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Method for detecting corrosion activity of inclusions in low alloy steel

A detection method and technology for low-alloy steel, applied in measuring devices, instruments, scientific instruments, etc., can solve the problems of inability to analyze the composition of inclusions, deteriorate the corrosion resistance of steel, etc., and achieve the effect of reliable data and simple operation.

Pending Publication Date: 2021-06-25
WUHAN UNIV OF SCI & TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The sample was treated with corrosive solution. After the pitting corrosion occurred, the inclusions that caused the pitting corrosion had fallen off or dissolved, and the composition of the inclusions could not be analyzed. Therefore, it was impossible to identify which composition of the inclusions deteriorated the durability of the steel. Corrosion performance, can not provide a reference for optimizing the composition system of inclusions in steel

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  • Method for detecting corrosion activity of inclusions in low alloy steel
  • Method for detecting corrosion activity of inclusions in low alloy steel
  • Method for detecting corrosion activity of inclusions in low alloy steel

Examples

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Embodiment 1

[0069] A method for detecting the corrosion activity of inclusions in low alloy steels. The steps of detection method described in the present embodiment are:

[0070] Step 1. Cut a sample of 10mm×10mm×10mm on the EH36 steel plate as the original sample to be tested;

[0071] Step 2: Polish the original sample to be tested with silicon carbide sandpaper, and then mechanically polish it until the surface roughness is less than 0.8 μm to obtain a polished sample to be tested; then use acetone, deionized water and alcohol to polish the sample to be tested in sequence. The test sample is cleaned and dried to obtain a prefabricated sample to be tested;

[0072] Step 3. Place the prefabricated sample to be tested in a fully automatic inclusion analyzer, and measure the number of inclusions in the prefabricated sample to be tested to be 475 and the density ρ to be 13mm -2 ; The inclusion density is the ratio of the number of inclusions in the statistical area to the area of ​​the s...

Embodiment 2

[0097] A method for detecting the corrosion activity of inclusions in low alloy steels. The steps of detection method described in the present embodiment are:

[0098] Step 1. Cut a sample of 10mm×10mm×10mm on the aluminum deoxidized X70 pipeline steel as the original sample to be tested;

[0099] Step 2: Polish the original sample to be tested with silicon carbide sandpaper, and then mechanically polish it until the surface roughness is less than 0.8 μm to obtain a polished sample to be tested; then use acetone, deionized water and alcohol to polish the sample to be tested in sequence. The test sample is cleaned and dried to obtain a prefabricated sample to be tested;

[0100] Step 3, place the prefabricated sample to be tested in the automatic inclusion analyzer, and measure the number of inclusions in the prefabricated sample to be tested to be 564, and the density ρ is 19mm -2 ; The inclusion density is the ratio of the number of inclusions in the statistical area to the...

Embodiment 3

[0122] A method for detecting the corrosion activity of inclusions in low alloy steels. The steps of detection method described in the present embodiment are:

[0123] Step 1. Cut a sample of 10mm×10mm×10mm on the Ti microalloyed X70 pipeline steel as the original sample to be tested;

[0124] Step 2: Polish the original sample to be tested with silicon carbide sandpaper, and then mechanically polish it until the surface roughness is less than 0.8 μm to obtain a polished sample to be tested; then use acetone, deionized water and alcohol to polish the sample to be tested in sequence. The test sample is cleaned and dried to obtain a prefabricated sample to be tested;

[0125] Step 3. Place the prefabricated sample to be tested in the automatic inclusion analyzer, and measure the number of inclusions in the prefabricated sample to be tested to be 3778, and the density ρ is 100mm -2 ; The inclusion density is the ratio of the number of inclusions in the statistical area to the a...

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Abstract

The invention relates to a method for detecting corrosion activity of inclusions in low alloy steel. According to the technical scheme, the method comprises the following steps of grinding, polishing, cleaning and blow-drying a low-alloy steel sample, sequentially putting the sample into a full-automatic inclusion analyzer and a field emission scanning electron microscope, measuring the type number of inclusions in the sample to be measured, selecting one inclusion from each type of inclusions, and sequentially recording the radius of the inclusion, then obtaining the residual stress sigmaRi at the interface of the ith type of inclusion and the steel substrate by utilizing the measurement result and combining with the physical property parameters of different types of inclusions, if the residual stress sigmaRi is greater than the compression yield strength sigmas of the low alloy steel, determining that the ith type of inclusions are corrosive active inclusions, otherwise, determining that the ith type of inclusions are non-corrosive active inclusions, and acquiring the corrosive activity of various selected inclusions in sequence. The method is simple to operate and reliable in data, and the capacity of inducing pitting corrosion by the inclusion in the low alloy steel can be accurately evaluated without corrosion treatment.

Description

technical field [0001] The invention belongs to the field of evaluation of corrosion-active inclusions, and in particular relates to a method for detecting the corrosion activity of inclusions in low-alloy steel. Background technique [0002] During the smelting and continuous casting of molten steel, various alloying elements in the steel react with non-metallic elements such as H, N, O, S, P to form inclusions, such as Al 2 o 3 , nCaO·mAl 2 o 3 , TiN, MnS and MgO·Al 2 o 3 wait. During the service of steel, MnS is prone to dissolution-induced pitting corrosion and hydrogen-induced cracks, which lead to the failure of steel structures. And Al 2 o 3 and MgO·Al 2 o 3 Such hard massive inclusions will not only reduce the corrosion resistance of steel, but also cause surface defects and cracks during processing. rich in Cl - In the ionic seawater and marine atmospheric environment, steel is extremely prone to corrosion, and pitting corrosion is one of the most common...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N23/2273G01N23/2202
CPCG01N23/2273G01N23/2202
Inventor 吴开明王宇航
Owner WUHAN UNIV OF SCI & TECH
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