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Dual-phase anti-corrosion stainless steel and corrosion resistance optimizing treatment process thereof

A duplex stainless steel, corrosion-resistant technology, applied in the field of metallurgy, can solve the problems of insufficient proportion of phase boundary, limited effect of refining structure and improving strip morphology, and the inability to eradicate the structure and morphology of duplex stainless steel strips, etc. Achieve the effects of improving corrosion resistance, improving intergranular corrosion resistance, and improving mechanical properties

Inactive Publication Date: 2016-03-09
SHANDONG UNIV OF TECH
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0003] Most of the existing processing methods for duplex stainless steel are based on duplex structure for cold and hot processing, and its microstructure mostly presents the stripe morphology of austenite and ferrite alternately, that is, the homogeneous grains are in the state of band aggregation , this kind of organization is destined to have a phase boundary ratio of less than 20%, and the ferrite that tends to grow is easy to coarsen by engulfing adjacent homogeneous grains along the strip direction, making the potential of duplex stainless steel fine grain (mainly a large number of phase boundary exists) can not be fully utilized
Moreover, the existing processing methods, such as rolling, are mostly unidirectional continuous rolling processes, and the strip structure morphology of two-phase stainless steel cannot be eradicated, and the subsequent solution heat treatment mainly restructures the structure through the recrystallization behavior of the two phases, and its fine The effect of organizing and improving the shape of the strips is also very limited.

Method used

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  • Dual-phase anti-corrosion stainless steel and corrosion resistance optimizing treatment process thereof
  • Dual-phase anti-corrosion stainless steel and corrosion resistance optimizing treatment process thereof
  • Dual-phase anti-corrosion stainless steel and corrosion resistance optimizing treatment process thereof

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Effect test

Embodiment 1

[0032] Optimizing the hot-rolled duplex stainless steel plate, the alloy composition is (mass ratio, wt%): 0.017C, 22.16Cr, 5.28Ni, 0.52Si, 1.11Mn, 0.151N, 0.026P, 0.0016S, 3.09Mo , the initial sample grain size was 30 μm.

[0033] In the first step, the hot-rolled sheet is heated to the solution temperature at a heating rate of 22° C. / min, then solid solutioned at 1250° C. for 20 minutes, and cooled to room temperature with water.

[0034] In the second step, the alloy plate after solid solution is subjected to cross rolling with ε=3.

[0035] In the third step, the rolled alloy plate is annealed. The temperature rise rate of the vacuum annealing furnace is 27°C / min.

[0036] The microstructure of the duplex stainless steel plate after optimization treatment is as follows figure 1 As shown, the average grain size is 2 μm. The proportion of low-energy grain boundaries after optimization is 83%.

Embodiment 2

[0038] The hot-rolled duplex stainless steel plate is optimized, and its composition is (wt%): 0.016C, 24.1Cr, 4.10Ni, 0.55Si, 1.10Mn, 0.2N, 0.025P, 0.002S, 3.0Mo, grain Initial sample with a size of 32 μm.

[0039] In the first step, the hot-rolled sheet is heated up to the solution temperature at a heating rate of 20°C / min, then solidified at 1200°C for 16 minutes, and cooled to room temperature with water.

[0040] In the second step, the alloy plate after solid solution is subjected to unidirectional rolling with ε=2.

[0041] In the third step, the rolled alloy plate is annealed. The temperature rise rate of the vacuum annealing furnace is 25° C. / min, and the temperature is kept at 1025° C. for 10 minutes, and then water-cooled.

[0042] The average grain size of the two phases of the stainless steel plate obtained after optimization treatment is about 3 μm, and the proportion of the low-energy interface grain boundary is 78%. Most of the interfaces of the corrosion mor...

Embodiment 3

[0044] Optimizing the hot-rolled duplex stainless steel plate, the alloy composition is (mass ratio, wt%): 0.020C, 22.1Cr, 5.3Ni, 0.50Si, 1.20Mn, 0.15N, 0.026P, 0.001S, 4.1Mo , the initial sample grain size was 30 μm.

[0045] In the first step, the hot-rolled sheet is heated to the solution temperature at a heating rate of 25° C. / min, then solid solutioned at 1300° C. for 30 minutes, and cooled to room temperature with water.

[0046] In the second step, the alloy plate after solid solution is subjected to cross-rolling of ε=3, and the rolling deformation of each pass is ε=0.2. After each pass of rolling, the plate is rotated 90 degrees and then cross-rolled, and so forth, After 15 passes, the desired amount of deformation is achieved.

[0047] In the third step, the rolled alloy plate is annealed. The temperature rise rate of the vacuum annealing furnace is 30° C. / min, and the temperature is kept at 1050° C. for 5 minutes, and then water-cooled.

[0048] The average grain ...

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Abstract

The invention discloses dual-phase anti-corrosion stainless steel and a corrosion resistance optimizing treatment process thereof and belongs to the technical field of metallurgy. The process is characterized in that an initial alloy solid solution process is clearly determined and then large-deformation cold rolling and annealing treatments for the stainless steel are performed. Low-angle grain boundary proportion of ferrites in the dual-phase stainless steel which is already subjected to optimizing treatment is increased obviously, low-angle grain boundaries are mostly located in the {111} position, twin boundaries inside austenite are {111} coherent twin boundaries, the proportion of phase boundaries satisfying a specific orientation relationship (K-S and N-W) is substantially increased, and the alloy intercrystalline corrosion resistance is improved through increase of the low-energy boundary density. On the basis of achieving alloy microstructure ultrafining (smaller than five micrometers), the corrosion resistance of the stainless steel is improved synchronously.

Description

technical field [0001] A dual-phase corrosion-resistant stainless steel and its corrosion-resistant optimization treatment process belong to the technical field of metallurgy. Background technique [0002] As an important engineering structural material, austenitic + ferritic duplex stainless steel is widely used in various industrial environments due to its good mechanical properties and excellent corrosion resistance. However, the mechanical properties and corrosion resistance of stainless steel are a pair of contradictions in many cases. For example, refining the structure is considered to be an effective way and an important method to strengthen stainless steel, but with the refinement of the structure, the interface (grain boundary and phase boundary) per unit volume increases, and the corrosion resistance of the alloy, especially the intergranular corrosion resistance , high temperature creep strength, etc. may be reduced due to phenomena such as interface precipitati...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C38/44C21D8/02
CPCC21D8/0236C21D8/0247C21D2211/001C21D2211/005C22C38/001C22C38/02C22C38/04C22C38/42C22C38/44
Inventor 方晓英张建胜朱言利尹文红秦聪祥
Owner SHANDONG UNIV OF TECH
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