High-wear-resistance steel for flange blank and preparation method of high-wear-resistance steel

Abstract

The invention discloses high-wear-resistance steel for a flange blank and a preparation method of the high-wear-resistance steel, and belongs to the technical field of steel preparation, and the high-wear-resistance steel comprises the following components in percentage by weight: 0.5-1.2% of C, 0.5-2% of Mn, 0.4-1.2% of Si, 1-2% of Cr, 0.01-0.03% of Ni, 0.03-0.06% of Nb, 0.06-0.12% of rare earth elements and the balance of Fe and inevitable trace elements. By means of the mode, the process route is optimized, microwave-induction cooker cooperative treatment is carried out after electron irradiation, defect repair and atomic diffusion in the steel are promoted, and the steel has high strength, high wear resistance and high toughness.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel production, in particular to a high-wear-resistance steel material for flange blanks and a preparation method thereof. BACKGROUND

[0002] As a key component of mechanical connection of pipelines, flanges are subjected to high pressure, friction and corrosive media for a long time. The traditional carbon steel flanges have low hardness and poor wear resistance, which easily leads to short sealing surface failure cycle. Frequent replacement of flanges will cause equipment downtime and economic losses.

[0003] The prior art has made many improvements to the preparation method of steel materials. For example, Chinese patent CN116516255B discloses a corrosion-resistant steel material and a preparation method thereof. The corrosion-resistant steel material comprises, by mass percentage: C 0.12-0.16%, Si 0.2-0.35%, Mn 1.25-1.4%, V 0.05-0.08%, N 0.005-0.007%, P≤0.02%, S≤0.008%, and the balance of Fe and unavoidable impurities. The corrosion-resistant steel material provided by the present application improves the corrosion resistance to some extent, but still has the following shortcomings: 1. The process of the above-mentioned application is relatively traditional and lacks advanced modification means. The yield strength and tensile strength of the prepared steel material are insufficient and need to be further improved.

[0004] 2. The improvement of wear resistance relies on V / N micro-alloying. No relevant data of the wear resistance of the steel material are provided, and it is difficult to evaluate the actual effect.

[0005] Therefore, the present application provides a high-wear-resistance steel material for flange blanks and a preparation method thereof to solve the above-mentioned problems. SUMMARY

[0006] In view of the above-mentioned shortcomings of the prior art, the present application provides a high-wear-resistance steel material for flange blanks and a preparation method thereof.

[0007] To achieve the above-mentioned purposes, the present application is implemented by the following technical solutions: A high-wear-resistance steel material for flange blanks, wherein the components in the high-wear-resistance steel material are as follows by weight percentage: C: 0.5-1.2%, Mn: 0.5-2%, Si: 0.4-1.2%, Cr: 1-2%, Ni: 0.01-0.03%, Nb: 0.03-0.06%, rare earth elements: 0.06-0.12%, and the balance of Fe and unavoidable trace elements. Further, the rare earth elements are Ce, La and Y, and the weight ratio of Ce, La and Y is 2.8:1.7:1. Further, the weight ratio of V, B and rare earth elements is 1.5-2:4-5:8-10; In order to better achieve the purpose of the present application, the present application further provides a preparation method of high wear-resistant steel material for flange blank, comprising the following steps: Electric arc furnace primary refining, LF furnace refining, first irradiation treatment, microwave-electromagnetic field co-treatment, continuous casting, second irradiation treatment, hot rolling, rapid cooling, tempering; Further, in the LF furnace refining step, the molten steel obtained by primary refining is added to the LF furnace for refining, and the total refining time is 35-45 min, and part of the rare earth elements are added after 20-30 min of LF furnace refining, and the addition is carried out in the order of adding Ce first, then adding La, and finally adding Y; Further, in the first irradiation treatment step, high-energy electron beams are used for irradiation treatment, the electron energy is 1-2 MeV, the electron beam flux is 5-8*10 13 e - ·cm -2 ·s -1 , and the irradiation time is 2-3 min; Further, in the microwave-electromagnetic field co-treatment step, the co-treatment time is 10-15 min, wherein the frequency of the microwave is 2.25-2.45 GHz, and the power is 6-8 kW; the electromagnetic field treatment adopts a pulsed magnetic field with a pulse width of 10 ms and an interval of 1 s, the frequency of the magnetic field is 8-10 kHz, and the magnetic field strength is 0.5-1 T; Further, in the second irradiation treatment step, direct current arc Ar plasma is used for irradiation treatment, the power density is 20-50 W / cm 2 , the ion flux is 1-2*10 17 ions / cm 2 ·s, and the plasma irradiation treatment time is 1-5 min.

[0008] Compared with the prior art, the present application has the following beneficial effects: 1. By optimizing the process route, microwave-electromagnetic oven co-treatment is carried out after electron irradiation, which promotes the defect repair and atomic diffusion in the steel material, so that the steel material has high strength, high wear resistance and high toughness; 2. Plasma secondary irradiation is carried out after continuous casting, which further improves the wear resistance of the steel material. DETAILED DESCRIPTION

[0009] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0010] Embodiment 1: A preparation method of high wear-resistant steel material for flange blank comprises the following steps: Step one: initial smelting in electric arc furnace Other raw materials except rare earth raw materials are added into the electric arc furnace for smelting, the voltage of the electric arc furnace is 380V, the current is 25kA, oxygen blowing operation is performed during the initial smelting process, the flow rate of the oxygen gas is 30Nm 3 / t molten steel, the end point control of the initial smelting is P≤0.015%, and the electric arc furnace discharge temperature is 1580℃.

[0011] Step two: refining in LF furnace The molten steel obtained by the initial smelting is added into the LF furnace for refining, the LF furnace inlet temperature is 1540℃, the outlet temperature is 1520℃, the total refining time is 35min, the bottom electromagnetic stirring is performed during the refining process, the frequency is 5Hz, the magnetic field strength is 0.03T, the rare earth raw materials are added after the LF furnace refining for 30min, the rare earth raw materials are added in the order of adding Ce first, then adding La, and finally adding Y.

[0012] Step three: first irradiation treatment The high-energy electron beam is used for irradiation treatment, the electron energy is 1MeV, the electron beam flux is 8×10 13 e - ·cm -2 ·s -1 , and the irradiation time is 2min.

[0013] Step four: microwave-electromagnetic field co-treatment The co-treatment time is 10min, the microwave frequency is 2.45GHz, and the power is 6kW; the pulse magnetic field with a pulse width of 10ms and an interval of 1s is used for electromagnetic field treatment, the magnetic field frequency is 10kHz, and the magnetic field strength is 0.5T.

[0014] Step five: continuous casting After the refining is completed, the continuous casting is performed, and the casting speed of the billet is 1m / min during the continuous casting process.

[0015] Step six: second irradiation treatment The direct current arc Ar plasma is used for irradiation treatment, the power density is 20W / cm 2 , and the ion flux is 2×1017 ions / cm 2 • s, the treatment time of the plasma irradiation is 1 min.

[0016] Step seven: hot rolling Firstly, heating at 1150℃ for 2h, then rough rolling at 1100℃ to 80mm intermediate blank, and finally finish rolling at 880℃ to 50mm thick plate.

[0017] Step eight: cooling and tempering Firstly, rapid cooling to 250℃ by water curtain with cooling rate of 40℃ / s, then gradient tempering, which is divided into three stages: first stage, heating at 930℃ for 0.5h, second stage, heating at 630℃ for 2h, and third stage, heating at 290℃ for 3h.

[0018] After the above steps, the high wear-resistant steel material obtained has the following components by weight percentage: C: 0.5%, Mn: 2%, Si: 0.4%, Cr: 2%, Ni: 0.01%, Nb: 0.06%, rare earth elements: 0.06%, and the balance of Fe and inevitable trace elements.

[0019] The rare earth elements are Ce, La and Y, and the weight ratio of Ce, La and Y is 2.8:1.7:1.

[0020] Example 2: A method for preparing a high wear-resistant steel material for a flange blank includes the following steps: Step one: initial smelting in an electric arc furnace Other raw materials except rare earth raw materials are added to the electric arc furnace for smelting, the electric arc furnace voltage is 420V, the electric current is 30kA, oxygen blowing operation is performed during the initial smelting process, the oxygen flow rate is 25Nm 3 / t molten steel, the initial smelting end point control P≤0.015%, the electric arc furnace discharge temperature is 1620℃.

[0021] Step two: refining in a LF furnace The molten steel obtained by initial smelting is added to the LF furnace for refining, the LF furnace inlet temperature is 1560℃, the outlet temperature is 1500℃, the total refining time is 45min, bottom electromagnetic stirring is performed during the refining process, the frequency is 2Hz, the magnetic field strength is 0.05T, the rare earth raw materials are added after 20min of LF furnace refining, the rare earth raw materials are added in the order of first adding Ce, then adding La, and finally adding Y.

[0022] Step three: first irradiation treatment High-energy electron beam is used for irradiation treatment, the electron energy is 2MeV, the electron beam flux is 6×10 13 e - ·cm -2 ·s-1 irradiation time is 3 min.

[0023] Step four: microwave-electromagnetic field co-treatment The co-treatment time is 15 min, the frequency of microwave is 2.25 GHz, the power is 8 kW, the pulse width of the electromagnetic field treatment is 10 ms, the interval is 1 s, the frequency of the magnetic field is 8 kHz, and the magnetic field strength is 1 T.

[0024] Step five: continuous casting After refining, continuous casting is performed, and the casting speed of the billet is 1.2 m / min during the continuous casting process.

[0025] Step six: secondary irradiation treatment The irradiation treatment is performed by using a direct current arc Ar plasma, the power density is 50 W / cm 2 , the ion flux is 1 x 10 17 ions / cm 2 ·s, and the treatment time of the plasma irradiation is 5 min.

[0026] Step seven: hot rolling First, heating at 1200℃ for 2h, then rough rolling at 1050℃ to 80mm intermediate billet, and finally finish rolling at 900℃ to 50mm thick plate.

[0027] Step eight: cooling and tempering First, rapid cooling to 250℃ by using a water curtain at a cooling rate of 70℃ / s, and then gradient tempering, which is divided into three stages: the first stage is heating at 900℃ for 1h, the second stage is heating at 660℃ for 1.5h, and the third stage is heating at 320℃ for 2.5h.

[0028] After the above steps, the high wear-resistant steel material obtained has the following components by weight percentage: C: 1.2%, Mn: 0.5%, Si: 1.2%, Cr: 1%, Ni: 0.03%, Nb: 0.03%, rare earth elements: 0.12%, and the balance of Fe and inevitable trace elements.

[0029] The rare earth elements are Ce, La and Y, and the weight ratio of Ce, La and Y is 2.8:1.7:1.

[0030] Example 3: A method for preparing a high wear-resistant steel material for a flange blank includes the following steps: Step one: initial smelting in an electric arc furnace Other raw materials except rare earth raw materials are added to the electric arc furnace for smelting, the voltage of the electric arc furnace is 400V, the current is 28kA, oxygen blowing is performed during the initial smelting process, and the flow rate of the oxygen introduced is 27Nm 3The t-steel, the initial smelting end point control P≤0.015%, the electric arc furnace out of furnace temperature is 1600℃.

[0031] Step two: LF furnace refining The initial smelting steel is added to the LF furnace for refining, the LF furnace temperature is 1550℃, the out of furnace temperature is 1510℃, the total refining time is 40min, the bottom electromagnetic stirring during refining, the frequency is 4Hz, the magnetic field strength is 0.04T, the LF furnace refining is added after 25min, the rare earth raw material is added according to the order of adding Ce first, then La, and finally Y.

[0032] Step three: first irradiation treatment The high energy electron beam is used for irradiation treatment, the electron energy is 1.8MeV, the electron beam flux is 7×10 13 e - ·cm -2 ·s -1 , the irradiation time is 2.5min.

[0033] Step four: microwave-electromagnetic field co-treatment The co-treatment time is 13min, the microwave frequency is 2.3GHz, the power is 7kW; the electromagnetic field treatment adopts pulse magnetic field with pulse width of 10ms and interval of 1s, the magnetic field frequency is 9kHz, the magnetic field strength is 0.8T.

[0034] Step five: continuous casting After refining, the continuous casting is carried out, the casting speed of the billet is 1.15m / min during continuous casting.

[0035] Step six: second irradiation treatment The direct current arc Ar plasma is used for irradiation treatment, the power density is 40W / cm 2 , the ion flux is 1.8×10 17 ions / cm 2 ·s, the plasma irradiation treatment time is 3.5min.

[0036] Step seven: hot rolling Firstly, heating at 1180℃ for 2h, then rough rolling at 1085℃, to 80mm of intermediate billet, finally, finish rolling at 890℃, to 50mm thick plate.

[0037] Step eight: cooling and tempering Firstly, water curtain rapid cooling to 250℃, the cooling rate is 60℃ / s, then gradient tempering, the gradient tempering is divided into three stages: the first stage is heating at 910℃ for 0.6h, the second stage is heating at 650℃ for 1.6h, the third stage is heating at 300℃ for 2.6h.

[0038] After the above steps, the high wear-resistant steel material obtained has the following components by weight percentage: C: 1%, Mn: 1.2%, Si: 0.8%, Cr: 1.6%, Ni: 0.025%, Nb: 0.04%, rare earth elements: 0.11%, and the balance of Fe and inevitable trace elements.

[0039] The rare earth elements are Ce, La, and Y, and the weight ratio of Ce, La, and Y is 2.8:1.7:1.

[0040] Example 4: A method for preparing a high wear-resistant steel material for a flange blank includes the following steps: Step one: initial smelting in an electric arc furnace Other raw materials except rare earth raw materials are added to the electric arc furnace for smelting, the electric arc furnace voltage is 390V, the electric current is 26kA, oxygen blowing is performed during the initial smelting process, and the oxygen flow rate is 27Nm 3 / t liquid steel, the initial smelting endpoint control P≤0.015%, and the electric arc furnace discharge temperature is 1585℃.

[0041] Step two: refining in an LF furnace The liquid steel obtained by initial smelting is added to the LF furnace for refining, the LF furnace inlet temperature is 1545℃, the outlet temperature is 1505℃, the total refining time is 37min, the bottom electromagnetic stirring is performed during the refining process, the frequency is 3Hz, the magnetic field strength is 0.035T, and the rare earth raw materials are added after 22min of LF furnace refining. The rare earth raw materials are added in the order of Ce first, La second, and Y last.

[0042] Step three: first irradiation treatment High-energy electron beams are used for irradiation treatment, the electron energy is 1.2MeV, the electron beam flux is 5.5×10 13 e - ·cm -2 ·s -1 , and the irradiation time is 2.5min.

[0043] Step four: microwave-electromagnetic field co-treatment The co-treatment time is 11min, the microwave frequency is 2.3GHz, and the power is 6.5kW; the electromagnetic field treatment adopts a pulsed magnetic field with a pulse width of 10ms and an interval of 1s, the magnetic field frequency is 8.5kHz, and the magnetic field strength is 0.6T.

[0044] Step five: continuous casting After refining is completed, continuous casting is performed, and the casting speed of the billet during continuous casting is 1.05m / min.

[0045] Step six: second irradiation treatment The direct current arc Ar plasma is used for irradiation treatment, the power density is 25 W / cm 2 , the ion flux is 1.1×10 17 ions / cm 2 ·s, and the plasma irradiation treatment time is 2 min.

[0046] Step seven: hot rolling First, heating at 1160℃ for 2h, then rough rolling at 1060℃ to 80mm intermediate blank, and finally finish rolling at 885℃ to 50mm thick plate.

[0047] Step eight: cooling and tempering First, water curtain rapid cooling to 250℃ at a cooling rate of 50℃ / s, and then gradient tempering, which is divided into three stages: the first stage is heating at 910℃ for 0.6h, the second stage is heating at 635℃ for 1.6h, and the third stage is heating at 300℃ for 2.7h.

[0048] After the above steps, the high wear-resistant steel material obtained has the following components by weight percentage: C: 0.6%, Mn: 0.6%, Si: 0.65%, Cr: 1.2%, Ni: 0.015%, Nb: 0.04%, rare earth elements: 0.07%, and the balance of Fe and inevitable trace elements.

[0049] Example 5: A method for preparing a high wear-resistant steel material for a flange blank includes the following steps: Step one: initial smelting in an electric arc furnace Other raw materials except rare earth raw materials are added to the electric arc furnace for smelting, the electric arc furnace voltage is 410V, the current is 29kA, oxygen blowing is performed during the initial smelting process, the oxygen flow rate is 28Nm 3 / t molten steel, the initial smelting endpoint control P≤0.015%, and the electric arc furnace discharge temperature is 1610℃.

[0050] Step two: refining in an LF furnace The molten steel obtained by initial smelting is added to the LF furnace for refining, the LF furnace inlet temperature is 1550℃, the outlet temperature is 1515℃, the total refining time is 40min, the bottom electromagnetic stirring is performed during the refining process, the frequency is 4Hz, the magnetic field strength is 0.04T, and the rare earth raw materials are added after 28min of LF furnace refining. The rare earth raw materials are added in the order of first adding Ce, then adding La, and finally adding Y.

[0051] Step three: first irradiation treatment High-energy electron beam is used for irradiation treatment, the electron energy is 1.85MeV, the electron beam flux is 6.5×10 13 e - ·cm -2·s -1 , the irradiation time is 2.8 min.

[0052] Step four: microwave-electromagnetic field co-treatment The co-treatment time is 14 min, the frequency of microwave is 2.4 GHz, the power is 7.8 kW, the pulse magnetic field is used for electromagnetic field treatment, the pulse width is 10 ms, the interval is 1 s, the frequency of magnetic field is 9.5 kHz, and the magnetic field strength is 0.9 T.

[0053] Step five: continuous casting After refining is completed, continuous casting is performed, and the casting speed of the billet is 1.15 m / min during the continuous casting.

[0054] Step six: secondary irradiation treatment The direct current arc Ar plasma is used for irradiation treatment, the power density is 45 W / cm 2 , the ion flux is 1.75 x 10 17 ions / cm 2 ·s, and the treatment time of the plasma irradiation is 4 min.

[0055] Step seven: hot rolling First, heating is performed at 1180 °C for 2 h, then rough rolling is performed at 1090 °C until the intermediate billet is 80 mm, and finally, finish rolling is performed at 890 °C until the 50 mm thick plate.

[0056] Step eight: cooling tempering First, water curtain rapid cooling is used to cool to 250 °C at a cooling rate of 65 °C / s, and then gradient tempering is performed, which is divided into three stages: the first stage is heating at 920 °C for 0.9 h, the second stage is heating at 650 °C for 1.8 h, and the third stage is heating at 310 °C for 2.9 h.

[0057] After the above steps, the high wear-resistant steel material obtained has the following components by weight percentage: C: 1.1%, Mn: 1.8%, Si: 1%, Cr: 1.6%, Ni: 0.025%, Nb: 0.05%, rare earth elements: 0.1%, and the balance is Fe and inevitable trace elements.

[0058] Comparative example 1: different from example 3, the weight ratio of the Ni, Nb and rare earth elements is adjusted to 2:2:1.

[0059] That is, the high wear-resistant steel material obtained has the following components by weight percentage: C: 1%, Mn: 1.2%, Si: 0.8%, Cr: 1.6%, Ni: 0.22%, Nb: 0.22%, rare earth elements: 0.11%, and the balance is Fe and inevitable trace elements.

[0060] The rare earth elements are Ce, La and Y, and the weight ratio of Ce, La and Y is 3:2:1.

[0061] Comparative Example 2: Different from Example 3, the microwave-electromagnetic field co-treatment of step four is not performed.

[0062] Comparative Example 3: Different from Example 3, the order of step three and step four is changed, that is, the microwave-electromagnetic field co-treatment is performed first, and then the irradiation treatment is performed.

[0063] Test Example: The flange blanks prepared from the high wear-resistant steel materials of Examples 1-3 and Comparative Examples 1-3 are subjected to the following performance tests: Vickers hardness: GB / T 4340.1-2024; Yield strength and tensile strength: GB / T 228.1-2021; The corrosion resistance of the sample is tested by the polarization test sample method, the test temperature is 30℃, the relative humidity is 30%, the neutral corrosion environment is 5% NaCl solution, the reference electrode is a saturated calomel electrode, the auxiliary electrode is a platinum electrode, the potential scanning rate is 0.5mV / s, and the self-corrosion potential is selected to represent the corrosion resistance of the sample; The wear resistance of the sample is tested by a Wangfu friction and wear testing machine, the friction pair is a corundum ball with a diameter of 4mm, the normal load is 6N, the frequency is 2.5Hz, the reciprocating distance is 5mm, the total distance is 30cm, the test temperature is 25℃, and the relative humidity is 65%.

[0064] The test results are shown in Table 1.

[0065] Table 1

[0066] As can be seen from Table 1, in Comparative Example 1, if the weight ratio of Ni, Nb and rare earth elements is changed, the hardness, yield strength and tensile strength of the prepared steel material are all reduced, and the hardness, corrosion resistance and wear resistance are significantly deteriorated; in Comparative Example 2, if step four is not performed, the yield strength and tensile strength of the prepared steel material are weakened, and the hardness, wear resistance and corrosion resistance are significantly deteriorated; in Comparative Example 3, if the order of step three and step four is changed, the wear resistance and hardness of the prepared steel material change little, the yield strength and tensile strength are weakened, and the corrosion resistance and wear resistance are significantly reduced.

[0067] And the hardness of the embodiment 1-3 in the application is 1118-1256HV, the yield strength is 897-954Mpa, the tensile strength is 1278-1395Mpa, namely the prepared steel material has excellent hardness and yield tensile strength, meanwhile in the corrosion resistance experiment, the self-corrosion potential is in the range of-132mV to-151mV, the wear volume is 6.01*10 -3 mm 3 In the following, it is proved that the product also has excellent corrosion resistance and wear resistance.

[0068] The above embodiments are only used to illustrate the technical solutions of the application, but not to limit it; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced by equivalents; and these modifications or replacements will not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the application.

Claims

1. A high wear-resistant steel material for flange blanks, characterized by: The components in the high wear-resistant steel are calculated by weight as follows: C: 0.5-1.2%, Mn: 0.5-2%, Si: 0.4-1.2%, Cr: 1-2%, Ni: 0.01-0.03%, Nb: 0.03-0.06%, rare earth elements: 0.06-0.12%, and the balance is Fe and inevitable trace elements.

2. The high wear-resistant steel material for flange blank according to claim 1, characterized in that: The rare earth elements are Ce, La and Y, and the weight ratio of Ce, La and Y is 2.8:1.7:

1.

3. The high wear-resistant steel material for flange blank according to claim 1, characterized in that: The weight ratio of V, B and rare earth elements is 1.5-2:4-5:8-10.

4. A method for preparing a high wear-resistant steel material for flange blank according to any one of claims 1 to 3, characterized in that: The following steps are involved: Electric arc furnace primary smelting, LF furnace refining, primary irradiation treatment, microwave-electromagnetic field co-treatment, continuous casting, secondary irradiation treatment, hot rolling, rapid cooling, and tempering.

5. The method for preparing high wear-resistant steel for flange blank according to claim 4, characterized in that: In the LF furnace refining step, the molten steel obtained from the primary refining is added to the LF furnace for refining, and the total refining time is 35-45 minutes. After refining in the LF furnace for 20-30 minutes, some rare earth elements are added in the order of first adding Ce, then adding La, and finally adding Y.

6. The method for preparing high wear-resistant steel for flange blank according to claim 4, characterized in that: In the step of the primary irradiation treatment, a high energy electron beam is used for irradiation treatment, the electron energy is 1-2 MeV, and the flux of the electron beam is 5-8×10 13 e - cm -2 ·s -1 , irradiation time is 2-3min.

7. The method for preparing high wear-resistant steel for flange blank according to claim 4, characterized in that: In the microwave-electromagnetic field co-treatment step, the co-treatment time is 10-15 minutes, wherein the microwave frequency is 2.25-2.45 GHz and the power is 6-8 kW; the electromagnetic field treatment adopts a pulsed magnetic field with a pulse width of 10 ms and an interval of 1 s, the magnetic field frequency is 8-10 kHz, and the magnetic field strength is 0.5-1 T.

8. The method for preparing high wear-resistant steel for flange blank according to claim 4, characterized in that: In the step of secondary irradiation treatment, DC arc Ar plasma is used for irradiation treatment with a power density of 20-50 W / cm 2 , the ion flux is 1-2×10 17 ions / cm 2 ·s, and the treatment time of plasma irradiation is 1-5min.

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