Super duplex stainless steel used in pump and valve products and preparation method thereof

A technology of duplex stainless steel and products, applied in the field of stainless steel, can solve the problems of inability to further improve the corrosion resistance and mechanical properties of duplex stainless steel, reduce the corrosion resistance of duplex stainless steel, limit the corrosion resistance and mechanical properties, etc. The effect of changing the chemical current range, not easy to crack, and improving corrosion resistance and mechanical properties

Active Publication Date: 2016-08-24
ZHANGJIAGANG FEILANG PUMP & VALVE
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, most of the pump and valve products are generally made of austenitic stainless steel or duplex stainless steel. Duplex stainless steel has a two-phase structure - austenitic structure and ferrite structure, which makes duplex stainless steel have both austenitic stainless steel The characteristics of the ferritic stainless steel and the characteristics of the ferritic stainless steel, so the application of the duplex stainless steel is particularly extensive; During the smelting process, alloying elements generally gather in the ferrite structure, so the ferrite structure will change during the smelting process, while the austenite structure will basically not change, and the corrosion resistance and mechanical properties of duplex stainless steel cannot be further improved , which limits the improvement of its corrosion resistance and mechanical properties
In addition, in the process of smelting and solidification, a large number of σ-equal brittle phases and γ-phases will be precipitated in the crystal structure, and the places where a large number of σ-equal brittle phases and γ-phases precipitate are Cr and Mo-poor areas, which will make duplex stainless steel It is easy to crack during forging, and pitting corrosion generally occurs near the σ phase and γ phase, which will greatly reduce the corrosion resistance of duplex stainless steel, so this type of pump and valve products are easy to be corroded, and the service life of pump and valve products is longer short

Method used

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  • Super duplex stainless steel used in pump and valve products and preparation method thereof

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] The super duplex stainless steel used in pump and valve products described in this embodiment is characterized in that its composition and weight percentage of each component are as follows: nickel: 6.5%, chromium: 25%, molybdenum: 4%, copper: 0.8 %, nitrogen: 0.25%, carbon ≤ 0.02%, manganese ≤ 1%, silicon ≤ 1%, phosphorus ≤ 0.03%, sulfur ≤ 0.025%, cerium: 0.05%, and the balance is iron.

[0010] The preparation method for preparing the above-mentioned super duplex stainless steel is as follows: put the relevant materials used into an intermediate frequency furnace for smelting, and after the materials are completely melted to form a molten metal melt, sample and analyze the molten metal melt and adjust the carbon content to make the carbon content The percentage by weight is not more than 0.02%, and then pour the covering agent into the intermediate frequency furnace. The scientific name of the covering agent described in this embodiment is: slag gathering agent. The ma...

Embodiment 2

[0015] The super duplex stainless steel used in pump and valve products described in this embodiment is characterized in that its composition and weight percentage of each component are as follows: nickel: 8.5%, chromium: 24%, molybdenum: 3.5%, copper: 0.5% %, nitrogen: 0.3%, carbon ≤ 0.01%, manganese ≤ 1%, silicon ≤ 1%, phosphorus ≤ 0.03%, sulfur ≤ 0.02%, cerium: 0.2%, and the balance is iron.

[0016] The preparation method for preparing the above-mentioned super duplex stainless steel is as follows: put the relevant materials used into an intermediate frequency furnace for smelting, and after the materials are completely melted to form a molten metal melt, sample and analyze the molten metal melt and adjust the carbon content to make the carbon content The weight percentage does not exceed 0.02%, and then pour the covering agent into the intermediate frequency furnace so that the covering agent completely covers the surface of the molten metal and raises the temperature in t...

Embodiment 3

[0019] The super duplex stainless steel used in pump and valve products described in this embodiment is characterized in that its composition and weight percentage of each component are as follows: nickel: 7%, chromium: 26%, molybdenum: 3%, copper: 1 %, nitrogen: 0.2%, carbon ≤ 0.02%, manganese ≤ 1%, silicon ≤ 1%, phosphorus ≤ 0.02%, sulfur ≤ 0.025%, cerium: 0.1%, and the balance is iron.

[0020] The preparation method for preparing the above-mentioned super duplex stainless steel is as follows: put the relevant materials used into an intermediate frequency furnace for smelting, and after the materials are completely melted to form a molten metal melt, sample and analyze the molten metal melt and adjust the carbon content to make the carbon content The weight percentage does not exceed 0.02%, and then pour the covering agent into the intermediate frequency furnace, so that the covering agent completely covers the surface of the molten metal and raises the temperature in the fu...

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Abstract

The invention discloses a super duplex stainless steel used in pump and valve products and a preparation method thereof. Its composition and weight percentage of each component are as follows: nickel: 6.5% to 8.5%, chromium: 24% to 26%, molybdenum: 3%~4%, copper: 0.5%~1%, nitrogen: 0.2%~0.3%, carbon: ≤0.02%, manganese: ≤1%, silicon: ≤1%, phosphorus: ≤0.03%, sulfur: ≤0.025 %, cerium: 0.05% ~ 0.2%, the balance is iron. The preparation method is: smelting, deoxidation and slagging, secondary deoxidation treatment, and finally adding manganese iron and refining agent. After the manganese iron and refining agent are completely melted into the subsequent molten metal, pouring can be performed to obtain super duplex stainless steel. The invention has the advantages of good corrosion resistance and good mechanical properties, which greatly improves the service life of this type of pump and valve products.

Description

technical field [0001] The invention relates to the field of stainless steel, in particular to a super duplex stainless steel used in pump valve products and a preparation method thereof. Background technique [0002] With the rapid development of my country's modern industry, the application of various fluids with strong acid properties makes the requirements for the manufacturing materials of pump and valve products higher and higher. Withstand the corrosion of various fluids with strong acid properties. At present, most of the pump and valve products are generally made of austenitic stainless steel or duplex stainless steel. Duplex stainless steel has a two-phase structure - austenitic structure and ferrite structure, which makes duplex stainless steel have both austenitic stainless steel The characteristics of the ferritic stainless steel and the characteristics of the ferritic stainless steel, so the application of the duplex stainless steel is particularly extensive; ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C38/44
Inventor 张莉华
Owner ZHANGJIAGANG FEILANG PUMP & VALVE
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