Corrosive for displaying austenitic stainless steel grain boundary of fine grains and method for preparing corrosive

A technology of austenitic stainless steel and fine grains, which is applied in the field of etchant and its preparation, can solve the problems of inconvenient material performance analysis, blurred grain boundaries of etchant, and influence on grain size rating, etc. The effect of clear boundary and little interference of grain boundary

Active Publication Date: 2014-05-14
SHANGHAI BOILER WORKS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the metallographic examination of fine-grained austenitic stainless steel in the original state and after heat treatment, the currently used etchant often has blurred grain boundaries and serious intragranular pollution, which seriously affects the rating of grain size.
This phenomenon is more prominent in the detection of fine-grained austenitic stainless steel after heat treatment, which brings a lot of inconvenience to the analysis of material properties.

Method used

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  • Corrosive for displaying austenitic stainless steel grain boundary of fine grains and method for preparing corrosive
  • Corrosive for displaying austenitic stainless steel grain boundary of fine grains and method for preparing corrosive
  • Corrosive for displaying austenitic stainless steel grain boundary of fine grains and method for preparing corrosive

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Experimental program
Comparison scheme
Effect test

Embodiment 4

[0034] The Super304H stainless steel alloy composition that adopts in embodiment 4 and comparative example 3 is as shown in table 2:

[0035] Table 2 Test Super304H stainless steel composition (wt%)

[0036] C

Embodiment 1

[0038] Formula: as shown in Table 3

[0039] table 3

[0040] h 2 o

hydrochloric acid

FeCl 3

CuCl 2 2H 2 0

Glacial acetic acid

New Gill

80mL

10mL

15g

10g

2mL

2 drops

[0041] Preparation:

[0042] 10g CuCl 2 2H 2 O is placed in a beaker, and then 15g FeCl is added 3 , then add 10 mL of 36% hydrochloric acid and 80 mL of distilled water, and stir well; finally add 2 mL of glacial acetic acid and 2 drops of neogilamine, and mix well.

[0043] experiment method:

[0044] Process the original fine-grained austenitic TP347HFG stainless steel into a metallographic sample. After polishing, immerse the sample in the above-mentioned corrosive agent for 35 seconds. When the surface is light gray, clean it with water, rinse it with alcohol, and dry it with a hair dryer. Metallographic structure observation with a metallographic microscope, such as figure 1 shown.

Embodiment 2

[0046] Formula: as shown in Table 4

[0047] Table 4

[0048] h 2 o

hydrochloric acid

FeCl 3

CuCl 2 2H 2 o

Glacial acetic acid

New Gill

100mL

15mL

18g

12g

5mL

4 drops

[0049] Preparation:

[0050] 12g CuCl 2 2H 2 O is placed in a beaker, and then 18g FeCl is added 3 , then add 15 mL of 36% hydrochloric acid and 100 mL of distilled water, and stir well; finally add 5 mL of glacial acetic acid and 4 drops of neogilamine, and mix well.

[0051] experiment method:

[0052] The original state, heat treatment for 10 minutes (heat treatment method: heat up to 950°C and then keep it for 10 minutes, air cool to room temperature), 20 minutes heat treatment (heat treatment method: heat up to 950°C and then hold for 20 minutes, air cool to room temperature) fine grains Austenitic TP347HFG stainless steel is processed into a metallographic sample. After polishing, the sample is immersed in the above-mentioned cor...

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Abstract

The invention discloses a corrosive for displaying austenitic stainless steel grain boundaries of fine grains and a method for preparing the corrosive. The corrosive is characterized by comprising the following components by weight: 80-150ml of H2O, 10-20ml of HCl, 15-25g of FeCl3, 10-15g of CuCl2 / H2O, 2.0-7.0ml of glacial acetic acid and 1-5 drops of benzalkonium bromide. The method comprises the steps of: placing CuCl2.H2O in a beaker; then adding FeCl3, and uniformly stirring after adding HCl and H2O; and uniformly mixing after adding glacial acetic acid and benzalkonium bromide finally. According to the corrosive for the austenitic stainless steel of the fine grains, the grain boundaries of the austenitic stainless steel of the fine grains in the original state and the thermal treatment state can be clearly displayed, the 100 times of rating on grain size can be easily performed, the grain boundaries are clear, the interference of a texture to the grain boundaries is small, and the corrosion effect is good.

Description

technical field [0001] The invention relates to an etchant for displaying fine-grain austenitic stainless steel grain boundaries and a preparation method thereof, belonging to the field of austenitic stainless steel manufacturing. Background technique [0002] The size of metal grains has a decisive influence on its mechanical properties at room temperature and high temperature. The size of the metal grain size is directly related to the mechanics and mechanical properties of the material, so in the metallographic structure analysis, the evaluation of the grain size is very important. [0003] The high-temperature pressure-bearing parts of ultra-(ultra)critical units (superheated hot section pipes, reheated hot-section pipes, etc.) are mainly made of fine-grained austenitic stainless steel, and the fine-grained austenitic stainless steel commonly used Mainly TP347HFG stainless steel, Super304H stainless steel and other materials. Among them, ASME SA213 requires the grain s...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C23F1/28G01N1/32
Inventor 李强李宝虎王崇斌张波金用强王建泳
Owner SHANGHAI BOILER WORKS
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