Corrosion method for quickly, simply, conveniently and clearly displaying original austenite grain boundary of pipeline steel

A technology for clearly displaying the austenite grain boundary, which is applied in the field of simple and clear display of the corrosion of the original austenite grain boundary of pipeline steel, and can solve the problems of cumbersome operation, unsafe manual operation, and yellow skin, etc., to achieve The effect of simple operation, eliminating unsafe hidden dangers, and fast corrosion rate

Inactive Publication Date: 2020-04-24
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The corrosion solution of the invention is composed of picric acid, dilute hydrochloric acid, detergent and deionized water. During corrosion, the sample needs to be placed in the solution at a constant temperature for 60 to 600 seconds, and the surface of the sample needs to be manually wiped with cotton. This corrosion method The operation is cumbersome, time-consuming, and manual operation is unsafe (picic acid is poisonous, excessive ingestion can cause skin damage, yellowing of the skin, contact dermatitis, conjunctivitis and bronchitis)

Method used

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  • Corrosion method for quickly, simply, conveniently and clearly displaying original austenite grain boundary of pipeline steel
  • Corrosion method for quickly, simply, conveniently and clearly displaying original austenite grain boundary of pipeline steel
  • Corrosion method for quickly, simply, conveniently and clearly displaying original austenite grain boundary of pipeline steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] In this example, the chemical composition of pipeline steel is: C: 0.055%, Si: 0.23%, Mn: 1.58%, P: 0.011%, S: 0.001%, Cu: 0.009%, Ni: 0.36%, Cr: 0.20 %, Nb: 0.038%, Mo: 0.005%, V: 0.006%, Ti: 0.016%, Al: 0.015%, and the balance is Fe.

[0035] In this embodiment, the pipeline steel is smelted in a 25kg vacuum induction furnace and forged into a 80mm×70mm×70mm square billet.

[0036] (1) Metallographic sample preparation:

[0037] A sample with a size of 10m×12m×16mm was cut by wire cutting on the billet, and quenched after being kept at 1000°C, 1100°C and 1200°C for 36 minutes, and then the test surface of the sample to be tested was ground and polished, and then After cleaning with deionized water and alcohol in turn, dry it for later use;

[0038] (2) Corrosion solution preparation:

[0039] Weigh 3g of picric acid and pour it into a beaker filled with 50ml of distilled water, place the beaker in an ultrasonic cleaner set at 70°C and vibrate for 5 minutes to obtai...

Embodiment 2

[0044]In this example, the chemical composition of pipeline steel is: C: 0.055%, Si: 0.23%, Mn: 1.58%, P: 0.011%, S: 0.001%, Cu: 0.009%, Ni: 0.36%, Cr: 0.20 %, Nb: 0.038%, Mo: 0.005%, V: 0.006%, Ti: 0.016%, Al: 0.012%, and the balance is Fe.

[0045] In this embodiment, the pipeline steel is smelted in a 25kg vacuum induction furnace and forged into a 80mm×70mm×70mm square billet.

[0046] (1) Metallographic sample preparation:

[0047] Cut a sample with a size of 10m×12m×16mm on the billet by wire cutting, heat it at 1150°C for 36min, 72min, and 108min, then quench it, then grind the testing surface of the sample to be tested and polish it, and then use After cleaning with deionized water and alcohol, dry it for later use;

[0048] (2) Corrosion solution preparation:

[0049] Weigh 3g of picric acid and pour it into a beaker filled with 50ml of distilled water, place the beaker in an ultrasonic cleaner set at 70°C and vibrate for 5 minutes to obtain a supersaturated picric...

Embodiment 3

[0054] In this example, the chemical composition of pipeline steel is: C: 0.043%, Si: 0.19%, Mn: 1.66%, P: 0.009%, S: 0.001%, Cu: 0.15%, Ni: 0.17%, Cr: 0.23 %, Nb: 0.057%, Mo: 0.13%, V: 0.006%, Ti: 0.014%, Al: 0.023%, and the balance is Fe.

[0055] In this embodiment, the pipeline steel is smelted in a 25kg vacuum induction furnace and forged into a 80mm×70mm×70mm square billet.

[0056] (1) Metallographic sample preparation:

[0057] Cut a sample with a size of 10m×12m×16mm on the billet by wire cutting, heat it at 1150°C for 36min, 72min, and 108min, then quench it, then grind the testing surface of the sample to be tested and polish it, and then use After cleaning with deionized water and alcohol, dry it for later use;

[0058] (2) Corrosion solution preparation:

[0059] Weigh 3g of picric acid and pour it into a beaker filled with 50ml of distilled water, place the beaker in an ultrasonic cleaner set at 70°C and vibrate for 5 minutes to obtain a supersaturated picric ...

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Abstract

The invention belongs to the technical field of metallographic detection, and particularly relates to a corrosion method for rapidly, simply, conveniently and clearly displaying the original austenitegrain boundary of pipeline steel. The corrosion method comprises the following steps: (1) carrying out conventional austenitizing heat treatment to obtain a quenched pipeline steel corrosion sample;(2) putting the polished surface of the sample upwards into an ultrasonic cleaner which is heated to 65-80 DEG C and contains a containing corrosive solution, and carrying out vibration etching for 2-5 minutes; and (3) taking out the sample, carrying out cleaning, blow-drying the polished surface of the sample treated in the step (2), and observing the sample under an optical microscope. The corrosion method provided by the invention can quickly, simply, conveniently, clearly and completely display the original austenite grain boundary of the quenched pipeline steel, and has the characteristics of simple and safe operation and high corrosion efficiency.

Description

technical field [0001] The invention belongs to the technical field of metallographic detection, and in particular relates to a fast, simple and clear corrosion method for displaying the original austenite grain boundary of pipeline steel. Background technique [0002] The size and uniformity of prior austenite grains in pipeline steel will have a great impact on the microstructure after phase transformation, thus directly affecting the final mechanical properties of the material. With the help of the display of austenite grains, the microstructure change of pipeline steel during controlled rolling and controlled cooling can be studied, which is one of the important factors to control the parameters of hot working process and ensure the performance of products. [0003] The difficulty of displaying the original austenite grains of pipeline steel depends on many factors such as the chemical composition of the steel, the state of heat treatment, the method of etching, etc., an...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N1/32
CPCG01N1/32
Inventor 史显波荀雨严伟杨振国单以银
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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