Thermal treatment method used for improving duplex stainless steel welded structure

A technology of duplex stainless steel and heat treatment method, used in heat treatment furnaces, heat treatment equipment, furnaces, etc., can solve problems such as no, and achieve the effect of improving the ability of pitting corrosion resistance

Inactive Publication Date: 2012-07-11
WENGFU (GRP) CO LTD
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Problems solved by technology

So far, there is no patent application related to the welding structure heat treatment technology of duplex stainless steel

Method used

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Embodiment

[0013] For the heat treatment of the weld seam and heat-affected zone obtained by ordinary argon arc welding of duplex stainless steel 2205, the method is to heat in an electric furnace at a temperature lower than and close to the phase transition temperature of duplex stainless steel 2205, and at the same time use electric pulse heating; Electric furnace heating and electric pulse heating are carried out in the range above the temperature, the heating speed is controlled at 1°C / s~50°C / s, and the pulse current of electric pulse heating is 1~60A / mm according to the cross-sectional area 2 The current density is determined, and the pulse frequency is controlled at 10-1000Hz. After heating, keep warm for 10-60 minutes, and then cool. The cooling is completed in three stages. The first stage: the temperature of the welded tissue is about 850°C, the cooling rate is controlled at 1°C / s-30°C / s, and pulse current is applied at the same time. Pulse current according to the cross-section...

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Abstract

The invention discloses a thermal treatment method used for improving a duplex stainless steel welded structure, which comprises the following steps: 1) heating by an electric oven at the temperature lower or close to duplex stainless steel phase transition when a duplex stainless steel weld seam and a heat affected zone are heated by a thermal treatment technology, simultaneously carrying out electric pulse heating; 2) insulating for 10-60 minutes after heating, cooling with three phases, wherein in a first phase, the temperature of the welded structure is 850 DEG C and the cooling speed is controlled at 1-30 DEG C/s, simultaneously providing pulse current; in a second phase: the temperature is decreased to 800-500 DEG C, the cooling speed is controlled at 5-50 DEG C/s, and the cooling speed is greater than that of the first phase; in a third phase: the temperature is decreased below 500 DEG C and the cooling speed is controlled more than 30 DEG C/s. The thermal treatment for duplex stainless steel welded seam and the heat affected zone can control the volume fraction and existence form of ferrite, avoid the precipitation of a brittleness phase in ferrite/austenite, ferrite/ferrite crystal boundary, and enhance the capability of pitting corrosion resistance of the duplex stainless steel.

Description

technical field [0001] The invention relates to metal heat treatment, in particular to heat treatment of duplex stainless steel welded structure. method. Background technique [0002] Due to the characteristics of two-phase structure, duplex stainless steel has the advantages of ferritic stainless steel and austenitic stainless steel. Compared with ferritic stainless steel, it has high toughness, low brittle transition temperature, intergranular corrosion resistance and good welding performance. At the same time, it retains the advantages of high thermal conductivity and small expansion coefficient of ferritic steel. Its yield strength is twice that of austenitic stainless steel, and its resistance to chloride stress corrosion cracking is significantly higher than that of 300 series austenitic stainless steel. The ability of pitting and crevice corrosion is similar to super austenitic stainless steel. The excellent comprehensive performance makes them widely used in marine,...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21D9/50
Inventor 向嵩严永友王权顶刘松林何勇岗马泽基
Owner WENGFU (GRP) CO LTD
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