Vanadium-nitrogen microalloyed steel and manufacturing method thereof

Abstract

The invention relates to the technical field of metal strengthening, in particular to vanadium-nitrogen microalloyed steel and a manufacturing method thereof. Comprising the following steps that firstly, after low-nitrogen vanadium-containing steel is cleaned and dried, the low-nitrogen vanadium-containing steel is pretreated through a laser shot peening technology, and pretreated vanadium-containing steel is obtained; secondly, nitriding treatment is conducted on the pretreated vanadium-containing steel through an ion nitriding technology, and nitrided vanadium-containing steel is obtained; and thirdly, the nitrided vanadium-containing steel is subjected to low-temperature aging treatment, and the vanadium-nitrogen microalloyed steel is obtained. According to the method, the low-nitrogen vanadium-containing steel is treated through the laser peening process, the ion nitriding process and the low-temperature aging treatment, the vanadium-nitrogen microalloyed steel with excellent performance is comprehensively obtained, and the applicability of similar low-nitrogen vanadium-containing steel is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal strengthening, in particular to a vanadium-nitrogen microalloyed steel and a manufacturing method thereof. Background Art

[0002] The vanadium-nitrogen microalloying technology optimizes the precipitation of vanadium by making full use of the cheap nitrogen element, so that it can better play the role of fine grain strengthening and precipitation strengthening in the metal. Therefore, the use of vanadium-nitrogen microalloying technology can obtain alloys with better performance at low vanadium content, and can also save vanadium and reduce the cost of steel. For some low-nitrogen vanadium-containing steels, the vanadium-nitrogen microalloying can also be promoted by increasing the nitrogen content, thereby enhancing the performance of the steel.

[0003] Based on this, the present invention will obtain a vanadium-nitrogen microalloyed steel by nitriding low-nitrogen vanadium-containing steel, which can expand the application of low-nitrogen vanadium-containing steel and is of great significance. Summary of the invention

[0004] The object of the present invention is to provide a vanadium-nitrogen microalloyed steel and a method for manufacturing the same, so as to solve the problems raised in the prior art.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A vanadium-nitrogen microalloyed steel is manufactured by sequentially subjecting low-nitrogen vanadium-containing steel to laser shot peening pretreatment, ion nitriding treatment, and low-temperature aging treatment.

[0007] Furthermore, the method for manufacturing the vanadium-nitrogen microalloyed steel comprises the following steps:

[0008] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0009] Step 2: nitriding the pretreated vanadium-containing steel using an ion nitriding process to obtain nitrided vanadium-containing steel;

[0010] Step 3: Perform low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel.

[0011] Furthermore, the low-nitrogen vanadium-containing steel is a steel material containing vanadium and 0 to 0.005 wt% of nitrogen; wherein the 0 to 0.005 wt% of nitrogen includes but is not limited to 0 wt% of nitrogen, 0.001 wt% of nitrogen, 0.002 wt% of nitrogen, 0.003 wt% of nitrogen, 0.004 wt% of nitrogen, and 0.005 wt% of nitrogen.

[0012] In the embodiment of the present invention, the low nitrogen vanadium-containing steel used includes the following chemical components in mass percentage: C 0.18wt%, Si 0.1wt%, Mn 0.8wt%, Cr 3.6wt%, Mo 3wt%, Ni 0.4wt%, B 0.002wt%, V 0.4wt%, Nb0.025wt%, Ti 0.015wt%, P 0.01wt%, S 0.01wt%, N 0.003wt%, and the balance is Fe and unavoidable impurities; the low nitrogen vanadium-containing steel is a product produced by the company itself.

[0013] Furthermore, the parameters of the laser peening process are: pulse power density is 1 to 10 GW / cm 2 , pulse width is 5 to 40ns, and coverage is 100 to 300%.

[0014] Nitrogen can form stable nitrides with metals such as chromium, aluminum, vanadium, and titanium in steel, thereby enhancing and improving the relevant mechanical properties of steel to a certain extent. However, if the residual nitrogen content in steel is too high, it will also lead to loose macroscopic structures of steel or defects such as pores, and if the mass percentage of nitrogen is greater than 0.16wt%, the oxidation resistance of steel will deteriorate. Therefore, in general, controlling the mass percentage of nitrogen in steel to ≤0.16wt% will make it easier to achieve the strengthening effect of nitrogen on steel. For some steels with low nitrogen content (≤0.005wt%), the performance of steel can be improved by appropriately increasing its nitrogen content. Based on this, the present invention treats low-nitrogen vanadium-containing steel through a laser shot peening process, so that the microstructure inside the surface layer of the low-nitrogen vanadium-containing steel evolves into a microscopic feature dominated by dislocations, which provides a gain premise for subsequent nitriding treatment. That is, as dislocations increase, the diffusion channels of nitrogen atoms increase, which has an extremely important promoting effect on nitriding. The nitriding quality of low-nitrogen vanadium-containing steel can also be further controlled by controlling the laser shot peening process parameters. In addition, after laser shot peening, the hardness of low-nitrogen vanadium steel will increase to a certain extent. At the same time, the laser shot peening process has limited damage to low-nitrogen vanadium steel and will not cause too much change to the morphology of low-nitrogen vanadium steel, which to a certain extent also ensures that the practical application of low-nitrogen vanadium steel will not be greatly affected.

[0015] Furthermore, the process parameters of the ion nitriding process are: nitriding temperature is 450-600°C, nitriding voltage is 600-650V, nitriding pressure is 250-400Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.5-1L / min, and nitriding depth is 3-100μm.

[0016] Furthermore, rare earth oxides are introduced into the ion nitriding process, and are prepared into anhydrous ethanol saturated solution of rare earth oxides, and then the solution is added into the ion nitriding furnace by controlling the amount of the solution through a mass flow meter.

[0017] Furthermore, the introduction rate of the saturated solution of anhydrous ethanol of the rare earth oxide is 5 to 69 mL / min.

[0018] Furthermore, as the nitriding depth increases, the amount of the rare earth oxide saturated anhydrous ethanol solution introduced is also adjusted accordingly, specifically:

[0019] If 3 μm≤nitriding depth≤10 μm, the amount of the rare earth oxide saturated solution of anhydrous ethanol is 5 mL / min;

[0020] If 10 μm < nitriding depth ≤ 50 μm, the amount of the rare earth oxide saturated solution of anhydrous ethanol is introduced starting from 5 mL / min and increasing by 0.5 mL / min for every 1 μm;

[0021] If 50 μm<nitriding depth≤80 μm, the flow rate of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 25 mL / min and increases by 0.8 mL / min for every 1 μm;

[0022] If 80 μm<nitriding depth≤100 μm, the flow rate of the saturated anhydrous ethanol solution of the rare earth oxide starts from 49 mL / min and increases by 1 mL / min for every 1 μm.

[0023] Furthermore, the rare earth oxide is obtained by mixing cerium oxide and lanthanum oxide in a mass ratio of 1:1.

[0024] In the present invention, an ion nitriding process is used to nitridize low-nitrogen vanadium-containing steel; however, the efficiency of nitriding will gradually slow down as the nitriding progresses, that is, the difficulty of nitriding will gradually increase. Therefore, in the present invention, nitriding is further promoted by adding rare earth oxides, wherein lanthanum oxide can enhance the adsorption capacity of nitrogen atoms on the steel surface, and cerium oxide can reduce the energy of nitrogen atoms diffusing into the steel, and the two synergistically achieve the purpose of promoting nitriding. Furthermore, in the present invention, the nitriding efficiency and carburizing quality at different nitriding depths can be effectively controlled by controlling the amount of rare earth oxides introduced and the nitriding parameters, so that the performance of the prepared nitrided vanadium-containing steel is more stable.

[0025] Furthermore, the parameters of the low-temperature aging treatment are: the treatment temperature is 290-330° C., and the treatment time is 2-4 hours.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. In the present invention, the microstructure of the surface of the low-nitrogen vanadium-containing steel is first improved by a laser shot peening process to obtain a pre-treated vanadium-containing steel, which provides effective support for the subsequent nitriding efficiency; the pre-treated vanadium-containing steel is further nitrided and strengthened by an ion nitriding process, thereby achieving the purpose of enhancing the vanadium-nitrogen microalloying degree in the low-nitrogen vanadium-containing steel and enhancing the performance of the low-nitrogen vanadium-containing steel;

[0028] 2. In the present invention, rare earth oxides are added in the ion nitriding process to further promote nitriding; and the amount of rare earth oxides introduced and the nitriding parameters at different nitriding depths are adjusted to obtain nitrided vanadium-containing steel with uniform and stable performance and quality;

[0029] 3. In the present invention, the nitrided vanadium-containing steel is further subjected to low-temperature aging treatment to obtain vanadium-nitrogen microalloyed steel; after the low-temperature aging treatment, the bonding force between the nitrided layer and the substrate is strongly enhanced, and it is not easy to fall off, and the life of the vanadium-nitrogen microalloyed steel is also improved;

[0030] 4. The present invention processes low-nitrogen vanadium-containing steel through "laser shot peening process + ion nitriding process + low-temperature aging treatment", and comprehensively obtains a vanadium-nitrogen micro-alloyed steel with excellent performance, thereby improving the applicability of similar low-nitrogen vanadium-containing steel.

[0031] 5. The present invention provides a direction for enhancing the performance of similar low-nitrogen vanadium-containing steels and expands their applications, which is of great significance. DETAILED DESCRIPTION

[0032] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that the process parameters not specified in the following examples are all conventional conditions; the raw materials can be obtained from public commercial channels.

[0034] The low-nitrogen vanadium-containing steel used in the embodiment of the present invention includes the following chemical components in mass percentage: C 0.18wt%, Si 0.1wt%, Mn 0.8wt%, Cr 3.6wt%, Mo 3wt%, Ni 0.4wt%, B 0.002wt%, V 0.4wt%, Nb 0.025wt%, Ti 0.015wt%, P 0.01wt%, S 0.01wt%, N 0.003wt%, and the balance is Fe and unavoidable impurities, and is produced by the company itself.

[0035] Preliminary preparation: adding cerium oxide and lanthanum oxide into an anhydrous ethanol solution to prepare an anhydrous ethanol saturated solution of rare earth oxides.

[0036] Example 1: A method for manufacturing vanadium-nitrogen microalloyed steel:

[0037] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0038] The process parameters of laser shot peening are: pulse power density is 8GW / cm 2 , pulse width is 25ns, coverage is 200%;

[0039] Step 2: nitriding the pretreated vanadium-containing steel in an LD-2-50A ion nitriding furnace to obtain nitrided vanadium-containing steel;

[0040] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0041] The process parameters of nitriding treatment are as follows: nitriding temperature is 500°C, nitriding voltage is 600V, nitriding pressure is 300Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0042] As the nitriding depth increases, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is: 3μm≤nitriding depth≤10μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide is 5mL / min; 10μm<nitriding depth≤50μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 5mL / min and increases by 0.5mL / min for every 1μm;

[0043] Step 3: performing low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel;

[0044] The parameters of the low-temperature aging treatment are: treatment temperature is 300°C and treatment time is 3h.

[0045] Embodiment 2: A method for manufacturing vanadium-nitrogen microalloyed steel:

[0046] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0047] The process parameters of laser shot peening are: pulse power density is 1GW / cm 2, pulse width is 5ns, coverage is 100%;

[0048] Step 2: nitriding the pretreated vanadium-containing steel in an LD-2-50A ion nitriding furnace to obtain nitrided vanadium-containing steel;

[0049] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0050] The process parameters of nitriding treatment are as follows: nitriding temperature is 450°C, nitriding voltage is 600V, nitriding pressure is 250Pa, nitrogen source is a mixed gas of N2, H2, and Ar with a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0051] As the nitriding depth increases, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is: 3μm≤nitriding depth≤10μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide is 5mL / min; 10μm<nitriding depth≤50μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 5mL / min and increases by 0.5mL / min for every 1μm;

[0052] Step 3: performing low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel;

[0053] The parameters of low-temperature aging treatment are: treatment temperature is 290°C, and treatment time is 2h.

[0054] Embodiment 3: A method for manufacturing vanadium nitrogen microalloyed steel:

[0055] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0056] The process parameters of laser shot peening are: pulse power density is 10GW / cm 2 , pulse width is 40ns, coverage is 300%;

[0057] Step 2: nitriding the pretreated vanadium-containing steel in an LD-2-50A ion nitriding furnace to obtain nitrided vanadium-containing steel;

[0058] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0059] The process parameters of nitriding treatment are as follows: nitriding temperature is 600°C, nitriding voltage is 650V, nitriding pressure is 400Pa, nitrogen source is a mixed gas of N2, H2, and Ar with a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0060] As the nitriding depth increases, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is: 3μm≤nitriding depth≤10μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide is 5mL / min; 10μm<nitriding depth≤50μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 5mL / min and increases by 0.5mL / min for every 1μm;

[0061] Step 3: performing low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel;

[0062] The parameters of low-temperature aging treatment are: treatment temperature is 330°C, and treatment time is 4h.

[0063] Based on Example 1, a control experiment was carried out, specifically Comparative Examples 1 to 5, as described below:

[0064] Comparative Example 1: Comparative Example 1 is based on Example 1, with the following adjustments: no laser shot peening pretreatment is performed on the low-nitrogen vanadium-containing steel, and other processes remain unchanged, specifically:

[0065] A method for manufacturing vanadium-nitrogen microalloyed steel:

[0066] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, nitriding the steel is performed in an LD-2-50A ion nitriding furnace to obtain nitrided vanadium-containing steel;

[0067] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0068] The process parameters of nitriding treatment are as follows: nitriding temperature is 500°C, nitriding voltage is 600V, nitriding pressure is 300Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0069] As the nitriding depth increases, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is: 3μm≤nitriding depth≤10μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide is 5mL / min; 10μm<nitriding depth≤50μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 5mL / min and increases by 0.5mL / min for every 1μm;

[0070] Step 2: performing low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel;

[0071] The parameters of the low-temperature aging treatment are: treatment temperature is 300°C and treatment time is 3h.

[0072] Comparative Example 2: Comparative Example 2 is based on Example 1, with the following modifications: During the nitriding treatment, no saturated solution of anhydrous ethanol of rare earth metal oxide is added, and other processes remain unchanged, specifically:

[0073] A method for manufacturing vanadium-nitrogen microalloyed steel:

[0074] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0075] The process parameters of laser shot peening are: pulse power density is 8GW / cm 2 , pulse width is 25ns, coverage is 200%;

[0076] Step 2: nitriding the pretreated vanadium-containing steel in an LD-2-50A ion nitriding furnace to obtain nitrided vanadium-containing steel;

[0077] The process parameters of nitriding treatment are as follows: nitriding temperature is 500°C, nitriding voltage is 600V, nitriding pressure is 300Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0078] Step 3: performing low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel;

[0079] The parameters of the low-temperature aging treatment are: treatment temperature is 300°C and treatment time is 3h.

[0080] Comparative Example 3: Comparative Example 3 is based on Example 1, except that: the amount of the saturated anhydrous ethanol solution of the rare earth metal oxide introduced remains unchanged, and other processes remain unchanged, specifically:

[0081] A method for manufacturing vanadium-nitrogen microalloyed steel:

[0082] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0083] The process parameters of laser shot peening are: pulse power density is 8GW / cm 2 , pulse width is 25ns, coverage is 200%;

[0084] Step 2: nitriding the pretreated vanadium-containing steel in an LD-2-50A ion nitriding furnace to obtain nitrided vanadium-containing steel;

[0085] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0086] The process parameters of nitriding treatment are as follows: nitriding temperature is 500°C, nitriding voltage is 600V, nitriding pressure is 300Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0087] The flow rate of the saturated solution of anhydrous ethanol of rare earth metal oxides was 5 mL / min;

[0088] Step 3: performing low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel;

[0089] The parameters of the low-temperature aging treatment are: treatment temperature is 300°C and treatment time is 3h.

[0090] Comparative Example 4: Comparative Example 4 is based on Example 1, with the following adjustments: no low-temperature aging treatment is performed on the nitrided vanadium-containing steel, and other processes remain unchanged, specifically:

[0091] A method for manufacturing vanadium-nitrogen microalloyed steel:

[0092] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel;

[0093] The process parameters of laser shot peening are: pulse power density is 8GW / cm 2 , pulse width is 25ns, coverage is 200%;

[0094] Step 2: nitriding the pretreated vanadium-containing steel in an LD-2-50A ion nitriding furnace to obtain vanadium-nitrogen microalloyed steel;

[0095] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0096] The process parameters of nitriding treatment are as follows: nitriding temperature is 500°C, nitriding voltage is 600V, nitriding pressure is 300Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0097] As the nitriding depth increases, the amount of anhydrous ethanol saturated solution of rare earth metal oxide introduced is: 3μm≤nitriding depth≤10μm, the amount of anhydrous ethanol saturated solution of rare earth oxide introduced is 5mL / min; 10μm<nitriding depth≤50μm, the amount of anhydrous ethanol saturated solution of rare earth oxide introduced starts from 5mL / min and increases by 0.5mL / min for every 1μm.

[0098] Comparative Example 5: Comparative Example 5 is based on Example 1, with the following adjustments: no laser shot peening pretreatment and low temperature aging treatment are performed on the low nitrogen vanadium-containing steel, and other processes remain unchanged, specifically:

[0099] A method for manufacturing vanadium-nitrogen microalloyed steel:

[0100] Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, nitriding is performed on it in an LD-2-50A ion nitriding furnace to obtain vanadium-nitrogen microalloyed steel;

[0101] During the nitriding treatment process, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is controlled by a mass flow meter, and the saturated solution of anhydrous ethanol of the rare earth metal oxide is added to the ion nitriding furnace;

[0102] The process parameters of nitriding treatment are as follows: nitriding temperature is 500°C, nitriding voltage is 600V, nitriding pressure is 300Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.8L / min, and nitriding depth is 50μm;

[0103] As the nitriding depth increases, the amount of the saturated solution of anhydrous ethanol of the rare earth metal oxide is: 3μm≤nitriding depth≤10μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide is 5mL / min; 10μm<nitriding depth≤50μm, the amount of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 5mL / min and increases by 0.5mL / min for every 1μm;

[0104] Performance test: The vanadium-nitrogen microalloyed steels obtained in the above-mentioned Examples 1 to 3 and Comparative Examples 1 to 5 were subjected to relevant performance tests and compared with untreated low-nitrogen vanadium-containing steels. The specific test methods are as follows:

[0105] Hardness test: Use MH-5D Vickers microscope hardness tester to test the hardness of vanadium nitrogen microalloyed steel, with a load of 50g and a loading time of 15s;

[0106] Corrosion resistance test: immerse the vanadium-nitrogen microalloyed steel in a mixed solution of 6wt% FeCl3+0.05mol / L HCl for 24h, and measure the weight loss rate of the sample to evaluate the corrosion resistance;

[0107] The results of the above-mentioned related performance tests are shown in Table 1 below:

[0108] Table 1

[0109]

[0110] Result analysis: From the data in Table 1 above, it can be seen that the hardness and corrosion resistance of the low-nitrogen vanadium-containing steel after "laser shot blasting process + ion nitriding process + low-temperature aging treatment" are significantly enhanced. Each step of the process is indispensable and has a significant impact on the performance of vanadium-nitrogen microalloyed steel; in addition, the introduction of rare earth oxides during the nitriding process has a significant impact on the nitriding quality of steel parts, which is also a major technical feature of the present invention.

[0111] In summary, the present invention finally prepares vanadium-nitrogen microalloyed steel with excellent hardness and corrosion resistance.

[0112] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A method for producing vanadium-nitrogen microalloyed steel, characterized in that: The following steps are involved: Step 1: After cleaning and drying the low-nitrogen vanadium-containing steel, the low-nitrogen vanadium-containing steel is pretreated by laser shot peening to obtain pretreated vanadium-containing steel; Step 2: nitriding the pretreated vanadium-containing steel using an ion nitriding process to obtain nitrided vanadium-containing steel; Step 3: Perform low temperature aging treatment on the nitrided vanadium-containing steel to obtain vanadium-nitrogen microalloyed steel.

2. The method for producing a vanadium-nitrogen microalloyed steel according to claim 1, characterized in that: The low-nitrogen vanadium-containing steel is a steel material containing vanadium and 0 to 0.005 wt % nitrogen.

3. The method for producing a vanadium-nitrogen microalloyed steel according to claim 1, characterized in that: The parameters of the laser peening process are: pulse power density of 1 to 10 GW / cm 2 , pulse width is 5~40ns, and coverage is 100~300%.

4. The method for producing a vanadium-nitrogen microalloyed steel according to claim 1, characterized in that: The process parameters of the ion nitriding process are: nitriding temperature is 450-600°C, nitriding voltage is 600-650V, nitriding pressure is 250-400Pa, nitrogen source is a mixed gas of N2, H2, and Ar in a mass percentage of 80:5:15, gas flow rate is 0.5-1L / min, and nitriding depth is 3-100μm.

5. The method for producing a vanadium-nitrogen microalloyed steel according to claim 1, characterized in that: Rare earth oxides are also introduced into the ion nitriding process by mixing them with anhydrous ethanol to prepare an anhydrous ethanol saturated solution of rare earth oxides, and then the introduction amount is controlled by a mass flow meter.

6. The method for producing a vanadium-nitrogen microalloyed steel according to claim 5, characterized in that: The rare earth oxide is obtained by mixing cerium oxide and lanthanum oxide in a mass ratio of 1:

1.

7. The method for producing vanadium-nitrogen microalloyed steel according to claim 5, characterized in that: The introduction rate of the saturated solution of anhydrous ethanol of the rare earth oxide is 5-69 mL / min.

8. The method for producing vanadium-nitrogen microalloyed steel according to claim 7, characterized in that: As the nitriding depth of claim 4 increases, the amount of the rare earth oxide saturated anhydrous ethanol solution introduced is also adjusted accordingly, specifically: If 3 μm≤nitriding depth≤10 μm, the amount of the rare earth oxide saturated solution of anhydrous ethanol is 5 mL / min; If 10 μm < nitriding depth ≤ 50 μm, the amount of the rare earth oxide saturated solution of anhydrous ethanol is introduced starting from 5 mL / min and increasing by 0.5 mL / min for every 1 μm; If 50 μm<nitriding depth≤80 μm, the flow rate of the saturated solution of anhydrous ethanol of the rare earth oxide starts from 25 mL / min and increases by 0.8 mL / min for every 1 μm; If 80 μm<nitriding depth≤100 μm, the flow rate of the saturated anhydrous ethanol solution of the rare earth oxide starts from 49 mL / min and increases by 1 mL / min for every 1 μm.

9. The method for producing vanadium-nitrogen microalloyed steel according to claim 5, characterized in that: The parameters of the low-temperature aging treatment are: the treatment temperature is 290-330° C., and the treatment time is 2-4 hours.

10. Vanadium-nitrogen microalloyed steel produced by the production method according to any one of claims 1 to 9.

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