Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt

A martensitic stainless steel and austenite grain boundary technology, which is applied in the field of prior austenite grain boundary corrosion of martensitic stainless steel used for steam turbine bolts, can solve the problem of not being able to show the prior austenite grain boundary, corrosive agent and corrosion resistance of the material. The lack of corrosion methods, inapplicability and other problems, to achieve the effect of promoting corrosion and tissue exposure, saving operation time, and reducing corrosion time

Inactive Publication Date: 2021-08-06
大唐锅炉压力容器检验中心有限公司 +5
View PDF13 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In particular, it is worth noting that the etchant composition of this patent includes picric acid, which is now a controlled drug and is no longer suitable for promotion as a generally applicable metallographic etchant composition
Patent CN103983502A discloses a metallographic corrosion method for clearly displaying the original austenite grain boundary of 9-12% Cr heat-resistant steel. The purpose of the original austenite grain boundary in this material
Patent CN107014661A discloses a corrosion method for displaying the original austenite grain boundary of high-nitrogen martensitic stainless steel, but it requires the content of N in the steel to be between 0.25-0.5%, while the content of N element in this material is 0.035-0.065% %, which is far from the patent requirements and therefore does not apply
[0005] It can be seen that there is a lack of etchant and corrosion methods for the prior austenite grain boundary of martensitic stainless steel used for steam turbine bolts in the prior art, and it is urgent to develop a metallographic etchant suitable for this material in order to study the structure and properties of this material. Provide reference for the formulation of heat treatment process

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt
  • Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt
  • Original austenite grain boundary corrosion method of martensitic stainless steel for steam turbine bolt

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A method for corrosion of prior austenite grain boundaries of martensitic stainless steel for steam turbine bolts, comprising the following steps:

[0037] (1) Preparation of metallographic samples: martensitic stainless steel for 2Cr11Mo1NiWVNbN steam turbine bolts was oil-quenched at 970°C for 30 minutes, and then oil-quenched. Grind from coarse to fine on 400#, 600#, 800#, 1000#, 1200# sandpaper. After grinding, use W3.5, W1.5, W0.5 diamond polishing paste to polish the sample. Then put it into an ultrasonic cleaning machine for cleaning and dry it with a hair dryer to obtain a metallographic sample with a bright and scratch-free testing surface;

[0038] (2) Preparation of metallographic etchant: first add distilled water to the beaker, then weigh potassium permanganate at a ratio of 1.8-2g per 100mL of distilled water, add it to the beaker and stir until the potassium permanganate is fully dissolved, then add Distilled water is added to the ratio of 6-8mL concentr...

Embodiment 2

[0044] A method for corrosion of prior austenite grain boundaries of martensitic stainless steel for steam turbine bolts, comprising the following steps:

[0045] (1) Preparation of metallographic samples: martensitic stainless steel for 2Cr11Mo1NiWVNbN steam turbine bolts is oil-quenched at 1070°C for 30 minutes and then oil-quenched. The detection surface of the oil-quenched 2Cr11Mo1NiWVNbN metallographic samples is sequentially placed on 180#, 200#, Grind from coarse to fine on 400#, 600#, 800#, 1000#, 1200# sandpaper. After grinding, use W3.5, W1.5, W0.5 diamond polishing paste to polish the sample. Then put it into an ultrasonic cleaning machine for cleaning and dry it with a hair dryer to obtain a metallographic sample with a bright and scratch-free testing surface;

[0046] (2) Preparation of metallographic etchant: first add distilled water to the beaker, then weigh potassium permanganate at a ratio of 1.8-2g per 100mL of distilled water, add it to the beaker and stir ...

Embodiment 3

[0052] A method for corrosion of prior austenite grain boundaries of martensitic stainless steel for steam turbine bolts, comprising the following steps:

[0053] (1) Preparation of metallographic samples: martensitic stainless steel for 2Cr11Mo1NiWVNbN steam turbine bolts was oil-quenched at 1120°C for 30 minutes, and then oil-quenched. Grind from coarse to fine on 400#, 600#, 800#, 1000#, 1200# sandpaper. After grinding, use W3.5, W1.5, W0.5 diamond polishing paste to polish the sample. Then put it into an ultrasonic cleaning machine for cleaning and dry it with a hair dryer to obtain a metallographic sample with a bright and scratch-free testing surface;

[0054] (2) Preparation of metallographic etchant: first add distilled water to the beaker, then weigh potassium permanganate at a ratio of 1.8-2g per 100mL of distilled water, add it to the beaker and stir until the potassium permanganate is fully dissolved, then add Distilled water is added to the ratio of 6-8mL concent...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
quality scoreaaaaaaaaaa
Login to View More

Abstract

The invention discloses an original austenite grain boundary corrosion method of martensitic stainless steel for a steam turbine bolt. The method comprises the following steps of preserving heat of the martensitic stainless steel for 2Cr11Mo1NiWVNbN steam turbine bolt at 970-1120 DEG C for 30 minutes, performing oil quenching, performing coarse grinding, fine grinding, polishing and ultrasonic cleaning, and blow-drying by using a blower to obtain a metallographic sample with a bright and scratch-free detection surface; the container containing the metallographic corrosive agent being placed in a constant-temperature water bath kettle at the room temperature, the test sample being placed in the metallographic corrosive agent with the detection face facing upwards, and the test sample being heated to 70-80 DEG C along with the water bath kettle and then kept at the constant temperature for 30-35 min; removing surface corrosion dirt by using an oxalic acid aqueous solution; and washing and blow-drying. By means of the method, the original austenite grain boundary of the martensitic stainless steel for the 2Cr11Mo1NiWVNbN steam turbine bolt can be clearly displayed, the defect that original austenite grains are difficult to clearly display due to the fact that other corrosive agents corrode a martensitic stainless steel matrix and the original austenite grains at the same time can be overcome, the corrosion time is shortened to about 35 min, operation is easy, and the time is saved.

Description

technical field [0001] The invention relates to the technical field of new materials, and more specifically relates to a prior austenite grain boundary corrosion method of martensitic stainless steel used for steam turbine bolts. Background technique [0002] With the continuous improvement of the steam parameters of the steam turbine thermal power generation unit, the performance requirements of the steam turbine high temperature bolts used to connect the cylinder flange and valve flange are getting higher and higher. 2Cr11Mo1NiWVNbN is a new type of martensitic heat-resistant steel developed on the basis of 12% Cr steel. Due to the addition of Nb, V, N and other elements in the steel, the precipitation strengthening effect of the steel is enhanced, and it has higher strength and With good high temperature performance, it is widely used in the flange connection of high parameter steam turbine units. [0003] 2Cr11Mo1NiWVNbN is a new type of martensitic stainless steel used...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): G01N1/32G01N1/34G01N21/84
CPCG01N1/32G01N1/34G01N21/84
Inventor 刘俊建吴跃王家庆杜晓东王建斌邵帅王齐宏
Owner 大唐锅炉压力容器检验中心有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com