Metallographic-phase corrosive liquid and corrosion method for austenite resisto

A nickel-iron-chromium alloy and austenitic technology, which is applied in the field of metallographic corrosion of nickel-based alloys, can solve the problems of grain rating interference, over-corrosion, and long corrosion time, and achieve improved metallographic analysis, complete grains, and clear border effect

Inactive Publication Date: 2016-11-16
ZHANGJIAGANG QINGYAN DETECTION TECH CO LTD
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  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The corrosive agent of existing austenitic nickel-iron-chromium alloy usually selects nitric acid and water or nitric acid, hydrochloric acid and water to prepare according to a certain ratio, these two types of corrosive agents have certain effect, but there are following deficiencies: the one, there is abnormality easily in grain Corrosion pits or plaques; second, the corrosion time is long, the corrosion time is not easy to control, and it is easy to form over-corrosion; third, the boundary line and contrast of different phases are not clear enough, which will interfere with the grain rating

Method used

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  • Metallographic-phase corrosive liquid and corrosion method for austenite resisto

Examples

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Effect test

Embodiment 1

[0027] First add 70ml of distilled water into the beaker, then add 10ml of nitric acid solution and 10ml of hydrogen fluoride solution with a disposable plastic dropper, and stir to obtain a metallographic corrosion solution. The mass percent concentration of hydrogen fluoride in the solution is 47%, and the mass percent concentration of nitric acid in the nitric acid solution is 65%.

[0028] Then take the No8825 nickel-iron-chromium alloy φ25mm×2mm pipe, use a saw to make a metallographic sample (austenitic nickel-iron-chromium alloy) of φ25mm×2mm×18mm, and use different water abrasive papers to grind from 400 mesh to 1500 mesh For polishing, rinse the sample with tap water before changing the sand paper; then use a silk polishing cloth to first use W1.5 diamond grinding paste for grinding and polishing for 3 minutes, and then choose W0.5 diamond grinding paste for grinding and polishing for 5 minutes. Observe that the surface of the sample is very smooth without any scratch...

Embodiment 2

[0031] First add 70ml of distilled water to the beaker, then add 10ml of nitric acid solution and 10ml of hydrogen fluoride solution with a disposable plastic dropper, and stir to obtain a metallographic corrosion solution. The mass percent concentration of hydrogen fluoride in the solution is 45%, and the mass percent concentration of nitric acid in the nitric acid solution is 68%.

[0032] Corrode with the prepared corrosive solution, take out the absorbent cotton in the corrosive solution with tweezers, and wipe the surface of the No8825 nickel-iron-chromium alloy sample after grinding and polishing in Example 1 for 12 seconds, rinse the surface with clean water, and then clean the surface with distilled water And blow dry, observe with metallographic microscope, get as follows figure 2 As shown in the optical microstructure, the figure 2 It is the optical microstructure under the 200X metallographic microscope, the original size of the picture is 11.37cm×14.65cm, from ...

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Abstract

The invention discloses metallographic-phase corrosive liquid for austenite resisto. The metallographic-phase corrosive liquid is prepared from ingredients of hydrogen fluoride solution, saltpeter solution and distilled water, and the volume ratio of the hydrogen fluoride to the saltpeter solution to the distilled water is 1:1:7. The metallographic-phase corrosive liquid can quickly and efficiently corrode a metallographic-phase tissue of a test sample (austenite resisto), the obtained corroded test sample is clear in crystal boundary and complete in crystal particle, and no abnormal corrosion pit or plaque is found in the single crystal particle; meanwhile, the metallographic-phase corrosive liquid is low in cost and easy to operate and has an important improvement effect on metallographic analysis of the austenite resisto.

Description

technical field [0001] The invention belongs to the technical field of metallographic corrosion of nickel-based alloys, and in particular relates to a metallographic corrosion solution and a corrosion method of an austenitic nickel-iron-chromium alloy. Background technique [0002] Austenitic nickel-iron-chromium alloy has excellent stress corrosion cracking resistance, pitting corrosion resistance and crevice corrosion resistance, excellent high temperature resistance, strong acid and strong alkali resistance, and is widely used in pressure vessels, oil pipelines and other fields. [0003] In the production process of austenitic nickel-iron-chromium alloy, it is necessary to analyze its structure and properties irregularly to determine whether the production process meets the conditions, and to adjust the production process in time according to the analysis results. The metallographic analysis of austenitic nickel-iron-chromium alloy plays a very important role in its rolli...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N17/00
CPCG01N17/006
Inventor 郑郧梁建国张金玲
Owner ZHANGJIAGANG QINGYAN DETECTION TECH CO LTD
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