High-strength and acid corrosion-resistance double-phase stainless steel and preparation method thereof

A duplex stainless steel, acid corrosion-resistant technology, applied in the field of stainless steel, can solve the problems of poor thermoplastic and welding formability, low strength, insufficient corrosion resistance of strong oxidizing acid medium, etc., and achieve the effect of good mechanical properties and excellent comprehensive performance.

Active Publication Date: 2018-09-25
CENT IRON & STEEL RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] In view of the above analysis, the present invention aims to provide a stainless steel and its preparation method to solve the problems of low strength of existing materials, insufficient corrosion resistance to strong oxidizing acid media, poor thermoplasticity and weldability

Method used

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  • High-strength and acid corrosion-resistance double-phase stainless steel and preparation method thereof
  • High-strength and acid corrosion-resistance double-phase stainless steel and preparation method thereof
  • High-strength and acid corrosion-resistance double-phase stainless steel and preparation method thereof

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preparation example Construction

[0042] In a second aspect, the present invention also provides a method for preparing duplex stainless steel, comprising the steps of:

[0043] Step S1: Melting molten steel in a vacuum induction furnace, the melting vacuum is 5-20 Pa, and the melting time is 10-20 minutes.

[0044] Step S2: Refining, pouring and solidifying the molten steel to obtain a steel ingot, adjusting the N content in the steel by adding high-purity ferrochrome nitride during the refining process, and adjusting the Y in the steel by adding metallic pure Y and ferroboron in the later stage of refining and B content.

[0045] Step S3: Carry out billet forging for the steel ingot, the temperature of the ingot forging is controlled within the range of 1050-1150° C., the temperature of the final forging is controlled at ≥800° C., and the total forging ratio is ≥3.

[0046] Step S4: Carry out rolling (hot rolling or cold rolling) to the forged steel ingot, solution heat treatment and cooling, the heat treat...

Embodiment 1

[0048] A 50kg vacuum induction furnace is used for vacuum induction smelting, the smelting vacuum degree is 20Pa, and the smelting time is 20min. Add high-purity ferrochromium nitride, metal pure Y and ferroboron to adjust the N, Y, and B contents in the steel, and the yields of each element are calculated by 90%, 98%, and 95% respectively, and smelting 1 heat of stainless steel (1# stainless steel ). The measured chemical composition (mass percentage%) of 1# stainless steel is: C 0.037, Si: 3.85, Mn 1.40, Cr 16.60, Ni 6.07, B 0.0051, N 0.11, W 1.38, Y 0.027, the rest is Fe and unavoidable impurities element. in,

[0049] K α / γ =(Si%+Cr%+30×B%+0.5×W%) / (35×C%+0.6×Mn%+Ni%+35×N%)≈1.8.

[0050] The starting forging temperature of 1# stainless steel ingot is 1130°C, the final forging temperature is about 900°C, the total forging ratio of the forging billet is about 3.5, and the thickness of the plate after forging is 10mm. Then carry out solution heat treatment at 1020°C for 3...

Embodiment 2

[0060] A 50 kg vacuum induction furnace was used for vacuum induction smelting, the smelting vacuum degree was 10 Pa, and the smelting time was 12 minutes. Add high-purity ferrochromium nitride, metal pure Y and ferroboron to adjust the N, Y, and B content in the steel, and the yields of each element are calculated according to 90%, 98%, and 95% respectively, and smelting 1 furnace of stainless steel (2# stainless steel ). The measured chemical composition (mass percentage%) of 2# stainless steel is: C 0.024, Si: 2.13, Mn 1.24, Cr 21.49, Ni 8.34, B 0.0032, N 0.15, W 0.51, Y 0.056, and the rest are Fe and unavoidable impurities element. in,

[0061] K α / γ =(Si%+Cr%+30×B%+0.5×W%) / (35×C%+0.6×Mn%+Ni%+35×N%)≈1.6.

[0062] The starting forging temperature of 2# stainless steel ingot is 1060°C, the final forging temperature is about 900°C, the total forging ratio of the forging billet is about 3.5, and the thickness of the forged plate is 10mm. Then carry out solution heat treat...

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Abstract

The invention discloses a high-strength and acid corrosion-resistance double-phase stainless steel and a preparation method thereof, which belong to the technical field of stainless steel and solve the problems of low strength, insufficient strong oxidizing acid medium corrosion resistance and poor thermoplasticity and welding forming property are in the existing materials. The double-phase stainless steel is prepared from the following components in percentage by mass: 0.01 to 0.04 percent of C, 2.0 to 4.0 percent of Si, 1.0 to 3.0 percent of Mn, 15.0 to 22.0 percent of Cr, 4.0 to 9.0 percentof Ni, 0.001 to 0.01 percent of B, 0.1 to 0.2 percent of N, 0.5 to 2.0 percent of W, 0.01 to 0.06 percent of Y and the balance of Fe and inevitable impurity elements; and the value of K Alpha / Gamma equals to (Si percent plus Cr percent plus 30*B percent plus 0.5*W percent) divided by (35*C percent plus 0.6*Mn percent plus Ni percent plus 35*N percent) is within a range between 0.9 and 2.5. The double-phase stainless steel and the preparation method thereof are applicable to special fields, such as the petrochemical industry and the nuclear spent fuel post-treatment industry.

Description

technical field [0001] The invention relates to a stainless steel, in particular to a duplex stainless steel with high strength, acid corrosion resistance, good thermal processing performance and welding performance and a preparation method thereof. Background technique [0002] Iron-nickel-based alloys and nickel-based corrosion-resistant alloys (usually with a Cr content of more than 30wt.%) are austenitic stainless steels with good stress corrosion resistance. It is generally believed that the corrosion resistance of these materials is based on the fact that Cr can form an effective passivation film in a corrosive medium environment, thereby preventing the corrosion medium from corroding the metal substrate. [0003] However, in some oxidative corrosion environments, such as concentrated nitric acid or concentrated sulfuric acid, the passivation mechanism of materials is different, and sufficient corrosion resistance cannot be guaranteed only by increasing the Cr content....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/58C22C38/54C22C38/44C22C38/02C22C38/04C22C33/06C21D8/02
CPCC21D8/0221C21D8/0247C21D2211/001C21D2211/005C22C33/06C22C38/001C22C38/005C22C38/04C22C38/34C22C38/44C22C38/54C22C38/58
Inventor 宋志刚丰涵郑文杰朱玉亮
Owner CENT IRON & STEEL RES INST
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