Nickel saving type 7Ni steel for ultralow temperature environment and heat treatment technology of nickel saving type 7Ni steel

An ultra-low temperature, nickel-saving technology, applied in the field of low-temperature steel, to achieve the effect of uniform distribution and dispersion of reversed austenite, fine structure, and saving Ni resources

Active Publication Date: 2018-04-20
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in China, the relevant research on nickel-saving 7Ni steel is still in its infancy, so it is necessary to conduct further research and discussion on it.

Method used

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  • Nickel saving type 7Ni steel for ultralow temperature environment and heat treatment technology of nickel saving type 7Ni steel
  • Nickel saving type 7Ni steel for ultralow temperature environment and heat treatment technology of nickel saving type 7Ni steel
  • Nickel saving type 7Ni steel for ultralow temperature environment and heat treatment technology of nickel saving type 7Ni steel

Examples

Experimental program
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Effect test

Embodiment 1

[0038] A nickel-saving 7Ni steel used in ultra-low temperature environments. The chemical composition of the nickel-saving 7Ni steel is as follows: Ni: 7.00-7.60%, C: 0.02-0.06%, Si: 0.03-0.06%, Mn : 0.70~0.90%, P≤0.010%, S≤0.005%, Cr: 0.30~0.60%, Nb: 0.01~0.03%; the balance is Fe (one of the specific components is shown in Table 1); smelting according to the above ratio , adopt corresponding desulfurization technology to control the impurity content; after that, carry out multi-step hot rolling on the cast ingot and then air cooling, and before finishing rolling, the thickness of the intermediate billet should be between 70 and 100mm; the rolled steel after air cooling should be subjected to QLT heat treatment ( Process parameters are shown in Table 2), such as figure 1 As shown, samples were taken from the steel plate after heat treatment, and the microstructure of the sample was observed with a scanning electron microscope. The specific microstructure is as follows figure...

Embodiment 2

[0040] A nickel-saving 7Ni steel used in ultra-low temperature environments. The chemical composition of the nickel-saving 7Ni steel is as follows: Ni: 7.00-7.60%, C: 0.02-0.10%, Si: 0.50-0.80%, Mn : 0.10~0.30%, P≤0.010%, S≤0.005%, Cr: 0.30~0.60%, Mo: 0.10~0.20%; the balance is Fe (one of the specific components is shown in Table 1); smelting according to the above ratio , adopt corresponding desulfurization technology to control the impurity content; after that, carry out multi-step hot rolling on the cast ingot and then air cooling, and before finishing rolling, the thickness of the intermediate billet should be between 70 and 100mm; the rolled steel after air cooling should be subjected to QLT heat treatment ( Process parameters are shown in Table 2), such as figure 1 As shown, samples were taken from the steel plate after heat treatment, and the microstructure of the sample was observed with a scanning electron microscope. The specific microstructure is as follows image ...

Embodiment 3

[0042] A nickel-saving 7Ni steel used in ultra-low temperature environments. The chemical composition of the nickel-saving 7Ni steel is as follows: Ni: 7.00-7.60%, C: 0.02-0.10%, Si: 0.50-0.80%, Mn : 0.10~0.30%, P≤0.010%, S≤0.005%, Cr: 0.30~0.60%, Mo: 0.10~0.20%, Nb: 0.03~0.06%; the balance is Fe (one of the specific components is shown in Table 1 ). Smelting according to the above ratio of ingredients, adopting corresponding desulfurization technology to control the impurity content; after that, the ingot is subjected to multi-step hot rolling and then air-cooled. The steel is subjected to QLT heat treatment (process parameters are shown in Table 2), such as figure 1 As shown, samples were taken from the steel plate after heat treatment, and the microstructure of the sample was observed with a scanning electron microscope. The specific microstructure is as follows Figure 4 shown.

[0043] The chemical composition of 7Ni steel smelted in Example 1-3 of Table 1 and its comp...

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Abstract

The invention discloses a nickel saving type 7Ni steel for an ultralow temperature environment and a heat treatment technology of the nickel saving type 7Ni steel, and belongs to the technical field of cryogenic steel. The nickel saving type 7Ni steel comprises the components of 7.00-7.60% of Ni, 0.02-0.06% of C, 0.03-0.80% of Si, 0.10-0.90% of Mn, 0.30-0.60% of Cr and the balance Fe and unavoidable impurities. The nickel saving type 7Ni steel is subjected to QLT heat treatment, specifically, a technology including a plurality of steps of high temperature quenching, two-phase region subcritical quenching and tempering is adopted. According to the nickel saving type 7Ni steel, excellent strength and plasticity combination and outstanding low-temperature toughness are achieved, the performance of the nickel saving type 7Ni steel reaches the level equal to 9Ni steel, the nickel saving type 7Ni steel can serve as structural steel in the ultralow temperature environment, the manufacturing cost is reduced, and very good economic applicability is achieved.

Description

technical field [0001] The invention relates to the technical field of low-temperature steel, in particular to a nickel-saving 7Ni steel used in an ultra-low temperature environment and a heat treatment process thereof. Background technique [0002] As a clean and efficient energy source, the demand for liquefied natural gas (LNG) is growing rapidly around the world. Liquefied natural gas is a liquid formed by cooling natural gas to -162°C under normal pressure. The liquefied natural gas is only 1 / 625 of the original gaseous volume, which is very convenient for storage and transportation. At present, the global demand for LNG is growing at an annual rate of about 8%, and Asia will grow faster in the next few years, while my country has become one of the world's top five natural gas importers and consumers, with an average annual growth rate of domestic natural gas consumption of more than 10%. In 2020, my country's natural gas consumption will reach 200 billion cubic meters....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/40C22C38/02C22C38/04C22C38/44C22C38/48C21D8/02C21D6/00C21D1/18
CPCC21D1/18C21D6/004C21D8/0205C21D8/0226C21D8/0247C22C38/02C22C38/04C22C38/40C22C38/44C22C38/48
Inventor 罗兴宏曹宏玮战国锋李书瑞刘实
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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