X70MS ERW welded pipe having excellent anti SSCC stress corrosion and manufacturing method thereof

A technology of stress corrosion and manufacturing methods, applied in the direction of manufacturing tools, furnace types, furnaces, etc., can solve problems such as SSCC and corrosion, and achieve the effects of reducing residual stress, ensuring continuity, and reducing welding power parameters

Active Publication Date: 2014-01-22
BC P INC CHINA NAT PETROLEUM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] With the improvement of steel grades, X70MS ERW welded pipes for domestic gathering and transportation need to have high H 2 S resistance and the required yield strength of SSCC is getting higher and higher, especially sensitive to the stress, which is the most critical index. The stress corrosion resistance of SSCC of ordinary welded pipes at home and abroad generally only reaches 72% of the specified yield strength σ s or 85% σ s , prone to SSCC

Method used

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  • X70MS ERW welded pipe having excellent anti SSCC stress corrosion and manufacturing method thereof
  • X70MS ERW welded pipe having excellent anti SSCC stress corrosion and manufacturing method thereof
  • X70MS ERW welded pipe having excellent anti SSCC stress corrosion and manufacturing method thereof

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Effect test

Embodiment 1

[0024] Example 1: Φ406.4×8mm X70MS steel grade ERW welded pipe resistant to SSCC stress corrosion and its manufacture

[0025] 1) Raw material: X70MS steel plate with a wall thickness of 8mm is used, and its chemical composition is analyzed as follows (wt%):

[0026] Table 1X70MS chemical composition analysis (wt%)

[0027] C Mn Si P S Al Ti V Nb Cu+Ni+Cr 0.03 112 0.18 0.009 0.0007 0.0039 0.014 0.05 0.049 0.32

[0028] 2) Production: X70MS hot-rolled coils are used to produce ERW welded steel pipes with an outer diameter of 406.4mm and a wall thickness of 8mm. After uncoiling, leveling and edge milling, the strip width is precisely controlled to be between 1283 and 1285mm. Adjust welding current and voltage process parameters. Adjust and control the extrusion amount of the welding seam to 4.5mm, so that the material can produce a welding seam metal flow rising angle of 65° to 80°. Control the opening angle, the welding speed is 22m / m...

Embodiment 2

[0037] Example 2: Φ219.1×12.7mm X70MS steel grade ERW welded pipe resistant to SSCC stress corrosion and its manufacture

[0038] 1) Raw material: X70MS steel plate with a wall thickness of 12.7mm is used, and its chemical composition is analyzed as follows (wt%):

[0039] Table 4X70MS chemical composition analysis (wt%)

[0040] C Mn Si P S Al Mo Ti V Nb Cu+Ni+Cr 0.04 112 0.19 0.004 0.0007 0.0036 0.09 0.015 0.02 0.42 0.45

[0041] 2) Production: X70MS hot-rolled coils are used to produce ERW welded steel pipes with an outer diameter of Φ219.1mm and a wall thickness of 12.7mm. After uncoiling, leveling and edge milling, the width of the strip is precisely controlled at 686-687mm, and the edge of the strip is milled, and the edge of the strip is controlled by roll forming. Adjust welding current and voltage process parameters. Adjust and control the extrusion amount of the welding seam to 6mm, so that the material can produce a weld...

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Abstract

The invention discloses an X70MS ERW welded pipe having excellent anti SSCC stress corrosion and a manufacturing method thereof. The manufacturing method comprises the steps of uncoiling and butt welding, edge planning, molding, high-frequency welding, heat treatment, sizing and flying shear, pipe cutting, straightening and other procedures. The high-frequency welding frequency is 400+/-30 KHZ, the welding speed is 20+/-5 m/min, the normalizing temperature of the heat treatment is 920-980 DEG C, and the cooling rate after the heat treatment is 3-15 DEG C/s. The X70MS ERW welded pipe and the manufacturing method have the beneficial effects that the reasonable molding technology is adopted to ensure board edge end faces achieve parallel H-shaped abutting joint, so as to reduce residual stress in the molding process; with adopting of a smaller squeeze amount and an opening angle, a welding power parameter is reduced, so that burrs are formed uniformly on the outer surface and the inner surface during the steel pipe welding process, so as to be beneficial for scraping and interrupting the burrs and guarantee the continuity of online production.

Description

Technical field: [0001] The invention belongs to the field of welding and relates to a welded pipe and a manufacturing method thereof, in particular to an X70MS steel grade ERW welded pipe for gathering and transportation with excellent SSCC stress corrosion resistance and a manufacturing method thereof. Background technique: [0002] H 2 S is one of the most corrosive and harmful media in oil and natural gas, which seriously affects the service life of oil and gas transmission pipelines. Among them, sulfide stress cracking (SSCC) is H 2 The main form of acid corrosion. [0003] When ERW welded pipes are used in corrosive environments, ERW welds are more sensitive to stress corrosion cracking and hydrogen-induced cracking than the base metal, which often leads to premature cracking of ERW welded pipes, resulting in serious leakage accidents and huge Economic losses. The reason for this phenomenon is the presence of inclusions and high residual stress in the weld. [0004...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/00C22C38/54C22C38/50C22C38/28C22C38/16C22C38/14C21D8/10C21D9/50
Inventor 毕宗岳黄晓辉牛辉张锦刚刘海璋张万鹏牛爱军赵红波张君刘斌陈长青杨军包志刚张鹏杨耀彬刘刚伟
Owner BC P INC CHINA NAT PETROLEUM CORP
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