High-chromium high-plasticity corrosion-resistant magnetically soft alloy and preparation method of bar of high-chromium high-plasticity corrosion-resistant magnetically soft alloy

Abstract

The invention relates to a corrosion-resistant magnetically soft alloy, in particular to a high-chromium high-plasticity corrosion-resistant magnetically soft alloy and a preparation method of a bar of the high-chromium high-plasticity corrosion-resistant magnetically soft alloy. Comprising the following steps: proportioning: weighing 2.2-2.8% by weight of silicon and 0.3-0.6% by weight of manganese as alloying raw materials; the method comprises the following steps: weighing 0.005 to 0.008 percent of carbon and 0.8 to 1.2 percent of aluminum as a deoxidizing and desulfurizing agent; 19.0-21.0% of chromium and the balance iron are weighed to serve as smelting raw materials; and vacuum melting, molten steel deoxidation, desulfurization and alloying, primary forging, secondary forging and heat treatment are conducted, and the high-chromium high-plasticity corrosion-resistant magnetically soft alloy bar is manufactured after heat treatment is completed. By increasing the content of chromium in the corrosion-resistant magnetically soft alloy and introducing the aluminum element, the corrosion resistance, plasticity, resistivity and magnetic performance of the corrosion-resistant magnetically soft alloy are improved.

Description

Technical Field

[0001] The invention relates to a corrosion-resistant soft magnetic alloy, and in particular to a high-chromium and high-plasticity corrosion-resistant soft magnetic alloy and a preparation method of a rod thereof. Background Art

[0002] Corrosion-resistant soft magnetic alloys play a vital role in the field of electronic components, and are particularly suitable for manufacturing corrosion-resistant electromagnetic control components such as three-proof aviation micromotors, automobile engine solenoid valve injectors, and gas water heater flameout automatic protectors. Given the complex and changeable application environments of these components, ensuring their reliability is crucial, which requires the components to meet the "three-proof" standards, namely, mold resistance, moisture and heat resistance, and the most critical salt spray resistance.

[0003] According to the national military standard GJB360.2-87, in the salt spray test of electronic and electrical components, the components must be able to withstand at least 48 hours of salt spray erosion to meet the B-level qualification standard, and those that can withstand 96 hours of salt spray erosion are considered to be Class A qualified. At the same time, these components must also meet specific magnetic properties and resistivity requirements, that is, the magnetic property Hc must be less than or equal to 48A / m, and the resistivity ρ must be greater than or equal to 70μΩ·cm.

[0004] Therefore, in order to meet the above high standards, it is urgent to develop a method for preparing high-chromium and high-plasticity corrosion-resistant soft magnetic alloy rods. Summary of the invention

[0005] The technical problem solved by the present invention is to provide a method for preparing a high-chromium and high-plasticity corrosion-resistant soft magnetic alloy and its rods, by increasing the chromium content in the corrosion-resistant soft magnetic alloy and introducing aluminum elements to improve the corrosion resistance, plasticity, resistivity and magnetic properties of the corrosion-resistant soft magnetic alloy.

[0006] To solve the above technical problems, the technical solutions provided by the present invention are as follows:

[0007] A high-chromium, high-plasticity, corrosion-resistant soft magnetic alloy comprises, by weight percentage, 2.2-2.8% silicon, 0.3-0.6% manganese, 0.005-0.008% carbon, 0.8-1.2% aluminum, 19.0-21.0% chromium, and the balance iron.

[0008] A method for preparing a high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rod comprises the following steps:

[0009] 1) Ingredients

[0010] In terms of weight percentage, 2.2-2.8% silicon and 0.3-0.6% manganese are weighed as alloying raw materials; 0.005-0.008% carbon and 0.8-1.2% aluminum are weighed as deoxidation and desulfurization agents; 19.0-21.0% chromium and the balance iron are weighed as smelting raw materials;

[0011] 2) Vacuum melting

[0012] Put the smelting raw materials into the crucible of the medium frequency induction furnace, first pre-evacuate the medium frequency induction furnace to 11Pa, and then preheat the smelting raw materials with 250-300kw power supply until they turn red;

[0013] The medium frequency induction furnace is evacuated to 1.3Pa, the power of the medium frequency induction furnace is increased to 450-500kw, the smelting raw materials are melted into molten steel, and the medium frequency induction furnace is heated to 1620-1640℃;

[0014] 3) Deoxidation, desulfurization and alloying of molten steel:

[0015] Add deoxidation and desulfurization agents into the molten steel, and refine the molten steel for 30-50 minutes; at the same time, add alloying raw materials 15 minutes before the molten steel enters the refining process; after the refining process, obtain the alloy liquid;

[0016] Adjust the temperature of the molten steel to the furnace temperature of 1570-1580℃; after the alloy liquid in the crucible is calm, pour the crucible with 100-150kw power, inject the alloy liquid into the tundish, filter the alloy liquid from the tundish and pour it into the alloy ingot mold, open the furnace and cool for 12 hours before demoulding to obtain the intermediate billet I;

[0017] 4) One-time forging

[0018] The intermediate billet I is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1150-1200°C to heat the intermediate billet I; after heating, the intermediate billet I is forged using an arched free forging electro-hydraulic hammer, and the forging ratio is ≥4; after forging, a square intermediate billet II is obtained by sand cooling;

[0019] 5) Secondary forging

[0020] The intermediate billet II is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1050-1080°C to heat the intermediate billet II; after the heating is completed, the intermediate billet II is forged using an arched free forging electro-hydraulic hammer, and the forging ratio is ≥3; after the forging is completed, the forged rod is obtained by sand cooling;

[0021] 6) Heat treatment

[0022] The forged rods are heat treated to produce high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods.

[0023] Furthermore, in step 2), when the smelting raw materials are loaded into the crucible of the medium frequency induction furnace, iron is loaded into the crucible first, and then chromium is loaded.

[0024] Furthermore, in step 3), the contents of carbon and sulfur in the molten steel in the crucible are detected by a carbon-sulfur detector, the addition amounts of carbon and aluminum in the deoxidation and desulfurization agent are calculated respectively, the corresponding addition amounts of carbon and aluminum are weighed respectively, and the carbon and aluminum are added to the molten steel.

[0025] Furthermore, in step 3), the deoxidizing and desulfurizing agent is added to the alloy liquid twice, and the interval between the two times is 5 to 8 minutes;

[0026] If the vacuum degree in the vacuum induction furnace is less than 11Pa after the first addition of deoxidation and desulfurization agent, the second addition of deoxidation and desulfurization agent shall be cancelled;

[0027] If the vacuum degree in the vacuum induction furnace is higher than or equal to 11Pa, continue to add deoxidation and desulfurization agent after 5 to 8 minutes.

[0028] Furthermore, in step 3), after the alloy liquid is filtered through the tundish and poured into the alloy ingot mold, a heating agent is immediately added to the cap opening of the alloy ingot mold, and the heating agent fully covers the riser of the alloy ingot mold.

[0029] Further, in step 4), the intermediate billet I is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1150-1200° C. The specific method for heating the intermediate billet I is as follows:

[0030] Place the intermediate billet I into an electric furnace, heat the intermediate billet I at 450-650°C, and keep it warm for 5-7 hours;

[0031] The electric furnace is heated to 830-860°C at a heating rate of 80-120°C / h to heat the intermediate billet I, and the insulation system is 0.3-0.6min / mm;

[0032] The electric furnace is heated to 1150-1200°C at a heating rate of 80-100°C / h to heat the intermediate billet I, and the insulation system is 0.2-0.5min / mm.

[0033] Furthermore, in step 4), when the forging temperature is lower than 900°C, the steel is immediately returned to the furnace and reheated to 1150-1200°C, with a heat preservation period of 0.1-0.3 min / mm.

[0034] Further, in step 5), the intermediate billet II is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1050-1080° C. The specific method for heating the intermediate billet II is as follows:

[0035] Place the intermediate billet II into an electric furnace, heat the intermediate billet II to 830-860°C at a heating rate of 80-120°C / h, and heat the intermediate billet II at a holding temperature of 0.3-0.6min / mm;

[0036] The electric furnace is heated to 1050-1080°C at a heating rate of 80-100°C / h to heat the intermediate billet II, and the insulation system is 0.2-0.5min / mm;

[0037] When the forging temperature is lower than 850℃, return to the furnace and reheat to 1050-1080℃ immediately, and the insulation system is 0.1-0.3min / mm.

[0038] Furthermore, in step 6), the specific method of heat treating the forged rod is:

[0039] Place the forged rod into an electric furnace, and heat the furnace to 1050-1150℃ at a heating rate of 5-10℃ / min in a protective atmosphere of vacuum, hydrogen or inert gas, and keep the temperature for 4-7h;

[0040] After the insulation is completed, the furnace is cooled to 100°C at a furnace cooling rate not exceeding 100-200°C / h, and the heat treatment is completed.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The preparation method of the high-chromium and high-plasticity corrosion-resistant soft magnetic alloy and its rod provided by the present invention is achieved by increasing the chromium content in the corrosion-resistant soft magnetic alloy to 19.0-21.0% (usually 12-17%), introducing 0.8-1.2% aluminum, and then using vacuum melting, molten steel deoxidation, desulfurization and alloying, primary forging, secondary forging and heat treatment processes to improve the corrosion resistance of the corrosion-resistant soft magnetic alloy while taking into account the improvement of resistivity, plasticity and magnetic properties, so that the corrosion-resistant soft magnetic alloy can meet more industrial production needs.

[0043] 2. The preparation method of high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rods provided by the present invention comprises the following steps: before melting the smelting raw materials, heating the smelting raw materials until they are red, so as to avoid the introduction of undesirable elements such as oxygen and hydrogen into the raw materials, and reducing the content of gas elements (O, H) in the manufactured high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy; adding a deoxidizing and desulfurizing agent during the refining process of the molten steel, so that the gas elements (O) in the molten steel react with carbon and aluminum to generate corresponding oxide inclusions or gaseous carbon oxides; the harmful elements (S) in the molten steel react with the added aluminum to generate aluminum sulfide inclusions, and during the pouring process, the oxide inclusions and sulfide inclusions are filtered by the pouring tundish, and the gaseous carbon oxides escape from the molten steel, so as to minimize the content of gas elements (O) and harmful elements (S) in the manufactured high-purity, low-alloy, ultra-high-strength steel, and reduce the reaction of aluminum, manganese and sulfur elements to generate oval brittle inclusions.

[0044] 3. The preparation method of the high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rod provided by the present invention does not add carbon and aluminum with the furnace during the smelting process to ensure the low carbon content of the alloy and reduce the burning loss of aluminum. After the molten steel is completely melted, samples are taken from the furnace to test the carbon and sulfur contents. According to the test results, carbon and aluminum are appropriately added to assist deoxidation and desulfurization.

[0045] 4. The preparation method of high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rods provided by the present invention comprises the following steps: after the casting of the intermediate billet I is completed, the demolding is performed after waiting for 24 hours; before forging, the intermediate billet I is kept at 450-650°C for 5-7 hours in an electric furnace; and a long-term homogenization treatment at this temperature can greatly reduce the internal dendrite density of the intermediate billet I, expand the spacing between the dendrites, and partially dissolve the fine and uneven precipitate phases produced by dendrite segregation in the crystal, thereby significantly reducing the volume fraction of the precipitates and eliminating microsegregation. The component distribution inside the intermediate billet I is more uniform, providing a better composition and microstructure basis for improving the plasticity of the alloy, so as to achieve the maximum plasticity of the cast structure of the alloy.

[0046] 5. The preparation method of high-chromium and high-plasticity corrosion-resistant soft magnetic alloy rods provided by the present invention has a forging temperature of 1150-1200°C for one forging and a forging ratio greater than 4; the intermediate billet I is greatly deformed, so that the inclusions gathered in the macro-segregation area, such as carbides, oxides, and sulfides, are broken during the large deformation, and the high-temperature diffusion and mutual dissolution are combined to make them more evenly dispersed in the intermediate billet I, thereby improving the macro-segregation of the intermediate billet I and further improving the organizational structure of the high-strength corrosion-resistant soft magnetic alloy.

[0047] 6. The preparation method of high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rods provided by the present invention, secondary forging is used to crush the coarse casting crystals inside the intermediate billet I, dynamic recrystallization effectively controls the alloy grain size and mechanical properties, and sand cooling after forging allows the alloy to maintain static recrystallization for a long time under slow cooling conditions, so that the broken grains produced in the thermal deformation process are fully recrystallized to obtain an intermediate billet II with better processability.

[0048] 7. The preparation method of high-chromium, high-plasticity, corrosion-resistant soft magnetic alloy rods provided by the present invention, after the structure of the intermediate billet II is homogenized and subjected to high-temperature thermal deformation, the alloy matrix structure is relatively coarse, which lays a good foundation for the alloy to have higher magnetic properties, and the coarse grains reduce the grain boundary density, increase the magnetic permeability, and reduce the difficulty of magnetic domain wall movement; at the same time, the larger grain boundary density will also reduce the constraints on magnetic domain nucleation and growth, thereby reducing the difficulty of rearranging the magnetic domains under the reverse magnetic field, reducing the coercive force, and the larger grains will reduce the stability of the magnetic domains, making it easier for the magnetic domains to rearrange or reverse near the grain boundaries; after high-temperature thermal deformation, the intermediate billet II obtains higher magnetic properties.

[0049] 8. The preparation method of high-chromium, high-plasticity, corrosion-resistant soft magnetic alloy rods provided by the present invention comprises an intermediate billet II which has undergone high-temperature deformation and slow cooling, and in its matrix structure there are high-temperature phases and low-temperature precipitation phases that cannot be re-dissolved. During the secondary forging, a lower heating temperature is selected to retain the high-temperature precipitation phase with a precipitation temperature higher than the deheating temperature inside the matrix, and the low-temperature precipitation phase with a precipitation temperature lower than the thermal deformation temperature is re-dissolved. The high-temperature precipitation phase forms Coriolis gas masses with edge dislocations inside the matrix to produce a pinning effect, thereby controlling the growth of the grain size inside the intermediate billet II during the heating process.

[0050] 9. The preparation method of high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rods provided by the present invention has a forging ratio of the secondary forging of ≥3, controls the deformation of the intermediate billet II in the second fire forging, appropriately reduces the grain size of the internal structure of the matrix, coordinates the magnetic properties of the alloy with the resistivity and plasticity, and then obtains the finished forged rods by sand cooling. DETAILED DESCRIPTION

[0051] The technical solutions in the present invention will be described clearly and completely below in conjunction with the embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. 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.

[0052] A high-chromium, high-plasticity, corrosion-resistant soft magnetic alloy comprises, by weight percentage, 2.2-2.8% silicon, 0.3-0.6% manganese, 0.005-0.008% carbon, 0.8-1.2% aluminum, 19.0-21.0% chromium, and the balance iron.

[0053] The present invention also provides a method for preparing a high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rod, which is as follows:

[0054] 1) Ingredients

[0055] In terms of weight percentage, 2.2-2.8% silicon and 0.3-0.6% manganese are weighed as alloying raw materials; 0.005-0.008% carbon and 0.8-1.2% aluminum are weighed as deoxidation and desulfurization agents; 19.0-21.0% chromium and the balance iron are weighed as smelting raw materials;

[0056] 2) Vacuum melting

[0057] The smelting raw materials are loaded into the crucible of the medium frequency induction furnace, wherein iron is loaded into the crucible first, and chromium is loaded secondly;

[0058] During smelting, first pre-evacuate the medium frequency induction furnace to 11Pa, and then preheat the smelting raw materials with 250-300kw power supply until they turn red;

[0059] The medium frequency induction furnace is evacuated to 1.3Pa, the power of the medium frequency induction furnace is increased to 450-500kw, the smelting raw materials are melted into molten steel, and the medium frequency induction furnace is heated to 1620-1640℃;

[0060] 3) Deoxidation, desulfurization and alloying of molten steel:

[0061] The carbon and sulfur content in the molten steel in the crucible is detected by a carbon-sulfur detector, and the addition amount of carbon and aluminum in the deoxidation and desulfurization agent is calculated respectively. The corresponding addition amount of carbon and aluminum is weighed respectively, and the carbon and aluminum are added to the molten steel twice, and the interval between the two times is 5 to 8 minutes;

[0062] If the vacuum degree in the vacuum induction furnace is less than 11Pa after the first addition of deoxidation and desulfurization agent, the second addition of deoxidation and desulfurization agent shall be cancelled;

[0063] If the vacuum degree in the vacuum induction furnace is higher than or equal to 11Pa, continue to add deoxidation and desulfurization agent after 5 to 8 minutes.

[0064] The molten steel is refined for 30-50 minutes; at the same time, alloying raw materials are added 15 minutes before the molten steel enters the refining stage; after the refining is completed, the alloy liquid is obtained;

[0065] Adjust the temperature of the molten steel to the furnace tapping temperature of 1570-1580°C; after the alloy liquid in the crucible is calm, pour the crucible with electricity of 100-150kw, inject the alloy liquid into the tundish, filter the alloy liquid through the tundish and pour it into the alloy ingot mold, immediately add a heating agent to the cap of the alloy ingot mold after the alloy liquid is poured into the alloy ingot mold, and the heating agent covers the riser of the alloy ingot mold; open the furnace and cool for 12 hours, then demould to obtain the intermediate billet I;

[0066] 4) One-time forging

[0067] Place the intermediate billet I into an electric furnace, heat the intermediate billet I at 450-650°C, and keep it warm for 5-7 hours;

[0068] The electric furnace is heated to 830-860°C at a heating rate of 80-120°C / h to heat the intermediate billet I, and the insulation system is 0.3-0.6min / mm;

[0069] The electric furnace is heated to 1150-1200°C at a heating rate of 80-100°C / h to heat the intermediate billet I, and the insulation system is 0.2-0.5min / mm;

[0070] After heating, the intermediate billet I is forged using an arched free forging electro-hydraulic hammer, with a forging ratio of ≥4; when the forging temperature is lower than 900°C, it is immediately returned to the furnace and reheated to 1150-1200°C, with a heat preservation system of 0.1-0.3min / mm; after forging, the square intermediate billet II is obtained by sand cooling;

[0071] 5) Secondary forging

[0072] Place the intermediate billet II into an electric furnace, heat the intermediate billet II to 830-860°C at a heating rate of 80-120°C / h, and heat the intermediate billet II at a holding temperature of 0.3-0.6min / mm;

[0073] The electric furnace is heated to 1050-1080°C at a heating rate of 80-100°C / h to heat the intermediate billet II, and the insulation system is 0.2-0.5min / mm;

[0074] After heating, the intermediate billet II is forged using an arched free forging electro-hydraulic hammer, with a forging ratio of ≥3; when the forging temperature is lower than 850°C, it is immediately returned to the furnace and reheated to 1050-1080°C, with a heat preservation system of 0.1-0.3min / mm; after forging, the forged rod is obtained by sand cooling;

[0075] 6) Heat treatment

[0076] Place the forged rod into an electric furnace, and heat the furnace to 1050-1150℃ at a heating rate of 5-10℃ / min in a protective atmosphere of vacuum, hydrogen or inert gas, and keep the temperature for 4-7h;

[0077] After the insulation is completed, the furnace is cooled to 100°C at a furnace cooling rate not exceeding 100-200°C / h, and the heat treatment is completed; a high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rod is produced.

[0078] Specific examples are given below.

[0079] Example 1

[0080] 1) Ingredients

[0081] In terms of weight percentage, 2.5% silicon and 0.4% manganese are weighed as alloying raw materials; 0.007% carbon and 1.0% aluminum are weighed as deoxidation and desulfurization agents; 20.5% chromium and the balance iron are weighed as smelting raw materials;

[0082] 2) Vacuum melting

[0083] The smelting raw materials are loaded into the crucible of the medium frequency induction furnace, wherein iron is loaded into the crucible first, and chromium is loaded secondly;

[0084] During smelting, the medium frequency induction furnace is pre-evacuated to 11Pa, and then 300kw of electricity is used to preheat the smelting raw materials until they turn red;

[0085] The medium frequency induction furnace is evacuated to 1.3 Pa, the power of the medium frequency induction furnace is increased to 450kw, the smelting raw materials are melted into molten steel, and the medium frequency induction furnace is heated to 1640℃;

[0086] 3) Deoxidation, desulfurization and alloying of molten steel:

[0087] Add deoxidation and desulfurization agents into the molten steel, and refine the molten steel for 45 minutes; at the same time, add alloying raw materials 15 minutes before the molten steel enters the refining stage; after the refining is completed, the alloy liquid is obtained;

[0088] Adjust the temperature of the molten steel to the furnace-out temperature of 1580°C; after the alloy liquid in the crucible is calm, pour the crucible with 100kw power on and pour the alloy liquid into the tundish, filter the alloy liquid through the tundish and pour it into the alloy ingot mold, immediately add a heating agent to the cap of the alloy ingot mold after the alloy liquid is poured into the alloy ingot mold, and the heating agent covers the riser of the alloy ingot mold; open the furnace and cool for 12 hours, then demould to obtain the intermediate billet I;

[0089] 4) One-time forging

[0090] Place the intermediate billet I into an electric furnace, heat the intermediate billet I at 600°C, and keep it warm for 7 hours;

[0091] The electric furnace is heated to 850°C at a heating rate of 100°C / h to heat the intermediate billet I, and the holding system is 0.6min / mm;

[0092] The electric furnace is heated to 1160°C at a heating rate of 90°C / h to heat the intermediate billet I, and the holding system is 0.3min / mm;

[0093] After heating, the intermediate billet I is forged using an arched free forging electro-hydraulic hammer with a forging ratio of 4. When the forging temperature is lower than 900°C, it is immediately returned to the furnace and reheated to 1160°C with a heat preservation system of 0.3min / mm. After forging, the square intermediate billet II is obtained by sand cooling.

[0094] 5) Secondary forging

[0095] The intermediate billet II is placed in an electric furnace, and the temperature of the electric furnace is raised to 850°C at a heating rate of 100°C / h to heat the intermediate billet II, and the insulation system is 0.6min / mm;

[0096] The electric furnace is heated to 1070°C at a heating rate of 90°C / h to heat the intermediate billet II, and the holding system is 0.3min / mm;

[0097] After heating, the intermediate billet II is forged using an arched free forging electro-hydraulic hammer with a forging ratio of 3. When the forging temperature is lower than 850°C, it is immediately returned to the furnace and reheated to 1070°C with a heat preservation system of 0.2min / mm. After forging, the forged rod is obtained by sand cooling.

[0098] 6) Heat treatment

[0099] Place the forged rod into an electric furnace, and heat the furnace to 1100°C at a rate of 8°C / min in a protective atmosphere of vacuum, hydrogen or inert gas, and keep the temperature for 6 hours;

[0100] After the insulation is completed, the furnace is cooled to 100°C at a furnace cooling rate of 100°C / h, and the heat treatment is completed; a high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rod is produced.

[0101] Example 2

[0102] The difference between Example 2 and Example 1 is that, by weight percentage, 19.5% of chromium and the remainder of iron are weighed as smelting raw materials.

[0103] Example 3

[0104] The difference between Example 3 and Example 1 is that the forged rod is placed in an electric furnace, and the temperature of the electric furnace is increased to 1050°C at a heating rate of 8°C / min under a protective atmosphere of vacuum, hydrogen or inert gas, and the temperature is kept for 6 hours.

[0105] The alloy element compositions of the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods prepared in Examples 1, 2 and 3 were respectively detected by direct reading spectrometer, and compared with the composition of the existing Core 18-FM alloy. The comparison results are shown in Table 1.

[0106] Table 1: Comparison of the composition of the alloy bars of Examples 1, 2 and 3 and the Core 18-FM alloy

[0107]

[0108] The magnetic properties of the high chromium, high plasticity, corrosion-resistant soft magnetic alloy rods made in Examples 1, 2 and 3 were respectively tested by a soft magnetic DC magnetic measurement system instrument, and compared with the magnetic properties of the existing Core 18-FM alloy. The comparison results are shown in Table 2.

[0109] Table 2: Comparison of magnetic properties of alloy rods of Examples 1, 2 and 3 and Core 18-FM alloy

[0110]

[0111]

[0112] The mechanical properties of the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods made of Examples 1, 2 and 3 were tested by a universal tensile machine and a Vickers hardness tester, and compared with the mechanical properties of the existing Core 18-FM alloy. The comparison results are shown in Table 3.

[0113] Table 3: Comparison of mechanical properties of alloy bars of Examples 1, 2 and 3 and Core 18-FM alloy

[0114] Yield strength Rp0.2(MPa) Tensile strength Rm(MPa) Elongation after break A(%) Sectional shrinkage Z(%) Example 1 312 455 35.5 80 Example 2 315 446 36 77 Example 3 320 446 35 75 Core18-FM Alloy 350 650 10 14

[0115] The physical properties of the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods made in Examples 1, 2 and 3 were tested by instruments such as a resistivity tester, and compared with the physical properties of the existing Core 18-FM alloy. The comparison results are shown in Table 4.

[0116] Table 4: Comparison of physical properties of alloy rods of Examples 1, 2 and 3 and Core 18-FM alloy

[0117] Resistivity ρel(μΩ*cm) <![CDATA[Density Ρ (g / cm 3 )]]> Example 1 90.83 7.7 Example 2 92.18 7.6 Example 3 93.64 7.7 Core18-FM Alloy 110 7.6

[0118] The corrosion resistance of the high chromium and high plasticity corrosion-resistant soft magnetic alloy bars made in Examples 1, 2 and 3 was tested by salt spray corrosion and immersion methods, and compared with the corrosion resistance of the existing Core 18-FM alloy. The comparison results are shown in Table 5.

[0119] Table 5: Comparison of corrosion resistance of alloy bars of Examples 1, 2 and 3 and Core 18-FM alloy

[0120]

[0121]

[0122] It can be seen from Tables 1 to 5 that compared with the Core 18-FM alloy, Examples 1, 2 and 3 have:

[0123] In terms of alloy element composition, the high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rods prepared in Examples 1, 2 and 3 have a higher Cr content than the Core 18-FM alloy. The corrosion resistance of the alloy is further improved by increasing the Cr content. At the same time, Al is introduced to improve the plasticity, resistivity and magnetic properties of the alloy.

[0124] In terms of magnetic properties, the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods made in Examples 1, 2 and 3 have a coercive force reduced by 90.5% compared with the Core18-FM alloy, and still have a higher magnetic induction intensity in a weaker magnetic field.

[0125] In terms of mechanical properties, the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods prepared in Examples 1, 2 and 3 have similar yield strength and tensile strength to the Core18-FM alloy, but the elongation after fracture is increased by 71.4% and the cross-sectional shrinkage is increased by 81.8%.

[0126] In terms of physical properties, the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods made in Examples 1, 2 and 3 have similar densities compared to the Core 18-FM alloy, but their resistivity is 19.6% lower than that of the Core 18-FM alloy, which means that their electrical conductivity is better; the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods made in Examples 1, 2 and 3 have a resistivity increased by 43% compared to traditional soft magnetic alloys (1J116, resistivity ρe l of 65μΩ*cm), which greatly reduces eddy current losses. The higher resistivity in a changing magnetic field allows the alloy to generate less Joule heat when the same current passes through it, reducing the impact on the magnetic properties of the alloy.

[0127] In terms of corrosion resistance, the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods made in Examples 1, 2 and 3 have a 50% higher salt spray corrosion resistance than the Core 18-FM alloy, and make up for the poor corrosion resistance of the Core 18-FM alloy in organic matter, thereby improving the service stability of the alloy components.

[0128] In summary, by increasing the Cr content and introducing Al, the corrosion resistance, plasticity, resistivity and magnetic properties of the alloy can be improved.

[0129] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy, characterized in that: In terms of weight percentage, it includes 2.2-2.8% silicon, 0.3-0.6% manganese, 0.005-0.008% carbon, 0.8-1.2% aluminum, 19.0-21.0% chromium, and the balance iron.

2. A method for preparing a high-chromium, high-plasticity, corrosion-resistant, soft magnetic alloy rod, characterized in that: The following steps are involved: 1) Ingredients In terms of weight percentage, 2.2-2.8% silicon and 0.3-0.6% manganese are weighed as alloying raw materials; 0.005-0.008% carbon and 0.8-1.2% aluminum are weighed as deoxidation and desulfurization agents; 19.0-21.0% chromium and the balance iron are weighed as smelting raw materials; 2) Vacuum melting Put the smelting raw materials into the crucible of the medium frequency induction furnace, first pre-evacuate the medium frequency induction furnace to 11Pa, and then preheat the smelting raw materials with 250-300kw power supply until they turn red; The medium frequency induction furnace is evacuated to 1.3Pa, the power of the medium frequency induction furnace is increased to 450-500kw, the smelting raw materials are melted into molten steel, and the medium frequency induction furnace is heated to 1620-1640℃; 3) Deoxidation, desulfurization and alloying of molten steel: Add deoxidation and desulfurization agents into the molten steel, and refine the molten steel for 30-50 minutes; at the same time, add alloying raw materials 15 minutes before the molten steel enters the refining stage; after the refining is completed, the alloy liquid is obtained; Adjust the temperature of the molten steel to the furnace temperature of 1570-1580℃; after the alloy liquid in the crucible is calm, pour the crucible with 100-150kw power, inject the alloy liquid into the tundish, filter the alloy liquid from the tundish and pour it into the alloy ingot mold, open the furnace and cool for 12 hours before demoulding to obtain the intermediate billet I; 4) One-time forging The intermediate billet I is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1150-1200°C to heat the intermediate billet I; after heating, the intermediate billet I is forged using an arched free forging electro-hydraulic hammer, and the forging ratio is ≥4; after forging, a square intermediate billet II is obtained by sand cooling; 5) Secondary forging The intermediate billet II is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1050-1080°C to heat the intermediate billet II; after the heating is completed, the intermediate billet II is forged using an arched free forging electro-hydraulic hammer, and the forging ratio is ≥3; after the forging is completed, the forged rod is obtained by sand cooling; 6) Heat treatment The forged rods are heat treated to produce high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rods.

3. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 2), when the smelting raw materials are loaded into the crucible of the medium frequency induction furnace, iron is loaded into the crucible first, and then chromium is loaded.

4. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 3), the contents of carbon and sulfur in the molten steel in the crucible are detected by a carbon-sulfur detector, the addition amounts of carbon and aluminum in the deoxidation and desulfurization agent are calculated, the corresponding addition amounts of carbon and aluminum are weighed, and the carbon and aluminum are added to the molten steel.

5. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 3, characterized in that: In step 3), the deoxidizing and desulfurizing agent is added to the alloy liquid twice, and the interval between the two times is 5 to 8 minutes; If the vacuum degree in the vacuum induction furnace is less than 11Pa after the first addition of deoxidation and desulfurization agent, the second addition of deoxidation and desulfurization agent shall be cancelled; If the vacuum degree in the vacuum induction furnace is higher than or equal to 11Pa, continue to add deoxidation and desulfurization agent after 5 to 8 minutes.

6. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 3), after the alloy liquid is filtered through the tundish and poured into the alloy ingot mold, a heating agent is immediately added to the cap of the alloy ingot mold, and the heating agent fully covers the riser of the alloy ingot mold.

7. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 4), the intermediate billet I is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1150-1200° C. The specific method for heating the intermediate billet I is as follows: Place the intermediate billet I into an electric furnace, heat the intermediate billet I at 450-650°C, and keep it warm for 5-7 hours; The electric furnace is heated to 830-860°C at a heating rate of 80-120°C / h to heat the intermediate billet I, and the insulation system is 0.3-0.6min / mm; The electric furnace is heated to 1150-1200°C at a heating rate of 80-100°C / h to heat the intermediate billet I, and the insulation system is 0.2-0.5min / mm.

8. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 4), when the forging temperature is lower than 900°C, the steel is immediately returned to the furnace and reheated to 1150-1200°C with a heat preservation period of 0.1-0.3 min / mm.

9. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 5), the intermediate billet II is placed in an electric furnace, and the temperature of the electric furnace is adjusted to 1050-1080° C. The specific method for heating the intermediate billet II is as follows: Place the intermediate billet II into an electric furnace, heat the intermediate billet II to 830-860°C at a heating rate of 80-120°C / h, and heat the intermediate billet II at a holding temperature of 0.3-0.6min / mm; The electric furnace is heated to 1050-1080°C at a heating rate of 80-100°C / h to heat the intermediate billet II, and the insulation system is 0.2-0.5min / mm; When the forging temperature is lower than 850℃, return to the furnace and reheat to 1050-1080℃ immediately, and the insulation system is 0.1-0.3min / mm.

10. The method for preparing the high chromium, high plasticity, corrosion-resistant, soft magnetic alloy rod according to claim 1, characterized in that: In step 6), the specific method of heat treating the forged rod is: Place the forged rod into an electric furnace, and heat the furnace to 1050-1150℃ at a heating rate of 5-10℃ / min in a protective atmosphere of vacuum, hydrogen or inert gas, and keep the temperature for 4-7h; After the insulation is completed, the furnace is cooled to 100°C at a furnace cooling rate not exceeding 100-200°C / h, and the heat treatment is completed.

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