Heterogeneous cold repair welding process for online repairing crack of plug valve of main steam pipeline

A main steam and crack technology, applied in the field of heterogeneous cold repair welding technology, can solve the problems of poor welding effect of main steam pipeline, difficulty in the arrangement of on-site heating devices, and difficulty in ensuring the quality of heat treatment, etc., to achieve guaranteed repair welding quality and plasticity Excellent, high-strength effect

Inactive Publication Date: 2019-08-23
史海燕
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Comparing the two welding repair processes, the alloy composition of the welding material in the thermal welding method is similar to that of the matrix, which belongs to the homogeneous welding repair process, but the heat treatment process of the thermal welding method is complicated, and the repairing condition is not good. Stress tempering treatment, due to the irregular shape of the valve body and large wall thickness, it is difficult to arrange the on-site h...

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  • Heterogeneous cold repair welding process for online repairing crack of plug valve of main steam pipeline

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Effect test

Embodiment 1

[0024] The invention provides a heterogeneous cold repair welding process for on-line repairing of main steam pipeline plugging cracks, and the specific operation steps are as follows:

[0025] Step 1: Judging the direction and depth of cracks, using an angle grinder to grind along the cracks to the depth of the inner wall, and coloring inspection while grinding, until the detection confirms that there are no cracks, measure the crack depth, and use 1 / 3 of the wall thickness as the judgment standard, select Welding method, if the crack depth is greater than 1 / 3 of the wall thickness, the hot welding repair welding process is adopted; if the crack depth is less than 1 / 3 of the wall thickness, and the crack does not extend further in the length direction, the cold welding repair process is used. The welding method selects high-chromium and high-nickel nickel-based welding consumables for repair, and the welding consumables select ENiCrFe-3 welding rods;

[0026] Step 2: Crack pr...

Embodiment 2

[0033] The invention provides a heterogeneous cold repair welding process for on-line repairing of main steam pipeline plugging cracks, and the specific operation steps are as follows:

[0034] Step 1: Judging the direction and depth of cracks, using an angle grinder to grind along the cracks to the depth of the inner wall, and coloring inspection while grinding, until the detection confirms that there are no cracks, measure the crack depth, and use 1 / 3 of the wall thickness as the judgment standard, select Welding method, if the crack depth is greater than 1 / 3 of the wall thickness, the hot welding repair welding process is adopted; if the crack depth is less than 1 / 3 of the wall thickness, and the crack does not extend further in the length direction, the cold welding repair process is used. The welding method selects high-chromium and high-nickel nickel-based welding consumables for repair, and the welding consumables select ENiCrFe-3 welding rods;

[0035] Step 2: Crack pr...

Embodiment 3

[0042] The invention provides a heterogeneous cold repair welding process for on-line repairing of main steam pipeline plugging cracks, and the specific operation steps are as follows:

[0043] Step 1: Judging the direction and depth of cracks, using an angle grinder to grind along the cracks to the depth of the inner wall, and coloring inspection while grinding, until the detection confirms that there are no cracks, measure the crack depth, and use 1 / 3 of the wall thickness as the judgment standard, select Welding method, if the crack depth is greater than 1 / 3 of the wall thickness, the hot welding repair welding process is adopted; if the crack depth is less than 1 / 3 of the wall thickness, and the crack does not extend further in the length direction, the cold welding repair process is used. The welding method selects high-chromium and high-nickel nickel-based welding consumables for repair, and the welding consumables select ENiCrFe-3 welding rods;

[0044] Step 2: Crack pr...

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Abstract

The invention discloses a heterogeneous cold repair welding process for online repairing a crack of a plug valve of a main steam pipeline, and particularly relates to the technical field of pipeline repair welding. The process includes the six steps of crack trend and depth judgment, crack pre-treatment, local preheating, welding, postweld treatment and welding detection. An angular grinder is used for grinding a welding repair U-type groove towards the deep position of the inner wall along the crack, the surface of a valve body around the crack is ground to serve as a repair welding region, apriming coat is subjected to welding deposition, and the repair welding region is evenly welded in a welding manner of priming coat and weld bead filling repair welding. The depth of the crack is judged, the trend and the length of the crack are comprehensively considered, the proper repair welding process is selected, a high-chromium high-nickel nickel-based welding material is selected by a cold welding method for repair, the course of the welding process is simple, the repair speed is high, the comprehensive cost is low, the crack is pre-treated, welding flux adhesion is convenient, the priming coat and the weld bead filling repair welding process is adopted, the welding quality is improved, and it is guaranteed that the pipeline is used under high-temperature high-strength working conditions.

Description

technical field [0001] The invention relates to the technical field of pipeline repair welding, and more specifically, the invention relates to a heterogeneous cold repair welding process for online repair of main steam pipeline valve blocking cracks. Background technique [0002] The designed operating temperature of the main steam pipeline of a 2×300MW subcritical parameter unit in a thermal power plant is 540°C, and the design pressure is 19.6MPa. When the unit has been running for 54,000 hours, it is found that there is a long line on the outer wall of the main steam pipeline at the junction of the valve body channel and the neck 200mm crack, the main steam pipe water pressure plug valve is cast steel, the material is ZG15Cr2Mo, the crack is on the steam outlet side of the valve, the valve body at the crack is 135mm thick, the surface crack is about 200mm long, and it is located at the junction of the valve body channel and the neck In the part where the cross-sectional ...

Claims

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Application Information

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IPC IPC(8): B23P6/04
CPCB23P6/04
Inventor 史海燕
Owner 史海燕
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