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A kind of micro-alloyed 25cr35ninb alloy steel for ethylene cracking furnace tube

An ethylene cracking furnace and micro-alloying technology, which is applied in the field of ethylene cracking furnace tube materials, can solve the problems affecting the long-term safe operation of the device and the poor quality stability of the furnace tube, so as to ensure the long-term safe operation and improve the high temperature lasting fracture time. Effect

Active Publication Date: 2017-09-26
HEFEI GENERAL MACHINERY RES INST +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, at present, the high-temperature durable fracture time of domestic furnace tubes cannot fully meet the above requirements, resulting in poor quality stability of the furnace tubes, frequent early failures, and seriously affecting the long-term safe operation of the device.

Method used

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  • A kind of micro-alloyed 25cr35ninb alloy steel for ethylene cracking furnace tube
  • A kind of micro-alloyed 25cr35ninb alloy steel for ethylene cracking furnace tube
  • A kind of micro-alloyed 25cr35ninb alloy steel for ethylene cracking furnace tube

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Experimental program
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Effect test

Embodiment 1

[0056] A microalloyed 25Cr35NiNb alloy steel for ethylene cracking furnace tubes, the chemical composition of which is shown in Table 1.

[0057] Table 1 Chemical composition of microalloyed 25Cr35NiNb alloy steel for ethylene cracking furnace tubes

[0058]

[0059] Note: The unit is mass percent.

[0060] After testing, the microalloyed 25Cr35NiNb furnace tube in this embodiment is etched by aqua regia, and the columnar crystals account for 89% of the wall thickness. After electrolytic etching with a volume fraction of 10% oxalic acid aqueous solution, its grain size grade is Level 5.2.

[0061] For the microalloyed 25Cr35NiNb furnace tube sample prepared with the ratio in Table 1, the high temperature endurance strength test was carried out three times under the test conditions of 1100 ° C and 17 MPa, and the test results are shown in Table 2.

[0062] Table 2 High temperature durability test results of microalloyed 25Cr35NiNb furnace tube

[0063]

[0064] It can ...

Embodiment 2

[0066] A microalloyed 25Cr35NiNb alloy steel for ethylene cracking furnace tubes, the chemical composition of which is shown in Table 3.

[0067] Table 3 Chemical composition of microalloyed 25Cr35NiNb alloy steel for ethylene cracking furnace tubes

[0068]

[0069] Note: The unit is mass percent.

[0070] After testing, the microalloyed 25Cr35NiNb furnace tube in this embodiment is etched by aqua regia, and the columnar crystals account for 100% of the wall thickness. After electrolytic etching with a volume fraction of 10% oxalic acid aqueous solution, its grain size grade is Level 5.5.

[0071] For the microalloyed 25Cr35NiNb furnace tube sample prepared in the ratio in Table 3, the high temperature endurance strength test was carried out three times under the test conditions of 1100 ° C and 17 MPa, and the test results are shown in Table 4.

[0072] Table 4 High temperature endurance test results of microalloyed 25Cr35NiNb furnace tube

[0073]

[0074] It can be...

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Abstract

The invention discloses a microalloyed 25Cr35NiNb alloy steel for ethylene cracking furnace tubes, which contains C: 0.40-0.45, Si: 1.5-1.8, Mn: 1.0-1.5, P: 0.001-0.020, S: 0.001 in mass percent ~0.010, Cr: 25~26, Ni: 35~36, Nb: 0.75~1.0, W: 0.01~0.20, Mo: 0.01~0.20, Cu: 0.01~0.30, Al: 0.01~0.20, Ti: 0.05~0.15 , Zr: 0.05-0.15, B: 0.0010-0.0050, As: 0-0.0020, Sn: 0-0.0020, Pb: 0-0.0020, Bi: 0-0.0001, and the balance is Fe. The alloy steel requires columnar grains to account for more than 70% of the wall thickness, and the grain size grade is 5-6. The invention can effectively improve the high-temperature durability performance of the ethylene cracking furnace tube, so that it meets the requirement that the high-temperature durable fracture time is greater than 100 hours under the conditions of 1100°C and 17MPa, thereby achieving the purpose of ensuring the long-term safe operation of the ethylene unit.

Description

technical field [0001] The invention belongs to the technical field of ethylene cracking furnace tube materials, and in particular relates to a microalloyed 25Cr35NiNb alloy steel for ethylene cracking furnace tubes. Background technique [0002] Ethylene cracking furnace tubes are widely used in petrochemical, electric power, metallurgy, gas and other pillar fields of the national economy. Once failure occurs, it will seriously affect the long-term safe operation of the entire device. In recent years, ethylene cracking furnaces have gradually developed towards high parameters and large scale. The service conditions of ethylene cracking furnace tubes have become more complex and harsh, and higher requirements have been placed on the high temperature performance of ethylene cracking furnace tubes. At present, the actual service life of the domestic ethylene cracking furnace tubes put into use in the market is uneven, and the actual service life of a large number of furnace tu...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/60C22C38/54
Inventor 陈学东陈涛刘春娇连晓明范志超
Owner HEFEI GENERAL MACHINERY RES INST
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