A YF928A alloy steel process for high magnetic permeability, high strength and fatigue resistance shaft

Abstract

The invention provides a YF928A alloy steel process for a high-magnetic permeability, high-strength and fatigue-resistant rotating shaft. The method comprises the following steps: performing smelting preparation, baking furnace charge, alloy material and auxiliary material according to corresponding processes; then charging after lime is placed on the furnace bottom of an electric furnace, sending electricity to melt, and after the furnace charge is fully melted, sampling and analysis are performed after stirring, degassing, removal of inclusions and composition adjustment are performed according to the analysis result, and then steel is mixed and punched out with slag; after the molten steel is put into a tank and smelted by an LF smelting process, the molten steel enters a VOD smelting process, the oxygen blowing amount is controlled by the VOD smelting process to perform carbon deoxidation, then lime, fluorite, Al block, Si-Ca and Si-Fe are added for reduction, and after slag melting, electrochemical alloy is sent, sampling is fully analyzed, sample return fine adjustment is performed, then casting is performed, and after the cast steel ingot is formed, the steel ingot is annealed; after the steel ingot is annealed by an annealing process, forging heating is performed, and forgings are forged by a 5000T press.

Description

Technical Field

[0001] The invention belongs to the field of rotating shaft forging, and particularly relates to a YF928A alloy steel process for a rotating shaft with high magnetic conductivity, high strength and fatigue resistance. Background Art

[0002] At present, there are many products in the field of steel processing technology that are forged products. These products are generally large in size, large in tonnage, and have large variations in size and shape. There are few standard parts and they cannot be produced by rolling technology. In the forging field, there are generally processes such as free forging with oil or hydraulic presses, free forging with radial forging machines, and blanking with oil or hydraulic presses followed by radial forging. These forging process designs have their own advantages and disadvantages, but none of them is the most perfect forging process, especially when producing roller forgings. Free forging with oil or hydraulic presses can forge straight tables, but the remaining weight control is not precise, the coaxiality cannot be guaranteed, the forging efficiency is low, the forgings cool down quickly, there are many fires, they are easy to crack, and the defective rate is high.

[0003] Forging is a processing method that uses forging machinery to apply pressure to metal blanks to cause them to undergo plastic deformation to obtain forgings with certain mechanical properties, shapes and sizes. It is one of the two major components of forging (forging and stamping). Forging can eliminate defects such as loose cast metal produced during the smelting process, optimize the microstructure, and at the same time, because the complete metal flow lines are preserved, the mechanical properties of forgings are generally better than those of castings of the same material. Forgings are mostly used for important parts with high loads and severe working conditions in related machinery, except for simpler shapes that can be rolled plates, profiles or welded parts. According to the forming mechanism, forging can be divided into free forging, die forging, ring rolling and special forging. Free forging. It refers to a processing method for forgings that uses simple general tools or directly applies external force to the blank between the upper and lower anvils of the forging equipment to deform the blank to obtain the required geometric shape and internal quality. Forgings produced by free forging are called free forgings. Free forging is mainly used to produce forgings with small batches. Forging equipment such as forging hammers and hydraulic presses are used to form the blanks to obtain qualified forgings. The basic processes of free forging include upsetting, drawing, punching, cutting, bending, twisting, shifting and forging. Free forging is all done by hot forging.

[0004] Therefore, there is an urgent need for a YF928A alloy steel process for high magnetic permeability, high strength and fatigue resistance shafts. Summary of the invention

[0005] The present invention proposes a YF928A alloy steel process for a high magnetic permeability, high strength and fatigue-resistant shaft, which solves the problem that the current processing technology in the prior art cannot make the magnetic properties of the shaft meet the set requirements, and during processing, the yield rate is low and the shaft processing efficiency is low.

[0006] The technical solution of the present invention is achieved as follows: a process for producing YF928A alloy steel for a high magnetic permeability, high strength and fatigue resistant shaft, the method comprising the following steps:

[0007] Carry out smelting preparation, bake the charge, alloy and auxiliary materials according to the corresponding process;

[0008] Then, lime is placed on the bottom of the electric furnace for loading, and electricity is supplied for melting. After the charge is fully melted, it is stirred and sampled for analysis. According to the analysis results, degassing, removal of inclusions and composition adjustment are carried out, and then steel is mixed with slag for flushing.

[0009] After the molten steel is put into the tank, it is smelted by LF smelting process, and then enters VOD smelting process, and the oxygen blowing amount is controlled by VOD smelting process for carbon deoxidation, and then lime, fluorite, Al block, Si-Ca, Si-Fe are added for reduction, and electrochemical alloy is sent after slag, and sampling is fully analyzed, and sample return fine adjustment is performed, and then pouring is carried out, and after the casting and forming of the steel ingot, the steel ingot is annealed by annealing process;

[0010] After the steel ingot is annealed through the annealing process, it is heated for forging, and the forging is forged by a 5000T press. After forging, it is hot-charged into an annealing furnace for post-forging heat treatment. After the post-forging heat treatment is completed, it is rough-processed by a vertical lathe, and then the performance heat treatment is performed. After the performance heat treatment is completed, UT inspection is performed;

[0011] After the UT inspection is completed, shot peening is carried out. After shot peening is completed, non-destructive testing acceptance is carried out. After the acceptance is completed, the samples are retained to complete the manufacturing process.

[0012] As a preferred embodiment, when preparing for smelting, the charge is composed of Cr stainless steel, carbon alloy, and Benxi steel return material. The alloy material is composed of CrFe plate, Ni plate, Fe-Mo, Cu plate, and Fe-Nb. The auxiliary materials are composed of lime, fluorite, dolomite, carbon powder, ferrosilicon powder, calcium silicon powder, aluminum powder and recarburizer.

[0013] As a preferred embodiment, when power is supplied for melting, the charge is fully melted at a temperature ≥1590°C, and oxygen is blown for decarburization at a temperature ≥1610°C, followed by at least 30 minutes of nitrogen or argon blowing to enhance stirring, and slag sampling is performed under conditions of deoxidation of the molten steel and good fluidity, and the sampling data is analyzed.

[0014] As a preferred embodiment, the LF smelting process measures the temperature for the first sampling after adding Al ingot after the molten steel enters the tank, then blows argon directly, adjusts the flow control after stirring for 3-8 minutes, adds lime and fluorite to adjust the slag, and adds carbon powder for reduction deoxidation and desulfurization.

[0015] As a preferred embodiment, when the slag turns white or slightly yellow and the temperature in the furnace is ≥1560°C, a full sample is taken for analysis, and the composition ratio is adjusted according to the analysis results and the requirements of the VOD process for entering the tank. Deoxidizer is continued to be added for deoxidation and desulfurization, so that the sulfur content in the molten steel is ≤0.006%, meeting the requirements of the VOD smelting process for entering the tank. After the alloy is completely molten and the temperature is ≥1630°C, the tank car is opened, the ladle is quickly lifted to remove the slag, and then the VOD smelting process is entered.

[0016] As a preferred embodiment, the VOD smelting process controls the carbon content of the molten steel at 0.30%±0.03% after carbon deoxidation by controlling the oxygen blowing amount, and maintains it in an environment with a vacuum carbon deoxidation limit vacuum degree of ≤500Pa for at least 20 minutes, and then adds lime, fluorite, Al block, Si-Ca, and Si-Fe for reduction, and the reduction evacuation and slag removal time is at least 20 minutes, and after slag removal, the electrochemical alloy is sent, the sampling is fully analyzed and then fine-tuned, and after alloying, according to the Si content in the furnace, an appropriate amount of Si-Ca wire is fed, Si is adjusted to 0.60%, the static argon blowing time is controlled to be ≥10min, and after the ladle temperature is 1540~1550℃, argon is used for protective pouring.

[0017] As a preferred embodiment, when the steel ingot is annealed, it is allowed to stand at 300°C±20°C, and then the electric furnace is heated to 750°C±10°C at a rate of 100°C per hour and maintained for at least 30 hours, and then the temperature of the electric furnace is cooled by 50°C per hour and taken out of the furnace when the furnace temperature drops to ≤300°C.

[0018] As a preferred embodiment, the forgings are placed in a forging furnace for heating and then forging. The forging furnace is heated to 400℃±30℃ and maintained for 3 hours. The forging furnace is then gradually heated to 850℃±20℃ within 5 hours and maintained for 6 hours. After maintaining for 6 hours, the temperature of the forging furnace is increased to 1190℃±10℃ within 3 hours and then forging begins.

[0019] As a preferred embodiment, during forging, a 5000T press is used to forge the forgings into workpieces with a drawing ratio of 5.86 and a roughening ratio of 7.84, the start forging temperature is ≥1050°C, the stop forging temperature is ≥850°C, the finishing and straightening stop forging temperature is ≥800°C for a reduction of <20mm, the compaction surface temperature at the center of the forging is 700~800°C, and the forging is hot-charged into an annealing furnace after forging.

[0020] As a preferred embodiment, the performance heat treatment is performed by heating the electric furnace to 650℃±10℃ and maintaining it for 5 hours, then heating it to 860℃±10℃ at a rate of less than or equal to 100℃ per hour, and then cooling it by oil cooling. After the oil cooling is completed, the electric furnace is heated to 350℃±10℃ at a rate of less than or equal to 100℃ per hour, and then maintaining it for 25 hours, and then cooling it by air cooling. After the air cooling is completed, the electric furnace is heated to 350℃±10℃ at a rate of less than or equal to 100℃ per hour, and maintaining it for 25 hours, and then air cooling it to room temperature.

[0021] After adopting the above technical scheme, the beneficial effects of the present invention are as follows: considering the comprehensive mechanical performance requirements of shaft parts, after smelting by LF smelting process, entering VOD smelting process, controlling oxygen blowing amount by VOD smelting process for carbon deoxidation, annealing the steel ingot by annealing process, forging heating, hot charging annealing furnace after forging, post-forging heat treatment, and improving the forging accuracy of forgings by multiple rounds of processes; the heat treatment process adopted after forging saves a lot of gas and electricity consumption, improves work efficiency, greatly reduces the labor intensity and production cost of workers, and can maximize the forging ratio of forging blanks. It can better forge the central defects of steel ingots, forge the internal porosity defects, and improve the forging quality of shafts. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a process flow chart of the present invention; DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. 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.

[0025] Example

[0026] like Figure 1 As shown, a YF928A alloy steel process for high magnetic permeability, high strength and fatigue resistance shaft, the method comprises the following steps:

[0027] Carry out smelting preparation, bake the charge, alloy and auxiliary materials according to the corresponding process;

[0028] Then, lime is placed on the bottom of the electric furnace for loading, and electricity is supplied for melting. After the charge is fully melted, it is stirred and sampled for analysis. According to the analysis results, degassing, removal of inclusions and composition adjustment are carried out, and then steel is mixed with slag for flushing.

[0029] After the molten steel is put into the tank, it is smelted by LF smelting process, and then enters VOD smelting process, through which the oxygen blowing amount is controlled for carbon deoxidation, and then lime, fluorite, Al block, Si-Ca, Si-Fe are added for reduction, and then electrochemical alloy is sent after slag, and sampling is fully analyzed, and sample return fine adjustment is performed, and then pouring is performed, and after the casting and forming of the steel ingot, the steel ingot is annealed;

[0030] After the steel ingot is annealed through the annealing process, it is heated for forging, and the forging is forged by a 5000T press. After forging, it is hot-charged into an annealing furnace for post-forging heat treatment. After the post-forging heat treatment is completed, it is rough-processed by a vertical lathe, and then the performance heat treatment is performed. After the performance heat treatment is completed, UT inspection is performed;

[0031] After the UT inspection is completed, shot peening is carried out. After shot peening is completed, non-destructive testing acceptance is carried out. After the acceptance is completed, the samples are retained to complete the manufacturing process.

[0032] The manufacturing process of the YF928A shaft verification part of this application document is as follows:

[0033] Ingot smelting → Ingot annealing → Ingot heating → Forging → Post-forging heat treatment → Rough machining → UT bottom inspection → Performance heat treatment → Machining → UT inspection → Shot peening → Sampling → Performance inspection.

[0034] The steel ingot smelting method adopts electric furnace + LF process + VOD process, the smelting ingot type setting standard is 10T, and the composition and composition control of the steel ingot are shown in the following table;

[0035]

[0036] Smelting preparation

[0037] The charge is composed of Cr stainless steel, carbon alloy, and similar Benxi Steel return material. The alloy material is composed of CrFe, Ni plate, Fe-Mo, Cu plate, Fe-Nb, etc. The auxiliary materials used are selected lime, fluorite, dolomite, carbon powder, ferrosilicon powder, calcium silicon powder, aluminum powder, and carburizer. Various raw and auxiliary materials should be baked according to standard process requirements.

[0038] Electric furnace smelting process

[0039] Alloy control nodes Cr: 14.20%, Cu: 0.50%, Mo: 0.80%, Ni: 0.75%, V: 0.30%, Nb: 0.12%, P ≤ 0.010%. When charging, lime is placed on the bottom of the furnace, then charging and power melting are carried out. The charge is fully melted, the temperature is ≥ 1590℃, fully stirred and sampled for full analysis, and oxygen is blown to remove C, degas, remove inclusions, and adjust the composition when the temperature is ≥ 1610℃. The pre-reduction time is ≥ 30 minutes, and nitrogen or argon is blown to strengthen stirring. Under the conditions of deoxidation of molten steel and good fluidity, the slag flow part is sampled for full analysis. Composition adjustment: According to the sampling results, adjust the chemical composition in the furnace, steel tapping: alloying is good, when the temperature is ≥ 1630℃, steel slag is mixed and punched out.

[0040] Then enter the LF smelting process

[0041] First, put it into the tank, feed Al wire (or add an equal amount of Al ingot), measure the temperature, and take samples; adjust the flow control after blowing Ar for 3-8 minutes of stirring; send electricity. According to the situation of the slag entering the tank, add appropriate amount of lime and fluorite to adjust the slag, and add sufficient carbon powder for reduction deoxidation and desulfurization. When the slag turns white or slightly yellow, and the fluidity and deoxidation are good, and the temperature is ≥1560℃, take samples for full analysis. According to the analysis results, adjust the composition according to the VOD tank requirements, send the alloy to the electrochemical, continue to add deoxidizer (C powder, Al powder, etc.) for deoxidation and deep desulfurization to S≤0.006% to meet the VOD tank requirements. When the alloy is completely well-melted, the composition is appropriate, and the temperature is ≥1630℃, drive the tank car, quickly lift the bag to remove all the slag, and then enter the VOD process.

[0042] VOD smelting process

[0043] First, control the oxygen blowing amount. After carbon deoxidation, C is controlled at 0.30%±0.03. Carbon deoxidation requirements: vacuum carbon deoxidation limit vacuum degree ≤500Pa, holding time ≥20 minutes. Then reduce: add lime, fluorite, Al block, Si-Ca, Si-Fe, evacuate slag time ≥20min, send electrochemical alloy after slag, take samples for full analysis. Sample back for fine adjustment. After alloying, according to the Si content in the furnace, feed an appropriate amount of Si-Ca wire, adjust Si to 0.60%, control the static argon blowing time ≥10min, and the bag temperature is 1540~1550℃.

[0044] pouring

[0045] Then, pouring is performed under Ar gas protection, and good filling is required for pouring.

[0046] Ingot annealing process

[0047] When annealing the steel ingot, let it stand at 300℃±20℃, then heat the electric furnace to 750℃±10℃ at a rate of 100℃ per hour and keep it for at least 30 hours, then reduce the temperature of the electric furnace by 50℃ per hour and take it out of the furnace when the furnace temperature drops to ≤300℃.

[0048] forging

[0049] Forging heating process: put the forging into the forging furnace for heating and then forging, heat the forging furnace to 400℃±30℃ and keep it for 3 hours, then gradually heat the forging furnace to 850℃±20℃ within 5 hours and keep it for 6 hours, after keeping it for 6 hours, raise the forging furnace temperature to 1190℃±10℃ within 3 hours and start forging. Forging equipment: 5000T press; forging weight: 6.14T; material utilization rate: 61.4%; drawing ratio 5.86; upsetting ratio 7.84. Process parameters: start forging temperature ≥1050℃; stop forging temperature ≥850℃; <20mm reduction finishing, straightening stop forging temperature ≥800℃; center compaction surface temperature 700~800℃.

[0050] Post-forging treatment:

[0051] For the hot-charged annealing furnace after forging, when the forging is ≤350℃, heat it to 650℃±10℃ at a rate of <80℃ per hour and maintain it for 5 hours, then heat it to 860℃±10℃ at a rate of <100℃ per hour and maintain it for 30 hours, then cool it to 300℃ at a rate of ≤50℃ per hour before taking it out of the furnace.

[0052] roughing

[0053] Use vertical lathe to process, and control the surface roughness Ra≤12.5.

[0054] Performance heat treatment control

[0055] Performance heat treatment adopts electric furnace heating; the heat treatment furnace condition and thermal instruments must be kept in good condition. Use fixing measures before loading the furnace to prevent the workpiece from sliding. Clean the furnace chamber, and do not leave oxide scale, steel head, and iron filings on the furnace bed. The second tempering temperature is adjusted according to the hardness after the first tempering.

[0056] For performance heat treatment, the electric furnace is heated to 650℃±10℃ and maintained for 5 hours, then heated to 860℃±10℃ at a rate of less than or equal to 100℃ per hour, and then cooled by oil cooling. After the oil cooling, the electric furnace is heated to 350℃±10℃ at a rate of less than or equal to 100℃ per hour, and then maintained for 25 hours, and then cooled by air cooling. After the air cooling, the electric furnace is heated to 350℃±10℃ at a rate of less than or equal to 100℃ per hour, and maintained for 25 hours, and then air cooled to room temperature.

[0057] Machining

[0058] After the performance heat treatment, machining is performed. The machining adopts vertical lathe processing and is machined into the corresponding shape according to the drawing requirements.

[0059] Shot peening

[0060] UT inspection is performed before shot peening, and oil stains on the workpiece surface are removed before shot peening. Metal shots are used for shot peening, and the particle size is selected to be ≥50 mesh to achieve the purpose of strengthening the workpiece surface. When positioning the workpiece, pay attention to the circumferential surface as the shot peening surface; establish a saturation curve to test the shot peening intensity to ensure that the nozzle can reach the required intensity; control the shot peening surface to be uniform, and the shot peening time is not less than 40 minutes.

[0061] acceptance

[0062] Nondestructive testing time: after rough processing before quenching and tempering, and after rough processing for performance heat treatment. Nondestructive testing: 100% ultrasonic flaw detection is performed on the verification piece, and the ultrasonic flaw detection results should meet the following requirements:

[0063] a) No defects such as cracks, white spots, shrinkage holes, etc. are allowed;

[0064] b) Continuous defect signals and floating defect signals with an equivalent diameter equal to or greater than 1.6 mm are not allowed. Defects with an equivalent diameter less than 1.6 mm are not counted, and defects with an equivalent diameter equal to or greater than 1.6 mm should be recorded;

[0065] c) Defects with an equivalent diameter of 1.6mm to 3.5mm are allowed to exist, but the distance between two adjacent defects shall not be less than 7 times the diameter of the larger equivalent defect, and the total number of defects shall not exceed 30;

[0066] d) In the area with greater stress (the core of the body), defects with an equivalent diameter greater than 2 mm and dense defect signals with an equivalent diameter greater than or equal to 1.6 mm are not allowed;

[0067] e) When using 2MHz to 2.5 MHz frequency for flaw detection, the attenuation of the bottom wave caused by the defect is not greater than 6dB, and the attenuation coefficient of the forging material is less than or equal to 4 dB / m. Then sample the verification piece.

[0068] Tensile test: Each core is subjected to six sets of room temperature tensile tests according to GB / T228.1: R m >1000MPa;Rp 0.2 >900MPa; pass rate ≥80%. Five groups of room temperature tensile tests are carried out on each surface according to GB / T228.1-2021: R m >1100MPa;Rp 0.2 >1000MPa; pass rate 100%.

[0069] Impact energy test: Each core is subjected to three sets of room temperature AKV impact energy tests in accordance with GB / T229, and the test values ​​are provided. 4.2 Each near surface is subjected to three sets of room temperature AKV impact energy tests in accordance with GB / T229, and the test results are KV2≥115J.

[0070] Fatigue performance test: Six groups of samples were taken from the core for fatigue performance test. The fatigue performance test was carried out according to GB / T15248-2008. The life under 120MPa~650MPa cycle load was ≥3×10 6 Weeks, pass rate ≥ 90%. Five groups of samples were taken near the surface for fatigue performance test. The fatigue performance test was carried out according to GB / T15248-2008. The life under 140MPa~700MPa cycle load was ≥3×10 6 Week, pass rate 100%.

[0071] Grain size inspection: Take a sample from each core and inspect the grain size according to GB / T6394-2017, and provide the test value. Take a sample from each near surface and inspect the grain size according to GB / T6394-2017, and meet the actual grain size of level 5 or finer.

[0072] Residual stress test: Use surface samples to test surface residual stress according to GB / T7704-2017. The surface residual compressive stress is ≥150MPa, and the surface residual compressive stress is ≥500MPa. Use core samples to test the core residual stress. There should be no residual stress in the core.

[0073] Magnetic property inspection: The verification piece shall be tested for magnetic properties according to ASTM A341-2016. The magnetic properties shall meet the following requirements:

[0074] a)H=(2.5×10 3 )A / m B≥1.44T;

[0075] b) H = (5.0 × 10 3 )A / m B≥1.60T;

[0076] c) H = (10.0 × 10 3 )A / m B≥1.72T;

[0077] d) H = (15.0 × 10 3 )A / m B≥1.80T;

[0078] e)H=(20.0×10 3 )A / m B≥1.87T;

[0079] f)H=(50.0×10 3 )A / m B≥2.0T;

[0080] Where H is the magnetic field intensity and B is the magnetic induction intensity.

[0081]

[0082] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for producing YF928A alloy steel for high magnetic permeability, high strength and fatigue resistance shaft, characterized in that: The process comprises the following steps: Carry out smelting preparation and bake the furnace charge, alloy material and auxiliary materials according to standard process; Then, lime is placed on the bottom of the electric furnace for loading, and electricity is supplied for melting. After the charge is fully melted, it is stirred and sampled for analysis. According to the analysis results, degassing, removal of inclusions and composition adjustment are carried out. After the adjustment is completed, steel is mixed with slag and flushed out; After the molten steel is put into the tank, the LF smelting process is carried out. After the smelting is completed, the VOD smelting process is entered. The oxygen blowing amount is controlled by the VOD smelting process for carbon deoxidation. Then lime, fluorite, Al block, Si-Ca, Si-Fe are added for reduction. After slagging, the electrochemical alloy is sent, the sampling is fully analyzed, the sample is returned for fine adjustment, and then pouring is carried out. After the casting and forming of the steel ingot, the steel ingot is annealed; In the LF smelting process, after the molten steel enters the tank, Al ingots are added and the temperature is measured for the first sampling, and then the Ar is blown directly for stirring for 3-8 minutes and the flow control is adjusted; power is supplied, and the slag is adjusted according to the slag entering the tank in an appropriate amount of lime and fluorite, and sufficient carbon powder is added for reduction deoxidation and desulfurization; when the slag turns white or slightly yellow and the temperature in the furnace is ≥1560°C, the whole sample is taken for analysis, and the composition ratio is adjusted according to the analysis results according to the requirements of the VOD process for entering the tank, and the deoxidizer is continued to be added for deoxidation and desulfurization, so that the sulfur content in the molten steel is ≤0.006%, meeting the requirements of the VOD smelting process for entering the tank, and after the alloy is completely molten and the temperature is ≥1630°C, the tank car is driven out, and the ladle is quickly lifted to remove the slag before entering the VOD smelting process; The VOD smelting process controls the carbon content of the molten steel to 0.30%±0.03% after carbon deoxidation by controlling the oxygen blowing amount, and keeps it in an environment with a vacuum carbon deoxidation limit vacuum degree of ≤500Pa for at least 20 minutes, then adds lime, fluorite, Al block, Si-Ca, and Si-Fe for reduction, and the reduction evacuation slag time is at least 20 minutes, and after slag is slaged, it is sent to electrochemical alloy, and the sampling is fully analyzed and then fine-tuned. After alloying, according to the Si content in the furnace, an appropriate amount of Si-Ca wire is fed, and Si is adjusted to 0.60%, and the static argon blowing time is controlled to be ≥10min. After the ladle temperature reaches 1540-1550°C, argon is used for protection casting; After the steel ingot is annealed through the annealing process, it is heated for forging, and the forging is forged by a 5000T press. After forging, it is hot-charged into an annealing furnace for post-forging heat treatment. After the post-forging heat treatment is completed, it is rough-processed by a vertical lathe, and then the performance heat treatment is performed. After the performance heat treatment is completed, UT inspection is performed; The YF928A alloy steel is composed of the following mass percentages, wherein C is 0.26-0.32, Si is 0.5-0.7, Mn is 0.6-0.9, P is less than or equal to 0.025, S is less than or equal to 0.01, Cr is 13.5-14.8, Ni is 0.6-0.9, Mo is 0.6-0.9, V is 0.25-0.4, Cu is 0.4-0.6, Nb is 0.08-0.15, Al is less than or equal to 0.1, and the rest is iron and unavoidable impurities; After UT inspection, shot peening is carried out. After shot peening, non-destructive testing acceptance is carried out. After acceptance, samples are retained to complete the manufacturing process; For the performance heat treatment, after the forging is placed in an electric furnace, the temperature of the electric furnace is increased to 650°C±10°C, and then maintained for 5 hours, the temperature is increased to 860°C±10°C at a rate of less than or equal to 100°C per hour, and then the forging is oil-cooled. After the oil cooling is completed, the forging is placed in an electric furnace, the temperature is increased to 350°C±10°C at a rate of less than or equal to 100°C per hour, and then maintained for 25 hours, and then the forging is air-cooled. After the air cooling is completed, the forging is placed in an electric furnace, the temperature is increased to 350°C±10°C at a rate of less than or equal to 100°C per hour, and then maintained for 25 hours, and then the forging is air-cooled in the electric furnace to room temperature.

2. A process for producing YF928A alloy steel for high magnetic permeability, high strength and fatigue resistance shaft according to claim 1, characterized in that: During smelting preparation, the charge is composed of Cr stainless steel, carbon alloy, and Benxi Steel return material. The alloy material is composed of CrFe plate, Ni plate, Fe-Mo, Cu plate, and Fe-Nb. The auxiliary materials are composed of lime, fluorite, dolomite, carbon powder, ferrosilicon powder, calcium silicon powder, aluminum powder, and recarburizer.

3. A process for producing YF928A alloy steel for high magnetic permeability, high strength and fatigue resistance shaft according to claim 1, characterized in that: Power is supplied for melting, and the charge is fully melted at a temperature ≥1590℃. It is fully stirred and sampled for full analysis. At a temperature ≥1610℃, oxygen is blown for decarburization, degassing, removal of inclusions, and composition adjustment. The pre-reduction time is ≥30 minutes, and nitrogen or argon is blown to enhance stirring. Under the conditions of deoxidation of the molten steel and good fluidity, the slag flow part is sampled and fully analyzed.

4. A process for producing YF928A alloy steel for high magnetic permeability, high strength and fatigue resistance shaft according to claim 1, characterized in that: When the steel ingot is annealed, it is allowed to stand at 300°C±20°C, and then the electric furnace is heated to 750°C±10°C at a rate of 100°C per hour and maintained for at least 30 hours, and then the temperature of the electric furnace is lowered by 50°C per hour and taken out of the furnace when the furnace temperature drops to ≤300°C.

5. A process for producing YF928A alloy steel for high magnetic permeability, high strength and fatigue resistance shaft according to claim 4, characterized in that: Place the forgings in a forging furnace for heating and then forging. Heat the forging furnace to 400℃±30℃ and keep it for 3 hours. Then gradually heat the forging furnace to 850℃±20℃ within 5 hours and keep it for 6 hours. After keeping it for 6 hours, increase the temperature of the forging furnace to 1190℃±10℃ within 3 hours and start forging.

6. A process for producing YF928A alloy steel for high magnetic permeability, high strength and fatigue resistance shaft according to claim 1, characterized in that: During forging, a 5000T press is used to forge the forgings into workpieces with a drawing ratio of 5.86 and an upsetting ratio of 7.

84. The start forging temperature is ≥1050℃, the stop forging temperature is ≥850℃, the finishing and straightening stop forging temperature of <20mm is ≥800℃, the compaction surface temperature of the forging center is 700-800℃, and the annealing furnace is hot loaded after forging.

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