Method for manufacturing low-cost high-toughness X70 steel spiral submerged arc welded pipe

A technology of submerged arc welded pipe and manufacturing method, which is applied in the field of low-cost and high-toughness X70 steel spiral submerged arc welded pipe manufacturing, can solve the problems of high cost and high alloy content of pipeline steel, and achieve the effect of reducing production cost

Inactive Publication Date: 2012-03-21
BC P INC CHINA NAT PETROLEUM CORP +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

On the other hand, the current steel pipe market is highly competitive, and the commonly used alloy content of pipeline steel is relatively high, resulting in high cost

Method used

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  • Method for manufacturing low-cost high-toughness X70 steel spiral submerged arc welded pipe
  • Method for manufacturing low-cost high-toughness X70 steel spiral submerged arc welded pipe

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Experimental program
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Effect test

Embodiment

[0017] The pipe diameter is Φ914mm, the wall thickness is 14.3mm, and the chemical composition is C 0.05~0.07%, Si 0.16~0.21%, Mn 1.49~1.59%, Cr 0.20~0.23%, Ni 0.014~0.019%, Al 0.029~0.054% , Cu 0.007~0.024%, Nb 0.030~0.046%, V 0.015~0.049%, Ti 0.012~0.021%, P 0.005~0.012%, S 0.001~0.001%, B 0.0001~0.0003%, N 0.0024~0.0085%, The X70 controlled-rolled steel plate with the quantity of iron is used to manufacture spiral submerged arc welded pipes. The manufacturing process is as follows:

[0018] The coils are uncoiled and leveled.

[0019] Edge milling: first rough milling, milling off the width of the plate edge by 0-10mm; then fine milling X-shaped groove, that is, the two butt-joint edges of the steel plate are respectively cut out with a blunt edge size of 8±1mm and a groove angle of 35° °~40° groove, the two sides of the steel plate are butted to form an X-shaped groove of 70°~80°.

[0020] Pre-bending: Pre-bend the delivery side and free side of the coiled plate on the t...

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Abstract

The invention discloses a method for manufacturing a low-cost high-toughness X70 steel spiral submerged arc welded pipe. The processing process of the method comprises the following steps of: uncoiling; leveling; milling an edge; pre-bending; forming; performing internal welding; performing external welding; expanding diameter at a pipe end; performing layered ultrasonic examination on a base material; performing weld joint X ray examination; performing a hydrostatic test; performing weld joint ultrasonic examination; chamfering the pipe end; and examining a finished product, wherein an bevel angle in the edge milling step is 70-80 degrees, and the bevel depth is 3-4 mm. Mo, Ni and Cu are not added into the base material adopted for manufacturing the low-cost high-toughness X70 steel spiral submerged arc welded pipe, and the content of alloy elements of Nb and the like is reduced, so that the production cost is reduced; in addition, by optimizing a forming process and a welding process, the manufactured spiral submerged arc welded pipe has the superior performance of low-temperature impact resistant toughness.

Description

technical field [0001] The invention relates to a manufacturing technology of a spiral submerged arc welded pipe, in particular to a method for manufacturing a spiral submerged arc welded pipe of low-cost and high-toughness X70 steel. Background technique [0002] The large-scale application of X70 pipeline steel in my country began in 2001 with the West-East Gas Pipeline Project, and the production technology of X70 grade pipeline steel and steel pipes has basically matured. In the construction of the first-line pipeline of West-to-East Gas Pipeline, my country has successfully developed and applied large-wall thickness X70 spiral submerged arc welded pipes. It has been widely used in construction; at the same time, it has formed the typical representatives of "Technical Conditions for Spiral Seam Submerged Arc Welded Pipes for West-East Gas Pipeline Project" and "Technical Conditions for X70 Spiral Seam Submerged Arc Welded Pipes for West-East Gas Pipeline Second Line Pipel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/38C22C38/28C22C38/32C22C38/54C22C38/58C22C38/16C22C38/14B23P15/00
Inventor 田鹏申立群李建一孙宏孙志刚石国红
Owner BC P INC CHINA NAT PETROLEUM CORP
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