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Welding process for preventing repair welding cracks on nickel base alloy bent pipes

A nickel-based alloy and welding process technology, which is applied in the field of welding process to avoid repair welding cracks in nickel-based alloy elbow pipes, can solve the problems of high scrap rate, brittle cracking of fusion line, and large welding stress, so as to avoid cracks, The effect of reducing welding stress and avoiding thermal cracks

Inactive Publication Date: 2020-02-11
HUSN CASTING ANHUI YINGLIU GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0002] Because nickel-based alloy castings are very sensitive to hot cracks, the method of one-time filling repair welding without preheating and low interpass temperature is generally used to complete the defect repair work. Cracks, but in the case of repair welding with large defects, the welding stress is large, and the casting material (such as A494 CW12MW) is very brittle, and its standard elongation is 4%, so it is easy to cause the fusion line after welding under the action of welding stress Brittle cracking, resulting in defect repair failure and extremely high scrap rate
Therefore, elbows made of nickel-based alloy materials often have cracks in the repair welding process, which not only greatly increases production costs, but also causes huge waste of materials

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A welding process for avoiding repair welding cracks in nickel-based alloy elbows, comprising the following steps:

[0023] 1) Use carbon arc gas to remove casting defects, and use grinding wheels to polish and clean the surface;

[0024] 2) Carry out PT inspection on the cleaned surface to confirm that the inspection meets the requirements;

[0025] 3) Surfacing the transition layer on the groove surface of the defective part first, using electrode arc welding, power supply polarity: DC reverse connection; electrode selection: SFA 5.11ENiCrMo-4, diameter 3.2mm; current selection: I=80—110A ;Voltage selection: U=22-26V, welding speed: 10-15cm / min; during the surfacing welding process, the position is always kept in the flat welding position, and the interpass temperature is lower than 60°C;

[0026] 4) Check the surfacing surface, the thickness of the surfacing layer is 3-4mm;

[0027] 5) After the surfacing layer has passed the inspection, put the product as a whole ...

Embodiment 2

[0031] A welding process for avoiding repair welding cracks in nickel-based alloy elbows, comprising the following steps:

[0032] 1) Use carbon arc gas to remove casting defects, and use grinding wheels to polish and clean the surface;

[0033] 2) Carry out PT inspection on the cleaned surface to confirm that the inspection meets the requirements;

[0034] 3) Surfacing the transition layer on the groove surface of the defective part first, using electrode arc welding, power supply polarity: DC reverse connection; electrode selection: SFA 5.11ENiCrMo-4, diameter 3.2mm; current selection: I=80—110A ;Voltage selection: U=22-26V, welding speed: 10-15cm / min; during the surfacing welding process, the position is always kept in the flat welding position, and the interpass temperature is lower than 60°C;

[0035] 4) Check the surfacing surface, the thickness of the surfacing layer is 3-4mm;

[0036] 5) After the surfacing layer has passed the inspection, put the product as a whole ...

Embodiment 3

[0040] A welding process for avoiding repair welding cracks in nickel-based alloy elbows, comprising the following steps:

[0041] 1) Use carbon arc gas to remove casting defects, and use grinding wheels to polish and clean the surface;

[0042] 2) Carry out PT inspection on the cleaned surface to confirm that the inspection meets the requirements;

[0043] 3) Surfacing transition layer is first carried out on the groove surface of the defective part. The number of transition layers for surfacing welding can be 1 or 2 layers, and the thickness of the transition layer is 3-4mm. Electrode arc welding is used, and the polarity of the power supply: DC reverse connection; Electrode selection: SFA 5.11ENiCrMo-4, diameter 3.2mm; current selection: I=80-110A; voltage selection: U=22-26V, welding speed: 10-15cm / min; during the surfacing welding process, the position is always kept in the flat welding position , the interpass temperature is lower than 60°C;

[0044] 4) Check the surfa...

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Abstract

The invention discloses a welding process for preventing repair welding cracks on nickel base alloy bent pipes. The welding process is characterized by comprising the steps of: 1) using carbon arc gasto remove defects of castings, and using a grinding wheel to polish and clean the surfaces; 2) performing the PT inspection on the cleaned surfaces, and confirming that the inspection meets requirements; 3) firstly overlaying transition layers on groove surfaces of defect parts; 4) inspecting the overlaid surfaces, wherein the thicknesses of overlaid layers are 3-4 mm; 5) totally placing productsinto a heating furnace for heating to reach a temperature of 180-220 DEG C for insulation by 2-3 hours after qualification of the overlaid layers; 6) performing the fill welding; and 7) polishing welding lines after the fill welding, and inspecting that welded surfaces of the products meet the requirements to finish the repair welding for defects of the nickel base alloy bent pipes. The welding process can prevent the crack defects of the nickel base alloy bent pipes in the repair welding process.

Description

technical field [0001] The invention relates to the technical field of welding production, in particular to a welding process method for avoiding repair welding cracks in nickel-based alloy elbow pipes. Background technique [0002] Because nickel-based alloy castings are very sensitive to hot cracks, the method of one-time filling repair welding without preheating and low interpass temperature is generally used to complete the defect repair work. Cracks, but in the case of repair welding with large defects, the welding stress is large, and the casting material (such as A494 CW12MW) is very brittle, and its standard elongation is 4%, so it is easy to cause the fusion line after welding under the action of welding stress Brittle cracking, resulting in defect repair failure and extremely high scrap rate. Therefore, the elbow pipe made of nickel-based alloy material often has cracks in the repair welding process, which not only greatly increases the production cost, but also c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B23K9/04B23K9/235
CPCB23K9/048B23K9/235B23K2101/06B23K2103/08
Inventor 李宏生杜应流杨亮徐映俞秀枝李成林
Owner HUSN CASTING ANHUI YINGLIU GROUP