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Preparation method of flange material for nuclear power

A technology using flanges and nuclear power, applied in the field of iron and steel metallurgy, can solve the problems of high cost of flange materials, poor mechanical properties and manufacturability, etc., and achieve the effect of excellent mechanical properties, good manufacturability and good benefits

Inactive Publication Date: 2021-09-17
CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the cost of manufacturing flange materials is relatively high, and the mechanical properties and manufacturability are poor, which urgently needs to be improved.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

preparation example Construction

[0028] The invention provides a method for preparing a flange material for nuclear power. The method sequentially includes the steps of electric furnace smelting, AOD refining, LF refining, VD refining, casting, forging and heat treatment, and then cooling to room temperature to obtain the flange material; The normalizing temperature is 1030-1080°C, the normalizing time is 4-5 hours, the tempering temperature is 730-780°C, and the tempering time is 2-3 hours.

[0029] Further, the steelmaking raw materials used in the electric furnace smelting process include chromium stainless steel return materials (Fe 80-85%, Cr 8-10%), low-phosphorus molybdenum iron (Mo 73-77%, Fe 22-26%), Ferrochrome (Cr 63-67%, Fe 28-32%), Ferro-Vanadium (V 48-52%, Fe 43-47%), Ferroniobium (Nb 93-97%, Fe 3-5%) or Ferro-boron (B28~32%, Fe 63~67%) at least one.

[0030] Further, in the electric furnace smelting process, the steel is tapped when the temperature of the molten steel is higher than 1650-1660°...

Embodiment 1

[0051] Smelting: Use 37000Kg of scrap steel (Fe 80-85%, Cr 8-10%); ~32%) 450~480Kg, vanadium iron (V 48~52%, Fe43~47%) 100Kg, niobium iron (Nb 93~97%, Fe 3~5%) 22Kg or boron iron (B 28~32%, Fe 63~67%) 10Kg. The tapping temperature is 1650°C.

[0052] AOD: N 2 / Ar gas blowing system: Nitrogen blowing during oxidation, argon blowing during reduction. The target temperature was set at 1680°C.

[0053] LF: Feed Al to 0.03%. After the slag is melted, add steel slag and other materials for reduction in batches. A small amount of carbon powder can be added in the early stage of the LF furnace to maintain the reducing atmosphere. According to the fluidity of the slag, add 200kg / furnace 80 refining slag in batches, according to the target value Adjust chemical composition.

[0054] VD: The thickness of the slag is 60mm. Under the condition of the ultimate vacuum degree of 65Pa, the holding time of the argon blowing flow rate is 120 liters per minute for 18 minutes. The static blo...

Embodiment 2

[0065] Smelting: Use 37000Kg of scrap steel (Fe 80-85%, Cr 8-10%); ~32%) 480Kg, vanadium iron (V 48~52%, Fe 43~47%) 100Kg, niobium iron (Nb 93~97%, Fe 3~5%) 40Kg or boron iron (B 28~32%, Fe 63~67%) 10Kg. The tapping temperature is 1650°C.

[0066] AOD: N 2 / Ar gas blowing system: Nitrogen blowing during oxidation, argon blowing during reduction. The target temperature was set at 1670°C.

[0067] LF: Feed Al to 0.03%. After the slag is melted, add steel slag and other materials for reduction in batches. A small amount of carbon powder can be added in the early stage of the LF furnace to maintain the reducing atmosphere. According to the fluidity of the slag, add 200kg / furnace 80 refining slag in batches, according to the target value Adjust chemical composition.

[0068] VD: The thickness of the slag is 100mm. Under the condition of the ultimate vacuum degree of 70Pa, the holding time of the argon blowing flow rate is 140 liters per minute for 22 minutes. Before breaking t...

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Abstract

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a preparation method of a flange material for a nuclear power. The invention aims to provide the preparation method of the flange for nuclear power, which is more stable in process and quality and lower in cost. The method sequentially comprises the steps of conducting electric furnace smelting, AOD refining, LF refining, VD refining, casting, forging and heat treatment, and then cooling to room temperature, thereby obtaining the flange material, wherein the process conditions of the heat treatment are as follows: the normalizing temperature is 1,030-1,080 DEG C, the normalizing time is 4-5 hours, the tempering temperature is 730-780 DEG C, and the tempering time is 2-3 hours. The flange material prepared by the method not only has excellent comprehensive mechanical properties, but also has excellent normal temperature performance, excellent durability and creep property at the temperature of below 650 DEG C, low linear expansion coefficient and good manufacturability. The method disclosed by the invention is stable in process and quality, low in cost and good in benefit, and can be popularized and used in the field.

Description

technical field [0001] The invention belongs to the technical field of iron and steel metallurgy, and in particular relates to a preparation method of a flange material for nuclear power. Background technique [0002] With the improvement of the design life and safety requirements of the third-generation nuclear power plants, pressure vessel forgings show a trend of large-scale and integrated. At present, the domestic demand for nuclear power is strong, and the overall safety goal of nuclear power plants is to establish and maintain effective defense against radioactive hazardous substances. Whether it is a container directly containing radioactive substances or a containment vessel as the last barrier, the sealing performance of the flanges on each equipment is self-evident for the safety of nuclear power plants. Bolted flange connection is a very common and widely used connection method in nuclear equipment, so the quality requirements for flange materials are very strict...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C33/06C22C38/02C22C38/04C22C38/06C22C38/44C22C38/46C22C38/48C21D1/18C21D1/28C21D6/00C21D8/00B21J5/00
CPCC22C33/06C22C38/02C22C38/04C22C38/06C22C38/44C22C38/48C22C38/46C21D1/28C21D1/18C21D6/004C21D6/005C21D6/008C21D8/005B21J5/002
Inventor 赵中清张军涂露寒尹凤先
Owner CHENGDU ADVANCED METAL MATERIALS IND TECH RES INST CO LTD