Valve manufacturing process for improving impact toughness of F92 butt welding heat affected area

A technology of impact toughness and heat-affected zone, which is applied in the field of valve manufacturing technology to improve the impact toughness of F92 butt welding heat-affected zone, can solve the problems of low effect and low impact toughness, and achieve the effect of improving dispersion and improving inhomogeneity

Active Publication Date: 2015-01-14
NANTONG POWER STATION VALVE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, to solve the problem of low impact toughness in the heat-affected zone of F92 butt welding, the idea is basically to optimize the welding process, post-weld stress relief treatment process, and control the cooling rate, etc., but with little effect

Method used

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  • Valve manufacturing process for improving impact toughness of F92 butt welding heat affected area
  • Valve manufacturing process for improving impact toughness of F92 butt welding heat affected area
  • Valve manufacturing process for improving impact toughness of F92 butt welding heat affected area

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Embodiment Construction

[0010] The heat treatment process in the present invention mainly includes forging→post-forging heat treatment→rough machining→butt welding→performance heat treatment→secondary tempering→surfacing welding sealing surface→post-welding heat treatment→finishing→inspection.

[0011] Heat treatment after forging: heat the forged piece in the furnace to 870±10°C, keep it warm for 2-4 hours, open the furnace door and cool it to 780±10°C, keep it warm for 1-2 hours, cool the furnace to 400°C and take it out of the furnace for air cooling.

[0012] Process purpose:

[0013] a. To spheroidize alloy carbides and improve the dispersion of alloy carbides;

[0014] b. Guarantee cutting performance;

[0015] c. Prepare the tissue for butt welding.

[0016] Performance heat treatment: heat in the furnace to 1050±10°C, keep warm for 2-4 hours, air cool below 300°C; reheat to 780±10°C, keep warm for 4-5 hours, then air-cool.

[0017] Process purpose:

[0018] a. Meet the mechanical performa...

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Abstract

The invention relates to a valve manufacturing process for improving impact toughness of an F92 butt welding heat affected area. The process mainly comprises the steps of forging, rough machining, butt welding, sealing surface surfacing, heat treatment after welding, fine machining and inspection; and the process is characterized in that heat treatment after forging is carried out after forging and performance heat treatment and secondary annealing are carried out in sequence after butt welding; the valve manufacturing process for improving the impact toughness of the F92 butt welding heat affected area, provided by the invention, has the advantages as follows: as corresponding heat treatment is carried out after each procedure, the form of F92 material alloy carbide is changed and the degree of dispersion of the alloy carbide is enhanced; the nonuniformity of welding stress distribution is improved; performance heat treatment is carried out after welding, so that coarse crystallines are completely eliminated; and through the adoption of a secondary annealing process, no marstenite quenching structure in a matrix is ensured. Through the implementation of the integrated process, the coarse crystalline structure of the weldment heat affected area can be fundamentally changed, and a difficulty problem that the impact toughness of the F92 butt welding heat affected area is substandard can be solved.

Description

technical field [0001] The invention relates to a heat treatment process, in particular to a valve manufacturing process for improving the impact toughness of the heat-affected zone of F92 butt welding. Background technique [0002] On the basis of F91 steel, F92 steel appropriately reduces the content of molybdenum (0.5% Mo), and at the same time adds a certain amount of tungsten (1.8% W) to change the molybdenum equivalent (Mo+0.5W) of the material from F91 steel to 1 % refers to about 1.5%, the steel also added a small amount of boron, after the above-mentioned alloying improvement, compared with other chromium-molybdenum heat-resistant steels, the high-temperature corrosion and oxidation resistance of F92 steel is similar to that of 9%Cr steel, However, the high-temperature strength and creep properties of the material have been further improved, and F92 steel also has better low-cycle thermal fatigue resistance than austenitic stainless steel (such as 347H). [0003] W...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23P15/00C21D8/00C21D9/00C21D6/00
Inventor 夏明民张建华
Owner NANTONG POWER STATION VALVE
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