Metallographic corrosion method for martensitic precipitation hardening stainless steel crystal boundary

A technology of precipitation hardening and metallographic corrosion, which is applied in the field of metallographic inspection of metal materials, can solve the problem that there is no suitable corrosion method for the grain boundary of martensitic precipitation hardening stainless steel, and achieve the effect of good grain boundary display and short corrosion time

Inactive Publication Date: 2012-05-09
725TH RES INST OF CHINA SHIPBUILDING INDAL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a metallographic corrosion method for the grain boundary of martensitic precipitation hardening stainless steel, to solve the problem that there is no suitable corrosion method for the grain boundary of 05Cr17Ni4Cu4Nb martensitic precipitation hardening stainless steel, and to provide a fast, simple and effective method The grain boundary corrosion method can clearly and completely display the grain boundary

Method used

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  • Metallographic corrosion method for martensitic precipitation hardening stainless steel crystal boundary
  • Metallographic corrosion method for martensitic precipitation hardening stainless steel crystal boundary
  • Metallographic corrosion method for martensitic precipitation hardening stainless steel crystal boundary

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Effect test

Embodiment 1

[0021] 1) Add 2m concentrated hydrochloric acid with a mass concentration of 36.5% to 30ml of concentrated nitric acid with a mass concentration of 69%, stir evenly and let it stand for 10 minutes before use.

[0022] 2) Wipe the polished surface with absorbent cotton dipped in the prepared etchant for 20 seconds, and the surface of the sample is observed to be gray in color.

[0023] 3) Rinse the sample with running water, rinse the sample with absolute ethanol, dry it with a hair dryer and observe it.

[0024] 4) Take pictures of the grain size. If you take a good picture, you can properly adjust the brightness and contrast of the picture. The purpose is to make the grain boundary darker, the contrast stronger, and the structure tend to be white and bright, so as to highlight the grain boundary morphology. The photo of its grain size is shown in image 3 .

[0025] visible, image 3 The medium grain boundary is clear and complete, and the color and shape of the structure ...

Embodiment 2

[0027] 1) Add 3ml of concentrated hydrochloric acid with a mass concentration of 36.5% to 30ml of concentrated nitric acid with a mass concentration of 69%, stir evenly and let it stand for 10 minutes before use.

[0028] 2) Wipe the polished surface with absorbent cotton dipped in the prepared etchant for 15 seconds, and the surface of the sample is observed to be gray in color.

[0029] 3) Rinse the sample with running water, rinse the sample with absolute ethanol, dry it with a hair dryer and observe it.

[0030] 4) Take pictures of the grain size. If you take a good picture, you can properly adjust the brightness and contrast of the picture. The purpose is to make the grain boundary darker, the contrast stronger, and the structure tend to be white and bright, so as to highlight the grain boundary morphology. The photo of its grain size is shown in Figure 4 .

[0031] visible, Figure 4 The medium grain boundary is clear and complete, and the color and shape of the stru...

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Abstract

The invention discloses a metallographic corrosion method for a martensitic precipitation hardening stainless steel crystal boundary, wherein the stainless steel is 05Cr17Ni4Cu4Nb martensitic precipitation hardening stainless steel. The method comprises the following steps: 1, coarsely grinding, finely grinding, polishing, cleaning and drying a metallographic sample to obtain a shine scratch-freepolished surface; and 2, picking up a corrosive agent, wiping the polished surface for 15-20s, flushing, and drying, wherein the corrosive agent is prepared by pouring 2-3ml of concentrated hydrochloric acid into 30ml of concentrated nitric acid, uniformly stirring and allowing the obtained solution to stand for above 5min. According to the invention, the 05Cr17Ni4Cu4Nb martensitic precipitation hardening stainless steel crystal boundary can be intelligibly and completely displayed, and the color and the morphology of the tissue have no influences on the observation of the contour of the crystal boundary. The method has the following advantages: the crystal boundary display effect is excellent; normal temperature corrosion and no need of heating are realized; and the corrosion time is short, and only 15-20 seconds are needed.

Description

technical field [0001] The invention relates to a technology in the field of metallographic inspection of metal materials, in particular to a method for metallographic corrosion of martensitic precipitation hardening stainless steel grain boundaries. Background technique [0002] The US grade of 05Cr17Ni4Cu4Nb martensitic precipitation hardening stainless steel is 17-4PH. In addition to directly obtaining martensitic structure after solution treatment, this steel is further strengthened by subsequent aging treatment to obtain precipitation hardening phase (copper-containing phase). The metallographic structure after solid solution aging is tempered sorbite with martensitic orientation + a small amount of delta ferrite + fine dispersed precipitates that are difficult to distinguish. The metallographic structure etchant of the steel is very mature, mainly including high ferric chloride + hydrochloric acid aqueous solution, aqua regia or hydrochloric acid nitric acid solution s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23F1/28G01N1/32
Inventor 郭海霞孙前进王春芬
Owner 725TH RES INST OF CHINA SHIPBUILDING INDAL CORP
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