Welding process of UNS N07208 superalloy pipe for boiler at 700 DEG C or above

A high-temperature alloy and welding process technology, applied in welding equipment, metal processing, welding accessories, etc., can solve the problems that the quality and joint performance cannot be guaranteed, the pass rate of welded joints is low, and welding research is relatively small. It can control welding defects, improve the pass rate of primary flaw detection, and ensure the effect of welding quality and performance

Inactive Publication Date: 2020-09-25
DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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Problems solved by technology

[0003] The superalloy UNS N07208 is considered to be the most potential material for the development of high-temperature key components of 700°C and higher ultra-supercritical boilers. Many experiments have been carried out at home and abroad. Welding process research, especially the welding research of large-diameter and t

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  • Welding process of UNS N07208 superalloy pipe for boiler at 700 DEG C or above

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Example Embodiment

[0018] The present invention will be described in further detail below in conjunction with the drawings.

[0019] Take a project as an example, such as figure 1 As shown, a welding process of UNS N07208 high-temperature alloy pipes for boilers exceeding 700°C includes the following steps: A) Two UNS N07208 high-temperature alloy pipes 1, 2 are grooved before welding, the outer diameter of the pipe is 45mm, and the groove surface 3 Use stainless steel or nickel-based material special polishing tools to polish and clean to a metallic luster within and around not less than 20mm. If the ambient temperature is lower than 10℃, the welding area and both sides of the area are not less than 3 times the wall thickness and not less than 100mm. Preheat the inside to 10℃ or more; B) Assemble as required, pass pure argon shielding gas into the two high temperature alloy tubes 1, 2 and use manual argon tungsten arc welding (GTAW). The welding wire material is SFA-5.14 ERNiCrCoMo- 2 or its impr...

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Abstract

The invention discloses a welding process of a UNS N07208 superalloy pipe for a boiler at 700 DEG C or above. The welding process comprises the following steps that (A) groove processing before welding is performed, a welding area is cleared, and preheating is performed; (B) assembling and welding are performed as required; (C) nondestructive flaw detection is performed after welding; and (D) post-welding heat treatment is performed after flaw detection is qualified. Welding materials adopted in the step (B) are SFA-5.14 ERNiCrCoMo-2 and an improved type thereof or SFA-5.14 ERNiCrCo-1 and an improved type thereof, and mixed gas of (60-80)% argon and (40-20)% helium is adopted as protective gas of a welding molten pool; and through the welding process, the defects such as slag inclusion, microcrack and incomplete fusion inside a welded seam can be eliminated, the welding quality and performance of a joint are ensured, the qualification rate of one-time flaw detection is increased, and conditions are created for future development of boilers at 700 DEG C and at the higher level and engineering application of a superalloy UNS N07208.

Description

technical field [0001] The invention relates to a welding process for UNS N07208 superalloy pipe. Background technique [0002] UNS N07208 is an aging-strengthened superalloy developed by Hastelloy International Corporation of the United States, and its typical chemical composition is well known. Due to its excellent high-temperature mechanical properties, corrosion resistance and good cold and hot processing properties, it is considered to be the most potential material for manufacturing key components such as high-temperature heating surfaces and headers of ultra-supercritical boilers at 700 °C and higher. [0003] The superalloy UNS N07208 is considered to be the most potential material for the development of high-temperature key components of 700°C and higher ultra-supercritical boilers. Many experiments have been carried out at home and abroad. Welding process research, especially the welding research of large-diameter and thick-walled pipes is relatively small, and th...

Claims

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Application Information

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IPC IPC(8): B23K9/167B23K9/32B23K9/235
CPCB23K9/167B23K9/32B23K9/235B23K2101/06
Inventor 张玮王林森张涛张明海刘洪伟
Owner DONGFANG BOILER GROUP OF DONGFANG ELECTRIC CORP
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