16cr3niwomoVNbE steel hot-rolled bar and preparation method thereof

Abstract

The application discloses a kind of 16Cr3NiWoMoVNbE steel hot-rolled bar and preparation method thereof, the mass percentage of each component in 16Cr3NiWoMoVNbE steel hot-rolled bar is as follows: C:0.16~0.18; Mn:0.55~0.65; Si:0.75~0.85; S:≤0.005; P:≤0.005; Ni:1.20~1.33; Cr:2.70~2.90; Mo:0.45~0.55; W:1.10~1.20; V:0.40~0.50; Nb:0.12~0.18; Ce:0.01~0.05; Al:0.04~0.06, the balance is Fe.The application obtains the 16Cr3NiWoMoVNbE steel bar with a diameter of 90~130mm by hot rolling, the 16Cr3NiWoMoVNbE steel hot-rolled bar is not found coarse grain defect by transverse macro-acid immersion corrosion detection, and has good tensile property and impact toughness under room temperature condition, the quality risk and cost increase problem caused by bar forging processing can be avoided, and the product shape, surface quality characteristics, mechanical property indexes and microstructure structure are fully satisfied.

Description

Technical Field

[0001] This invention relates to the field of steel preparation technology, and more specifically to a hot-rolled bar of 16Cr3NiWoMoVNbE steel and its preparation method. Background Technology

[0002] 16Cr3NiWoMoVNbE steel is a premium structural steel, primarily strengthened by martensite and multi-element precipitation composite reinforcement. It possesses excellent hardenability, high tensile strength, and high toughness and plasticity, exhibiting outstanding high-temperature performance and capable of long-term service at temperatures below 300℃. Therefore, 16Cr3NiWoMoVNbE steel is widely used in the manufacture of transmission gears for aero-engines, meeting the requirements of high power, high speed, and high meshing temperature in engine gear transmissions, and has promising market application prospects.

[0003] 16Cr3NiWoMoVNbE steel has a high degree of alloying, with carbide precipitates playing a dominant strengthening role. During hot working deformation of the steel bars, improper control of process parameters such as deformation amount, deformation speed, and temperature can lead to uneven distribution and fragmentation of the carbide microstructure. Abnormal grain growth occurs during pressure deformation, resulting in finished products prone to low-magnification coarse grains and mixed grain defects, failing to meet technical standards and adversely affecting mechanical properties. Currently, bars with diameters of 20–89 mm are produced by hot rolling, exhibiting good physical and chemical properties; bars with diameters of 90–130 mm are produced by forging, which results in severe low-magnification coarse grain defects.

[0004] Therefore, it is necessary to develop a method for preparing and heat treating 16Cr3NiWoMoVNbE steel bars to solve the problem of low-magnification coarse grains in Ф90~130mm bars and improve the mechanical property stability of the steel. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a hot-rolled bar of 16Cr3NiWoMoVNbE steel and its preparation method, so as to solve the problems in the background art.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows.

[0007] A hot-rolled bar of 16Cr3NiWoMoVNbE steel, wherein the mass percentages of each component in the hot-rolled bar of 16Cr3NiWoMoVNbE steel are as follows: C: 0.16~0.18; Mn: 0.55~0.65; Si: 0.75~0.85; S: ≤0.005; P: ≤0.005; Ni: 1.20~1.33; Cr: 2.70~2.90; Mo: 0.45~0.55; W: 1.10~1.20; V: 0.40~0.50; Nb: 0.12~0.18; Ce: 0.01~0.05; Al: 0.04~0.06, with the balance being Fe.

[0008] A method for preparing hot-rolled bars of 16Cr3NiWoMoVNbE steel includes the following steps:

[0009] S1. Electrode rods are formed by high-temperature casting of 16Cr3NiWoMoVNbE steel hot-rolled bars configured in a certain proportion using vacuum induction melting technology; the cast electrode rods are remelted and cooled using an electroslag remelting continuous directional crystallizer to prepare electroslag ingots.

[0010] S2. Heat the electroslag ingot to 1030℃~1160℃, hold for 3~4 hours, place it on a high-speed forging machine, and perform one-pass upsetting and drawing forging to form a square billet;

[0011] S3. The forged billet is loaded into the furnace and heated to 1150℃~1200℃. After holding at the temperature, it is hot rolled in one pass. The billet is rough rolled and finished rolled into finished product using a continuous rolling mill.

[0012] S4. Rolling utilizes the residual heat from hot rolling for straightening, avoiding microstructural changes and abnormal grain growth caused by reheating;

[0013] S5. After hot-rolled straightening, the black leather material is cooled to 700℃ by air cooling. After the surface color turns black, it is placed in a slow cooling box and slow cooled for ≥24 hours.

[0014] S6. After slow cooling, the black leather material is subjected to high-temperature tempering to eliminate residual stress during hot deformation and obtain 16Cr3NiWoMoVNbE steel hot-rolled bar.

[0015] To further optimize the technical solution, in step S1, the 16Cr3NiWoMoVNbE steel hot-rolled bar is cast at a high temperature of 1560℃~1580℃.

[0016] To further optimize the technical solution, in step S2, the initial forging temperature is ≥930℃ and the final forging temperature is ≥830℃.

[0017] To further optimize the technical solution, in step S3, during hot rolling, the initial rolling temperature is 1000℃~1150℃, and the final rolling temperature is 900℃~1000℃.

[0018] To further optimize the technical solution, in step S3, the material is hot-rolled in one pass, 10 to 15 passes, with a deformation amount of 6% to 10% per pass and a total deformation amount of 70% to 90%.

[0019] To further optimize the technical solution, in step S4, the straightening temperature is 890℃~990℃.

[0020] To further optimize the technical solution, in step S6, the tempering temperature is 650℃~720℃ and the time is ≥25h.

[0021] Due to the adoption of the above technical solutions, the technical progress achieved by this invention is as follows.

[0022] This invention provides a hot-rolled 16Cr3NiWoMoVNbE steel bar and its preparation method. The method adopts a rolling forging process to obtain 16Cr3NiWoMoVNbE steel bars with a diameter of 90~130mm through hot rolling. No coarse grain defects were found in the transverse low-magnification acid immersion corrosion test of the hot-rolled 16Cr3NiWoMoVNbE steel bar, and it has good tensile properties and impact toughness at room temperature. The quality risks and cost increases caused by bar forging are avoided, and the product shape, surface quality characteristics, mechanical properties and microstructure are fully satisfied. Attached Figure Description

[0023] Figure 1 This is a schematic diagram showing the Y-direction as the rolling direction in the bar rolling process of the present invention;

[0024] Figure 2 This is a rolling diagram of the roughing process of hot-rolled bar stock according to the present invention;

[0025] Figure 3 This is a rolling diagram of the hot-rolled bar stock finished into finished product according to the present invention;

[0026] Figure 4 OM microstructure diagram of the hot-rolled steel bar of the present invention;

[0027] Figure 5 These are low-magnification transverse acid-etched specimens of hot-rolled and forged steel bars of the present invention.

[0028] Figure 6 This is an OM grain size diagram of the hot-rolled and forged steel bars in this invention. Detailed Implementation

[0029] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0030] A hot-rolled bar of 16Cr3NiWoMoVNbE steel has the following composition by mass percentage: C: 0.16~0.18; Mn: 0.55~0.65; Si: 0.75~0.85; S: ≤0.005; P: ≤0.005; Ni: 1.20~1.33; Cr: 2.70~2.90; Mo: 0.45~0.55; W: 1.10~1.20; V: 0.40~0.50; Nb: 0.12~0.18; Ce: 0.01~0.05; Al: 0.04~0.06, with the balance being Fe.

[0031] A method for preparing hot-rolled bars of 16Cr3NiWoMoVNbE steel includes the following steps:

[0032] S1. Melting: The hot-rolled bars of 16Cr3NiWoMoVNbE steel, which are configured in proportion, are cast at high temperature of 1560℃~1580℃ using vacuum induction melting technology to form electrode bars.

[0033] Electroslag remelting: Defects such as iron oxide scale and bulges, as well as dust and other contaminants, are removed from the surface of the electrode rod. The cast electrode rod is remelted using a continuous directional crystallizer and cooled to prepare an electroslag ingot with a diameter of 360~590mm. Argon is purged before power supply, with an Ar flow rate of 6m³ / h. 3 The oxygen content is ≤3%; the melting rate of electroslag remelting is 3.5~6.5 kg / min, and the slag system used is SD-73 (Al2O3:CaF2=30%:70% binary slag system) pre-melted slag. The total cooling time is 36~72 h.

[0034] S2. Forging: Heat the electroslag ingot to 1030℃~1160℃ and hold for 3~4 hours. Place it on a high-speed forging machine and perform one-pass upsetting and drawing forging to obtain a square billet with a side length of 200~300mm. The initial forging temperature is ≥930℃ and the final forging temperature is ≥830℃.

[0035] S3. Hot Rolling: The forged billet is loaded into a furnace and heated to 1150℃~1200℃. It is held at this temperature for a duration calculated based on the ingot thickness, using a speed of 1~1.5mm / min. Then, hot rolling is performed. The initial rolling temperature is 1000℃~1150℃, and the final rolling temperature is 900℃~1000℃. A continuous rolling mill is used for roughing the billet and finishing the finished product.

[0036] Hot rolling is a single-pass process, involving 10-15 passes, with each pass yielding a deformation of 6%-10%, resulting in a total deformation of 70%-90%. A schematic diagram of bar rolling, where the Y-axis represents the rolling direction, is shown below. Figure 1 As shown, Figure 2 This is a rolling diagram for roughing out billets. Figure 3 This is a rolling diagram for finished products.

[0037] S4. Straightening: The rolling process utilizes residual heat for straightening to avoid defects such as changes in microstructure and abnormal grain growth caused by reheating. Within the designed heating temperature range, the final rolling temperature is 900℃~1000℃, and the straightening temperature is 890℃~990℃, which can meet the straightening conditions for varieties with a hardness of less than 230.

[0038] S5. Slow cooling: After hot rolling and straightening, the black leather is air-cooled to 700℃. After the surface color turns black, it is put into a slow cooling box for slow cooling for ≥24 hours.

[0039] S6. Heat Treatment: The slowly cooled black steel bar is subjected to high-temperature tempering to eliminate residual stress from hot deformation and improve the stability of the bar, obtaining 16Cr3NiWoMoVNbE steel hot-rolled bars. The tempering temperature is 650℃~720℃ and the time is ≥25h. The OM microstructure of the hot-rolled steel bar is shown below. Figure 4 As shown.

[0040] Example 1 provides a 16Cr3NiWoMoVNbE steel ingot, the preparation method of which includes the following steps:

[0041] 1.1 Melting: Vacuum induction melting technology uses raw materials prepared according to the following chemical composition content by mass percentage, and high-temperature casting is carried out at 1560℃~1580℃ to form an electrode rod with a diameter of 340mm;

[0042] The chemical composition of 16Cr3NiWoMoVNbE steel is as follows: C: 0.175; Mn: 0.63; Si: 0.780; S: ≤0.005; P: ≤0.005; Ni: 1.25; Cr: 2.80; Mo: 0.50; W: 1.15; V: 0.45; Nb: 0.15; Ce: 0.03; Al: 0.06, with the balance being Fe.

[0043] 1.2 Electroslag remelting: The electrode rod cast in step 1.1 was remelted and cooled using an electroslag remelting continuous directional crystallizer to obtain a steel ingot with a diameter of 480 mm; wherein, the electroslag remelting speed was 5.0 kg / min and the cooling time was 56 h; the slag system used was SD-73 (Al2O3:CaF2=30%:70% binary slag system) premelted slag.

[0044] The composition of the 16Cr3NiWoMoVNbE steel ingot obtained in Preparation Example 1 was analyzed, and the results are shown in Table 1.

[0045] Table 1. Composition content of the steel ingot provided in Preparation Example 1 Example

[0046] A method for preparing hot-rolled bars of 16Cr3NiWoMoVNbE steel is provided, comprising the following steps:

[0047] 1. Smelting: Smelting was carried out according to the method of Preparation Example 1 to obtain 16Cr3NiWoMoVNbE steel electroslag ingots with a diameter of 480 mm.

[0048] 2. Forging: First, the 16Cr3NiWoMoVNbE steel electroslag ingot undergoes multi-stage homogenization treatment to reduce the segregation of alloying elements and provide softening conditions for forging. The heating temperature is 1140℃, and the holding time is 3.5h. Then, a 25MN high-speed forging mill is used for one-time upsetting and drawing to obtain a square billet with a side length of 280mm. The initial forging temperature is 980℃, and the final forging temperature is 930℃.

[0049] 3. Hot rolling: The square billet with a side length of 280mm obtained by forging is heated to 1170℃ and held for 3.5h. Then it is hot rolled by using a continuous rolling mill for rough rolling and finish rolling into finished products.

[0050] Specifically, the roughing process involves 9 passes, from Ф280mm to Ф170mm; the finishing process involves 4 passes: 2 square holes, 1 oval hole, and 1 round hole, from Ф170mm to Ф130mm. The finished product is formed in one rolling pass, with an initial rolling temperature of 1055℃ and a final rolling temperature of 970℃.

[0051] 4. Straightening: The residual heat from rolling is used for straightening, and the straightness of the straightened bar is less than 5 mm / m.

[0052] 5. Slow cooling: After hot rolling and straightening, the black leather is air-cooled to 700℃. After the surface color turns black, it is put into a slow cooling box for 24 hours.

[0053] 6. Heat treatment: The black leather material after slow cooling is subjected to high-temperature tempering treatment. The tempering temperature is 685℃, the holding time is 25h, and then it is furnace cooled to 300℃ and air cooled to obtain 16Cr3NiWoMoVNbE steel hot-rolled bars. Example

[0054] A method for preparing hot-rolled bars of 16Cr3NiWoMoVNbE steel, which differs from Example 1 in that it involves hot rolling, as detailed below:

[0055] 3. Hot rolling: The square billet with a side length of 280mm obtained by forging is heated to 1170℃ and held for 3.5h. Then it is hot rolled by using a continuous rolling mill for rough rolling and finish rolling into finished products.

[0056] Specifically, the roughing process involves 9 passes, from Ф280mm to Ф170mm; the finishing process involves 5 passes: 2 square holes, 2 oval holes, and 1 round hole, from Ф170mm to Ф120mm. The finished product is formed in one rolling pass, with an initial rolling temperature of 1035℃ and a final rolling temperature of 960℃.

[0057] 4. Straightening: The residual heat from rolling is used for straightening, and the straightness of the straightened bar is less than 5 mm / m.

[0058] 5. Slow cooling: After hot rolling and straightening, the black leather is air-cooled to 700℃. After the surface color turns black, it is put into a slow cooling box for 24 hours.

[0059] 6. Heat treatment: The black leather material after slow cooling is subjected to high-temperature tempering treatment. The tempering temperature is 685℃, the holding time is 25h, and then it is furnace cooled to 300℃ and air cooled to obtain 16Cr3NiWoMoVNbE steel hot-rolled bars.

[0060] A method for preparing 16Cr3NiWoMoVNbE steel forged bars is provided, which differs from the embodiments in that the forging and hot rolling processes are different, as detailed below:

[0061] 2. Forging: First, the 16Cr3NiWoMoVNbE steel electroslag ingot is subjected to multi-stage homogenization treatment to reduce the degree of alloy element segregation and provide softening conditions for forging. Then, it is fast forged into a billet and hammer forged into a finished product.

[0062] 2.1 Rapid Forging: An electroslag ingot with a diameter of 480mm is loaded into a furnace and heated to 1100℃ for 3.5 hours. It is then upsetting and drawing in one pass using a 25MN rapid forging mill to obtain a square billet with a side length of 250mm and a deformation of 65.4%. The initial forging temperature is 960℃ and the final forging temperature is 910℃.

[0063] 2.2 Hammer Forging: The square billet with a side length of 250mm obtained from the above rapid forging is subjected to three hammer forging processes. The specific steps are as follows:

[0064] First forging: The forged billet is heated to 1100℃ and held for 1.5 hours; then hammer forging is performed to obtain a square billet with a side length of 170mm and a deformation of 53.8%. The initial forging temperature is 950℃ and the final forging temperature is 900℃.

[0065] Second forging: The square billet with a side length of 170mm is heated to 1080℃ and held for 1.5h; then hammer forging is performed to obtain a rough round billet with a diameter of 130mm and a deformation of 54.1%. The initial forging temperature is 930℃ and the final forging temperature is 880℃.

[0066] Third forging: The rough round billet with a diameter of 130 mm is heated to 1030℃ and held for 25 minutes; then hammer forging is performed to obtain a bar with a diameter of 118 mm and a deformation of 24.2%. The initial forging temperature is 910℃ and the final forging temperature is 860℃.

[0067] 5. Slow cooling: The black leather material after hammer forging is slowly cooled for 48 hours.

[0068] 6. Heat treatment: The black leather material after slow cooling is subjected to normalizing and high-temperature tempering treatment. The normalizing temperature is 945℃ and the holding time is 5h. The tempering temperature is 685℃ and the holding time is 25h. Then, it is furnace cooled to 300℃ and air cooled to obtain 16Cr3NiWoMoVNbE steel forged bars.

[0069] The mechanical properties and grain size of the 16Cr3NiWoMoVNbE steel bars obtained in Examples 1-2 and Comparative Example 1 were tested through performance testing. The testing methods for each mechanical property, low magnification, and grain size are as follows:

[0070] (1) According to the standard Q / S10-0361-2004, the mechanical property test blanks were quenched and tempered. The heat treatment regime was 910℃*1h, oil cooling + 330℃*3h, and air cooling. The grain size test specimens were quenched and tempered. The heat treatment regime was 900℃*1h, and oil cooling.

[0071] (2) According to GB / T 228-1987 standard, the above sample blanks were machined and their tensile properties at room temperature were tested, including tensile strength Rp, yield strength Rm, elongation after fracture A, and reduction of area Z.

[0072] (3) According to GB / T 229 standard, the above sample blanks were machined and the impact toughness KU2 at room temperature was tested.

[0073] (4) According to GB / T 6394 standard, the above grain size samples were ground, polished and etched and the grain size grade was tested.

[0074] The test results are shown in Table 2 below.

[0075] Table 2. Mechanical property test results of 16Cr3NiWoMoVNbE steel bars from Examples 1-2 and Comparative Example 1

[0076] Rp (MPa) Rm (MPa) A% Z% KU2(J) Grain size Example 1 1410 1181 15 63 104.4 9.5 Example 2 1400 1172 15.5 61 106.5 9.5 Comparative Example 1 1358 1143 13 61 78.8 7.0-10.0（45%）

[0077] The room temperature tensile test results show that the room temperature tensile strength Rp of the 16Cr3NiWoMoVNbE steel hot-rolled bars prepared in Examples 1-2 of this application is 1410-1400 MPa, the room temperature yield strength Rm is 1181-1172 MPa, the elongation after fracture A is 15%-15.5%, and the reduction of area is 63%-61%. In contrast, the room temperature tensile strength Rp of the 16Cr3NiWoMoVNbE steel forged bars prepared in Comparative Example 1 is 1358 MPa, the room temperature yield strength Rm is 1143 MPa, the elongation after fracture A is 13%, and the reduction of area is 61%. This indicates that the room temperature tensile properties of the 16Cr3NiWoMoVNbE steel bars prepared in Examples 1-2 are superior to those of the 16Cr3NiWoMoVNbE steel bars prepared in Comparative Example 1.

[0078] The room temperature impact test results show that the room temperature impact toughness of the 16Cr3NiWoMoVNbE steel hot-rolled bars prepared in Examples 1-2 of this application is 104.4-106.5 J; while the room temperature impact toughness of the 16Cr3NiWoMoVNbE steel forged bars prepared in Comparative Example 1 is 78.8 J. This indicates that the 16Cr3NiWoMoVNbE steel bars prepared in Examples 1-2 have better impact toughness at room temperature than those prepared in Comparative Example 1.

[0079] The results of the transverse low-magnification acid immersion corrosion test show that the acid-immersed low-magnification specimens are as follows: Figure 5 As shown, Figure 5 (a) is a low-magnification sample of hot-rolled bar material after acid leaching. Figure 5 (b) Low-magnification acid-etched specimens of forged bars. The low-magnification specimens of the 16Cr3NiWoMoVNbE steel hot-rolled bars prepared in Examples 1-2 of this application, after acid etching for 20 minutes, showed no coarse grains or other metallurgical defects on the surface. Figure 5 As shown in (a); however, the low-magnification specimen of the 16Cr3NiWoMoVNbE steel forged bar prepared in Comparative Example 1 has coarse grain defects of about 20 mm at the edge, as shown in (a). Figure 5 (b) shows that the low-magnification microstructure of the 16Cr3NiWoMoVNbE steel bars prepared in Examples 1-2 meets the technical standard requirements, and no metallurgical defects such as shrinkage cavities, low-magnification coarse grains, inclusions and white spots are visible to the naked eye.

[0080] The results of the grain size test show that, for example Figure 6 As shown, Figure 6 (a) represents the grain size of the hot-rolled bar. Figure 6 (b) refers to the grain size of the forged bar. The grain size of the 16Cr3NiWoMoVNbE steel hot-rolled bar obtained in Examples 1-2 of this application is grade 9.5. Figure 6 As shown in (a); while the 16Cr3NiWoMoVNbE steel hot-forged bar obtained in Comparative Example 1 has a grain size of grade 8.0 and exhibits grade 5.0 mixed grain phenomenon, as shown in (a). Figure 6 As shown in (b), the uniformity of the grain structure of the 16Cr3NiWoMoVNbE steel bars prepared in Examples 1-2 is significantly improved compared with that in Comparative Example 1. This phenomenon shows a clear positive correlation with the mechanical property test results.

[0081] In summary, the preparation method of 16Cr3NiWoMoVNbE steel hot-rolled bars provided in this application can produce 16Cr3NiWoMoVNbE steel hot-rolled bars with a diameter of 90~130mm. Low-magnification corrosion testing of the materials showed no coarse grain defects, and the bars exhibited excellent tensile strength, yield strength and impact toughness at room temperature, meeting the technical standard requirements.

Claims

1. A method for preparing hot-rolled bars of 16Cr3NiWoMoVNbE steel, characterized in that: The mass percentage of each component in the hot-rolled 16Cr3NiWoMoVNbE steel bar is: C: 0.16~0.18; Mn: 0.55~0.65; Si: 0.75~0.85; S: ≤0.005; P: ≤0.005; Ni: 1.20~1.33; Cr: 2.70~2.90; Mo: 0.45~0.55; W：1.10~1.20； V：0.40~0.50； Nb ：0.12~0.18； Ce: 0.01~0.05; Al: 0.04~0.06, balance Fe; A method for preparing 90-130mm hot-rolled steel bars includes the following steps: S1. Using vacuum induction melting technology, hot-rolled bars of 16Cr3NiWoMoVNbE steel in proportion are cast at high temperature of 1560℃~1580℃ to form electrode rods; the cast electrode rods are remelted and cooled using an electroslag remelting continuous directional crystallizer to prepare electroslag ingots with a diameter of 360~590mm; the electroslag remelting melting rate is 3.5~6.5kg / min, and the slag system used is SD-73 pre-melted slag; S2. Heat the electroslag ingot to 1030℃~1160℃, hold for 3~4 hours, place it on a high-speed forging machine, and perform one-pass upsetting and drawing forging to form a square billet with a side length of 200~300mm. S3. The forged billet is loaded into the furnace and heated to 1150℃~1200℃. After holding at this temperature, it is hot rolled in one pass. The billet is rough rolled and finished rolled into finished product using a continuous rolling mill. During hot rolling, the initial rolling temperature is 1000℃~1150℃ and the final rolling temperature is 900℃~1000℃. The product is produced in one pass, with 10~15 passes. The deformation per pass is 6%~10%, and the total deformation is 70%~90%. S4. Rolling utilizes the residual heat from hot rolling for straightening, avoiding microstructural changes and abnormal grain growth caused by reheating; S5. After hot-rolled straightening, the black leather material is cooled to 700℃ by air cooling. After the surface color turns black, it is placed in a slow cooling box and slow cooled for ≥24 hours. S6. After slow cooling, the black leather material is subjected to high-temperature tempering treatment at a temperature of 685℃ and a holding time of 25h. Then, it is furnace cooled to 300℃ and air cooled after removal from the furnace. This process eliminates residual stress during hot deformation and yields 16Cr3NiWoMoVNbE steel hot-rolled bars.

2. The method for preparing a hot-rolled bar of 16Cr3NiWoMoVNbE steel according to claim 1, characterized in that: In step S1, the 16Cr3NiWoMoVNbE steel hot-rolled bar is cast at a high temperature of 1560℃~1580℃.

3. The method for preparing a hot-rolled bar of 16Cr3NiWoMoVNbE steel according to claim 1, characterized in that: In step S2, the initial forging temperature is ≥930℃ and the final forging temperature is ≥830℃.

4. The method for preparing a hot-rolled bar of 16Cr3NiWoMoVNbE steel according to claim 1, characterized in that: In step S4, the straightening temperature is 890℃~990℃.

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