Repair method and device of welding defect of inner hole welding in U-shaped pipe type heat exchanger

A technology for welding defects and heat exchangers, applied in welding equipment, arc welding equipment, manufacturing tools, etc., can solve the problems of large-scale application of difficult maintenance, difficult operation, and scrapped heat exchangers, and promote large-scale application. , strong process adaptability, and the effect of improving maintainability

Pending Publication Date: 2020-07-14
725TH RES INST OF CHINA SHIPBUILDING INDAL CORP
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AI Technical Summary

Problems solved by technology

[0004] Inner hole welding requires high technology and difficult operation. Small changes in welding parameters and welding environment will lead to welding defects, and U-shaped tube heat exchangers in important occasions usually require compact structure, so the arrangement of heat exchange tubes is relatively dense. , the operating space is small, once any welding defect occurs, it can only be remedied by plugging the tube holes of the tube sheet, and when there are many tube holes with welding defects, the entire heat exchanger will be scrapped
At present, the difficult maintenance of the inner hole welding seam has become an important factor restricting its large-scale application. However, in addition to the above-mentioned method of sealing the tube hole of the tube sheet, there are no other methods for the repair of inner hole welding defects. in newspaper

Method used

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  • Repair method and device of welding defect of inner hole welding in U-shaped pipe type heat exchanger
  • Repair method and device of welding defect of inner hole welding in U-shaped pipe type heat exchanger
  • Repair method and device of welding defect of inner hole welding in U-shaped pipe type heat exchanger

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Embodiment 1

[0032] combine Figure 1~4 This embodiment will be described. This embodiment provides a repair method for inner hole welding defects in titanium alloy U-shaped tube heat exchangers. The inner hole welding seams 23 that generate defects are in the form of a butt joint structure. The 211 sets of ring-shaped bosses on the top are welded against each other, and the inner holes are welded by inner hole welding. After each row of heat exchange tubes is welded, visual inspection and radiographic flaw detection are carried out, and the next row is replaced after confirming that there are no welding defects. Welding of heat pipes. After the welding of a certain row of heat exchange tubes is completed, visual inspection finds that there is a phenomenon of welding leakage, and the width of the welding leakage point is greater than the width of the inner hole welding seam 23 . According to the existing inner hole welding technology, the repair welding method cannot be used to realize t...

Embodiment 2

[0057] This embodiment provides a repair method for inner hole welding defects in a stainless steel U-shaped tube heat exchanger, which is basically the same as the repair method provided in Example 1, and only the differences will be further described below.

[0058] The welding defect of the inner hole in the stainless steel U-shaped tube heat exchanger is a single pore, and the size of a single pore exceeds 1 / 2 of the wall thickness of the U-shaped heat exchange tube, which cannot meet the requirements of "qualified according to NB / T 47013.2 Class II" Flaw detection requirements. When using the rework device 1 to completely remove the generated defects and open a new inner hole welding groove on the tube sheet 21, the cutting position is set at a position about 1mm below the edge of the weld. Porosity, on the other hand, is to remove the weld seam together with the heat-affected zone, so as to avoid the deterioration of the performance of the welded joint caused by the seco...

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Abstract

The invention relates to a repair method and device of a welding defect of inner hole welding in a U-shaped pipe type heat exchanger. The repair method uses a designed repair device to completely remove an inner hole welding line generating the defects, and form a new inner hole welding groove in a pipe plate, an original U-shaped heat exchange pipe is drawn out and replaced with a new U-shaped heat exchange pipe is replaced, and inner hole welding is carried out on the new U-shaped heat exchange pipe and a pipe plate set again, the repair device comprises a height fixing nut, a cushion block,a positioning ring, a push rod, a shaft sleeve, a pin shaft and a cutting blade, according to the repair method and device of the welding defect of inner hole welding in the U-shaped pipe type heat exchanger, the phenomenon that after a defect appears in an inner hole welding line at present, a manner of blocking a pipe hole of a pipe plate is only adopted for repair can be avoided thoroughly, the inner hole welding line maintainability is greatly improved, and the large-scale application of the inner hole welding technology can be greatly promoted.

Description

technical field [0001] The invention belongs to the field of welding technology, and in particular relates to a method and a device for repairing welding defects of inner hole welding in a U-shaped tube heat exchanger. Background technique [0002] U-shaped tube heat exchanger is a kind of tube-and-tube heat exchanger. It has many advantages such as simple and compact structure, good thermal compensation, and easy cleaning. It is widely used in petroleum, chemical, energy and other industries. As the name implies, the heat exchange tube of the U-shaped tube heat exchanger is U-shaped, and it is generally connected to the tube sheet by welding to form a tube bundle. The weld quality of the heat exchange tube and the tube sheet directly affects the heat exchange performance and working stability of the U-shaped tube heat exchanger. The traditional welded joints of heat exchange tubes and tube sheets are located at the end of the tube sheet, which is a typical fillet joint, s...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23P6/00B23D79/00B23K9/167
CPCB23D79/00B23K9/167B23P6/00
Inventor 李炳王乃友李瑞武张毅王岗
Owner 725TH RES INST OF CHINA SHIPBUILDING INDAL CORP
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