Nickel-based alloy as-cast grain corrosion method for ultra-supercritical turboset

A technology of nickel-based alloys and steam turbines, which is applied in the field of metallographic detection and corrosion, can solve the problems that it is difficult to display the as-cast grain boundary, the morphology of as-cast grains, the average size of grains, and the change of grains. Good effect, good reproducibility and high stability

Active Publication Date: 2020-04-28
CHINA FIRST HEAVY IND +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] Due to the high content of alloy elements and strong corrosion resistance of grain boundaries of nickel-based alloys, it is difficult to display the as-cast grain boundaries with existing corrosive agents, which makes the follow-up research on the

Method used

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  • Nickel-based alloy as-cast grain corrosion method for ultra-supercritical turboset
  • Nickel-based alloy as-cast grain corrosion method for ultra-supercritical turboset
  • Nickel-based alloy as-cast grain corrosion method for ultra-supercritical turboset

Examples

Experimental program
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Effect test

Embodiment 1

[0024] The present embodiment uses this method to corrode the as-cast grain size of the modified IN617 nickel-based alloy, and the specific steps are as follows:

[0025] Step 1: Prepare the metallographic detection sample of the modified IN617 alloy

[0026] The sample is subjected to mechanical rough grinding, fine grinding, polishing, cleaning and drying according to the conventional preparation method of metallographic samples;

[0027] Step 2: Oxidize the polished sample

[0028] Raise the temperature of the ordinary heat treatment furnace to 600°C, put the polished sample into the furnace, keep it warm for 2 hours, and then take it out of the furnace to air cool, and pay attention to the protection of the polished surface during the heat treatment process;

[0029] Step 3: Preparation of copper sulfate corrosion solution

[0030] According to the ratio of copper sulfate pentahydrate: water: concentrated hydrochloric acid: concentrated sulfuric acid = 20g: 80ml: 150ml: ...

Embodiment 2

[0034] The present embodiment uses this method to corrode the as-cast grain size of the modified IN706 nickel-based alloy, and the specific steps are as follows:

[0035] Step 1: Prepare the metallographic detection sample of the modified IN706 alloy

[0036] The sample is subjected to mechanical rough grinding, fine grinding, polishing, cleaning and drying according to the conventional preparation method of metallographic samples;

[0037] Step 2: Oxidize the polished sample

[0038] Raise the temperature of the ordinary heat treatment furnace to 800°C, put the polished sample into the furnace, keep it warm for 3 hours, and then take it out of the furnace to air cool, and pay attention to the protection of the polished surface during the heat treatment;

[0039] Step 3: Preparation of copper sulfate corrosion solution

[0040] According to the ratio of copper sulfate pentahydrate: water: concentrated hydrochloric acid: concentrated sulfuric acid = 20g: 80ml: 150ml: 5ml, add...

Embodiment 3

[0044] Present embodiment is to adopt this method to corrode the as-cast grain size of IN740 nickel-base alloy, and concrete steps are as follows:

[0045] Step 1: Prepare test samples of IN740 alloy

[0046] The sample is subjected to mechanical coarse grinding, fine grinding, polishing, cleaning and drying according to the conventional preparation method of metallographic samples;

[0047] Step 2: Oxidize the polished sample

[0048] Raise the temperature of the ordinary heat treatment furnace to 750°C, put the polished sample into the furnace, keep it warm for 2 hours, and then take it out of the furnace to air cool, and pay attention to the protection of the polished surface during the heat treatment;

[0049] Step 3: Preparation of copper sulfate corrosion solution

[0050] According to the ratio of copper sulfate pentahydrate: water: concentrated hydrochloric acid: concentrated sulfuric acid = 20g: 80ml: 150ml: 5ml, add water, concentrated sulfuric acid, copper sulfate...

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Abstract

The invention discloses a nickel-based alloy as-cast grain corrosion method for an ultra-supercritical turboset. The method is suitable for several typical nickel-based high-temperature alloys and nickel-based alloys obtained by optimizing and improving the components of the nickel-based high-temperature alloys, such as IN617, IN706, IN740, IN625, Hynes282 and improved alloys thereof. Firstly, a nickel-based alloy as-cast metallographic specimen is subjected to mechanical grinding, polishing, cleaning and blow-drying; then the metallographic specimen is put into a heat treatment furnace and subjected to oxidation treatment for 1-3 hours under the condition that the temperature is kept at 600-800 DEG C; after discharging and air cooling, an original polished surface is directly and moderately polished, cleaned and blow-dried; and then the polished surface is immersed into newly prepared copper sulfate corrosive liquid with the ratio of copper sulfate pentahydrate to water to concentrated hydrochloric acid to concentrated sulfuric acid being 20g: 80ml: 150ml: 5ml to be corroded for 10-30 seconds, and a clear and complete grain boundary can be obtained after cleaning and blow-drying.The method is safe, efficient, stable in display effect and good in reproducibility.

Description

technical field [0001] The invention belongs to the technical field of metallographic detection and corrosion, and in particular relates to a nickel-based alloy as-cast grain corrosion method for an ultra-supercritical steam turbine unit. Background technique [0002] In recent years, in order to solve the current energy and greenhouse gas emission problems, many countries are striving to develop advanced ultra-supercritical coal-fired power generation technology above 650 °C, and the steam temperature parameters required by the units are as high as 650 °C or even 700 °C. In order to meet the application requirements of this technology, nickel-based superalloys have been extensively studied as important candidate materials. For example, Europe has launched the AD700 research and development plan, and the candidate materials for the cylinder and valve body of the 700°C advanced ultra-supercritical steam turbine are determined as IN617 and IN625 alloys. The 760°C ultra-superc...

Claims

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Application Information

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IPC IPC(8): G01N1/32G01N1/34
CPCG01N1/32G01N1/34
Inventor 寇金凤聂义宏白亚冠张鑫郭伟李红梅
Owner CHINA FIRST HEAVY IND
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