide a treatment method for promoting the rapid formation of a dense and stable protective rust layer on the surface of weathering steel. SUMMARY

[0008] The application aims to provide a weathering steel surface rust layer stabilizing treatment liquid and a treatment method, which can accelerate the formation of a dense and stable protective rust layer on the surface of the weathering steel by treating the surface of the weathering steel with the treatment liquid.

[0009] The specific technical scheme of the application is as follows:

[0010] A weathering steel surface rust layer stabilizing treatment liquid comprises the following components in percentage by mass:

[0011] Cu(NO3)2: 0.5-1.0%, FeCl3: 0.5-1.0%, NaHSO3: 0.1-0.5%, Na2MoO4: 0.05-0.15%, Fe3O4: 0.5-2.0%, and the rest is deionized water.

[0012] The percentage by mass of NaHSO3, FeCl3 and Na2MoO4 in the weathering steel surface rust layer stabilizing treatment liquid also needs to satisfy the formula (5*NaHSO3+FeCl3) / Na2MoO4=20-25. The content of the accelerators NaHSO3 and FeCl3 and the corrosion inhibitor Na2MoO4 needs to be controlled within a certain range, so as to accelerate the corrosion of the weathering steel material to form a rust layer and avoid excessive corrosion of the base material.

[0013] The application provides a weathering steel surface rust layer stabilizing treatment method, which adopts the above treatment liquid and specifically comprises the following steps:

[0014] 1) removing the rust layer on the surface of the weathering steel;

[0015] 2) spraying the treatment liquid uniformly on the surface of the weathering steel, and then spraying water uniformly on the surface of the weathering steel after drying.

[0016] Step 1) removes the rust layer on the surface of the weathering steel by pickling or shot blasting.

[0017] In step 2), the drying is performed for 10-30 minutes before spraying water on the surface of the weathering steel.

[0018] In step 2), the drying is performed for 60-120 minutes.

[0019] In step 2), the treatment liquid is evenly sprayed on the surface of the weathering steel to completely cover the surface of the weathering steel.

[0020] In step 2), the spraying amount of the treatment liquid is 0.30-0.50 μL / mm 2 ;

[0021] In step 2), water is sprayed on the surface of the weathering steel to completely cover the surface of the weathering steel.

[0022] Further, step 2) is repeated, and the treatment liquid and water are sprayed for 2-5 cycles, and the amount of the treatment liquid sprayed each time is the same, and the amount of water sprayed each time is the same.

[0023] Further, the treatment liquid should be sprayed when the weather is dry. It should not be sprayed in rain, snow or heavy fog to avoid the stabilized treatment liquid on the surface of the weathering steel being washed away and thus losing its effect.

[0024] After the above treatment method, the rust layer on the surface of the weathering steel is stabilized after 58-63 days of atmospheric exposure.

[0025] The application also provides a weathering steel suitable for the above surface rust layer stabilization treatment method, and the weathering steel comprises the following components in mass percentage: C: 0.04%-0.12%, Si: 0.20%-0.50%, Mn: ≤1.50%, P: 0.06%-0.15%, S: ≤0.005%, Cr: 0.30%-1.00%, Ni: ≤0.30%, Cu: 0.20%-0.40%, Alt: 0.020%-0.040%, and the rest is Fe and inevitable impurity elements. In order to improve the strength and plasticity of the weathering steel, micro-alloy elements such as Nb, V and Ti can also be added as needed.

[0026] The design idea of the application is as follows:

[0027] Cu(NO3)2 is a modifier, and copper elements are enriched in the rust layer to fill the cracks of the rust layer, improve the density of the rust layer, and prevent the diffusion of corrosive media to the substrate; it can also promote the positive shift of the electrode potential in this area, inhibit the corrosion tendency of the substrate, and slow down the corrosion of the substrate.

[0028] NaHSO3 and FeCl3 are accelerators, which form a weak acidic environment and provide Cl - , promote the initial corrosion of the substrate material, and make the weathering steel corrode quickly to form a rust layer.

[0029] Na2MoO4 is a slow-release agent, which reacts with the steel substrate to form a difficult-to-dissolve passivation film attached to the surface of the substrate, thereby improving the protection of the rust layer.

[0030] Fe3O4 is an inducer, which induces the nucleation of the rust layer, induces the transformation of γ-FeOOH in the rust layer to stable and dense α-FeOOH, accelerates the formation of the dense inner rust layer, and shortens the stabilization period of the rust layer.

[0031] Deionized water: as a solvent, dissolving chemical reagents.

[0032] Compared with the prior art, the weathering steel surface rust layer stabilization treatment method provided by the application can promote the rapid formation of dense and stable α-FeOOH on the surface of the weathering steel, and improve the atmospheric corrosion resistance. After about 60 days of atmospheric exposure, the rust layer on the surface of the weathering steel reaches stability, and the corrosion weight loss rate is ≤75% relative to the untreated weathering steel. The treated weathering steel can be used in industrial atmospheres, rural atmospheres and other climate environments. The weathering steel surface rust layer stabilization treatment method also has the advantages of simple preparation, convenient construction, economy and environmental protection. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The macroscopic morphology of the example and bare steel after different periods of atmospheric exposure;

[0034] Figure 2 Comparison of the corrosion rates of the example and bare steel. DETAILED DESCRIPTION

[0035] The weathering steel surface rust layer stabilization treatment liquid provided by the application comprises the following components in mass percentage:

[0036] Cu(NO3)2: 0.5-1.0%, FeCl3: 0.5-1.0%, NaHSO3: 0.1-0.5%, Na2MoO4: 0.05-0.15%, Fe3O4: 0.5-2.0%, and the rest is deionized water;

[0037] In the composition of the weathering steel surface rust layer stabilization treatment, the mass percentages of NaHSO3, FeCl3 and Na2MoO4 also need to satisfy: (5*NaHSO3+FeCl3) / Na2MoO4=20-25.

[0038] The weathering steel surface rust layer stabilization treatment method provided by the application is obtained by using the above treatment liquid, and the specific treatment method is as follows:

[0039] 1) The treatment liquid is prepared according to the above chemical components and mass fractions, and is uniformly mixed;

[0040] 2) The weathering steel surface is removed by pickling or shot blasting;

[0041] 3) The treatment liquid is uniformly sprayed on the surface of the weathering steel, and the spraying amount of the treatment liquid is 0.30-0.50 μL / mm 2, so that the treatment liquid evenly covers the entire substrate. After the weathering steel surface is dried for 10 to 30 minutes, water is evenly sprayed on the weathering steel surface. After the weathering steel surface is dried for 60-120 minutes, the treatment liquid is evenly sprayed on the weathering steel surface. This cycle of spraying treatment liquid and water is repeated 2-5 times.

[0042] 4) The treatment liquid should not be sprayed in rain, snow or dense fog to avoid the stabilization treatment liquid sprayed on the surface of the weathering steel being washed away and thus losing its effect.

[0043] 5) The treated weathering steel comprises the following composition by mass percentage: C: 0.04% to 0.12%, Si: 0.20% to 0.50%, Mn: ≤1.50%, P: 0.06% to 0.15%, S: ≤0.005%, Cr: 0.30% to 1.00%, Ni: ≤0.30%, Cu: 0.20% to 0.40%, Alt: 0.020% to 0.040%, with the remainder being Fe and unavoidable impurity elements. Microalloying elements such as Nb, V, and Ti may also be added as needed to improve the strength and ductility of the weathering steel.

[0044] The above treatment method promotes the rapid formation of dense and stable α-FeOOH on the surface of weathering steel, improving its atmospheric corrosion resistance. After approximately 60 days of atmospheric exposure, the rust layer on the surface of the weathering steel stabilizes, and its corrosion weight loss rate is ≤75% of that of untreated weathering steel. The treated weathering steel is suitable for use in both industrial and rural environments.

[0045] The technical solution of the present application is further described below in conjunction with various embodiments and comparative examples.

[0046] Example 1 A treatment solution for stabilizing rust layer on the surface of weathering steel comprises the following components in percentage by mass:

[0047] 0.6% Cu(NO3)2, 0.6% FeCl3, 0.4% NaHSO3, 0.12% Na2MoO4, 1.2% Fe3O4, and the balance is deionized water, where (5×NaHSO3+FeCl3) / Na2MoO4=21.7.

[0048] A method for stabilizing the rust layer on the surface of weathering steel is obtained by treating with the treatment solution of Example 1 above. The specific treatment method is:

[0049] 1) Prepare the treatment liquid according to the above chemical composition and its mass fraction and mix it evenly.

[0050] 2) Weathering steel samples of 40mm x 60mm x 4mm were processed, which included the following mass percentages: C: 0.07%, Si: 0.45%, Mn: 1.05%, P: 0.09%, S: 0.005%, Cr: 0.79%, Ni: 0.20%, Cu: 0.29%, Alt: 0.026%, with the balance being Fe and unavoidable impurities. The surface of the weathering steel sample was cleaned by pickling to remove the surface scale;

[0051] 3) The prepared stabilizing treatment solution was uniformly sprayed on the surface of the sample, with a spraying amount of 0.42 μL / mm 2 . After the surface was dried for 18 min, water was uniformly sprayed on the surface of the weathering steel, and after the surface was dried for 65 min, the stabilizing treatment solution was uniformly sprayed on the surface of the weathering steel. After the surface was dried, water was uniformly sprayed on the surface of the weathering steel after 18 min, and the surface was dried for 65 min.

[0052] 4) After the treatment was completed, the weathering steel sample was directly placed in the atmosphere for exposure, and after the rust layer was stabilized (63 days), a rust removal solution was used to remove the rust layer on the surface of the weathering steel. After drying for 24 h, the corrosion weight loss rate was calculated, and the corrosion weight loss rate of the relative bare steel (without rust layer stabilization treatment) was 75%. The formula of the rust removal solution was: 500 ml of hydrochloric acid + 500 ml of deionized water + 3.5 g of hexamethylenetetramine.

[0053] Example 2

[0054] A weathering steel surface rust layer stabilization treatment solution, including the following mass percentage components:

[0055] 0.8% Cu(NO3)2, 0.9% FeCl3, 0.2% NaHSO3, 0.08% Na2MoO4, 1.8% Fe3O4, with the balance being deionized water, wherein (5 x NaHSO3 + FeCl3) / Na2MoO4 = 23.75.

[0056] A weathering steel surface rust layer stabilization treatment method, which is obtained by using the treatment solution of the above-mentioned Example 2, and the specific treatment method is as follows:

[0057] 1) The treatment solution was prepared according to the above-mentioned chemical components and mass fractions and mixed uniformly.

[0058] 2) Weathering steel samples of 40mm x 60mm x 4mm were processed, which included the following mass percentages: C: 0.07%, Si: 0.45%, Mn: 1.05%, P: 0.09%, S: 0.005%, Cr: 0.79%, Ni: 0.20%, Cu: 0.29%, Alt: 0.026%, with the balance being Fe and unavoidable impurities. The surface of the weathering steel sample was cleaned by pickling to remove the surface scale;

[0059] 3) The prepared stabilizing treatment solution is evenly sprayed on the surface of the sample, with a spraying amount of 0.35 μL / mm 2 After the surface is dried for 15 min, water is evenly sprayed on the surface of the weathering steel, and the surface is dried for 86 min. The stabilizing treatment solution and water are sprayed in cycles for 5 times.

[0060] 4) After the treatment is completed, the weathering steel is directly placed in the atmosphere for exposure, and after the rust layer is stabilized (58 days), a rust removal solution is used to remove the rust layer on the surface of the weathering steel. After being dried for 24 h, the corrosion weight loss rate is calculated, which is 73% relative to the corrosion weight loss rate of bare steel (without rust layer stabilization treatment). The formula of the rust removal solution is: 500 ml of hydrochloric acid + 500 ml of deionized water + 3.5 g of hexamethylenetetramine.

[0061] Example 3

[0062] A rust layer stabilization treatment solution for a weathering steel surface includes the following mass percentage components:

[0063] 1.0% Cu(NO3)2, 0.75% FeCl3, 0.3% NaHSO3, 0.1% Na2MoO4, 0.7% Fe3O4, and the balance is deionized water, wherein (5 x NaHSO3 + FeCl3) / Na2MoO4 = 22.5.

[0064] A rust layer stabilization treatment method for a weathering steel surface is obtained by using the treatment solution in Example 3 above, and the specific treatment method is as follows:

[0065] 1) The treatment solution is prepared according to the above chemical components and mass fractions and is mixed uniformly.

[0066] 2) A weathering steel sample with a size of 40 mm x 60 mm x 4 mm is processed, and the weathering steel includes the following mass percentage components: C: 0.05%, Si: 0.38%, Mn: 0.76%, P: 0.07%, S: 0.002%, Cr: 0.90%, Ni: 0.05%, Cu: 0.21%, Alt: 0.035%, Nb: 0.020%, Ti: 0.015%, and the balance is Fe and unavoidable impurity elements. The rust layer on the surface of the sample is removed by pickling;

[0067] 3) The prepared stabilizing treatment solution is evenly sprayed on the surface of the sample, with a spraying amount of 0.47 μL / mm 2 After the surface is dried for 26 min, water is evenly sprayed on the surface of the weathering steel, and the surface is dried for 110 min. The stabilizing treatment solution and water are sprayed in cycles for 3 times.

[0068] 4) After the treatment, the weathering steel was directly placed in the atmosphere for exposure, and after the rust layer was stabilized (60 days), a rust removal liquid was used to remove the rust layer on the surface of the weathering steel. After drying for 24 h, the corrosion weight loss rate was calculated, and the corrosion weight loss rate relative to bare steel (not subjected to rust layer stabilization treatment) was 72%. The formula of the rust removal liquid was: 500 ml of hydrochloric acid + 500 ml of deionized water + 3.5 g of methenamine.

[0069] Comparative Example 1

[0070] A rust layer stabilization treatment liquid for the surface of weathering steel, comprising the following mass percentage components: 0.1% Cu(NO3)2, 0.7% FeCl3, 0.3% NaHSO3, 0.02% Na2MoO4, 0.9% Fe3O4, and the balance being deionized water, wherein (5 x NaHSO3 + FeCl3) / Na2MoO4 = 110.

[0071] A rust layer stabilization treatment method for the surface of weathering steel, which is obtained by using the treatment liquid of the above-mentioned Comparative Example 1, and the specific treatment method is as follows:

[0072] 1) The treatment liquid is prepared according to the above-mentioned chemical components and mass fractions and mixed uniformly.

[0073] 2) A weathering steel sample with a size of 40 mm x 60 mm x 4 mm is processed, and the weathering steel has a composition of C: 0.09%, Si: 0.36%, Mn: 1.25%, P: 0.08%, S: 0.004%, Cr: 0.68%, Ni: 0.25%, Cu: 0.33%, and Alt: 0.029%. The iron oxide scale on the surface of the sample is removed by acid pickling;

[0074] 3) The prepared stabilization treatment liquid is uniformly sprayed on the surface of the sample at a spraying amount of 0.39 μL / mm 2 . After the surface is dried for 15 min, water is uniformly sprayed on the surface of the weathering steel, and after the surface is dried, the stabilization treatment liquid is uniformly sprayed on the surface of the weathering steel again after 75 min. After the surface is dried, water is uniformly sprayed on the surface of the weathering steel again after 15 min. After the treatment, the weathering steel is directly placed in the atmosphere for exposure, and after the rust layer is stabilized (127 days), a rust removal liquid is used to remove the rust layer on the surface of the weathering steel. After drying for 24 h, the corrosion weight loss rate is calculated, and the corrosion weight loss rate relative to bare steel (not subjected to rust layer stabilization treatment) is 90%. The formula of the rust removal liquid is: 500 ml of hydrochloric acid + 500 ml of deionized water + 3.5 g of methenamine.

[0075] Comparative Example 2

[0076] A rust layer stabilization treatment liquid for the surface of weathering steel, comprising the following mass percentage components:

[0077] 0.7% Cu(NO3)2, 0.8% FeCl3, 0.2% NaHSO3, 0.09% Na2MoO4, 1.0% Fe3O4, the balance being deionized water, wherein (5 x NaHSO3 + FeCl3) / Na2MoO4 = 20.

[0078] A weathering steel surface rust layer stabilization treatment method is obtained by using the above-described Comparative Example 1 treatment solution, and the specific treatment method is as follows:

[0079] 1) The treatment solution is prepared according to the above-mentioned chemical components and mass fraction, and mixed uniformly.

[0080] 2) A weathering steel sample of 40 mm x 60 mm x 4 mm is processed, and the weathering steel includes the following mass percentage components: C: 0.10%, Si: 0.39%, Mn: 0.69%, P: 0.11%, S: 0.003%, Cr: 0.51%, Ni: 0.09%, Cu: 0.28%, Alt: 0.025%, and the balance is Fe and inevitable impurity elements; the scale on the surface of the sample is removed by pickling;

[0081] 3) The prepared stabilization treatment solution is uniformly sprayed on the surface of the sample, and the spraying amount is 0.15 μL / mm 2 After the treatment, the weathering steel is directly placed in the atmosphere for sun exposure, and after the rust layer is stabilized (103 days), a rust removal solution is used to remove the rust layer on the surface of the weathering steel, and after drying for 24 h, the corrosion weight loss rate is calculated, which is 82% relative to the corrosion weight loss rate of bare steel (without rust layer stabilization treatment). The formula of the rust removal solution is: 500 ml hydrochloric acid + 500 ml deionized water + 3.5 g methenamine.

[0082] Comparative Example 3

[0083] A weathering steel surface rust layer stabilization treatment solution includes the following mass percentage components: 0.6% Cu(NO3)2, 0.5% FeCl3, 0.12% NaHSO3, 0.14% Na2MoO4, 0.7% Fe3O4, and the balance is deionized water, wherein (5 x NaHSO3 + FeCl3) / Na2MoO4 = 7.9.

[0084] A weathering steel surface rust layer stabilization treatment method is obtained by using the above-described Comparative Example 3 treatment solution, and the specific treatment method is as follows:

[0085] 1) The treatment solution is prepared according to the above-mentioned chemical components and mass fraction, and mixed uniformly.

[0086] 2) Weathering steel samples of 40mm x 60mm x 4mm were processed, which included the following mass percentage components: C: 0.08%, Si: 0.31%, Mn: 0.69%, P: 0.07%, S: 0.001%, Cr: 0.75%, Ni: 0.16%, Cu: 0.23%, Alt: 0.038%, and the rest was Fe and inevitable impurity elements; the surface scale of the sample was removed by pickling;

[0087] 3) The prepared stabilizing treatment solution was uniformly sprayed on the surface of the sample, with a spraying amount of 0.33 μL / mm 2 After the surface was dried for 12 min, water was uniformly sprayed on the surface of the weathering steel, and after the surface was dried, the stabilizing treatment solution was uniformly sprayed on the surface of the weathering steel again, and after the surface was dried for 12 min, water was uniformly sprayed on the surface of the weathering steel, and dried for 65 min. After the treatment was completed, the weathering steel was placed in the atmosphere for exposure, and after the rust layer was stabilized (86 days), a rust removal solution was used to remove the rust layer on the surface of the weathering steel, and after drying for 24 h, the corrosion weight loss rate was calculated, which was 78% relative to the corrosion weight loss rate of bare steel (without rust layer stabilization treatment). The formula of the rust removal solution used was: 500 ml of hydrochloric acid + 500 ml of deionized water + 3.5 g of hexamethylenetetramine. The samples treated by the stabilization treatment (example) and the untreated samples (bare steel) were placed outdoors for atmospheric exposure. After different periods of exposure, the macroscopic morphology of the surface of the sample of Example 3 is shown in Figure 1 After the weathering steel was treated by the stabilization treatment, a uniform and dense rust layer was quickly formed on the surface, and the rust layer covered the entire matrix, thereby protecting the matrix, and no rust solution dripping phenomenon occurred; the untreated sample preferentially underwent local pitting, and then slowly expanded until covering the entire matrix.

[0088] The above underlined data do not meet the requirements of the present application.

[0089] After different periods of atmospheric exposure, the corrosion rate of the sample of Example 3 relative to the sample without rust layer stabilization treatment (bare steel) as a function of the exposure period is shown in Figure 2 At the initial stage of the rust layer stabilization treatment, the corrosion rate of the weathering steel increased significantly, and a dense protective rust layer was quickly formed. With the increase of the exposure period, the corrosion rate of the sample treated by the rust layer stabilization treatment gradually decreased, and after about 60 days of exposure, it reached a stable value, and the corrosion rate was ≤75% relative to the untreated sample.

Claims

1. A treatment solution for stabilizing rust layer on the surface of weathering steel, characterized in that: The treatment solution includes the following components in percentage by weight: Cu(NO3)2: 0.5-1.0%, FeCl3: 0.5-1.0%, NaHSO3: 0.1-0.5%, Na2MoO4: 0.05-0.15%, Fe3O4: 0.5-2.0%, and the rest is deionized water; The composition of the weathering steel surface rust layer stabilization treatment solution includes NaHSO3, FeCl3, and Na2MoO4 in a mass percentage that satisfies the following conditions: (5×NaHSO3+FeCl3) / Na2MoO4=20-25; After being treated with the rust layer stabilization treatment liquid on the surface of the weathering steel, the rust layer on the surface of the weathering steel becomes stable after being exposed to the atmosphere for 58-63 days.

2. A method for stabilizing the rust layer on the surface of weathering steel, characterized by The treatment liquid treatment according to claim 1 specifically comprises the following steps: 1) Remove the iron oxide scale on the surface of weathering steel; 2) Spray the treatment liquid evenly on the surface of the weathering steel. After it dries, spray water evenly on the surface of the weathering steel and dry it.

3. The processing method according to claim 2, characterized in that Step 1) Use pickling or shot blasting to remove the iron oxide scale on the surface of the weathering steel.

4. The processing method according to claim 2, characterized in that In step 2), the treatment liquid spraying amount is 0.30-0.50 μL / mm 2 .

5. The processing method according to claim 2 or 4, characterized in that: In step 2), the waiting to be dried refers to spraying water on the surface of the weathering steel after drying for 10 to 30 minutes.

6. The processing method according to claim 2, characterized in that In step 2), the drying refers to drying for 60-120 minutes.

7. The processing method according to any one of claims 2 to 6, characterized in that: Repeat step 2) and circulate the spraying liquid and water 2-5 times.

8. The processing method according to any one of claims 2 to 7, characterized in that The weathering steel comprises the following components by mass percentage: C: 0.04% to 0.12%, Si: 0.20% to 0.50%, Mn: ≤1.50%, P: 0.06%~0.15%, S:≤0.005%, Cr:0.30%~1.00%, Ni:≤0.30%, Cu:0.20%~0.40%, Alt:0.020%~0.040%, and the rest are Fe and unavoidable impurity elements.

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