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Method for improving corrosion resistance of nitrogen-containing duplex stainless steel

A duplex stainless steel and corrosion-resistant technology, which is applied in the field of improving the corrosion resistance of nitrogen-containing duplex stainless steel, can solve the problems of high economic cost and complicated control process, and achieve the effect of reducing sulfur content and good desulfurization ability

Active Publication Date: 2021-08-10
NORTHEASTERN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The above measures can reduce the damage of inclusions to corrosion resistance to a certain extent, but cannot completely avoid the corrosion failure caused by inclusions, and the control process of these measures is complicated and the economic cost is high

Method used

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  • Method for improving corrosion resistance of nitrogen-containing duplex stainless steel
  • Method for improving corrosion resistance of nitrogen-containing duplex stainless steel
  • Method for improving corrosion resistance of nitrogen-containing duplex stainless steel

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0099] Example 1 Preparation of niobium microalloyed nitrogen-containing duplex stainless steel

[0100] This example provides a method for preparing niobium microalloyed nitrogen-containing duplex stainless steel. The specific process flow is "EAF smelting-AOD smelting-LF refining-continuous casting / die casting-hot rolling-heat treatment", 1#~4# Examples are smelted steels of the present invention, and comparative examples 5# to 8# are commercially available nitrogen-containing duplex stainless steels.

[0101] Step 1: Smelting of niobium microalloyed nitrogen-containing duplex stainless steel

[0102] (1) Smelting 1# to 4# molten steel, after AOD or VOD decarburization and chromium reduction, adjust the composition, control the content of Mn, Cr, Mo, and Ni elements within the range required by the finished product, and then carry out the slag removal operation, After slag removal, enter the LF refining station, adjust the temperature and argon flow, and then add lime (98wt.%...

Embodiment 2

[0130] Example 2 Statistics of inclusions and niobium-containing phases in nitrogen-containing duplex stainless steel

[0131] 1#~4# embodiment steel grades and commercially available 5#~8# comparative steel grades were prepared into metallographic samples of 10mm×10mm by wire cutting, polished and polished, and metallographic microscope, scanning electron microscope and The IPP6.0 software analyzes and counts the inclusions and niobium-containing phases, and the results are shown in Table 7 and Figure 1-8 shown.

[0132] Table 7 Statistical results of inclusions and niobium-containing phases in 1#~8# nitrogen-containing duplex stainless steel

[0133]

[0134]

[0135] It can be seen from Table 7 that although the inclusions in the 1# to 4# embodiments of the present invention and the comparative examples 5# to 8# steel types are mainly CaO-Al 2 o 3 , MgO-Al 2 o 3 、CaO-Al 2 o 3 -MgO and MnS, but the present invention significantly increases the proportion of MgO...

Embodiment 3

[0137] Example 3 Immersion Corrosion of Niobium Microalloyed Nitrogen-Containing Duplex Stainless Steel

[0138] According to the ASTM G48-11 standard, immersion corrosion samples of 50mm × 20mm × 5mm were prepared from 1# to 4# examples and 5# to 8# comparative steel types, respectively. 3 After soaking in the solution for 72 hours, the sample was taken out, cleaned with ultrasonic vibration to remove corrosion products, and weighed to calculate the corrosion rate after drying. The results were as follows: Figure 9 shown. from Figure 9 It can be seen that the corrosion rate of 1#~4# embodiment steel grades of the present invention is significantly lower than that of 5#~8# comparative steel grades, and compared with the comparative steel grades without adding niobium, the corrosion rate of 1#~4# steel grades of the present invention The corrosion rate of embodiment has reduced 1.3~2.8mm·a -1 . It shows that the niobium-containing phase formed by the addition of niobium w...

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Abstract

The invention belongs to the technical field of nitrogen-containing duplex stainless steel production, and provides a method for improving the corrosion resistance of nitrogen-containing duplex stainless steel. A trace amount of niobium is added into nitrogen-containing stainless steel, niobium-containing Z-phase wrapping inclusions are easy to precipitate, and the corrosion resistance of the duplex stainless steel is improved. By optimizing the refining process, the inclusions are fine and dispersed and are easily wrapped by the niobium-containing phase; in the casting process, the cooling strength is controlled to be the lowest cooling strength in the casting process in the area corresponding to the temperature interval where the niobium-containing phase is precipitated, precipitation of the niobium-containing phase with the inclusion as the core is promoted, and the proportion of the inclusion wrapped by the niobium-containing phase is increased; then the cooling strength is improved, and excessive growth of niobium-containing phases and precipitation of harmful phases are avoided; and according to the method provided by the invention, the corrosion problem caused by inclusions can be effectively avoided, and a good guarantee is provided for long-life and stable service of the material in a typical environment.

Description

technical field [0001] The invention relates to the technical field of nitrogen-containing duplex stainless steel production, in particular to a method for improving the corrosion resistance of nitrogen-containing duplex stainless steel. Background technique [0002] Nitrogen-containing duplex stainless steel is a type of stainless steel with a two-phase structure of ferrite and austenite and an equal proportion of the two phases. It has both excellent corrosion resistance and good comprehensive mechanical properties. It is widely used in desalination and other fields. In recent years, with the increasingly harsh service environment, higher requirements have been put forward for the corrosion resistance of nitrogen-containing duplex stainless steel. Therefore, it is very important to develop methods to effectively improve the corrosion resistance of nitrogen-containing duplex stainless steel to ensure the long life and stable service of this type of material. [0003] Incl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C21C7/064C21C7/06C21C7/00B22D11/22B22D27/04C22C38/02C22C38/04C22C38/58C22C38/44C22C38/42C22C38/48
CPCC21C7/0645C21C7/06C21C7/0056B22D11/002B22D11/225B22D27/04C22C38/02C22C38/04C22C38/58C22C38/44C22C38/42C22C38/001C22C38/48
Inventor 李花兵张树才蔺岳姜周华冉铭泽张彬彬冯浩胡建瑞朱红春贺彤
Owner NORTHEASTERN UNIV
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