A nickel-saving high-manganese austenitic stainless steel and a fine-grain treatment method thereof
By combining solution treatment, cold rolling, and inversion annealing, the problem of insufficient mechanical properties of nickel-saving austenitic stainless steel was solved, achieving grain refinement and performance improvement, simplifying the process and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2023-03-15
- Publication Date
- 2026-03-24
AI Technical Summary
While existing austenitic stainless steels save nickel, they are difficult to achieve both high strength and excellent ductility. Traditional strengthening methods are cumbersome and costly.
By employing a combination of solution treatment, cold rolling, and inversion annealing, and controlling the holding temperature and time, the stainless steel grains are refined and its mechanical properties are improved through deformation-induced martensite inversion and recrystallization.
A nickel-saving high-manganese austenitic stainless steel with fine grains and excellent mechanical properties was prepared, simplifying the process and reducing costs.
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Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal material preparation, and in particular to a nickel-saving high-manganese austenitic stainless steel and a fine-grain treatment method thereof. BACKGROUND
[0002] Nickel is one of the key elements for forming and stabilizing austenite, but the cost of nickel element is high, so currently austenitic stainless steel usually adds manganese or other elements to replace part of nickel to achieve the purpose of saving cost, but this method will affect the number of austenite in the austenitic stainless steel, and then affect its mechanical properties. Therefore, other methods are needed to improve the mechanical properties of stainless steel.
[0003] At present, the main methods to improve the mechanical properties of materials are solid solution strengthening, dislocation strengthening, second phase strengthening and fine-grain strengthening. Compared with fine-grain strengthening, solid solution strengthening, dislocation strengthening and second phase strengthening all have disadvantages. Among them, solid solution strengthening and dislocation strengthening usually increase the strength of the material while reducing its plasticity, so that it is difficult to have both high strength and excellent plasticity, and second phase strengthening needs to consider factors such as size, morphology and distribution of the second phase, so many means such as alloy composition, preparation process and parameters need to be controlled to achieve the target effect, so the process is complicated and the production cost is high.
[0004] Therefore, it is urgent to provide a fine-grain treatment method for nickel-saving austenitic stainless steel, which can achieve good fine-grain effect of nickel-saving austenitic stainless steel and thus has excellent mechanical properties. SUMMARY
[0005] The purpose of the present application is to provide a nickel-saving austenitic stainless steel and a fine-grain treatment method thereof. The nickel-saving austenitic stainless steel prepared by the fine-grain treatment method has fine grains and excellent mechanical properties.
[0006] In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solutions:
[0007] The present application provides a fine-grain treatment method for a nickel-saving high-manganese austenitic stainless steel, comprising the following steps:
[0008] (1) solid solution treatment of the nickel-saving high-manganese austenitic stainless steel to be treated to obtain a solid solution alloy;
[0009] (2) cold rolling and reverse annealing treatment of the solid solution alloy obtained in step (1) in sequence to obtain a nickel-saving high-manganese austenitic stainless steel; the holding temperature of the reverse annealing treatment is 600-900℃, and the holding time of the reverse annealing treatment is 100-1000s.
[0010] Preferably, the total deformation amount of cold rolling in step (2) is 40-80%.
[0011] Preferably, the pass of cold rolling in the step (2) is 8-20 times, and the single-pass deformation of cold rolling is 4-5%.
[0012] Preferably, the initial temperature of cold rolling in the step (2) is room temperature.
[0013] Preferably, the heating rate of reverse transformation annealing treatment in the step (2) is 60-80 ℃ / s.
[0014] Preferably, the cooling rate of reverse transformation annealing treatment in the step (2) is 25-35 ℃ / s.
[0015] Preferably, the nickel-saving high-manganese austenitic stainless steel to be treated in the step (1) comprises 1Cr18Mn8Ni5 stainless steel, 1Cr17Mn6Ni5N stainless steel, 12Cr18Mn9Ni5N stainless steel or 10Cr17Mn9Ni4N stainless steel.
[0016] Preferably, the holding temperature of solid solution treatment in the step (1) is 1000-1100 ℃, and the holding time of solid solution treatment is 20-40 min.
[0017] Preferably, the cooling mode of solid solution treatment in the step (1) is water cooling to room temperature.
[0018] The application further provides a nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain treatment method.
[0019] The application provides a fine-grain treatment method of a nickel-saving high-manganese austenitic stainless steel, which comprises the following steps: subjecting the nickel-saving high-manganese austenitic stainless steel to be treated to solid solution treatment to obtain a solid solution alloy; and subjecting the solid solution alloy to cold rolling and reverse transformation annealing treatment in sequence to obtain the nickel-saving high-manganese austenitic stainless steel; the holding temperature of the reverse transformation annealing treatment is 600-900 DEG C, and the holding time of the reverse transformation annealing treatment is 100-1000 s. The application can make the precipitated phase in the alloy matrix fully dissolve by solid solution treatment, so that a uniform solid solution structure is obtained, and the cold rolling deformation is more favorable. The application can make the austenite transform into deformation-induced martensite (gamma→M) under the action of cold rolling deformation, which is due to the fact that the brittle and hard martensite is crushed due to the interaction between dislocations in the deformation process, and the relatively soft austenite grains are gradually flattened to form a fibrous structure, i.e., deformation-induced martensite, under the action of cold rolling deformation. Subsequent reverse transformation annealing treatment can make the deformation-induced martensite in the structure reverse transform into austenite structure. Meanwhile, the application can make the reverse transformation amount of the martensite increase with the increase of the holding temperature of the reverse transformation annealing treatment and reach a stable value under the set holding time by controlling the temperature and time of the reverse transformation annealing treatment. The recrystallization phenomenon also occurs in the stainless steel during the reverse transformation annealing treatment, which effectively refines the grains and improves the mechanical properties of the stainless steel.
[0020] The experimental results show that the nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain treatment method has a grain size in the range of 0.2-2.2 mu m and 2.8-5.5 mu m, and the proportions of the grains in the two ranges are 47.5-56% and 31-39% respectively. The yield strength, tensile strength and elongation of the nickel-saving high-manganese austenitic stainless steel are 0.682-0.748 GPa, 1.255-1.345 GPa and 60-63% respectively, and the performance of the nickel-saving high-manganese austenitic stainless steel is better than that of the alloy to be treated. BRIEF DESCRIPTION OF DRAWINGS
[0021] Figure 1 The SEM image of the nickel-saving high-manganese austenitic stainless steel prepared in Example 1 of the application;
[0022] Figure 2 The optical metallographic photo of the nickel-saving high-manganese austenitic stainless steel prepared in Example 2 of the application;
[0023] Figure 3 The optical metallographic photo of the nickel-saving high-manganese austenitic stainless steel to be treated provided in Comparative Example 1 of the application;
[0024] Figure 4 The columnar graph of the statistical results of the bimodal grain size distribution of the nickel-saving high-manganese austenitic stainless steel in Example 1 of the application;
[0025] Figure 5A histogram of statistical results of bimodal grain size distribution of the nickel-saving high-manganese austenitic stainless steel in Example 2 of the present application;
[0026] Figure 6 A schematic diagram of a tensile specimen specification of the nickel-saving high-manganese austenitic stainless steel in Examples 1-2 and Comparative Example 1 of the present application;
[0027] Figure 7 A stress-strain curve diagram obtained by tensile testing of the nickel-saving high-manganese austenitic stainless steel in Example 1 and Comparative Example 1 of the present application;
[0028] Figure 8 A stress-strain curve diagram obtained by tensile testing of the nickel-saving high-manganese austenitic stainless steel in Example 2 and Comparative Example 1 of the present application. DETAILED DESCRIPTION
[0029] The present application provides a fine-grain processing method of a nickel-saving high-manganese austenitic stainless steel, comprising the following steps:
[0030] (1) subjecting the nickel-saving high-manganese austenitic stainless steel to be processed to solid solution treatment to obtain a solid solution alloy;
[0031] (2) sequentially subjecting the solid solution alloy obtained in step (1) to cold rolling and inverse annealing treatment to obtain a nickel-saving high-manganese austenitic stainless steel; the holding temperature of the inverse annealing treatment is 600-900℃, and the holding time of the inverse annealing treatment is 100-1000s.
[0032] The present application subjects the nickel-saving high-manganese austenitic stainless steel to be processed to solid solution treatment to obtain a solid solution alloy.
[0033] In the present application, the nickel-saving high-manganese austenitic stainless steel to be processed preferably includes 1Cr18Mn8Ni5 stainless steel, 1Cr17Mn6Ni5N stainless steel, 12Cr18Mn9Ni5N stainless steel, or 10Cr17Mn9Ni4N stainless steel.
[0034] In the present application, the state of the nickel-saving high-manganese austenitic stainless steel to be processed is preferably as-cast. The present application does not have special limitations on the source of the nickel-saving high-manganese austenitic stainless steel to be processed, and any commercially available nickel-saving high-manganese austenitic stainless steel of a brand can be used.
[0035] In the present application, the holding temperature of the solid solution treatment is preferably 1000-1100℃, and the holding time of the solid solution treatment is preferably 20-40min. By controlling the holding temperature and holding time of the solid solution treatment within the above ranges, the present application is more conducive to the complete dissolution of precipitated phases, thereby obtaining a solid solution alloy with uniform structure.
[0036] In the present application, the cooling mode of the solid solution treatment is preferably water cooling to room temperature. The present application can make the alloy obtain a faster cooling rate by adopting the water cooling mode, so that the precipitated phase cannot precipitate in time, thereby obtaining a uniform solid solution alloy.
[0037] After obtaining the solid solution alloy, the present application sequentially carries out cold rolling and inverse transformation annealing treatment on the solid solution alloy to obtain a nickel-saving high-manganese austenitic stainless steel.
[0038] In the present application, the total deformation amount of the cold rolling is preferably 40-80%, more preferably 50-70%, and more preferably 60%. By controlling the total deformation amount of the cold rolling within the above range, the present application can make the austenite in the stainless steel undergo a microstructure evolution of deformation-induced martensite (γ→M), thereby obtaining more deformation-induced martensite, which is more conducive to forming more inverse transformation martensite in the subsequent annealing process to refine the grains of the stainless steel and improve the mechanical properties of the stainless steel.
[0039] In the present application, the pass of the cold rolling is preferably 8-20 times, and the single-pass deformation amount of the cold rolling is preferably 4-5%. By controlling the pass and single-pass deformation amount of the cold rolling within the above range, the present application is more conducive to more fully transforming the microstructure of the stainless steel and not causing cracks under the condition of multi-pass deformation.
[0040] In the present application, the initial temperature of the cold rolling is preferably room temperature. By starting the cold rolling at room temperature, the present application can inhibit the growth of dynamic recrystallization of the grains during deformation, thereby avoiding grain coarsening during subsequent annealing.
[0041] In the present application, the heating rate of the inverse transformation annealing treatment is preferably 60-80℃ / s, more preferably 65-75℃ / s, and most preferably 70℃ / s. By controlling the heating rate of the inverse transformation annealing treatment within the above range, the present application is more conducive to uniform heating of the stainless steel and more conducive to sufficient inverse transformation of the deformation-induced martensite.
[0042] In the present application, the holding temperature of the inverse transformation annealing treatment is 600-900℃, preferably 650-850℃, more preferably 700-800℃, and most preferably 750℃; the holding time of the inverse transformation annealing treatment is 100-1000s, preferably 200-900s, more preferably 300-800s, most preferably 400-700s, and further preferably 500-600s. By controlling the temperature and time of the inverse transformation annealing treatment, the present application can make the inverse transformation amount of the martensite increase with the increase of the holding temperature of the inverse transformation annealing treatment and reach a stable state under the set holding time; at the same time, under the conditions of the above holding temperature and holding time of the inverse transformation annealing treatment, recrystallization also occurs in the stainless steel, effectively refining the grains and improving the mechanical properties of the stainless steel.
[0043] In the present application, the cooling rate of the reverse annealing treatment is preferably 25-35℃ / s, more preferably 30℃ / s. The present application is more conducive to the stability of the reverse martensite and avoids grain coarsening by controlling the cooling rate of the reverse annealing treatment within the above range.
[0044] The fine-grain treatment method provided by the present application has the advantages that the nickel-saving austenitic stainless steel prepared by the method has fine grains and excellent mechanical properties, the fine-grain treatment method is simple and easy to implement, the parameters are easy to control, and the cost is low.
[0045] The present application also provides a nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain treatment method.
[0046] The nickel-saving austenitic stainless steel provided by the present application has fine grains and excellent mechanical properties.
[0047] The technical solutions in the present application will be clearly and completely described below with reference to the embodiments in the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.
[0048] Embodiment 1
[0049] A fine-grain treatment method of a nickel-saving high-manganese austenitic stainless steel, specifically comprising the following steps:
[0050] (1) performing solid solution treatment on the nickel-saving high-manganese austenitic stainless steel to be treated to obtain a solid solution alloy; wherein the nickel-saving high-manganese austenitic stainless steel to be treated is 1Cr18Mn8Ni5; the holding temperature of the solid solution treatment is 1050℃, the holding time of the solid solution treatment is 30min; and the cooling mode of the solid solution treatment is water cooling to room temperature.
[0051] (2) sequentially performing cold rolling and reverse annealing treatment on the solid solution alloy obtained in the step (1) to obtain a nickel-saving high-manganese austenitic stainless steel; wherein the heating rate of the reverse annealing treatment is 70℃ / s; the holding temperature of the reverse annealing treatment is 900℃, the holding time of the reverse annealing treatment is 100s; the cooling rate of the reverse annealing treatment is 30℃ / s; the initial temperature of the cold rolling is room temperature; the pass of the cold rolling is 10 times, the single-pass deformation amount of the cold rolling is 5%, and the total deformation amount of the cold rolling is 50%.
[0052] The fine-grain treatment method prepares the nickel-saving high-manganese austenitic stainless steel.
[0053] Embodiment 2
[0054] The cold rolling pass of step (2) in Example 1 is replaced by 20 passes, the single pass deformation of cold rolling is replaced by 4%, the total deformation of cold rolling is replaced by 80%, the holding temperature of annealing treatment is replaced by 850℃, and the other technical features are the same as those of Example 1.
[0055] Comparative Example 1
[0056] The sample (i.e. as-received) of Comparative Example 1 is prepared from the nickel-saving high-manganese austenitic stainless steel to be treated in step (1) of Example 1.
[0057] The nickel-saving high-manganese austenitic stainless steel provided in Examples 1-2 and the as-received sample of Comparative Example 1 are observed by a FEI scanning electron microscope and by a MDS 400 optical microscope. The SEM image of Example 1 is shown in Figure 1 , the optical micrograph of Example 2 is shown in Figure 2 , and the optical micrograph of Comparative Example 1 is shown in Figure 3 .
[0058] According to Figures 1 to 3 , it can be seen that the grain size of the samples provided in Examples 1-2 is 5-8 times smaller than that of the as-received sample of Comparative Example 1, and the samples exhibit a bimodal grain size characteristic.
[0059] In order to further understand the bimodal grain size distribution characteristic, the grain sizes under the two process conditions of Examples 1-2 are counted, and the counting results are shown in Figures 4 to 5 , wherein Figure 4 is the column chart of the counting results of Example 1, Figure 5 is the column chart of the counting results of Example 2.
[0060] According to Figures 4 to 5 , it can be seen that the grain sizes of the nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain treatment method of Example 1 are mainly concentrated in the ranges of 1-2.2 μm and 4.3-5.5 μm, and the proportions are 56% and 39% respectively, and the grain sizes of the nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain treatment method of Example 2 are mainly concentrated in the ranges of 0.2-1.9 μm and 2.8-4.2 μm, and the proportions are 47.5% and 31% respectively.
[0061] The nickel-saving high-manganese austenitic stainless steel provided in Examples 1-2 and the as-received sample of Comparative Example 1 are subjected to uniaxial tensile test at room temperature according to the standard GB / T228.1-2010 by using a WDW3100 microcomputer-controlled electronic universal testing machine of the Chinese Academy of Sciences, and the tensile rate is 1.5 mm / min. The tensile sample specifications of Examples 1-2 and Comparative Example 1 are shown in Figure 6 , and the tensile test results are shown in Figures 7 to 8 , wherein Figure 7Tensile curve graph for Example 1 and Comparative Example 1, Figure 8 Tensile curve graph for Example 2 and Comparative Example 1.
[0062] By Figures 7 to 8 It can be seen that the yield strength, tensile strength and elongation of the stainless steel of Example 1 are 0.748 GPa, 1.345 GPa and 60% respectively, which are 1.6 times, 1.31 times and 0.97 times of Comparative Example 1 respectively; the yield strength, tensile strength and elongation of Example 2 are 0.682 GPa, 1.255 GPa and 63% respectively, which are 1.57 times, 1.33 times and 0.89 times of Comparative Example 1 respectively.
[0063] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the scope of protection of the present application.
Claims
1. A method for refining the grain size of nickel-saving high-manganese austenitic stainless steel, comprising the following steps: (1) The nickel-saving high-manganese austenitic stainless steel to be treated is subjected to solid solution treatment to obtain a solid solution alloy. (2) The solid solution alloy obtained in step (1) is subjected to cold rolling and inversion annealing in sequence to obtain nickel-saving high manganese austenitic stainless steel; the holding temperature of the inversion annealing is 600~900℃ and the holding time of the inversion annealing is 100~1000s. The nickel-saving high-manganese austenitic stainless steel to be treated in step (1) includes 1Cr18Mn8Ni5N stainless steel, 1Cr17Mn6Ni5N stainless steel, 12Cr18Mn9Ni5N stainless steel or 10Cr17Mn9Ni4N stainless steel. In step (2), the total deformation of cold rolling is 40-80%, the number of cold rolling passes is 8-20, and the deformation per cold rolling pass is 4-5%. The heating rate of the inverter annealing process in step (2) is 60~80℃ / s, and the cooling rate of the inverter annealing process is 25~35℃ / s. The nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain treatment method has bimodal grain characteristics, with the proportions of grains in the range of 0.2~2.2μm and 2.8~5.5μm being 47.5~56% and 31~39%, respectively.
2. The fine-grain processing method as described in claim 1, characterized in that, The initial temperature of cold rolling in step (2) is room temperature.
3. The fine-grain processing method as described in claim 1, characterized in that, The heat preservation temperature of the solution treatment in step (1) is 1000~1100℃, and the heat preservation time of the solution treatment is 20~40min.
4. The fine-grain processing method as described in claim 1, characterized in that, The cooling method for the solution treatment in step (1) is water cooling to room temperature.
5. A nickel-saving high-manganese austenitic stainless steel prepared by the fine-grain processing method according to any one of claims 1 to 4.
Citation Information
Patent Citations
Economical fine-grained austenitic stainless steel and manufacturing method thereof
CN110373615A