A kind of high manganese medium aluminum austenitic steel and preparation method thereof

Abstract

The invention discloses a high manganese medium aluminum austenitic steel and a preparation method thereof, which belongs to the technical field of alloy steel and solves the problem that the erosion resistance and toughness and plasticity of the erosion-resistant steel for dredging pipes in the prior art cannot be taken into account at the same time. The components of the high manganese medium aluminum austenitic steel include, by mass percentage: C: 0.8% to 1.5%; Mn: 10.0% to 18.0%; Al: 3.0% to 6.0%, and the balance is Fe and unavoidable impurities. The structure of the high manganese medium aluminum austenitic steel of the invention is a uniform austenitic structure, and the steel of the invention has a high yield strength and excellent plasticity and toughness, and has excellent resistance to seawater mortar erosion.

Description

Technical Field

[0001] The invention relates to the technical field of alloy steels, and in particular to a high-manganese medium-aluminum austenitic steel with excellent seawater mortar erosion resistance and a preparation method thereof. Background Art

[0002] In order to rationally plan and utilize the advantages of the coastline, it is often necessary to transform the natural landform, and dredging projects are an important part of this. Under harsh working conditions, the existing transmission pipeline materials in my country are seriously subject to abrasion failure. The carbon steel Q235B and Q355B currently used in large quantities have a service life of about 1 to 2 years under medium conditions such as silt and fine sand, while under medium conditions containing a variety of coarse sand, coral rock, etc., the pipe body will generally be worn out within 9 months. Severe wear of the pipeline not only reduces the safety of dredging operations, but also increases the cost of pipeline replacement and maintenance, causing the entire ship to stop working and bringing great economic losses. Therefore, it is of great significance to break through the technical bottleneck of high-wear-resistant pipeline materials. In recent years, China has developed high-hardness martensitic wear-resistant steel for dredging pipes. Its erosion resistance is significantly improved compared with Q235B and Q355B steels, but its plasticity and toughness are poor and it is difficult to process and shape. For example, the high-hardness (500HB, 550HB, 600HB) corrosion-resistant steel plates for slurry dredging pipes and their production methods disclosed in recent years (patent publication numbers: CN201710383618.4, CN108950422A, CN108950421A) have a yield strength of more than 1200MPa, but its pipe forming is difficult and the internal stress after pipe making is very large, resulting in a greater tendency for the pipeline to crack during service, posing serious hidden dangers. Summary of the invention

[0003] In view of the above situation, the present invention aims to provide a high manganese medium aluminum austenitic steel with excellent resistance to seawater mortar erosion and a preparation method thereof, which is used to solve the following technical problems: the corrosion resistance and toughness and plasticity of the existing corrosion-resistant steel for dredging pipes cannot be taken into account at the same time.

[0004] The purpose of the present invention is mainly achieved through the following technical solutions:

[0005] The invention provides a high manganese medium aluminum austenitic steel. The components of the high manganese medium aluminum austenitic steel include, by mass percentage: C: 0.8%-1.5%; Mn: 10.0%-18.0%; Al: 3.0%-6.0%, and the balance is Fe and inevitable impurities.

[0006] Furthermore, the components of the high manganese medium aluminum austenitic steel also include: V: 0.02% to 0.3%.

[0007] Furthermore, the components of the high manganese medium aluminum austenitic steel are also added with one or more of the following elements, in percentage by mass: Ni: 0.1% to 3.0%; Mo: 0.05% to 0.6%; Si: 0.05% to 2%; B: 0.0005% to 0.005%; Nb: 0.02% to 0.1%; Ti: 0.05% to 0.25%; Cu: 0.20% to 2.0%; N: 0.002% to 0.50%; RE: 0.002% to 0.10%; Ca: 0.005% to 0.03%.

[0008] Furthermore, the components of the high manganese medium aluminum austenitic steel include, by mass percentage: C: 0.9% to 1.4%; Mn: 11.0% to 17.0%; Al: 3.0% to 5.5%, and the remainder is Fe and unavoidable impurities.

[0009] The present invention also provides a method for preparing high manganese medium aluminum austenitic steel, which is used to prepare the high manganese medium aluminum austenitic steel, comprising:

[0010] Step 1, smelting and pouring to obtain a casting blank or an ingot;

[0011] Step 2: forging the cast billet or ingot into a forging billet, subjecting the forging billet to high temperature homogenization treatment and then rolling it, rapidly cooling it to below 400° C. after rolling and then air cooling it to finally obtain a finished steel plate.

[0012] Furthermore, in step 2, the step of high temperature homogenization treatment includes: heating the billet or ingot to 1100-1200° C. in a heating furnace, and maintaining the temperature at 1100-1200° C. for more than 1 hour.

[0013] Furthermore, in step 2, the final rolling temperature is 750-1000°C.

[0014] Furthermore, in step 2, the rolling includes multiple rolling passes.

[0015] Furthermore, in step 2, the reduction amount in each pass is 10% to 50%.

[0016] Furthermore, in step 2, the structure of the finished steel plate is a uniform austenite structure.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] a) The steel of the present invention is designed with high carbon, high manganese and added aluminum elements, and combined with a suitable hot rolling process, so that the structure of the steel of the present invention is a single austenite structure. The steel of the present invention has a high yield strength and excellent plastic toughness, and has excellent resistance to seawater mortar erosion. While ensuring the seawater mortar erosion resistance of the steel plate, the high-density dislocations in the structure after quenching are entangled and accumulated with each other, mainly strengthening by dislocations, thereby ensuring the excellent plastic toughness of the steel plate.

[0019] b) The mechanical properties of the steel of the present invention are as follows: room temperature yield strength ≥530MPa (e.g. 530-880MPa), tensile strength ≥980MPa (e.g. 987-1165MPa), elongation ≥35% (e.g. 35%-51%), -20°C Charpy impact energy KV2 ≥200J (e.g. 200-295J), hardness ≥240HB (e.g. 242-315HB).

[0020] c) The steel of the present invention also has the advantage of low density, density <7.3g / cm 3 , which helps to reduce equipment weight and save energy.

[0021] d) The preparation method of the steel of the present invention is simple and has the prospect of large-scale promotion and application.

[0022] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0024] Figure 1 is a microstructure diagram of the steel plate of Example 1 of the present invention;

[0025] Figure 2 This is a microstructure diagram of the steel plate of Example 2 of the present invention;

[0026] Figure 3 This is a microstructure diagram of the steel plate of Example 3 of the present invention. DETAILED DESCRIPTION

[0027] Preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used to explain the principles of the present invention together with the embodiments of the present invention.

[0028] The invention provides a high manganese medium aluminum austenitic steel. The components of the high manganese medium aluminum austenitic steel include, by mass percentage: C: 0.8%-1.5%; Mn: 10.0%-18.0%; Al: 3.0%-6.0%, and the balance is Fe and inevitable impurities.

[0029] Specifically, since Mn deteriorates the corrosion resistance, the Al content needs to be appropriately increased as the Mn content increases within a specified range.

[0030] The following is a detailed description of the effects and dosage of the components in the present invention:

[0031] Carbon: C can increase the stability of austenite and make it easier to obtain a fully austenite structure; C has a strong solid solution strengthening effect, which improves the strength and hardness of steel; but too high a C content can easily lead to the formation of a large number of carbides, affecting plasticity and toughness. The present invention takes into account that a fully austenite structure may not be obtained when the C content is less than 0.8%, and a large amount of carbides will precipitate when the C content is greater than 1.5%; therefore, the present invention controls the C content in the steel to be in the range of 0.8% to 1.5%.

[0032] Manganese: Mn is an element that expands the austenite phase region and is conducive to the formation of a single austenite structure; an appropriate Mn content can keep the stacking fault energy of austenite in a reasonable range, thereby obtaining a greater work hardening ability and toughness and plasticity of the steel. In the present invention, it is considered that when the content is less than 10%, it may not be possible to obtain a full austenite structure and the toughness and plasticity are low, and when the content is greater than 18%, the stacking fault energy is too high, which reduces the work hardening ability of the steel; therefore, the present invention controls the Mn content range to be 10.0% to 18.0%.

[0033] Aluminum: Al is a key alloying element of the steel of the present invention. It can improve the seawater corrosion resistance of the steel and inhibit the precipitation of carbides during hot rolling to a certain extent, so that the steel can be rolled at a lower temperature without precipitation of carbides, which is beneficial to grain refinement and yield strength improvement; Al can also reduce the density of steel, which helps to make the equipment lighter. However, excessive Al will greatly increase the stacking fault energy of austenite, weaken its work hardening ability, and is not conducive to improving wear resistance, so the aluminum content in the steel of the present invention is in the range of 3.0% to 6.0%.

[0034] In order to further improve the comprehensive performance of the above-mentioned high manganese medium aluminum austenitic steel, V: 0.02% to 0.3% may be added to the components of the above-mentioned high manganese medium aluminum austenitic steel.

[0035] In order to further improve the comprehensive properties of the above-mentioned high manganese medium aluminum austenitic steel, the components of the above-mentioned high manganese medium aluminum austenitic steel can also be added with one or more of the following elements, in terms of mass percentage, including: Ni: 0.1%~3.0%; Mo: 0.05%~0.6%; Si: 0.05%~2%; B: 0.0005%~0.005%; Nb: 0.02%~0.1%; Ti: 0.05%~0.25%; Cu: 0.20%~2.0%; N: 0.002%~0.50%; RE: 0.002%~0.10%; Ca: 0.005%~0.03%.

[0036] The functions and proportions of the above elements are as follows:

[0037] Nickel: An austenite stabilizing element that can improve atmospheric corrosion resistance, but it is relatively expensive. Taking all factors into consideration, it should be controlled within 3.0%.

[0038] Silicon: inhibits the precipitation of carbides, but excessive silicon is detrimental to the toughness and welding performance of steel. Taking the above into consideration, the silicon content of the steel of the present invention is in the range of 0.05% to 2%.

[0039] Vanadium: It is a strong C and N compound forming element, which plays a pinning role on the austenite grain boundary, inhibits the growth of austenite grains during heating, and precipitates during rolling and tempering, significantly improving the strength and toughness of steel. At the same time, the synergistic effect with Al element in Fe-Mn-Al-C series steel greatly improves the yield strength. Adding an appropriate amount can improve the performance. When it is higher than 0.3%, it is easy to form large particles of nitride, which reduces the toughness and plasticity. Therefore, the vanadium content is controlled in the range of 0.02% to 0.3%.

[0040] Boron: It is strongly concentrated in austenite grain boundaries and other crystal defects, and can significantly purify grain boundaries. The effect is not obvious when the content is less than 0.0005%, and the effect is not obvious when it is higher than 0.005%. Therefore, the B content should be controlled in the range of 0.0005% to 0.005%.

[0041] Niobium: It has a strong effect of refining the structure after phase transformation. The precipitation of Nb (C, N) through solid solution and deformation induction strongly affects the degree of austenite recrystallization. The content of the steel of the present invention should be controlled within 0.1%. If it exceeds 0.1%, the further refinement effect of the structure becomes less obvious and the cost increases. Therefore, the niobium content is controlled in the range of 0.02% to 0.1%.

[0042] Titanium: Titanium is a strong carbonitride-forming element, which can form fine dispersed carbonitrides and play a role in refining austenite grains. In the present invention, its content should be controlled at 0.05% to 0.25%.

[0043] Molybdenum: It can strengthen the grain boundary and improve the strength of the steel plate without affecting the low temperature impact performance of the steel plate; it can also increase the tempering resistance of the steel plate, so that the strength of the steel plate does not decrease at a higher temperature. When its content is less than 0.05%, it is difficult to play the above role, but when the content is greater than 0.6%, the effect is saturated and the cost is high. Therefore, the molybdenum content in the present invention is controlled at 0.05% to 0.6%.

[0044] Calcium: deoxidizes and desulfurizes, and deforms inclusions, thereby improving the toughness and plasticity of steel. In the present invention, its content should be controlled within the range of 0.005% to 0.03%.

[0045] Rare earth: It plays the role of purifying molten steel, denaturing inclusions and improving toughness and plasticity, and also improves the corrosion resistance of steel. Considering that the above effects are not obvious when the content is less than 0.002%, and when it is higher than 0.10%, the above effects are saturated and intermetallic compounds will be formed, which will damage toughness and plasticity; the rare earth content in the present invention should be controlled in the range of 0.002% to 0.1%.

[0046] Copper: It is an austenite stabilizing element, and can also improve the corrosion resistance of steel, inhibit the precipitation of carbides along grain boundaries, and improve the toughness and plasticity of steel. In the present invention, the addition range of Cu is 0.20% to 2.0%.

[0047] Phosphorus: As an impurity element, it seriously damages the toughness and plasticity of steel. The content is controlled at P≤0.015%.

[0048] Nitrogen: Combined with microalloying elements and Al in steel, it forms various fine carbonitrides, which has the effect of refining grains; solid solution N can expand the austenite phase region and has a strong solid solution strengthening effect. The N content should be controlled within the range of 0.002% to 0.50%.

[0049] Sulfur: A harmful element in steel that has an adverse effect on the plasticity and toughness of the material. A high sulfur content easily forms long inclusions such as MnS, which leads to anisotropy of the steel plate and prone to delamination and cracking. Therefore, the present invention requires that S≤0.010%.

[0050] In order to further improve the comprehensive performance of the above-mentioned high manganese medium aluminum austenitic steel, the components of the above-mentioned high manganese medium aluminum austenitic steel can be calculated by mass percentage: C: 0.9%~1.4%; Mn: 11.0%~17.0%; Al: 3.0%~5.5%, and the remainder is Fe and inevitable impurities.

[0051] Specifically, V: 0.02% to 0.29%.

[0052] The present invention also provides a method for preparing the high manganese medium aluminum austenitic steel, comprising:

[0053] Step 1, smelting and pouring to obtain a casting blank or an ingot;

[0054] Step 2: Forge the cast billet or ingot into a forging billet, and perform high-temperature homogenization treatment on the forging billet before rolling. After rolling, quickly cool it to below 400° C. and then air cool it to finally obtain a finished steel plate. Pay attention to avoid overburning during high-temperature homogenization treatment.

[0055] Specifically, in the above step 1, a converter, an electric furnace or an induction furnace may be used for smelting, and continuous casting may be used to produce billets, or mold casting may be used to produce ingots.

[0056] Specifically, in the above step 2, during the high temperature homogenization treatment, it is considered that too high a holding temperature may cause overburning and affect the performance; too low a holding temperature may lead to insufficient grain recovery and growth; too long a holding time may affect processing efficiency and increase energy consumption; too short a holding time may not meet the homogenization requirements. Therefore, the specific steps of controlling the high temperature homogenization treatment in the above step 2 include: heating the billet or ingot to 1100-1200°C in a heating furnace and maintaining it at 1100-1200°C for more than 1 hour.

[0057] Specifically, in the above step 2, the final rolling temperature is 750-1000°C.

[0058] Specifically, in the above step 2, rolling includes multiple rolling passes (for example, 3 to 7 passes). Considering that too small a reduction in each pass will result in too many rolling passes and the temperature will be difficult to control, and too large a reduction will result in increased width and excessive rolling stress, which will increase the difficulty of forming, therefore, the reduction in each pass is controlled to be 10% to 50%.

[0059] Specifically, in the above step 2, during the rolling process, the thickness deformation of the latter pass is smaller than that of the previous pass.

[0060] Specifically, in the above step 2, if the cooling rate after rolling is too low, carbide precipitation will occur, affecting plastic toughness. Therefore, the cooling rate of rapid cooling is controlled to be greater than 10°C / s.

[0061] Specifically, in the above step 2, the structure of the finished steel plate is a uniform austenite structure with an average grain size of ≤20 μm. Specifically, the shape of the grains is related to the final rolling temperature. As the final rolling temperature increases from low to high, the structure composition gradually transitions from elongated grains and fine grains to simple equiaxed grains. When the final rolling temperature is lower, the resistance to seawater mortar erosion is higher.

[0062] Specifically, in the above step 2, the mechanical properties of the finished steel plate are as follows: room temperature yield strength ≥530MPa (e.g. 530-880MPa), tensile strength ≥980MPa (e.g. 987-1165MPa), elongation ≥35% (e.g. 35%-51%), -20°C Charpy impact energy KV2 ≥200J (e.g. 200-295J), hardness ≥240HB (e.g. 242-315HB), density <7.3g / cm3 The high manganese medium aluminum austenitic steel of the present invention has excellent low temperature toughness and high yield strength.

[0063] Specifically, in the above step 2, the finished steel plate has excellent corrosion resistance under simulated erosion by a mixed slurry of 3.5wt% NaCl seawater acidity and 3mm quartz sand. For example, the test sample is stirred in the slurry at a linear speed of 3.28m / s (150r / min angular velocity), with a total stroke of 5934m (45000 revolutions), and an actual weight loss of less than 0.2g.

[0064] Compared with the prior art, the steel of the present invention is designed with high carbon, high manganese and added aluminum elements, and combined with a suitable hot rolling process, so that the structure of the steel of the present invention is a single austenite structure. The steel of the present invention has a high yield strength and excellent plastic toughness, and has excellent resistance to seawater mortar erosion. While ensuring the seawater mortar erosion resistance of the steel plate, the high-density dislocations inside the structure after quenching are entangled and accumulated with each other, mainly strengthening by dislocations, thereby ensuring the excellent plastic toughness of the steel plate.

[0065] The mechanical properties of the steel of the present invention are as follows: room temperature yield strength ≥530MPa (e.g. 530-880MPa), tensile strength ≥980MPa (e.g. 987-1165MPa), elongation ≥35% (e.g. 35%-51%), -20°C Charpy impact energy KV2 ≥200J (e.g. 200-295J), hardness ≥240HB (e.g. 242-315HB), density <7.3g / cm 3 .

[0066] The steel of the present invention also has the advantage of lower density, which helps to reduce equipment weight and save energy and reduce consumption.

[0067] The steel preparation method of the invention is simple and has the prospect of large-scale promotion and application.

[0068] Examples 1-6

[0069] Embodiments 1-6 of the present invention provide a high manganese medium aluminum austenitic steel and a preparation method thereof. The components of the steels of Embodiments 1-6 include, by mass percentage: C: 0.8% to 1.5%; Mn: 10.0% to 18.0%; Al: 3.0% to 6.0%, and the balance is Fe and unavoidable impurities. It may also include: Ni: 0.1% to 3.0%; Mo: 0.05% to 0.6%; Si: 0.05% to 2%; B: 0.0005% to 0.005%; Nb: 0.02% to 0.1%; Ti: 0.05% to 0.25%; V: 0.02% to 0.3%; Cu: 0.20% to 2.0%; N: 0.002% to 0.50%; RE: 0.002% to 0.10%; Ca: 0.005% to 0.03%.

[0070] The method for preparing the steel of Example 1 comprises:

[0071] The ingot is smelted and poured in a 100kg vacuum induction furnace, forged into a 120mm (width) * 60mm (thickness) * L billet, cut into 150mm long billets for rolling; the rolling process includes: 1100℃ insulation for 3h, rolling after being taken out of the furnace, water quenching to below 400℃ after rolling, and air cooling to room temperature. The reduction / temperature: 60mm-48mm-(950℃)38mm-30mm-(900℃)24mm-19mm-(850℃)15mm, and the thickness of the steel plate is 15mm.

[0072] The method for preparing the steel of Example 2 comprises:

[0073] The 100kg vacuum induction furnace is used to smelt and pour the ingot, which is forged into a 120mm (width) * 60mm (thickness) * L billet, cut into 150mm long billets for rolling; the rolling process includes: 1150℃ insulation for 3h, rolling after being taken out of the furnace, water quenching to below 400℃ after rolling, and air cooling to room temperature. The reduction / temperature: 60mm-48mm-(950℃)38mm-30mm-(850℃)24mm-19mm-(750℃)15mm, and the thickness of the steel plate is 15mm.

[0074] The method for preparing the steel of Example 3 comprises:

[0075] The ingot is smelted and poured in a 100kg vacuum induction furnace, forged into a 120mm (width) * 60mm (thickness) * L billet, cut into 150mm long billets for rolling; the rolling process includes: 1200℃ insulation for 3h, rolling after furnace removal, water quenching to below 400℃ after rolling, and air cooling to room temperature. Reduction / temperature: 60mm-48mm-(1000℃)38mm-30mm-(900℃)24mm-19mm-(850℃)15mm, and the thickness of the steel plate is 15mm.

[0076] The method for preparing the steel of Example 4 comprises:

[0077] The ingot is smelted and poured in a 100kg vacuum induction furnace, forged into a 120mm (width) * 60mm (thickness) * L billet, cut into 150mm long billets for rolling; the rolling process includes: 1200℃ insulation for 3h, rolling after furnace removal, water quenching to below 400℃ after rolling, and air cooling to room temperature. Reduction / temperature: 60mm-48mm-(1000℃)38mm-30mm-(900℃)24mm-19mm-(900℃)15mm, and the thickness of the steel plate is 15mm.

[0078] The method for preparing the steel of Example 5 comprises:

[0079] The 100kg vacuum induction furnace is used to smelt and pour the ingot, which is forged into a 120mm (width) * 60mm (thickness) * L billet, cut into 150mm long billets for rolling; the rolling process includes: 1200℃ insulation for 3h, rolling after the furnace is taken out, and water quenching to room temperature after rolling. The rolling reduction / temperature distribution is as follows: 60mm-48mm-(1000℃)38mm-30mm-(900℃)24mm-19mm-(850℃)15mm, and the thickness of the steel plate is 15mm.

[0080] The method for preparing the steel of Example 6 comprises:

[0081] The ingot is smelted and poured in a 100kg vacuum induction furnace, forged into a 120mm (width) * 60mm (thickness) * L billet, cut into 150mm long for rolling; the rolling process includes: 1200℃ insulation for 3h, rolling after furnace removal, and water quenching to room temperature after rolling. The rolling reduction / temperature distribution is as follows: 60mm-48mm-(1000℃)38mm-30mm-(900℃)24mm-19mm-(800℃)15mm, and the thickness specification of the steel plate is 15mm.

[0082] The specific composition of the steel plates of Examples 1-6 is shown in Table 1 below. The microstructure of the steel plates of Examples 1-3 is shown in Table 1 below. Figure 1-Figure 3 As shown, the microstructure of the steel plates of Examples 1 and 3 is uniform austenite with an average grain size of ≤20μm; Example 2 is a flattened austenite structure, which is mainly due to the different final rolling temperatures causing different degrees of recrystallization of the austenite structure. These two structures will only cause differences in mechanical properties and will not affect the resistance to seawater mortar erosion. The mechanical properties of the steel plates of Examples 1-6 are shown in Table 2 below. The relative resistance to seawater mortar erosion of the steel plates of Examples 1-6 is shown in Table 3 below. It can be seen that the steel of the present invention has a greatly improved resistance to seawater mortar erosion compared to the austenitic steel of Comparative Example 1.

[0083] Specifically, the relative anti-seawater mortar erosion performance test method adopts the rotational motion test method, which measures the relative abrasiveness of the material by measuring the metal loss of the sample in a circular motion in the slurry of the mixing barrel. Since different groups in this test process are prone to changes in working conditions, it is a comparative experiment, and the measurement result is relative abrasiveness.

[0084] The composition of the erosion test medium in the detection method is shown in Table 4: the 3.5wt% seawater solution is fixed, so the water and NaCl are fixed, and the amount of sand is determined by the 2-4mm sand just being submerged by the water surface, so the weight of the sand is about 35Kg. This slurry combination is to simulate the harsh working conditions of seawater. The test sample is stirred in the slurry at a linear speed of 3.28m / s (150r / min angular velocity), with a total stroke of 5934m (45000 revolutions), and it takes about 5h to complete a set of tests. Table 3 shows the actual weight loss and relative anti-seawater mortar erosion performance of the embodiments and comparative examples.

[0085] Table 1 Main chemical components of steel of Examples and Comparative Examples (%)

[0086]

[0087]

[0088] Table 2 Properties of steels in Examples and Comparative Examples

[0089]

[0090]

[0091] Table 3 Relative seawater mortar erosion resistance of steel in the examples and comparative examples

[0092] Serial number Actual weight loss / g Relative resistance to seawater mortar erosion Example 1 0.1962 2.36 Example 2 0.1795 2.58 Example 3 0.1921 2.41 Example 4 0.1852 2.50 Example 5 0.1962 2.36 Example 6 0.1816 2.55 Comparative Example 1 0.4632 1.00

[0093] Table 4 Erosion test medium composition

[0094] Element Weight / g Mass fraction / % water 14000 NaCl 508 3.5 Quartz sand 35000 70.7 total 49508

[0095] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A high manganese medium aluminum austenitic steel, characterized in that: The components of the high manganese medium aluminum austenitic steel include, by mass percentage: C: 1.18% to 1.4%; Mn: 10.0% to 14.57%; Al: 3.29% to 5.5%, and the balance is Fe and unavoidable impurities; The preparation method of the high manganese medium aluminum austenitic steel comprises: Step 1, smelting and pouring to obtain a casting blank or an ingot; Step 2, forging the cast billet or ingot into a forged billet, subjecting the forged billet to high temperature homogenization treatment and then rolling, rapidly cooling to below 400° C. after rolling and then air cooling, finally obtaining a finished steel plate; During the rolling process, the thickness deformation of the latter pass is smaller than that of the previous pass; In step 2, the cooling rate of rapid cooling is controlled to be greater than 10°C / s; The structure of the finished steel plate is a uniform austenite structure with an average grain size of ≤20μm, and high-density dislocations inside the structure are entangled and accumulated with each other.

2. The high manganese medium aluminum austenitic steel according to claim 1, characterized in that: The components of the high manganese and medium aluminum austenitic steel also include: RE: 0.002% to 0.10%, Ca: 0.005% to 0.03%.

3. The high manganese medium aluminum austenitic steel according to claim 1, characterized in that: The components of the high manganese and medium aluminum austenitic steel also include: V: 0.02% to 0.3%.

4. The high manganese medium aluminum austenitic steel according to claim 1, characterized in that: The components of the high manganese and medium aluminum austenitic steel are further added with one or more of the following elements, which are calculated by mass percentage: Ni: 0.1% to 3.0%; Mo: 0.05% to 0.6%; Si: 0.05% to 2%; B: 0.0005% to 0.005%; Nb: 0.02% to 0.1%; Ti: 0.05% to 0.25%; Cu: 0.20% to 2.0%; N: 0.002% to 0.50%; RE: 0.002% to 0.10%; Ca: 0.005% to 0.03%.

5. The high manganese medium aluminum austenitic steel according to claim 1, characterized in that: The components of the high manganese and medium aluminum austenitic steel include, by mass percentage: C: 1.18% to 1.27%; Mn: 13.29% to 14.57%; Al: 3.29% to 4.12%, and the remainder is Fe and unavoidable impurities.

6. A method for preparing high manganese and medium aluminum austenitic steel, characterized in that: For preparing the high manganese medium aluminum austenitic steel according to any one of claims 1 to 5, comprising: Step 1, smelting and pouring to obtain a casting blank or an ingot; Step 2: forging the cast billet or ingot into a forging billet, subjecting the forging billet to high temperature homogenization treatment and then rolling it, rapidly cooling it to below 400° C. after rolling and then air cooling it to finally obtain a finished steel plate.

7. The preparation method according to claim 6, characterized in that: In step 2, the step of high temperature homogenization treatment includes: heating the billet or ingot to 1100-1200° C. in a heating furnace and maintaining the temperature at 1100-1200° C. for more than 1 hour.

8. The preparation method according to claim 6, characterized in that: In the step 2, the final rolling temperature is 750-1000°C.

9. The preparation method according to claim 6, characterized in that: In the step 2, the rolling includes multiple rolling passes.

10. The preparation method according to claim 6, characterized in that: In the step 2, the reduction amount in each pass is 10% to 50%.

11. The preparation method according to any one of claims 6 to 10, characterized in that: In the step 2, the structure of the finished steel plate is a uniform austenite structure.

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