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

Heat treatment method for X80 bent pipe welding joint with excellent low-temperature toughness

A heat treatment method and welding joint technology, applied in heat treatment furnaces, heat treatment equipment, manufacturing tools, etc., can solve the problems of harsh operating environment, complex process, and large environmental pollution, and achieve simple operation, simplified operation process, and tensile elongation. Good results

Active Publication Date: 2019-12-20
XIAN UNIV OF TECH
View PDF7 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, the main defects of the heat treatment technology of X80 elbow welded joints are: the quenching heating is usually heated to the quenching temperature at one time, the cooling method is oil cooling, the process is complex, the operating environment is harsh, and the environment is polluted. Therefore, it is necessary to further optimize the X80 elbow. Heat treatment process for pipe welded joints, thereby improving the overall low temperature mechanical properties of the bend

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
  • Heat treatment method for X80 bent pipe welding joint with excellent low-temperature toughness
  • Heat treatment method for X80 bent pipe welding joint with excellent low-temperature toughness

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Step 1, choose X80 pipeline steel, the components according to mass percentage are as follows: C is 0.02%, Si is 0.1%, Mn is 1.25%, P is 0.018%, S is 0.004%, Nb is 0.04%, and Ti is 0.1% , Al is 0.18%, V is 0.10%, Ni is 0.10%, Mo is 0.15%, Cu is 0.2%; Cr is 0.02%, Bi is 0.005%, the balance is Fe, and the carbon equivalent Ceq is 0.31; using standard grades NS-2 submerged arc welding wire three-wire two-layer two-pass welding, the welding process temperature is 180°C, and the heat input is 30kJ / cm;

[0030] Step 2: Bending the straight-welded main pipe obtained by the submerged arc welding method with intermediate frequency induction overall heating, the normalizing heating temperature is 880°C, the advancing speed is 10mm / min, and the cooling method is air cooling to room temperature;

[0031] Step 3: Perform overall tempering treatment on the elbow welded joints obtained in step 2: the heating instrument is a box-type resistance furnace, the tempering temperature is 630...

Embodiment 2

[0033] Step 1, choose X80 pipeline steel, the composition according to mass percentage is as follows: C is 0.03%, Si is 0.2%, Mn is 1.58%, P is 0.016%, S is 0.002%, Nb is 0.07%, and Ti is 0.2% , Al is 0.2%, V is 0.18%, Ni is 0.2%, Mo is 0.19%, Cu is 0.1%; Cr is 0.01%, Bi is 0.004%, the balance is Fe, and the carbon equivalent Ceq is 0.35; the standard grade is adopted NS-2 submerged arc welding wire three-wire two-layer two-pass welding, the welding process temperature is 160°C, and the heat input is 33kJ / cm;

[0034] Step 2: Bending the straight-welded main pipe obtained by the submerged arc welding method with intermediate frequency induction overall heating, the normalizing heating temperature is 920°C, the advancing speed is 13mm / min, and the cooling method is air cooling to room temperature;

[0035] Step 3, conduct overall tempering treatment on the elbow welded joint obtained in step 2: the heating instrument is a box-type resistance furnace, the tempering temperature i...

Embodiment 3

[0037] Step 1, choose X80 pipeline steel, the components according to mass percentage are as follows: C is 0.04%, Si is 0.2%, Mn is 1.86%, P is 0.015%, S is 0.001%, Nb is 0.08%, and Ti is 0.2% , Al is 0.31%, V is 0.35%, Ni is 0.23%, Mo is 0.28%, Cu is 0.15%; Cr is 0.01%, Bi is 0.005%, the balance is Fe, and the carbon equivalent Ceq is 0.42; the standard grade is adopted NS-2 submerged arc welding wire three-wire two-layer two-pass welding, the welding process temperature is 120°C, and the heat input is 38kJ / cm;

[0038] Step 2: Bending the straight-welded main pipe obtained by the submerged arc welding method with intermediate frequency induction overall heating, the normalizing heating temperature is 940°C, the advancing speed is 16mm / min, and the cooling method is air cooling to room temperature;

[0039]Step 3, conduct overall tempering treatment on the elbow welded joint obtained in step 2: the heating instrument is a box-type resistance furnace, the tempering temperature...

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
tensile strengthaaaaaaaaaa
impact absorption energyaaaaaaaaaa
tensile strengthaaaaaaaaaa
Login to View More

Abstract

The invention discloses a heat treatment method for the X80 bent pipe welding joint with the excellent low-temperature toughness. The heat treatment method comprises the following steps of firstly, carrying out three-wire two-layer two-pass welding on the X80 pipeline steel by adopting a standard submerged arc welding wire to obtain a straight weld joint welding joint; secondly, the obtained straight weld joint welding joint is subjected to normalizing heat treatment through a high-temperature induction heating furnace, heat treatment is carried out at the same time, direct air cooling is conducted, and a bent pipe welding joint is obtained; and finally, the obtained bent pipe welding joint is placed in a box-type resistance furnace, and heat treatment is carried out again and air-cooled to room temperature. Compared with the prior art, the method is simple and easy to operate, the operation flow is simplified, the mechanical property reduction caused by heating bending of the X80 bentpipe welding joint is greatly improved, the low-temperature impact absorption work at the X80 bent pipe is guaranteed, the tensile elongation is good, and the yield strength and the tensile strengthare higher.

Description

technical field [0001] The invention belongs to the technical field of pipeline welding, and in particular relates to a heat treatment method for an X80 elbow welded joint with excellent low-temperature toughness. Background technique [0002] In recent years, China's West-East Gas Pipeline Second and Third Line Natural Gas Pipeline Project, Central Asia Natural Gas Pipeline Project, China-Russia Natural Gas Pipeline Project and Zhonggui Natural Gas Pipeline Project, the main lines all use X80 steel grade, and X80 pipelines have also been applied in foreign countries. . Elbows are widely used as a necessary structure to change the direction of pipelines. In the construction of oil and gas pipelines such as the West-to-East Gas Pipeline, China-Russia, and Central Asia, especially the China-Russia East Route project needs to pass through the extremely cold and permafrost regions, and the pipelines and elbows at some stations need to be exposed to low temperature environments....

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): C21D9/50C21D1/18C21D1/28C21D6/00C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/58
CPCC21D1/18C21D1/28C21D6/004C21D6/005C21D6/008C21D9/505C22C38/002C22C38/02C22C38/04C22C38/06C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/58
Inventor 张敏李洁毕宗岳余唅张万鹏仝雄伟许帅
Owner XIAN UNIV OF TECH
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