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Method for optimizing weld seam structure and properties of HFW(High Frequency Welded) pipes

A welded pipe and performance technology, applied in the field of optimizing the structure and performance of the weld of HFW welded pipe, can solve problems such as reducing the quality of the weld, and achieve the effect of improving the toughness of the weld, improving the corrosion resistance and plastic toughness, and improving the structure and performance.

Inactive Publication Date: 2012-04-25
BAOJI PETROLEUM STEEL PIPE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Greatly reduces the quality of the weld and has a great impact on the groove corrosion sensitivity and plastic toughness of the weld

Method used

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  • Method for optimizing weld seam structure and properties of HFW(High Frequency Welded) pipes
  • Method for optimizing weld seam structure and properties of HFW(High Frequency Welded) pipes
  • Method for optimizing weld seam structure and properties of HFW(High Frequency Welded) pipes

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Experimental program
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Embodiment Construction

[0017] 1. The medium frequency induction furnace is used to carry out overall continuous, rapid heating and rapid heat penetration of the HFW welded pipe with a specification of Φ193.7×7.41mm and removal of internal and external burrs. The heating rate is 40-100°C / s, so that the HFW welded pipe exits the medium frequency induction furnace outlet The temperature reaches 975±15℃;

[0018] 2. The HFW welded pipe enters the hot rolling reducing unit at a speed of 0.48m / s at a temperature of 975±15°C and uses 12 extrusion rolls for thermomechanical rolling;

[0019] 3. Adjust the extrusion force of the extrusion roller so that the specification of the HFW welded pipe exiting the hot rolling reducing unit is reduced to Φ139.7×7.72mm;

[0020] 4. The HFW hot-rolled reducing pipe enters the subsequent processing process.

[0021] The chemical composition of the steel alloy material for HFW welded pipes is: 0.295% C, 0.252% Si, 1.20% Mn, 0.019% P, 0.008% S, 0.019% Cr, and the balance ...

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Abstract

The invention relates to a method for optimizing the weld seam structure and properties of HFW(High Frequency Welded) pipes, comprising the following steps of: firstly, continuously and quickly heating an HFW pipe by a medium-frequency induction furnace to above an austenite phase transition temperature and quickly thoroughly heating; and then performing hot mechanical rolling treatment on the HFW pipe at the austenitizing temperature for eliminating the residual stress of a weld seam and thinning grains in the weld seam and heat-affected zones under the effects of mechanical extrusion force and rolling temperature, so that the structure and mechanical property of the weld seam reach basically the same degrees as the parent metal. The method for optimizing the weld seam structure and properties of HFW pipes improves the structure and properties of the weld seam, obviously increases the grain size of the weld seam from 2-4 levels to 8-11 levels, obviously reduces the groove corrosion sensitivity coefficient of the weld seam, and improves the corrosion resistance, plasticity and toughness of the weld seam.

Description

technical field [0001] The invention belongs to the technical field of welded pipe manufacturing, and in particular relates to a method for optimizing the weld seam structure and performance of HFW welded pipes. Background technique [0002] In recent years, with the continuous improvement of the quality and steel grade of HFW welded pipes, the requirements for weld quality have become more stringent, and the weld structure and performance are the most direct factors affecting welding quality. According to the characteristics of HFW welded pipe forming welding, the structure and performance of the weld and heat-affected zone are quite different from those of the base metal. Generally, the grain size of the weld and heat-affected zone is about 2 to 4, while the base metal is basically 8 ~ Grade 11, in addition, there is a large stress concentration in the weld. The quality of the weld is greatly reduced, and it has a great influence on the groove corrosion sensitivity and pl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D8/10
Inventor 毕宗岳张锦刚韦奉李周波党涛李根社苏琬
Owner BAOJI PETROLEUM STEEL PIPE
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