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Solution and method for detecting ferrite pollution on surface of austenitic stainless steel

A technology of austenitic stainless steel and ferrite, which is applied in the direction of material analysis by observing the influence of chemical indicators, and analysis by making materials undergo chemical reactions, which can solve the problems of short storage period, human and environmental hazards, and toxicity Environmental and other issues, to achieve the effect of long storage period, small damage and wide application range

Inactive Publication Date: 2010-09-08
DALIAN UNIV OF TECH
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Problems solved by technology

Among them, the potassium ferricyanide-nitric acid test method and the copper sulfate method have the characteristics of high sensitivity and easy operation, which can meet the strict requirements of the nuclear industry, aviation, chemical industry and other industries, and have become the test methods that are mainly concerned at present. However, From the perspective of test efficiency and environmental friendliness, the above two methods have serious deficiencies
[0004] The reaction product of the copper sulfate method is tiny copper particles. When the product is small, it is difficult to directly distinguish it with the naked eye on a rough surface; at the same time, the surface of the sample is required to be kept in a wet state for 6 minutes during the test, and the test effect is easily affected by the parts. Size limitation; the copper sulfate method is only suitable for detecting free iron on the surface of austenitic stainless steel. However, during the cutting process, the tiny iron particles embedded on the stainless steel surface are prone to oxidation in a humid environment, and the formed iron oxide will be significantly reduced. Test sensitivity
[0005] Potassium ferricyanide-nitrate test is referred to as the blue dot method. At present, this method is widely used because of its high detection sensitivity, but there are problems such as potential toxicity and environmental pollution.
Although potassium ferricyanide solution itself is non-toxic, it is easy to volatilize highly toxic hydrogen cyanide gas under heating or light conditions, which is a serious hazard to the surrounding people and the environment. Therefore, the blue dot test has potential toxicity. At the same time, the requirements for the technical level of the inspectors are quite high.
The important thing is that the discharge of waste liquid without treatment will pollute the environment, and the current testing standards and literature do not propose a treatment method for the waste liquid of the blue dot test
The blue dot test solution also has a short storage period and needs to be prepared and used immediately, which is inconvenient to use
Therefore, the blue dot method is not suitable for popularization and promotion in enterprises

Method used

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  • Solution and method for detecting ferrite pollution on surface of austenitic stainless steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The test solution solute composition and mass percentage % used in the inventive method are:

[0029] Raw material mass percentage

[0030] ① Citric acid (C 6 h 8 o 7 ·H 2 O) 29.7%

[0031] ② Sodium citrate (C 6 h 5 o 7 Na 3 2H 2 O) 59.9%

[0032] ③O-phenanthroline (C 12 h 8 N 2 ·H 2 O) 1.7%

[0033] ④Hydroxylamine hydrochloride (HONH 3 Cl) 8.7%

[0034] The method for detecting ferrite contamination on the surface of austenitic stainless steel using the test solution in the above-mentioned embodiment 1 may further comprise the steps:

[0035] (1) First rinse the surface of austenitic stainless steel with clean water, and use trisodium phosphate (Na 3 PO 4 12H 2 O) Degreasing the surface of the sample, if necessary, add an appropriate amount of surfactant (4g / LOP-10 emulsifier), then wash it with hot water, and finally wash the surface with water and dry it.

[0036] (2) get citric acid (C 6 h 8 o 7 ·H 2 O) Dissolve in 20ml of clean water, add s...

Embodiment 2

[0044] The test solution solute composition and mass percentage % used in the inventive method are:

[0045] Raw material mass percentage

[0046] ① Citric acid (C 6 h 8 o 7 ·H 2 O) 43.2%

[0047] ② Sodium citrate (C 6 h 5 o 7 Na 3 2H 2 O) 45.6%

[0048] ③O-phenanthroline (C 12 h 8 N 2 ·H 2 O) 7.6%

[0049] ④Hydroxylamine hydrochloride (HONH 3 Cl) 3.6%

[0050] The method for detecting ferrite contamination on the surface of austenitic stainless steel using the test solution in the above-mentioned embodiment 2 is the same as that in embodiment 1.

[0051] The results show that there is no orange-red complex on the surface of 1# sample, a small amount of orange-red spots appear on the surface of 2# sample, the surface of 3# sample is covered with a layer of obvious orange-red precipitation, and the surface of 4# sample has obvious orange-red spots. Red complex. The experimental results show that the above method can detect free iron and rust pollution on the ...

Embodiment 3

[0053] The test solution solute composition and mass percentage % used in the inventive method are:

[0054] Raw material mass percentage

[0055] ① Citric acid (C 6 h 8 o 7 ·H 2 O) 78.9%

[0056] ② Sodium citrate (C 6 h 5 o 7 Na 3 2H 2 O) 8.5%

[0057] ③O-phenanthroline (C 12 h 8 N 2 ·H 2 O) 6.3%

[0058] ④Hydroxylamine hydrochloride (HONH 3 Cl) 6.3%

[0059] The method for detecting ferrite contamination on the surface of austenitic stainless steel using the test solution in the above-mentioned embodiment 3 is the same as that in embodiment 1.

[0060] The results show that there is no orange-red complex on the surface of 1# sample, a small amount of orange-red spots appear on the surface of 2# sample, the surface of 3# sample is covered with a layer of obvious orange-red precipitation, and the surface of 4# sample has obvious orange-red spots. Red complex. The experimental results show that the above method can detect free iron and rust pollution on the s...

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Abstract

The invention relates to solution and a method for detecting ferrite pollution on the surface of austenitic stainless steel. The invention is characterized in that the testing solution comprises the following solutes by weight percent: 28.7-82.3 percent of citric acid, 8.2-62.1 percent of sodium citrate, 5.2-10.4 percent of reducing agent and 1.7-6.3 percent of phenanthroline; and the detection method comprises the following steps that: (1) citric acid and sodium citrate are dissolved in clean water to obtain solution I, reducing agent is dissolved in clean water to obtain solution II and phenanthroline (C12H8N2.H2O) is taken and dissolved in clean water to obtain solution III; the obtained solution is mixed and is evenly agitated; and (2) filter paper is attached on the surface of a sample after the filter paper is dipped in the solution, the surface is kept to be wet and whether orange red sediments occur on the surface of the filter paper and the surface of the sample is observed to determine whether ferrite pollution exists. The invention has the advantages of no toxicity and taste, high sensitivity, high rapidness, high accuracy and convenient operation.

Description

technical field [0001] The invention belongs to the technical field of material surface detection, and relates to a solution and a method for detecting ferrite pollution on the surface of austenitic stainless steel. Background technique [0002] Austenitic stainless steel has good corrosion resistance, high temperature oxidation resistance, good low temperature mechanical properties, excellent machining performance and exquisite appearance. In recent years, it has been widely used in atomic energy, aviation, chemical industry, food, marine, etc. industry. [0003] Ferrite pollution on the surface of stainless steel is a very common phenomenon. Ferrite pollution destroys the integrity of the surface passivation film. Yellow rust spots or rust spots will appear on the surface of stainless steel materials with pollution, which not only destroys the appearance of the material properties, and adversely affect the corrosion resistance and other properties of the material. During...

Claims

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Application Information

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IPC IPC(8): G01N21/75G01N21/78
Inventor 赵杰宋冠宇雷明凯
Owner DALIAN UNIV OF TECH
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