Local heat treatment method after repair welding of inner wall of large quenched and tempered steel pressure vessel

A local heat treatment and pressure vessel technology, applied in heat treatment furnaces, heat treatment equipment, heat treatment process control, etc., can solve problems such as stress corrosion failure, equipment safety operation threat, improper temperature gradient, etc., to reduce residual stress and avoid sensitization cracks , to ensure the consistency of the effect

Active Publication Date: 2022-06-07
CHINA UNIV OF PETROLEUM (EAST CHINA)
View PDF3 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Cracks, corrosion, wear and other defects will inevitably occur in the process of pressure vessel manufacturing, installation and service. If not dealt with in time, it will pose a great threat to the safe operation of the equipment
In order to prolong the service life of the pressure vessel and reduce the production cost, it is usually necessary to partially repair the pressure vessel by means of repair welding to restore its structural integrity. Residual stress, the existence of residual stress has a great impact on the later service life of repair welding equipment, especially it is easy to cause stress corrosion failure
Local heat treatment after repair welding is an effective means to eliminate residual stress after repair welding, but the current domestic and foreign heat treatment standards have not made detailed regulations on the local heat treatment process after repair welding, such as heating method, heating range, heat preservation range, etc. These parameters It is the key to affect the stress relief effect of repair welding heat treatment
If the key process is not properly selected, an improper temperature gradient will be generated, new thermal stress and residual deformation will be introduced, and the heat treatment effect will be affected

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
  • Local heat treatment method after repair welding of inner wall of large quenched and tempered steel pressure vessel
  • Local heat treatment method after repair welding of inner wall of large quenched and tempered steel pressure vessel
  • Local heat treatment method after repair welding of inner wall of large quenched and tempered steel pressure vessel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0057] In this embodiment, two cylinders with a material of 12Cr2Mo1V, a diameter of 1m and a wall thickness of 130mm are selected. Submerged arc welding is used to weld the two cylinders together. The width of the inner wall weld is 10mm. After the welding is completed, the overall heat treatment in the furnace is performed. After heat treatment, a defect with a length of 20mm is processed in the girth weld on the inner wall of the cylinder, and then the defect is repaired by manual arc welding. The length of the repair welding seam is 26mm, and the width of the repair welding seam is 10mm. After the repair welding, the residual stress on the surface of the repair welding seam was tested by the indentation strain method.

[0058] After repair welding, the residual stress in the weld area increases. In order to eliminate the residual stress after repair welding, the local heat treatment method after repair welding of the inner wall of a large quenched and tempered steel pressur...

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
residual stressaaaaaaaaaa
Login to view more

Abstract

The invention discloses a local heat treatment method after repair welding of the inner wall of a large-scale quenched and tempered steel pressure vessel, which comprises the following steps: (1) determining the relevant size parameters of the repair welding area of ​​the quenched and tempered steel vessel; (2) determining the heating mode of the local heat treatment; (3) ) Determine the heating and cooling times of local heat treatment; (4) Determine the heating range of local heat treatment; (5) Determine the heat preservation range of local heat treatment; (6) Determine the heating process of local heat treatment: including heat treatment temperature and heat preservation time; (7) Arrange temperature measurement and temperature control thermocouple; (8) heat treatment is implemented, and the heat treatment temperature curve is recorded. The invention provides a local heat treatment method after repair welding of the inner wall of a large-scale quenched and tempered steel pressure vessel, which provides strict standard operation for the post-weld heat treatment and can effectively reduce the residual stress in the repair welding area.

Description

technical field [0001] The invention relates to the technical field of post-weld heat treatment of pressure vessels, in particular to a method for local heat treatment after repair welding of the inner wall of a large-scale quenched and tempered steel pressure vessel. Background technique [0002] In the process of manufacturing, installation and service of pressure vessels, various defects such as cracks, corrosion and wear will inevitably occur. If they are not dealt with in time, they will pose a great threat to the safe operation of the equipment. In order to prolong the service life of the pressure vessel and reduce the production cost, it is usually necessary to partially repair the pressure vessel by means of repair welding to restore its structural integrity. Residual stress, the existence of residual stress has a great impact on the later service life of repair welding equipment, especially easy to cause stress corrosion failure. Partial heat treatment after repair...

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 Patents(China)
IPC IPC(8): C21D1/10C21D9/50C21D11/00
CPCC21D1/10C21D9/50C21D11/00Y02P10/25
Inventor 蒋文春罗云金强谷文斌解学方李少华沈溃领赵旭曹怀祥
Owner CHINA UNIV OF PETROLEUM (EAST CHINA)
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products