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A kind of high-strength low-temperature resistant steel and its heat treatment process

A low-temperature-resistant, high-strength technology, applied in the fields of high-strength low-temperature resistant steel and its heat treatment process, high-strength low-Ni series ferritic low-temperature resistant steel and its heat treatment process, can solve the problem of lack of low-temperature strong-toughness composite structural steel, etc.

Active Publication Date: 2017-04-19
SHANGHAI JIAOTONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a high-strength low-temperature resistant steel and its heat treatment process, which is used to solve the lack of a combination of good low-temperature strength and toughness in the prior art and can be used in low-temperature environments. The problem of structural steel and its preparation method

Method used

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  • A kind of high-strength low-temperature resistant steel and its heat treatment process
  • A kind of high-strength low-temperature resistant steel and its heat treatment process
  • A kind of high-strength low-temperature resistant steel and its heat treatment process

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0072] The formula of high strength and low temperature resistant steel material is as follows: Ni: 6.85-7.05%; C: 0.045-0.060%; Si: 0.05-0.08%; Mn: 0.69-5.00%; Cr: 0.3-0.4%; Mo: 0.05-0.4% ; Cu: 0.02-0.3%; Al: 0.036-0.040%; P: ≤0.009%; S: ≤0.002%; N: 0.004-0.005%; O: 0.0005-0.002%; For Fe.

[0073] The elemental components in the above formula are mixed according to the ratio and then smelted, and then the slab is continuously cast into an ingot, which is air-cooled after multi-step hot rolling, and the thickness of the ingot is 240mm. Among them, the multi-step hot rolling conditions are: continuous temperature of 1050, 980, 850, 830, 810, 780, 770, and 750°C respectively, and the reduction rates are 29.17%, 29.41%, 25%, 22.22%, and 21.43%. , 20%, 20%, 21.88%, the holding time is 170, 120, 90, 70, 50, 40, 32, 25 minutes respectively. The specific data of multi-step hot rolling is shown in Table 1, and the specific steps are shown in figure 1 . The hot-rolled ingot was ins...

Embodiment 2

[0076] The formula of high strength and low temperature resistant steel material is as follows: Ni: 2.0-5.75%; C: 0.02-0.1%; Si: 0.02%-0.1%; Mn: 4.75-8.00%; Cr: 0.3-0.4%; Mo: 0.15-0.60 %; Cu: 0.02-0.3%; Al: 0.044-0.048%; P: ≤0.009%; S: ≤0.002%; N: 0.004-0.005%; The amount is Fe.

[0077] The elemental components in the above formula are mixed according to the ratio and then smelted, and then the slab is continuously cast into an ingot, which is air-cooled after multi-step hot rolling, and the thickness of the ingot is 240mm. Among them, the multi-step hot rolling conditions are: continuous temperature of 1050, 980, 850, 830, 810, 780, 770, and 750°C respectively, and the reduction rates are 29.17%, 29.41%, 25%, 22.22%, and 21.43%. , 20%, 20%, 21.88%, the holding time is 170, 120, 90, 70, 50, 40, 32, 25 minutes respectively. The specific data of multi-step hot rolling is shown in Table 1, and the specific steps are shown in figure 1 . The hot-rolled ingot was inspected unde...

Embodiment 3

[0082] The high-strength and low-temperature-resistant steel material samples 1-2# in Example 1-2 were respectively observed with an optical microscope for structure and retained austenite. For specific results, see figure 2 a, 2b, 3a, 3b.

[0083] Depend on figure 2 a, 2b, 3a, and 3b, it can be seen that the structure of the sample in the hot-rolled state is relatively disordered, the deformation is severe, and there are many dislocations and defects. The toughness of this structure is bound to be poor, but after QLT treatment, the structure All are tempered martensite + acicular ferrite + a small amount of austenite, the deformation caused by hot rolling is eliminated by heat treatment, and the structure is also refined.

[0084] At the same time, the retained austenite content measured by magnetic field is shown in Table 2 for specific data. It can be seen from Table 2 that the austenite content of the steel after QLT heat treatment has increased significantly, thereby ...

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Abstract

The invention provides high-strength low-temperature-resistant steel. The steel is composed of, by mass, 2.0-7.05% of nickel, 0.02-0.1% of carbon, 0.02-0.1% of silicon, 0.60-8.00% of manganese, 0.3-0.5% of chrome, 0.05-0.6% of molybdenum, 0.02-0.3% of copper, 0.03-2.0% of aluminum, smaller than or equal to 0.010% of phosphorus, smaller than or equal to 0.002% of sulfur, 0.004-0.010% of nitrogen, 0.0005-0.002% of oxygen, 0.0005-0.005% of calcium, and the balance iron. The invention further provides the heat processing technology and application of the high-strength low-temperature-resistant steel. By the adoption of the high-strength low-temperature-resistant steel and the heat processing technology thereof, low-temperature toughness is high, structural steel used in a low-temperature environment can be manufactured, application cost is reduced, and economical applicability is high.

Description

technical field [0001] The invention belongs to the technical field of low-temperature steel, and relates to a high-strength low-temperature resistant steel and a heat treatment process thereof, in particular to a high-strength low-Ni series ferritic low-temperature resistant steel and a heat treatment process thereof. Background technique [0002] In the context of increasingly tense energy sources, the global production and trade of liquefied natural gas (LNG) has become increasingly active. Liquefied natural gas (LNG for short) is natural gas that is compressed and cooled to its boiling point (-161.5°C) and becomes liquid. Usually, liquefied natural gas is stored in a low-temperature storage tank at -161.5°C and 0.1MPa. Compared with gaseous natural gas, liquefied natural gas is only 1 / 625 of the original volume, which is very convenient for storage and transportation, and the ground transportation cost of LNG per unit weight is only 1 / 6-1 / 7 of the pipeline transportation...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/44C22C38/58C21D8/00
Inventor 金学军李伟金明江黎雨王钟炜
Owner SHANGHAI JIAOTONG UNIV
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