Shot blasting treatment method for improving erosion corrosion resistance of Cr 20# seamless steel tubes

A seamless steel pipe, corrosion performance technology, applied in the field of surface strengthening of 20-control Cr steel pipe

Inactive Publication Date: 2015-02-04
TIANJIN UNIV
View PDF3 Cites 3 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Ultrasonic impact treatment is a general method to change the residual stress on the surface of metal products and has been successfully applied in the improvement of fatigue life of ultra-high-strength steel and metal welds. Fatigue life, and has been successfully applied to the manufacture of aircraft landing gear; in the treatment of steel welds, ultrasonic shot peening is often used to eliminate the residual stress of welds; for deep-sea oil and gas transmission pipeline steel and high-sulfur ultra-deep well pipeline steel need to improve the resistance h 2 In order to meet the requirements of S stress corrosion performance, in the design of steel composition, attention should be paid to adding alloy elements with high sulfur corrosion resistance (such as Cr, Mo and V, etc.) and strictly limiting impurity elements such as P and S. Ultrasonic impact treatment is used to change the residual stress state. And improve steel pipe resistance to H 2 S stress corrosion performance has achieved good results, but there is a threshold compressive stress value in the modified treatment method, and the resistance to H 2 The improvement of S stress corrosion performance needs to obtain a residual stress greater than the threshold compressive stress value on the surface of high sulfur resistant steel pipe

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
  • Shot blasting treatment method for improving erosion corrosion resistance of Cr 20# seamless steel tubes
  • Shot blasting treatment method for improving erosion corrosion resistance of Cr 20# seamless steel tubes
  • Shot blasting treatment method for improving erosion corrosion resistance of Cr 20# seamless steel tubes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] The inner wall of the 20-control Cr seamless steel pipe currently used in the nuclear power conventional island according to the alloy composition in Table 1 will be subjected to ultrasonic shot peening impact treatment, and the treatment process is shown in the diagram figure 1 , select the ultrasonic shock amplitude as 100% and the firing pin diameter as 5 mm, and the ultrasonic shot peening shock treatment time is 30 minutes to change the residual stress state of the inner wall of the steel pipe,

[0029] After cleaning the inner wall of the steel pipe after ultrasonic shot peening, the room temperature corrosion rate measured on the inner wall of the steel pipe is 4.65×10 －4 mm / year, compared with the room temperature corrosion rate of steel pipes without ultrasonic shot peening (7.01×10 －4 mm / year), the corrosion rate of the inner wall of the steel pipe is only 9% of that before treatment, and the corrosion resistance of the steel pipe is obviously improved.

Embodiment 2

[0031] The inner wall of the 20-control Cr seamless steel pipe currently used in the nuclear power conventional island according to the alloy composition in Table 1 will be subjected to ultrasonic shot peening impact treatment, and the treatment process is shown in the diagram figure 1 , the selected ultrasonic shock amplitude is 60%, the striker diameter is 3.5mm, and the ultrasonic shot peening shock treatment time is 60 minutes, to change the residual stress state of the inner wall of the steel pipe.

[0032] After cleaning the inner wall of the steel pipe after ultrasonic shot peening, the measured corrosion rate of the inner wall of the steel pipe at room temperature is 4.11×10 －4 mm / year, compared with the room temperature corrosion rate of steel pipes without ultrasonic shot peening (7.01×10 －4 mm / year) is relatively significantly improved.

Embodiment 3

[0034] The inner wall of the 20-control Cr seamless steel pipe currently used in the nuclear power conventional island according to the alloy composition in Table 1 will be subjected to ultrasonic shot peening impact treatment, and the treatment process is shown in the diagram figure 1 , select the ultrasonic shock amplitude as 10% and the firing pin diameter as 1.5 mm, and the ultrasonic shot peening shock treatment time is 90 minutes to change the residual stress state of the inner wall of the steel pipe.

[0035] After cleaning the inner wall of the steel pipe after ultrasonic shot peening, the measured corrosion rate at room temperature is 6.02×10 －4 mm / year, compared with the room temperature corrosion rate of steel pipes without ultrasonic shot peening (7.01×10 －4 mm / year) is less improved.

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

No PUM Login to View More

Abstract

The invention relates to a shot blasting treatment method for improving the erosion corrosion resistance of Cr 20# seamless steel tubes. The method comprises the following steps: carrying out room temperature ultrasonic shot blasting treatment on the inner walls of the Cr 20# seamless steel tubes under an ultrasonic impact amplitude of 10-100% and a firing pin diameter of 1.5-5mm for 30-90min; and cleaning the inner surfaces of the ultrasonic shot blasted inner surfaces of the Cr 20# seamless steel tubes. With the increase of the firing pin diameter and the impact amplitude and the prolongation of the impact treatment time in the ultrasonic shot blasting treatment process, the erosion corrosion resistance of the Cr 20# seamless steel tubes first increases and then remains unchanged or slightly decreases, so the residual stress state of the Cr 20# seamless steel tubes for nuclear power can be substantially changed through the shot blasting treatment method, concretely the impact amplitude and the firing pin diameter, thereby the erosion corrosion resistance of the steel tubes is significantly influenced; and the method is universal and important in the production process.

Description

technical field [0001] The invention belongs to the technical field of surface strengthening of 20-control Cr steel pipes, and in particular relates to a treatment method for improving the high-temperature and room-temperature erosion-corrosion resistance of the inner wall of the steel pipe by shot blasting at room temperature for 20-control Cr seamless steel pipes. Background technique [0002] With the rapid development of China's economy, the power supply is becoming increasingly tense. While vigorously developing advanced coal-fired power generation technology, nuclear power, as a clean energy, has been highly valued and vigorously developed by countries all over the world. According to the requirements of China's medium and long-term nuclear power development plan, China will build 3 to 4 new 1,000,000-kilowatt nuclear power units every year, and has become the country with the most nuclear power projects under construction in the world. [0003] The construction of co...

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
IPC IPC(8): C21D10/00
Inventor刘永长余黎明马宗青李冲王东坡
OwnerTIANJIN UNIV