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Duplex stainless steel for ozone-containing water

A technology of duplex stainless steel and ozone water, applied in the field of stainless steel for ozone-containing water, can solve the problems of increased manufacturing cost, safe waste liquid, no corrosion inhibition, etc., and achieves excellent corrosion resistance and improved corrosion resistance.

Active Publication Date: 2016-10-12
NIPPON STEEL STAINLESS STEEL CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this surface film does not have the effect of inhibiting corrosion in water containing Al, Si, Ti, etc., and chloride ions.
[0015] In addition, in the method of Patent Document 7, it is necessary to immerse in an ozone-containing acid solution before use in ozone-containing water, which increases the production cost.
In addition, there are also problems of safety when handling acid liquid and waste liquid after treatment.
[0016] In addition, in the method of Patent Document 8, it is necessary to expose to high-concentration ozone gas or humid ozone gas before using in ozone-containing water, which increases the manufacturing cost.
In addition, there are also problems of safety when handling ozone gas and waste gas after treatment.
In addition, in the methods of Patent Documents 7 and 8, Cr is not concentrated in the surface film, and good corrosion resistance cannot be obtained in ozone-containing water.

Method used

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  • Duplex stainless steel for ozone-containing water
  • Duplex stainless steel for ozone-containing water
  • Duplex stainless steel for ozone-containing water

Examples

Experimental program
Comparison scheme
Effect test

no. 1 Embodiment approach

[0122] The first embodiment relates to duplex stainless steel in a state where no treatment with ozone-containing water has been performed.

[0123] The duplex stainless steel of the present embodiment includes a base material and a first oxide film formed on the surface of the base material.

[0124] The metal structure of the duplex stainless steel (base material) according to the present embodiment is mainly composed of two phases, a ferrite phase and an austenite phase.

[0125] First, the limited range of the amount of each component element in the entire duplex stainless steel of the present embodiment and the reasons thereof will be described. In addition, unless otherwise specified, % which shows a steel component means mass %.

[0126] C: C ensures the corrosion resistance of stainless steel, so the amount of C is limited to 0.1% or less. If C is contained in excess of 0.1%, Cr carbides are formed, deteriorating the corrosion resistance. On the other hand, C is an ...

no. 2 Embodiment approach

[0174] The second embodiment relates to duplex stainless steel in a state treated with ozone-containing water.

[0175] The duplex stainless steel according to the present embodiment includes a base material and a second oxide film formed on the surface of the base material.

[0176] The metal structure of the duplex stainless steel (base material) according to the present embodiment is mainly composed of two phases, a ferrite phase and an austenite phase.

[0177] The overall chemical composition of the duplex stainless steel according to the present embodiment (second embodiment) is the same as that of the first embodiment, and thus detailed description thereof will be omitted.

[0178] The second oxide film of the duplex stainless steel according to this embodiment will be described.

[0179] The second oxide film formed on the surface of the base metal has thickness, and the Cr concentration on the outermost surface is 0.15 to 0.50 in terms of cation fraction.

[0180]...

Embodiment

[0197] Hereinafter, in order to confirm the effect of this invention, the following Example was performed. In addition, this Example shows one Example of this invention, and this invention is not limited to the following structure. In the present invention, various conditions can be adopted within the scope of achieving the object of the present invention without departing from the requirements of the present invention.

[0198] In addition, the underline in a table|surface indicates that it exceeds the range of this embodiment.

[0199] Stainless steel having the chemical composition shown in Tables 1 and 2 was melted in a vacuum induction melting furnace and cast. Then, soaking was performed at 1200° C., followed by hot forging. Hot rolled to a thickness of 6 mm, annealed and pickled. Thereafter, it was cold-rolled to a thickness of 1 mm, and then annealed and pickled again. A duplex stainless steel plate was produced as described above.

[0200] Pickling was performed ...

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Abstract

Duplex stainless steel for ozone-containing water, in one state, comprises, based on a mass percentage, C no more than 0.1%, 0.01-5.0% of Si, 0.01-8.0% of Mn, P no more than 0.1%, S no more than 0.05%, 1.0-10.0% of Ni, 20.0-30.0 of Cr, 0.1-6.0% of Mo, 0.01-5% of Cu and 0.05-0.8% of N with the balance being iron and inevitable impurities. The surface of the duplex stainless steel has a scale film. The ratio CuF / CuM of the maximum CuF of the Cu positive ion fraction of the scale film to the Cu positive ion fraction CuM in parent metal is no less than 1.5.

Description

technical field [0001] The present invention relates to stainless steel for ozone-containing water, and more specifically, to a duplex stainless steel for ozone-containing water used in an environment where ozone gas is used for water treatment of upper water and sewage. Background technique [0002] Due to its excellent corrosion resistance in water environment, duplex (ferrite-austenitic) stainless steel (hereinafter referred to as duplex stainless steel) is used in tanks, piping and tap water or industrial water of water treatment facilities. Water tank. [0003] In recent years, the demand for the safety of tap water and the reduction of the environmental impact of waste water have increased, so ozone gas is used for water sterilization, bleaching, and deodorization. Ozone has very high bactericidal, bleaching, and deodorizing powers, so it is possible to produce high-quality water that was difficult to obtain with conventional filtration, coagulation, and chlorine trea...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/58C22C38/44C22C38/42C22C38/36C22C38/02C22C38/04C22C38/60C22C38/50C22C38/48C22C38/46C22C38/06C22C38/54
CPCC22C38/001C22C38/002C22C38/004C22C38/005C22C38/008C22C38/02C22C38/04C22C38/06C22C38/36C22C38/42C22C38/44C22C38/46C22C38/48C22C38/50C22C38/54C22C38/58C22C38/60
Inventor 吉见敏彦石丸咏一朗柘植信二西村敏和
Owner NIPPON STEEL STAINLESS STEEL CORP