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Rolling method for puller bolt of steam generator of pressurized-water reactor nuclear power station

A pressurized water reactor nuclear power plant and steam generator technology, applied in metal rolling and other directions, can solve the problems of high cost and easy fracture pass rate, and achieve the effects of low cost, difficult processing of cracks, and increased impact resistance

Inactive Publication Date: 2012-07-11
JIANGSU NEW HENGJI SPECIAL EQUIP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to solve the problems of high cost, easy breakage and low qualified rate in the forging processing method commonly used for fixed-distance tie rods, and to process a pressurized water reactor nuclear power plant that meets the technical procurement requirements by adjusting the material formula and adopting the rolling processing method Rolling method of distance tie rods for steam generators

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] A method for rolling fixed-distance tie rods of a steam generator in a pressurized water reactor nuclear power plant, comprising the following steps:

[0022] 1. Select steel ingots that meet the following weight percentage requirements: C: 0.10%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.03%; P: ≤0.030%; Cr: 11%; Ni: 0.25%, The balance is Fe and unavoidable impurities;

[0023] 2. Rolling the above steel ingot into a round steel billet;

[0024] 3. Heat the green body generated in step 2 to 800°C and keep it warm for about 4 hours, then water-cool;

[0025] 4. Heat the green body to 850°C (or the same 800°C as step 3) and keep it warm for about 4 hours, and then water-cool it. After the heat treatment process in steps 3 and 4, the crystal structure of the material can undergo two phase transitions to improve The intergranular structure is improved, which is beneficial to improve the overall mechanical properties;

[0026] 5. Heat the green body that has been heated twice and wate...

Embodiment 2

[0029] A method for rolling fixed-distance tie rods of a steam generator in a pressurized water reactor nuclear power plant, comprising the following steps:

[0030] 1. Select steel ingots with the following weight percentages: C: 0.12%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.03%; P: ≤0.030%; Cr: 112%; The amount is Fe and unavoidable impurities;

[0031] 2. Rolling the above steel ingot into a round steel billet;

[0032] 3. Heat the green body generated in step 2 to 980°C and keep it warm for about 4 hours, then water-cool;

[0033] 4. Heat the green body to 900°C (or 980°C as in step 3) and keep it warm for about 4 hours, then water-cool;

[0034] 5. Heat the green body that has been heated twice and water-cooled to 700°C and keep it warm for 4 hours, and then air-cool to room temperature;

[0035] 6. Machining the green body generated in step e) results in a tensile strength of 960MPa at room temperature and a yield strength of 700MPa; at 350°C, the yield strength is 600MPa; at 0°...

Embodiment 3

[0037] A method for rolling fixed-distance tie rods of a steam generator in a pressurized water reactor nuclear power plant, comprising the following steps:

[0038] 1. Select steel ingots with the following weight percentages: C: 0.11%; Si: ≤1.0%; Mn: ≤1.0%; S: ≤0.03%; P: ≤0.030%; Cr: 11.5%; The amount is Fe and unavoidable impurities;

[0039] 2. Rolling the above steel ingot into a round steel billet;

[0040] 3. Heat the green body generated in step 3 to 900°C and keep it warm for 4 hours, then water-cool;

[0041] 4. Reheat the green body to 950°C (or the same 900°C as step 3) and keep it warm for 4 hours, then water-cool;

[0042] 5. Heat the green body after two times of heat preservation and water cooling to 650°C and keep it for 4 hours, and then air cool to room temperature;

[0043] 6. Machining the green body generated in step 5, the tensile strength at room temperature is 900MPa, and the yield strength is 650MPa; at 350°C, the yield strength is 550MPa; at 0°C, ...

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Abstract

A rolling method for a puller bolt of a steam generator of a pressurized-water reactor nuclear power station is characterized by including the steps: selecting a steel ingot comprising 0.10%-0.12% of C (carbon), less than or equal to 1.0% of Si (silicon), less than or equal to 1.0% of Mn (manganese), less than or equal to 0.03% of S (sulfur), less than or equal to 0.030% of P (phosphorus), 11%-12% of Cr (chromium), 0.25%-0.6% of Ni (nickel), the balance Fe (ferrum) and inevitable impurities; rolling the steel ingot into a round steel billet; heating the generated billet to 800-980 DEG C, preserving heat for 4h and then cooling the generated billet with water; after repeatedly heating, heating the billet after two-time heating, heat preservation and water cooling again to 600-700 DEG C, preserving heat for 4h and then air-cooling the billet to normal temperature; and machining the generated billet to obtain the puller bolt with tensile strength higher than or equal to 800-960MPa and yield strength higher than or equal to 600MPa at room temperature, wherein the yield strength of the puller bolt is higher than or equal to 500MPa at the temperature of 350 DEG C, and at the temperature of 0 DEG C, the average value of the impacting energy of the puller bolt is higher than or equal to 80J, and the single minimum impacting energy of the puller bolt is higher than or equal to 50J. The rolling method for machining the steel ingot has the advantages of low cost, difficulty in generating machining cracks and high qualification rate, and overcomes the defects of forging and pressing.

Description

technical field [0001] The invention relates to a component of a nuclear power plant, in particular to a method for manufacturing a fixed-distance tie rod, in particular to a rolling method for a fixed-distance tie rod of a steam generator in a pressurized water reactor nuclear power plant. Background technique [0002] At present, due to the rising cost of oil, natural gas and coal, the Chinese government reviewed and approved in principle the "Nuclear Power Medium and Long-Term Development Plan (2005-2020)", and it is estimated that by 2020, my country's nuclear power installed capacity will increase from the current 8.7 million kilowatts Reaching 40 million kilowatts, the capacity of 40 million kilowatts means that from now to 2020, my country still needs to start construction of about 30 new million-kilowatt-level nuclear power units, and build another 30 nuclear power plants. Nuclear power construction will take place in these 15 years. Make a sea change. Due to its spec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21B1/02C22C38/40C21D8/06
Inventor 向田法王槐春
Owner JIANGSU NEW HENGJI SPECIAL EQUIP