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Corrosive agent and corrosion method for displaying original austenite grain boundary of martensitic stainless steel

A martensitic stainless steel and austenite grain boundary technology, applied in the field of metallographic structure observation, can solve the problems of picric acid poisoning, corrosive agent failure, high service temperature, etc., and achieve simple use steps, easy preparation, and increased sensitivity Effect

Pending Publication Date: 2021-10-26
XIAN THERMAL POWER RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The formula does not contain concentrated strong acid and corrosive acid. The formula is simple, but the use temperature is relatively high. It needs to be heated and kept warm in a water bath of 70-85°C, which may easily cause the volatilization of picric acid and the failure of the corrosive agent. Adverse reactions such as picric acidosis

Method used

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  • Corrosive agent and corrosion method for displaying original austenite grain boundary of martensitic stainless steel
  • Corrosive agent and corrosion method for displaying original austenite grain boundary of martensitic stainless steel
  • Corrosive agent and corrosion method for displaying original austenite grain boundary of martensitic stainless steel

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Embodiment 1

[0047] The present invention provides an etchant for displaying the grain boundaries of prior austenite in martensitic stainless steel, which consists of the following components according to the weight ratio: 100ml of saturated alcohol solution of picric acid, 2g of sodium dodecylbenzenesulfonate, HCl solution 3 drops (about 0.15ml), and finally add a small piece of steel about 0.2g; the sample to be corroded is 9Cr0.5Mo1.8WVNb steel (P92 steel) aged at 600°C for 100h.

[0048] Preparation and cleaning steps:

[0049] (1) First, put 9g of picric acid into a flask, add 100ml of absolute ethanol, heat slowly over low heat and stir gently until the crystals are completely dissolved, prepare a saturated picric acid alcohol solution, let it stand for 1 day, and wait for crystals to precipitate Take the supernatant and let it stand for later use.

[0050] (2) Take 100ml of the supernatant of the above-mentioned saturated picric acid alcohol solution after fully standing, add 2g of...

Embodiment 2

[0059] The present invention provides a corrosion agent for displaying the grain boundaries of prior austenite in martensitic stainless steel, which consists of the following components according to the weight ratio: 100ml of saturated alcohol solution of picric acid, 2g of sodium tridecylbenzenesulfonate, HCl solution 5 drops (about 0.25ml), and finally add a small piece of steel about 1g; the sample to be corroded is 9Cr0.5Mo1.8WVNb steel (P92 steel) aged at 600°C for 1000h.

[0060] Preparation and cleaning steps:

[0061] (1) First, put 9g of picric acid into a flask, add 100ml of absolute ethanol, heat slowly over low heat and stir gently until the crystals are completely dissolved, prepare a saturated picric acid alcohol solution, let it stand for 1 day, and wait for crystals to precipitate Take the supernatant and let it stand for later use.

[0062] (2) Take 100ml of the supernatant of the above-mentioned saturated picric acid alcohol solution after fully standing, ad...

Embodiment 3

[0071] The present invention provides a corrosion agent for displaying the grain boundaries of prior austenite in martensitic stainless steel, which consists of the following components according to the weight ratio: 100ml of saturated alcohol solution of picric acid, 10g of sodium dodecylbenzenesulfonate, and HCl solution 8 drops (about 0.4ml), and finally add a small piece of steel about 2g; the sample to be corroded is 11Cr0.3Mo1.5W1.5CoSiVNb steel (VM12 steel) aged at 600°C for 100 hours.

[0072] Preparation and cleaning steps:

[0073] (1) First, put 9g of picric acid into a flask, add 100ml of absolute ethanol, heat slowly over low heat and stir gently until the crystals are completely dissolved, prepare a saturated picric acid alcohol solution, let it stand for 1 day, and wait for crystals to precipitate Take the supernatant and let it stand for later use.

[0074] (2) Take 100ml of the supernatant of the above-mentioned saturated picric acid alcohol solution after fu...

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Abstract

The invention provides a corrosive agent and a corrosion method for displaying the original austenite grain boundary of martensitic stainless steel. The corrosive agent comprises a saturated picric acid alcoholic solution, and every 100 ml of the saturated picric acid alcoholic solution contains 2-10 g of an anionic surfactant with a corrosion inhibition effect, not less than 3 drops of a hydrochloric acid solution and 0.2-2 g of a steel sheet. A sample is put into the corrosive agent, and metallographic corrosion is carried out under the room temperature condition. The corrosive agent is simple in formula component, low in strong acid content, low in corrosivity, free of heat treatment or heating etching, short in corrosion time, clear in crystal boundary display, excellent in applicability and especially suitable for high-chromium martensitic stainless steel with the Cr content ranging from 9% to 12%.

Description

technical field [0001] The invention belongs to the field of metallographic structure observation of metal materials, and in particular relates to an etchant for displaying the grain boundary of prior austenite in martensitic stainless steel and its preparation and corrosion method, especially suitable for high chromium with a chromium content of 9-12%. Display and observation of prior-austenite grain boundaries in martensitic stainless steel. Background technique [0002] Low-carbon high-alloy martensitic stainless steel is widely used in high-parameter thermal power units, fourth-generation nuclear power, and aerospace due to its excellent comprehensive performance. An important material for large castings and forgings. [0003] Martensitic stainless steel obtains martensite structure after quenching treatment, but its original austenite grain boundaries still remain. Observation and rating of astenite grain size is extremely important for evaluating the performance of s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F1/28G01N1/32
CPCC23F1/28G01N1/32
Inventor 李季侯淑芳唐丽英周荣灿宁娜李江王博涵
Owner XIAN THERMAL POWER RES INST CO LTD
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