CN114774805A - Memory type duplex stainless steel and preparation thereof - Google Patents
Memory type duplex stainless steel and preparation thereof Download PDFInfo
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- CN114774805A CN114774805A CN202210507188.3A CN202210507188A CN114774805A CN 114774805 A CN114774805 A CN 114774805A CN 202210507188 A CN202210507188 A CN 202210507188A CN 114774805 A CN114774805 A CN 114774805A
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- 229910001039 duplex stainless steel Inorganic materials 0.000 title claims abstract description 52
- 238000002360 preparation method Methods 0.000 title abstract description 13
- 239000010959 steel Substances 0.000 claims abstract description 42
- 238000005242 forging Methods 0.000 claims abstract description 41
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 39
- 238000001816 cooling Methods 0.000 claims abstract description 32
- 230000003446 memory effect Effects 0.000 claims abstract description 22
- 238000000137 annealing Methods 0.000 claims abstract description 13
- 238000011084 recovery Methods 0.000 claims abstract description 11
- 238000005098 hot rolling Methods 0.000 claims abstract description 10
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000003723 Smelting Methods 0.000 claims abstract description 8
- 238000005266 casting Methods 0.000 claims abstract description 8
- 239000012535 impurity Substances 0.000 claims abstract description 8
- 238000000034 method Methods 0.000 claims abstract description 8
- 239000002994 raw material Substances 0.000 claims abstract description 8
- 239000011651 chromium Substances 0.000 claims description 17
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 17
- 229910001566 austenite Inorganic materials 0.000 claims description 14
- 229910052804 chromium Inorganic materials 0.000 claims description 9
- 229910000859 α-Fe Inorganic materials 0.000 claims description 9
- 229910052759 nickel Inorganic materials 0.000 claims description 7
- 239000000463 material Substances 0.000 abstract description 15
- 238000000265 homogenisation Methods 0.000 abstract description 7
- 238000005096 rolling process Methods 0.000 abstract description 7
- 229910001220 stainless steel Inorganic materials 0.000 abstract description 3
- 239000010935 stainless steel Substances 0.000 abstract description 2
- 230000007797 corrosion Effects 0.000 description 14
- 238000005260 corrosion Methods 0.000 description 14
- 229910018643 Mn—Si Inorganic materials 0.000 description 11
- 229910045601 alloy Inorganic materials 0.000 description 11
- 239000000956 alloy Substances 0.000 description 11
- 229910001285 shape-memory alloy Inorganic materials 0.000 description 9
- 229910052748 manganese Inorganic materials 0.000 description 6
- 229910000734 martensite Inorganic materials 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000002161 passivation Methods 0.000 description 3
- 230000001105 regulatory effect Effects 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- 238000001887 electron backscatter diffraction Methods 0.000 description 2
- 238000005530 etching Methods 0.000 description 2
- 239000008204 material by function Substances 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000010587 phase diagram Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 229910018125 Al-Si Inorganic materials 0.000 description 1
- 229910018520 Al—Si Inorganic materials 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- 229910002551 Fe-Mn Inorganic materials 0.000 description 1
- 229910004337 Ti-Ni Inorganic materials 0.000 description 1
- 229910011209 Ti—Ni Inorganic materials 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- KHYBPSFKEHXSLX-UHFFFAOYSA-N iminotitanium Chemical compound [Ti]=N KHYBPSFKEHXSLX-UHFFFAOYSA-N 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 230000000087 stabilizing effect Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of silicon
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
- C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
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- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
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- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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- C21D2201/00—Treatment for obtaining particular effects
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- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/005—Ferrite
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Abstract
The invention relates to memory type duplex stainless steel and a preparation method thereof, belonging to the technical field of steel materials, wherein the steel comprises the following components in percentage by mass: 0.01-0.1% of C, 2-5% of Si, 7-16% of Mn, less than or equal to 0.01% of P, less than or equal to 0.01% of S, less than or equal to 1% of Ni, 0.2-1% of Al, 10-20% of Cr, 0.2-1% of Co, and the balance of Fe and inevitable impurities. The preparation process comprises the following steps: (1) selecting raw materials according to set components, smelting, casting into a steel ingot, hot forging the steel ingot into a forging blank at 1050-1250 ℃, and cooling to room temperature, wherein: the method comprises the following steps of enabling the thickness of a forging blank to be 40-60 mm, carrying out homogenization treatment on the forging blank for 5-8 hours at 1200-1250 ℃, carrying out hot rolling on the homogenized forging blank at 1150-1200 ℃, enabling the finishing rolling temperature to be 850-1050 ℃, immediately carrying out water cooling on a hot rolled steel plate to fix a high-temperature tissue, enabling the thickness of the hot rolled plate to be 2-6 mm, and annealing the hot rolled plate at 750-1000 ℃ for 30-180 min to obtain the duplex stainless steel with the excellent shape memory effect. The stainless steel has simple components, low cost and excellent performance, the shape recovery rate is more than or equal to 45 percent, the yield strength is more than or equal to 500MPa, the tensile strength is more than or equal to 850MPa, the elongation is more than or equal to 40 percent, and the pitting potential is more than or equal to 200 MV.
Description
Technical Field
The invention belongs to the technical field of steel materials, and particularly relates to memory type duplex stainless steel and preparation thereof.
Background
With the social development and the progress of science and technology, the functional materials and the functional materialsThe research of the application is more and more emphasized by people. Shape memory alloys have entered the human vision as functional materials. The shape memory effect of Fe-Mn-Si based alloys is induced by stress
Martensitic transformation. Considered as a possible candidate material for expensive Ti-Ni based shape memory alloys due to their low cost and good processability, are expected to find applications in many mechanical and construction fields. Despite the unique properties of Fe-Mn-Si alloys, they are currently less practical to use, primarily due to their poor corrosion resistance, which limits their use to some extent.
Aiming at the requirement of the Fe-Mn-Si-based shape memory alloy on corrosion resistance at present, a novel Fe-Cr-Mn-Al-Si memory type duplex stainless steel with memory effect, corrosion resistance and mechanical property is developed by regulating and controlling components and adopting a novel preparation process on the basis of the Fe-Mn-Si-based shape memory alloy, so that the technical problem of low corrosion resistance of the Fe-Mn-Si-based shape memory alloy can be solved, and the method has important significance for expanding the application range of the duplex stainless steel in the steel industry.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide a memory type duplex stainless steel and a preparation method thereof. In general, Si and Co elements lower the neel temperature (T) of steelN) And austenite, but it is not easy to add too much because of the high price of Co. 1% Si can make T of steelNThe temperature is reduced by about 25K. However, too high a Si content causes an increase in brittleness of the alloy. In the present invention, it is considered that the content of the element Si can be appropriately reduced by substituting Co for Si. By adding Co element to replace Si element, the brittleness problem caused by high Si is solved on the premise of ensuring good memory effect, and the influence rule of the Co element on the memory effect is explored. Simultaneously, an appropriate annealing process system is assisted to the duplex stainless steelThe phase composition, the grain size and the volume fraction of the microstructure are regulated and controlled, and the duplex stainless steel with better shape memory effect, good mechanical property and corrosion resistance matching is developed.
In order to achieve the purpose, the invention adopts the following technical scheme:
a memory type duplex stainless steel comprises the following components by mass percent: 0.01-0.1% of C, 2-5% of Si, 7-16% of Mn, less than or equal to 0.01% of P, less than or equal to 0.01% of S, less than or equal to 2% of Ni, 0.2-1% of Al, 10-20% of Cr, 0.2-1% of Co, and the balance Fe and inevitable impurities.
The shape recovery rate of the duplex stainless steel is up to 45-65%, the yield strength is 500-800 MPa, the tensile strength is 850-1000 MPa, the elongation is 40-65%, and the pitting potential is 200-450 MV.
The preparation method of the memory type duplex stainless steel comprises the following steps:
(1) selecting raw materials according to set components, smelting, and casting into steel ingots;
(2) and (3) hot forging the steel ingot into a forging blank at 1050-1250 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 40-60 mm;
(3) homogenizing the forging stock at 1200-1250 ℃ for 5-8 h;
(4) hot rolling the homogenized forging stock at 1150-1200 ℃, wherein the finish rolling temperature is 850-1050 ℃, immediately carrying out water cooling on a hot rolled steel plate to fix a high-temperature structure, and the thickness of the hot rolled plate is 2-6 mm;
(5) and cooling the hot rolled plate to room temperature, and annealing at 750-1000 ℃ for 30-180 min to obtain the duplex stainless steel with excellent shape memory effect.
In the step (2), the cooling mode after the hot forging is water cooling.
In the steps (4) and (5), the residence in the sigma phase forming temperature range is avoided, the hot rolled plate is cooled to room temperature by adopting an ultra-fast cooling mode after being finally rolled at 850-1050 ℃, the annealed steel plate is cooled to room temperature by adopting an ultra-fast cooling mode, and the ultra-fast cooling speed is more than or equal to 100 ℃/s.
The design principle of the component control of the invention is as follows:
cr is one of the most important alloying elements in duplex stainless steels. It is not only a strong ferrite forming element to control the ferrite proportion in the duplex stainless steel, but also a main element to improve corrosion resistance. The Cr element can improve the corrosion resistance of steel mainly because the Cr element can form stable and compact Cr on the surface of steel2O3The protective film reduces the surface passivation current density of the steel, promotes the passivation of the stainless steel and reduces the dissolution speed of the steel under the passivation condition. Cr can remarkably reduce the neel temperature of the Fe-Mn-Si-based alloy, promote stress-induced epsilon-martensite phase transformation, and can also reduce the Ms point of the alloy.
Al is ferrite forming element, and Al forms Al with protective effect on the metal surface in the Fe-Mn alloy system2O3The layer, Al and Cr, act in the same way, and improve the corrosion resistance of the steel by forming a passive film on the metal surface. Therefore, it is considered that Al is used in place of a part of Cr element, so that the cost can be remarkably reduced and the corrosion resistance can be secured.
In the duplex stainless steel, Ni is a strong austenite forming element, an austenite phase region is enlarged, and the proportion of ferrite and austenite phases can be adjusted by adjusting the Ni element, if the content of the Ni element in the duplex stainless steel is too high, the volume fraction of the ferrite in the steel is low, and the proportion of the two phases is disordered, so that elements such as Cr, Mo and the like are enriched in the ferrite, sigma phases are easy to generate when the material is subjected to heat treatment at the temperature of 700-950 ℃, the ductility and corrosion resistance of the steel are obviously reduced, but if the content of the Ni element is too low, the volume fraction of the austenite in the material is too low, the toughness of the material is reduced, and the shape memory effect of the material is reduced.
Mn is an austenite-forming element, enlarging an austenite phase region and stabilizing an austenite phase, but the role of Mn is equivalent to half of that of Ni. Mn can be used for replacing part of Ni in the duplex stainless steel, and the cost is obviously reduced. However, the addition of the Mn element generally reduces the pitting corrosion resistance of the material, and meanwhile, when the content of the Mn element is higher, the Mn and S are promoted to be combined at grain boundaries to form MnS inclusions, so that the toughness of the material is obviously reduced.Mn element is one of the basic elements of the Fe-Mn-Si-based shape memory alloy, and the addition of the Mn element can reduce the Ms point and increase the stacking fault energy and the neel temperature of austenite. When Ms is<TNIn this case, the martensite transformation is suppressed, which is disadvantageous in the shape memory effect, and therefore, the Mn content must be properly controlled.
The addition of the Si element has two advantages: firstly, the stacking fault energy of a parent phase can be reduced, and incomplete dislocation is increased; second, the T of the alloy is obviously reducedN. And Si element can inhibit the sliding deformation of parent phase austenite and promote the formation of stress-induced epsilon-martensite. However, the addition of Si increases the hardness of the alloy and increases the brittleness, and when the Si content exceeds 6.5%, the material becomes very brittle.
The increase of the content of C element in the steel increases the yield strength and tensile strength of the steel, strengthens the austenite phase, and thus improves the shape memory effect of the alloy, but the plasticity and impact toughness are decreased, and the content of C element should be controlled within a proper range. The addition of Co element not only reduces the stacking fault energy of the alloy, but also reduces TNAnd (3) temperature.
The invention has the beneficial effects that:
(1) the memory type duplex stainless steel has simple components and low cost, and particularly, when the memory type duplex stainless steel is applied to the manufacture of structural members to replace the traditional duplex stainless steel, the cost is greatly reduced;
(2) the invention successfully improves the shape memory effect and the corrosion resistance of the Fe-Mn-Si base by adding elements such as chromium (Cr), nickel (Ni), cobalt (Co) and the like, solves the problem of poor corrosion resistance of the Fe-Mn-Si base shape memory alloy, and expands the application of the Fe-Mn-Si base shape memory alloy to a certain extent. Simultaneously endows the duplex stainless steel with shape memory effect, and expands the application field of the duplex stainless steel;
(3) according to the duplex stainless steel, the Co element is added to replace the Si element, so that the brittleness problem caused by high Si content of the traditional Fe-Mn-Si-based shape memory alloy is solved on the premise of ensuring a good memory effect;
(4) the steel plate obtained by the invention is duplex stainless steel with better shape memory effect and matched good mechanical property and corrosion resistance.
Drawings
FIG. 1 is a schematic diagram of shape recovery measurement in a bending test in example 1 of the present invention;
FIG. 2 is a hot-rolled microstructure of a memory type duplex stainless steel according to example 1 of the present invention;
FIG. 3 is a calculated equilibrium phase diagram for Thermo-Calc software of the memory type duplex stainless steel of example 1 of the present invention;
FIG. 4 is a drawing showing an annealed microstructure after hot rolling of a memory type duplex stainless steel according to example 1 of the present invention;
FIG. 5 is a microstructure view of a deformed memory type duplex stainless steel according to example 1 of the present invention;
FIG. 6 is a microstructure after recovery of the memory type duplex stainless steel of example 1 of the present invention;
FIG. 7 is a schematic diagram of an etching performance test in an embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to examples.
In the implementation case of the invention, the ferrite and austenite two-phase ratio is regulated and controlled by annealing, and the selection of the annealing temperature is based on a Thermo-Calc thermodynamic equilibrium phase diagram.
In the embodiment of the invention, the observation microstructure is detected by adopting an EBSD system on a Zeiss Ultra 55 type field emission scanning electron microscope, the accelerating voltage of EBSD detection is selected to be 20kV, and the step length is selected to be 0.2 mu m.
The principle of the shape recovery rate of the alloy in the embodiment of the invention is schematically shown in FIG. 1.
The etching performance of the embodiment of the invention is performed on an electrochemical workstation, and a schematic diagram thereof is shown in fig. 7.
The following are preferred embodiments of the present invention.
Example 1
The memory type duplex stainless steel comprises the following components in percentage by mass: 0.03 percent of C, 4 percent of Si, 12 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, 0.2 percent of Al, 15 percent of Cr, 0.958 percent of Ni, 0.5 percent of Co, and the balance of Fe and inevitable impurities.
The preparation method of the memory type duplex stainless steel comprises the following steps:
selecting raw materials according to set components, smelting, casting into a steel ingot, hot forging the steel ingot into a forging stock at 1150 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 50mm, the forging stock is subjected to homogenization treatment for 5 hours at 1250 ℃, the homogenized forging stock is subjected to hot rolling at 1180 ℃, the finish rolling temperature is 920 ℃, a hot rolled steel plate is immediately subjected to water cooling to fix a high-temperature structure, and the thickness of the hot rolled plate is 5 mm; and cooling the hot rolled plate to room temperature, and then annealing at 850 ℃ for 60min to obtain the duplex stainless steel with excellent shape memory effect. The material has yield strength of 580-630 MPa, tensile strength of 860-875 MPa, elongation of 40-48%, pitting potential of 320-350 MV, and shape recovery rate as high as 48-52%.
Example 2
The memory type duplex stainless steel comprises the following components in percentage by mass: 0.05 percent of C, 5 percent of Si, 13 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, 0.3 percent of Al, 13 percent of Cr, 0.8 percent of Ni, 0.3 percent of Co, and the balance of Fe and inevitable impurities.
The preparation method of the memory type duplex stainless steel comprises the following steps:
selecting raw materials according to set components, smelting, casting into a steel ingot, hot forging the steel ingot into a forging stock at 1200 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 60mm, the forging stock is subjected to homogenization treatment for 5 hours at 1250 ℃, the homogenized forging stock is subjected to hot rolling at 1200 ℃, the finish rolling temperature is 1000 ℃, a hot rolled steel plate is immediately subjected to water cooling to fix a high-temperature structure, and the thickness of the hot rolled plate is 5 mm; and cooling the hot rolled plate to room temperature, and then annealing at 930 ℃ for 60min to obtain the duplex stainless steel with excellent shape memory effect. The material has yield strength of 570-610 MPa, tensile strength of 848-858 MPa, elongation of 42-50%, pitting potential of 230-245 MV, and shape recovery rate of 46-51%.
Example 3
The duplex stainless steel of the embodiment comprises the following components in percentage by mass: 0.03 percent of C, 5 percent of Si, 12 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, 0.5 percent of Al, 20 percent of Cr, 1 percent of Ni, 0.6 percent of Co, and the balance of Fe and inevitable impurities.
The preparation method of the memory type duplex stainless steel comprises the following steps:
selecting raw materials according to set components, smelting, casting into a steel ingot, hot forging the steel ingot into a forging stock at 1050 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 40mm, the forging stock is subjected to homogenization treatment for 5h at 1200 ℃, the forging stock after the homogenization treatment is subjected to hot rolling at 1150 ℃, the finish rolling temperature is 850 ℃, a hot rolled steel plate is immediately subjected to water cooling to fix a high-temperature structure, and the thickness of the hot rolled plate is 2 mm; and cooling the hot rolled plate to room temperature, and annealing at 750 ℃ for 60min to obtain the duplex stainless steel with excellent shape memory effect. The material has yield strength of 780-790 MPa, tensile strength of 970-985 MPa, elongation of 40-43%, pitting potential of 430-450 MV, and shape recovery rate of 55-60%.
Example 4
The duplex stainless steel of the embodiment comprises the following components in percentage by mass: 0.03 percent of C, 4 percent of Si, 14 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, 1 percent of Al, 10 percent of Cr, 1 percent of Ni, 0.5 percent of Co, and the balance of Fe and inevitable impurities.
The preparation method of the memory type duplex stainless steel comprises the following steps:
selecting raw materials according to set components, smelting, casting into a steel ingot, hot forging the steel ingot into a forging stock at 1250 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 50mm, the forging stock is subjected to homogenization treatment for 5h at 1250 ℃, the homogenized forging stock is hot-rolled at 1200 ℃, the finish rolling temperature is 1050 ℃, the hot-rolled steel plate is immediately subjected to water cooling to fix a high-temperature structure, and the thickness of the hot-rolled plate is 5 mm; and cooling the hot rolled plate to room temperature, and then annealing at 980 ℃ for 60min to obtain the duplex stainless steel with excellent shape memory effect. The material has the yield strength of 578-585 MPa, the tensile strength of 800-830 MPa, the elongation of 45-50%, the pitting potential of 230-250 MV and the shape recovery rate of 45-52%.
Example 5
The duplex stainless steel of the embodiment comprises the following components in percentage by mass: 0.05 percent of C, 4 percent of Si, 12 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, 1 percent of Al, 18 percent of Cr, 1 percent of Ni, 0.6 percent of Co, and the balance of Fe and inevitable impurities.
The preparation method of the memory type duplex stainless steel comprises the following steps:
selecting raw materials according to set components, smelting, casting into a steel ingot, hot forging the steel ingot into a forging stock at 1100 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 50mm, the forging stock is subjected to homogenization treatment for 5h at 1220 ℃, the homogenized forging stock is subjected to hot rolling at 1170 ℃, the finish rolling temperature is 880 ℃, a hot rolled steel plate is immediately subjected to water cooling to fix a high-temperature structure, and the thickness of the hot rolled plate is 4 mm; and cooling the hot rolled plate to room temperature, and annealing at 850 ℃ for 60min to obtain the duplex stainless steel with excellent shape memory effect. The material has the yield strength of 705-730 MPa, the tensile strength of 940-975 MPa, the elongation of 40-45%, the pitting potential of 420-440 MV, and the shape recovery rate of 50-54%.
Claims (5)
1. A low-chromium low-nickel duplex stainless steel with a shape memory effect comprises the following components in percentage by mass: 0.01-0.1% of C, 2-5% of Si, 7-16% of Mn, less than or equal to 0.01% of P, less than or equal to 0.01% of S, less than or equal to 1% of Ni, 0.2-1% of Al, 10-20% of Cr, 0.2-1% of Co, and the balance of Fe and inevitable impurities.
2. The duplex stainless steel with the shape memory effect according to claim 1, wherein the hot-rolled structure of the shape memory duplex stainless steel is ferrite and austenite, but most of the structure is ferrite, the volume fraction of austenite is 5% -15%, the proportion of the two phases is greatly adjusted mainly through the annealing process after hot rolling, the volume fraction of austenite can reach 30% -70%, the shape recovery rate of the shape memory duplex stainless steel is as high as 45% -65%, the yield strength is 500-800 MPa, the tensile strength is 850-1000 MPa, the elongation is 40-65%, and the pitting potential is 200-450 MV.
3. The method for preparing a shape memory duplex stainless steel according to claim 1, comprising the steps of:
(1) selecting raw materials according to set components, smelting, and casting into steel ingots;
(2) and (3) hot forging the steel ingot into a forging blank at 1050-1250 ℃, and cooling to room temperature, wherein: the thickness of the forging stock is 40-60 mm;
(3) homogenizing the forging stock at 1200-1250 ℃ for 5-8 h;
(4) hot rolling the homogenized forging stock at 1150-1200 ℃, wherein the finishing temperature is 850-1050 ℃, immediately cooling the hot rolled steel plate by water to fix a high-temperature structure, and the thickness of the hot rolled plate is 2-6 mm;
(5) and cooling the hot rolled plate to room temperature, and annealing at 750-1000 ℃ for 30-180 min to obtain the duplex stainless steel with excellent shape memory effect.
4. The method of preparing a shape memory duplex stainless steel according to claim 3, wherein in said step, the steel sheet is cooled by water after hot rolling and annealing.
5. The method for preparing shape memory duplex stainless steel according to claim 3, wherein in the step (4), the hot rolled plate cooling process comprises: and after the temperature of the hot rolled plate is reduced to 800-1000 ℃, cooling to room temperature by adopting an ultra-fast cooling mode, wherein the ultra-fast cooling speed is more than or equal to 100 ℃/s.
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| CN116219259A (en) * | 2023-03-10 | 2023-06-06 | 佛山市高明欧一电子制造有限公司 | Preparation method of memory metal for temperature control device |
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