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Post-weld heat treatment method for welded structural parts of nickel-based superalloys resistant to molten salt corrosion

A nickel-based superalloy, post-welding heat treatment technology, applied in heat treatment furnaces, heat treatment equipment, furnace types, etc., can solve problems such as the decline in mechanical properties of welded joints, achieve the effect of improving plasticity and durability, and improving safety

Active Publication Date: 2017-06-16
上海联和日环能源科技有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The technical problem to be solved by the present invention is to overcome the problem of decreased mechanical properties of welded joints existing in the prior art, and to provide a post-weld heat treatment method for molten salt corrosion-resistant nickel-based superalloy welded structural parts, which can effectively improve molten salt corrosion resistance The morphology of eutectic carbides in nickel-based superalloy welded joints makes them spheroidized. While maintaining its strength level, it can significantly improve the plasticity and durability of welded joints and reduce the residual stress of welded joints.

Method used

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  • Post-weld heat treatment method for welded structural parts of nickel-based superalloys resistant to molten salt corrosion
  • Post-weld heat treatment method for welded structural parts of nickel-based superalloys resistant to molten salt corrosion
  • Post-weld heat treatment method for welded structural parts of nickel-based superalloys resistant to molten salt corrosion

Examples

Experimental program
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Effect test

Embodiment 1

[0047] The 20mm thick GH3535 alloy (chemical composition weight percentage: 70.8Ni, 6.96Cr, 16.7Mo, 4.2Fe, 0.35Si, 0.053C, 0.001S, 0.002P, 0.002B, 0.71Mn, 0.014Al was welded by manual argon tungsten arc welding ,0.011Ti, other ≤0.5) plates are welded into test plates, and the welding material used is the same composition as the base metal welding wire, the welding specifications are: welding current 140-155A, welding voltage 10-14V, welding speed 60-80mm / min, gas flow 10-12L / min (99.99% pure argon protection), interpass temperature control at ≤90 ℃. During the welding process, due to the heat of the arc, the matrix near the weld is rapidly heated to above 1300 °C, causing the primary carbides in this area to start to melt and transform into eutectic carbides during the subsequent cooling process. figure 1 Before welding, in the base metal matrix is ​​M 6 C-type spherical carbide, Figure 2a and Figure 2b They are lamellar eutectic carbides that appear in the heat-affecte...

Embodiment 2

[0050] Adopted GH3535 material and welding process are identical with embodiment 1, and the heat treatment process adopted is as follows:

[0051] Use anhydrous ethanol to clean the oil stains and other impurities on the surface of the welding test plate, then coat the anti-decarburization agent containing borax and water glass, put it in a box-type electric furnace, and heat it at a rate of 600 ° C / h in the atmosphere Carry out heating with the furnace, the temperature is 1170°C±10°C, and the holding time is 10 minutes. Then cool down to 760°C at a cooling rate of 200°C / h, and start heat preservation for aging. The heat preservation time is 90±0.1h. After the aging time is over, control the cooling rate to 55°C / h and cool to 400°C. out of the furnace at room temperature; the temperature curve of the entire post-weld heat treatment process is as follows image 3 Shown in the dotted curve in .

[0052] After the heat treatment in Example 1, the welded heat-affected zone and...

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Abstract

The invention discloses a post-welded heat treatment method of a fused salt corrosion-resistant nickel-based high temperature alloy welded structure part, and belongs to the technical field of heat treatment of metal materials. The method comprises the following steps: 1, carrying out solid solution heat treatment: heating a welded structure part to 1150-1180DEG C, and carrying out heat insulation; 2, carrying out ageing treatment: directly cooling the heated welded structure part to 850-870DEG C at a cooling speed of 200-220DEG C after the heat insulation process of the solid solution heat treatment step ends, and carrying out heat insulation for 5.9-6.1h; or cooling the heated welded structure part to 750-770DEG C, and carrying out heat insulation for 89.9-90.1h; and 3, carrying out step cooling: cooling the aged welded structure part to 400DEG C at a cooling speed of 50-55DEG C, and naturally cooling the cooled welded structure part to room temperature. The invention also discloses the fused salt corrosion-resistant nickel-based high temperature alloy welded structure part. The method spheroidizes eutectic carbides in welded joints, does not reduce the strength level of the welded structure part, can substantially improve the plasticity and the lasting life of the welded joint, and reduces the residual stress of the welded joint.

Description

technical field [0001] The invention relates to the technical field of heat treatment of metal materials, in particular to a post-weld heat treatment method for welded structural parts of nickel-based superalloys resistant to molten salt corrosion. Background technique [0002] The fourth-generation nuclear reactor-molten salt reactor has become an important development direction in the future nuclear power field because of its inherent safety and high efficiency. The reactor operates at a temperature of 600°C to 700°C, uses highly corrosive molten salt as the coolant, and uses nickel-based superalloys resistant to molten salt corrosion (such as Hastelloy N alloy developed by Oak Ridge Laboratory in the United States or developed by Chinese scientific research institutes) GH3535 alloy) as a structural material. [0003] Molten salt corrosion-resistant nickel-based superalloys are austenitic nickel-based alloys, mainly developed for molten salt reactors, and have very good r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22F1/10C21D9/50
CPCC21D9/50C22F1/10
Inventor 黎超文李志军陈双建玉昆李肖科蒋力王晚霞
Owner 上海联和日环能源科技有限公司