Hot-rolled pickled steel plate for spinning belt pulley and manufacturing method of hot-rolled pickled steel plate

Abstract

The invention discloses a hot-rolled pickled steel plate for a spinning belt pulley and a manufacturing method of the hot-rolled pickled steel plate. The technical problems that an existing hot-rolled pickled steel plate for the spinning belt pulley is large in anisotropy and large in springback amount are mainly solved. According to the technical scheme, the hot-rolled pickled steel plate for the spinning belt pulley comprises chemical components in percentage by weight as follows: 0.008%-0.023% of C, 0.001%-0.034% of Si, 0.1%-0.2% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.0105% of S, 0.015%-0.055% of Al, 0.01%-0.02% of Ti, 0.0005%-0.0020% of B and the balance of Fe and inevitable impurity elements. The metallographic structure of the hot-rolled pickled steel plate is ferrite and a small amount of pearlite, and the hot-rolled pickled steel plate with the thickness of 3.0-5.0 mm | r | is less than or equal to 0.15; the method is mainly used for manufacturing high-precision spinning belt wheels and other components.

Description

Technical Field

[0001] The invention relates to a hot-rolled pickled steel plate, in particular to a hot-rolled pickled steel plate for a spinning pulley and a manufacturing method thereof, belonging to the technical field of iron-based alloys. Background Art

[0002] Hot-rolled pickled steel plates are obtained by straightening and pickling the hot-rolled plates to remove the surface oxide scale. The hot-rolled pickled steel plates have greatly improved surface quality, which is convenient for subsequent painting and welding. In addition, their mechanical properties and plate shape are better than those of hot-rolled plates, and they can partially replace cold-rolled plates, which can reduce the production and manufacturing costs of enterprises. Therefore, they are widely used in fields with high requirements on material performance, such as automotive structures.

[0003] The pulley is an important mechanical transmission part and is widely used in the transmission of various mechanical equipment.

[0004] As a transmission part, the pulley requires stable size and high precision to avoid adverse effects on the energy consumption and vibration of the automobile engine. Therefore, the size and shape accuracy of the pulley are very high; the pulley produced by spinning process requires high dimensional accuracy and high requirements for steel plates, requiring the steel plate to have small anisotropy, good rebound performance, high thickness accuracy, stable performance, and easy cutting.

[0005] The existing hot-rolled pickled steel plates are processed into pulleys, and the dimensional accuracy of the pulleys is low. The tooth tips of the toothed pulleys, especially the tooth tips on both sides, have a large rebound amount, which cannot meet the requirement that the adjacent tooth tip angle of the pulley is 39°~41°. In addition, the rebound rules of different pieces are inconsistent, and the thickness difference of the same plate causes the dimensional accuracy and weight to be inconsistent. The comprehensive performance of the hot-rolled pickled steel plate cannot meet the processing requirements of the spinning pulley.

[0006] The existing hot-rolled pickled steel plates are used to make spun pulleys, which have problems such as large anisotropy, large material springback, and poor thickness accuracy. As a result, the spun pulleys have tooth tips, especially large springback of the tooth tips on both sides, which cannot meet the precision requirement of 39° to 41° for the angle between adjacent tooth tips of the pulley. The qualified rate of finished products is low, only 2%. Summary of the invention

[0007] The purpose of the present invention is to provide a hot-rolled pickled steel plate for a spinning pulley and a manufacturing method thereof, mainly to solve the technical problems of large anisotropy and large springback of the existing hot-rolled pickled steel plate for a spinning pulley; the springback of the tooth tips on both sides of the spinning pulley made of the hot-rolled pickled steel plate of the present invention is small, meeting the precision requirement that the angle between adjacent tooth tips of the pulley is 39° to 41°; the hot-rolled pickled steel plate of the present invention meets the quality requirements for preparing pulleys by spinning process.

[0008] The technical idea of ​​the present invention is to improve the performance of hot-rolled pickled steel plates through scientific configuration of hot rolling process; (1) the finishing temperature of finishing rolling is set to 900-940°C, which is above the Ar3 line of steel, which can effectively reduce the appearance of mixed crystals, make the structure more uniform, and reduce the mismatch of tooth tip angle caused by material fluctuations such as springback during spinning; (2) the target value of the convexity of the hot-rolled steel plate is set to 0.03mm, which can effectively reduce the same-plate difference of the pulley, avoid weight mismatch, and improve the assembly accuracy of the spinning pulley; (3) the coiling temperature is 580-620°C, and high-temperature coiling is conducive to the recovery of grains, making the grains more equiaxial, thereby reducing the anisotropy of the material; (4) the laminar cooling after finishing rolling adopts the front-stage cooling method, which has a fast cooling rate, finer grains, better toughness of the material, smoother and finer surface of the finished product, and more uniform distribution of internal impurities, without defects such as pitting, meteor tails, depressions and protrusions, which is very beneficial to meet the spinning process that has high requirements on the internal quality of the material.

[0009] The technical solution adopted by the present invention is a hot-rolled pickled steel plate for a spinning pulley, whose chemical composition weight percentage is: C: 0.008% ~ 0.023%, Si: 0.001% ~ 0.034%, Mn: 0.1% ~ 0.2%, P≤0.015%, S≤0.0105%, Al: 0.015% ~ 0.055%, Ti: 0.01% ~ 0.02%, B: 0.0005% ~ 0.0020%, and the remainder is Fe and unavoidable impurity elements.

[0010] The metallographic structure of the hot-rolled pickled steel plate of the present invention is ferrite + a small amount of pearlite, the proportion of pearlite in the metallographic structure is less than 5% by area percentage, and the grain size of the ferrite is 7.0 to 8.0; the yield strength R of the 3.0 to 5.0 mm thick hot-rolled pickled steel plate is P0.2 180~240MPa, the difference of transverse and longitudinal yield strength is ≤20MPa, and the tensile strength R m 255~380MPa, yield strength ratio is 0.6~0.7, elongation after fracture A 50 mm It is 46% to 65%, the anisotropy of plastic strain ratio │△r│≤0.15, and the convexity of hot-rolled pickled steel plate is ≤0.035mm; according to the American Society for Testing and Materials "ASTM E45-13 Standard Test Method for Determination of Inclusion Content in Steel", method A is used for inspection, and the inclusions of Class A, Class B, Class C and Class D in the hot-rolled pickled steel plate are below Grade 2.0.

[0011] The reasons why the chemical composition of the hot-rolled pickled steel sheet of the present invention is limited to the above range are as follows:

[0012] Carbon: Carbon is the main alloying element in steel. As the carbon content increases, the strength and hardness of the steel increase, while the plasticity and impact toughness decrease. The present invention is a low-carbon design. In order to ensure the spinning effect, the carbon content must be strictly controlled. When the carbon content is greater than 0.023%, it is not conducive to spinning and cutting processing, but when the carbon content is less than 0.008%, it cannot meet the strength requirements. In order to ensure the toughness of the steel, the C content set in the present invention is 0.008% to 0.023%.

[0013] Silicon: When melting, the steel contains an appropriate amount of silicon, which is beneficial to deoxidation and desulfurization. Silicon has a relatively strong deoxidation ability, and generates slag with FeO in the molten steel to remove the adverse effects of FeO on the quality of steel. It can also dissolve in ferrite to produce solid solution strengthening, improve the strength and hardness of steel, and silicon is a beneficial element in steel. However, if the silicon content is too high, the plasticity and toughness of the material will be reduced, and the high silicon design will cause red iron scale on the surface of the material, which will have a certain impact on the surface quality. Taking comprehensive considerations, the Si content designed in the present invention is 0.001% to 0.034%.

[0014] Manganese: Manganese is a beneficial element in steel. It has good deoxidation ability and can remove FeO in steel and reduce the brittleness of steel. The hot-rolled pickled plate contains an appropriate amount of manganese, which is beneficial to desulfurization and can also have a certain strengthening effect. However, a high Mn content increases the structural segregation in the steel, affects the structural uniformity and impact performance of the steel, increases the cost of the steel accordingly, and also increases the carbon equivalent, which is not conducive to welding. In order to ensure the stability of the spinning process, it is necessary to reduce the fluctuation of the material strength, and it is also necessary to limit the range of manganese content. The present invention limits the range of Mn content to 0.1% to 0.2%.

[0015] Phosphorus: Phosphorus is brought in from ore during ironmaking. Phosphorus can dissolve into ferrite at room temperature, improving the strength and hardness of steel, and is easily segregated at the grain boundary, thereby causing segregation and reducing the plasticity and toughness of the steel plate. In general steel, phosphorus is a harmful element and should be strictly controlled. Therefore, considering the actual process control capability, in the present invention, P is controlled to be ≤ 0.015%.

[0016] Sulfur: Sulfur is brought in by ore and fuel during iron making. It is insoluble in iron but exists in the form of compound FeS. FeS forms a low melting point eutectic (melting point is 985°C) with Fe and is distributed on the grain boundaries of austenite. When the steel is hot-worked at 1000-1250°C, the eutectic melts at the grain boundaries, which will cause the steel to become brittle and reduce toughness, making it unfavorable for spinning. Therefore, the S content in the steel should be as low as possible. Combined with the actual control capability and cost requirements on site, the S content in the present invention is controlled to be below 0.0105%.

[0017] Aluminum: Aluminum is a commonly used deoxidizer in steel. Adding a small amount of aluminum to steel can refine the grains, improve impact toughness, and is beneficial to spinning. However, the disadvantage of aluminum is that it affects the hot working performance, welding performance and cutting performance of steel. Therefore, considering the performance of the material, the Al content of the present invention is 0.015% to 0.055%.

[0018] Titanium: Ti is a strong carbonitride forming element. Adding an appropriate amount of Ti to steel can effectively improve strength and improve cementite segregation. The present invention combines low C and low Mn with the effect of Ti element, fully considering the required strength and manufacturing cost. The Ti content of the present invention is 0.01% to 0.02%.

[0019] Boron: The main function of boron is to improve the hardenability of steel. It can also reduce the chemical inhomogeneity of the continuous casting billet, refine the columnar crystals, and finally form the best metallographic structure. At the same time, it reduces the aging hardening effect and is very beneficial to the spinning process. However, the appropriate amount should also be considered. Taking all factors into consideration, the B content of the present invention is 0.0005% to 0.0020%.

[0020] A method for manufacturing a hot-rolled pickled steel plate for a spinning pulley, the method comprising:

[0021] The molten steel is subjected to vacuum degassing treatment in an RH ladle furnace and then continuously poured to obtain a continuous casting slab. The chemical composition of the continuous casting slab is as follows: C: 0.008% to 0.023%, Si: 0.001% to 0.034%, Mn: 0.1% to 0.2%, P≤0.015%, S≤0.0105%, Al: 0.015% to 0.055%, Ti: 0.01% to 0.02%, B: 0.0005% to 0.0020%, and the balance is Fe and unavoidable impurity elements; the inclusion level in the continuous casting slab is controlled, and according to the American Society for Testing and Materials "ASTM E45-13 Standard Test Method for Determining Inclusion Content in Steel", method A is used for inspection, and the inclusions of type A, type B, type C and type D in the hot-rolled pickled steel plate are below grade 2.0;

[0022] The continuous casting slab is heated in a heating furnace and then hot rolled. The heating temperature of the continuous casting slab is 1170-1230°C and the heating time is 210-270min. The hot rolling is a two-stage rolling process. The rough rolling is 6 continuous rollings. The rough rolling end temperature is 1020-1050°C. The finishing rolling is 7 continuous rollings. The finishing rolling is carried out in the austenite single phase region. The finishing rolling end temperature is 900-940°C and the finishing rolling reduction rate is 35%-37%. After finishing rolling, the steel plate convexity is controlled to be ≤0.035mm, the steel plate thickness is 3.0-5.0mm, the laminar cooling adopts front-stage cooling, and the laminar cooling rate is 20-50°C / s. The coiling temperature is 580-620°C to obtain the hot rolled steel coil.

[0023] The hot rolled steel coil is unrolled again on the unwinding machine, and after being straightened and pickled, the finished hot rolled pickled steel plate is obtained. The straightening elongation is 0.40% to 1.20%.

[0024] The reasons for the production process adopted by the present invention are as follows:

[0025] 1. Setting of finishing temperature

[0026] If the steel plate is finish rolled in the two-phase region, mixed crystal structure will appear. Due to the difference in the properties of the material due to the mixed crystal, defects such as dimensional deviation will be caused due to springback and other reasons during spinning. Therefore, the finishing temperature needs to be higher than the Ar3 phase transition point of the material. The Ar3 phase transition point temperature of the steel of the present invention is 890°C. The purpose of this scheme is to obtain a hot-rolled pickled plate with good spinning performance. The final rolling temperature can be slightly higher, which is conducive to reducing the dislocation density in the austenite. However, too high a temperature will make the grains abnormally coarse, which is not conducive to improving the spinning performance of the material. Therefore, this scheme fully considers the temperature drop on the left and right edges in the width direction of the plate, and sets the finishing temperature to 900-940°C.

[0027] 2. Setting of convexity and thickness accuracy of hot-rolled plates

[0028] In order to ensure that the steel plate does not move on both sides during the rolling process, the hot-rolled steel plate is usually slightly thinner on both sides and slightly thicker in the middle in the plate width direction. During hot rolling, the roller crown can be adjusted so that the roller crown adjustment value just offsets the change in roller elastic deformation caused by the rolling force change to ensure a good plate shape. However, if the crown is too large, it will cause large fluctuations in the thickness in the plate width direction, and wrinkles, springback and other defects will occur during the spinning process. The hot-rolled steel plate crown set by the present invention is ≤0.035mm.

[0029] 3. Setting of laminar cooling method and cooling speed after finishing rolling

[0030] By controlling the cooling method and cooling rate of the steel plate after fine rolling, the desired metallographic structure and mechanical properties can be obtained. The front-end cooling method is adopted, the cooling rate is fast, the grains are finer, the toughness of the material is better, the surface of the finished product is smoother and more delicate, the internal impurities are more evenly distributed, and there will be no defects such as pitting, meteor tails, depressions and protrusions. It is very beneficial for the spinning process that has high requirements on the internal quality of the material. Therefore, the present invention sets the laminar cooling method as the front-end cooling, and the cooling rate is 20-50℃ / s.

[0031] 4. Setting of hot rolling coiling temperature

[0032] The coiling temperature has a certain influence on the surface quality and mechanical properties of the steel plate. If the coiling temperature is too high, more iron oxide scale will be generated on the surface of the steel plate, which is not conducive to the subsequent pickling and affects the surface quality of the finished product. If the coiling temperature is too low, the strength of the steel plate will increase, while the elongation will decrease, which will have an adverse effect on the spinning forming, and it is easy to cause spinning cracking and dimensional accuracy in large-scale production. Appropriate high-temperature coiling is conducive to the recovery of the grains, making the grains more equiaxial, thereby reducing the anisotropy of the material and preventing the tooth tip angle of the spun parts. Therefore, the coiling temperature of the present invention is set to 580-620°C.

[0033] 5. Setting of elongation of tension straightening

[0034] The steel plate is straightened by stretching before pickling, which is to repeatedly bend and straighten the steel plate by mechanical external force, which can destroy the combination of the iron oxide scale on the surface of the steel plate and the matrix, and can obtain better surface quality after pickling; after stretching, bending and straightening, the wave edge, wave shape, scoop and slight sickle bend of the plate surface can be eliminated, thereby greatly improving the straightness of the steel plate; because the yield limit of the thin plate in the longitudinal and transverse directions is often anisotropic, stretching, bending and straightening are beneficial to improve the anisotropy of the material. However, if the straightening rate is too high, the work hardening of the steel plate will be more serious, and the elongation and forming performance will be reduced. Therefore, the present invention sets the straightening elongation to 0.40% to 1.20%.

[0035] The metallographic structure of the hot-rolled pickled steel plate obtained by the present invention is ferrite + a small amount of pearlite, the proportion of pearlite in the metallographic structure is less than 5% by area percentage, and the grain size of the ferrite is 7.0-8.0; the yield strength R of the 3.0-5.0 mm thick hot-rolled pickled steel plate is P0.2 180~240MPa, the difference of transverse and longitudinal yield strength is ≤20MPa, and the tensile strength R m 255~380MPa, yield strength ratio is 0.6~0.7, elongation after fracture A 50 mm It is 46% to 65%, the anisotropy of plastic strain ratio │△r│≤0.15, and the convexity of hot-rolled pickled steel plate is ≤0.035mm; according to the American Society for Testing and Materials "ASTM E45-13 Standard Test Method for Determination of Inclusion Content in Steel", method A is used for inspection, and the inclusions of Class A, Class B, Class C and Class D in the hot-rolled pickled steel plate are below Grade 2.0.

[0036] Compared with the prior art, the present invention has the following positive effects: 1. The present invention optimizes the composition design to match the hot rolling process and the pickling process, with lower alloy cost and wider production and manufacturing process, and the obtained hot-rolled pickled steel plate has good spinning processing performance, which is particularly suitable for making high-precision spinning pulleys; the finishing temperature of the present invention is 900-940°C, above the Ar3 line, and the high finishing temperature can reduce the appearance of mixed crystals, and the uniformity of the material is better; the coiling temperature is 580-620°C, and high-temperature coiling is conducive to the recovery of the grains, making the grains more equiaxial, thereby reducing the anisotropy of the material, so that the rebound of the material in the spinning process is smaller, and the dimensional accuracy of the parts can be effectively guaranteed. 2. The laminar cooling of the method of the present invention is the front-stage cooling, the cooling rate is fast, the grains are more refined, the toughness of the material is better, the surface of the finished product is smoother and more delicate, the internal impurities are more evenly distributed, and there will be no defects such as pitting, meteor tails, depressions and protrusions, which is very beneficial to the spinning process that has high requirements on the internal quality of the material. 3. The present invention adopts small convexity control, and the convexity of the hot-rolled steel plate is ≤0.035mm, which can effectively reduce the same-plate difference of the pulley, avoid weight discrepancy, and improve the assembly accuracy of the spinning pulley. 4. The hot-rolled pickled steel plate of the present invention has fine grains, small plane anisotropy, uniform internal quality, and high dimensional accuracy. It can meet the user's requirements for material spinning processing and the accuracy requirements of the adjacent tooth tip angle of the pulley of 39° to 41°. The parts meet the assembly and use requirements, and achieve efficient and high-quality production. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 This is a metallographic structure photograph of the hot-rolled pickled steel plate according to an embodiment of the present invention, and its magnification is 100 times. DETAILED DESCRIPTION

[0038] The present invention is further described below in conjunction with Examples 1 to 6, as shown in Tables 1 to 4.

[0039] The grade of the steel in the embodiment of the present invention is BRC3; Table 1 shows the chemical composition (by weight percentage) of the steel in the embodiment of the present invention, and the balance is Fe and unavoidable impurities.

[0040] Table 1 Chemical composition of the steel of the present invention, unit: weight percentage.

[0041]

[0042]

[0043] Molten steel meeting the basic requirements of chemical composition is obtained by converter smelting, the molten steel is subjected to vacuum circulation degassing treatment in an RH ladle furnace, and continuous casting is used to obtain continuous casting slabs; the inclusion level in the continuous casting slabs is controlled, and the test is carried out using method A according to "ASTM E45-13 Standard Test Method for Determination of Inclusion Content in Steel" of the American Society for Testing and Materials, wherein Class A, Class B, Class C and Class D inclusions are below Class 2.0; the continuous casting slab has a thickness of 210 to 230 mm, a width of 900 to 1650 mm, and a length of 8000 to 11000 mm.

[0044] The slab produced by steelmaking is sent to the heating furnace of the hot rolling mill for reheating, and then sent to the hot rolling mill for rolling after being removed from the furnace and dephosphorized. The rolling is controlled by the roughing mill and the finishing rolling mill, and the coiling is carried out after laminar cooling. The laminar cooling adopts the front cooling to produce qualified hot-rolled steel coils; the thickness of the hot-rolled steel plate is 3.0-5.0 mm, and the hot rolling process control parameters are shown in Table 2.

[0045] Table 2 Hot rolling process control parameters of the embodiment of the present invention

[0046]

[0047] The hot rolled steel coil is unrolled on the unwinding machine, and is subjected to straightening and pickling to obtain a finished hot rolled pickled steel plate; the straightening elongation is 0.40% to 1.20%. The straightening parameters of the embodiment of the present invention are shown in Table 3.

[0048] Table 3 Straightening process parameters of the embodiment of the present invention

[0049] Hot rolling parameters Hot rolled pickled steel plate thickness / mm Tensile elongation / % The present invention 3.0～5.0 0.4～1.2 Example 1 3.0 0.95 Example 2 3.2 0.95 Example 3 3.6 0.85 Example 4 3.8 0.80 Example 5 4.0 0.70 Example 6 4.2 0.70

[0050] The hot-rolled pickled steel sheet obtained by the above method is shown in Figure 1 The metallographic structure of the hot-rolled pickled steel plate is ferrite + a small amount of pearlite. The proportion of pearlite in the metallographic structure is less than 5% by area, and the grain size of ferrite is 7.0-8.0; the yield strength R of the 3.0-5.0mm thick hot-rolled pickled steel plate is P0.2 180~240MPa, the difference of transverse and longitudinal yield strength is ≤20MPa, and the tensile strength R m 255~380MPa, yield strength ratio is 0.6~0.7, elongation after fracture A 50 mm It is 46% to 65%, the anisotropy of plastic strain ratio │△r│≤0.15, and the convexity of hot-rolled pickled steel plate is ≤0.035mm; according to the American Society for Testing and Materials "ASTM E45-13 Standard Test Method for Determination of Inclusion Content in Steel", method A is used for inspection, and the inclusions of Class A, Class B, Class C and Class D in the hot-rolled pickled steel plate are below Grade 2.0.

[0051] The hot-rolled pickled steel plate obtained by the present invention is subjected to a tensile test according to "GB / T228.1-2010 Tensile test of metallic materials Part 1: Room temperature test method"; inclusion rating is performed using method A according to "ASTME45-13 Standard test method for determination of inclusion content in steel"; the performance parameters of the hot-rolled pickled steel plate are shown in Table 4.

[0052] Table 4 Mechanical properties of hot-rolled pickled steel plates according to the present invention

[0053]

[0054] The hot-rolled pickled steel plates produced by the method of the present invention are used to prepare spun pulleys. The adjacent tooth tip angles of the hot-rolled pickled steel plates prepared into spun pulleys in Examples 1-6 are 39.98°, 40.25°, 40.05°, 39.93°, 40.28°, and 40.10°, respectively; the adjacent tooth tip angles of the hot-rolled pickled steel plates prepared into spun pulleys in Examples 1-6 are 39° to 41°, and the dimensional accuracy of the parts meets the assembly requirements.

[0055] In addition to the above embodiments, the present invention may also have other implementation modes. Any technical solution formed by equivalent replacement or equivalent transformation falls within the protection scope required by the present invention.

Claims

1. A hot-rolled pickled steel plate for a spinning pulley, wherein the chemical composition by weight is: C: 0.008% to 0.023%, Si: 0.001% to 0.034%, Mn: 0.1% to 0.2%, P≤0.015%, S≤0.0105%, Al: 0.015% to 0.055%, Ti: 0.01% to 0.02%, B: 0.0005% to 0.0020%, the remainder being Fe and unavoidable impurity elements; the metallographic structure of the hot-rolled pickled steel plate is ferrite + a small amount of pearlite, and the grain size of the ferrite is 7.0 to 8.0; the yield strength R of the 3.0 to 5.0 mm thick hot-rolled pickled steel plate is P0.2 180~240MPa, the difference of transverse and longitudinal yield strength is ≤20MPa, and the tensile strength R m 255~380MPa, yield strength ratio is 0.6~0.7, elongation after fracture A 50mm It is 46% to 65%, the anisotropy of plastic strain ratio │△r│≤0.15, and the convexity of hot-rolled pickled steel plate is ≤0.035mm; according to the American Society for Testing and Materials "ASTM E45-13 Standard Test Method for Determination of Inclusion Content in Steel", method A is used for inspection, and the inclusions of Class A, Class B, Class C and Class D in the hot-rolled pickled steel plate are below Grade 2.

0.

2. The hot-rolled pickled steel plate for spinning pulleys according to claim 1, characterized in that: In the metallographic structure of the hot-rolled pickled steel plate, the proportion of pearlite is less than 5% by area percentage.

3. The hot-rolled pickled steel plate for spinning pulley according to claim 1, characterized in that: The angle between adjacent tooth tips of the pulley made of the hot-rolled pickled steel plate is 39° to 41°.

4. The method for manufacturing a hot-rolled pickled steel sheet for a spinning pulley according to claim 1, wherein: The following steps are involved: The molten steel is subjected to vacuum degassing treatment in an RH ladle furnace and then continuously poured to obtain a continuous casting slab. The chemical composition of the continuous casting slab is as follows: C: 0.008% to 0.023%, Si: 0.001% to 0.034%, Mn: 0.1% to 0.2%, P≤0.015%, S≤0.0105%, Al: 0.015% to 0.055%, Ti: 0.01% to 0.02%, B: 0.0005% to 0.0020%, and the balance is Fe and unavoidable impurity elements; the inclusion level in the continuous casting slab is controlled, and according to the American Society for Testing and Materials "ASTM E45-13 Standard Test Method for Determining Inclusion Content in Steel", method A is used for inspection, and the inclusions of type A, type B, type C and type D in the hot-rolled pickled steel plate are below grade 2.0; The continuous casting slab is heated in a heating furnace and then hot rolled. The heating temperature of the continuous casting slab is 1170-1230°C and the heating time is 210-270min. The hot rolling is a two-stage rolling process. The rough rolling is 6 continuous rollings. The rough rolling end temperature is 1020-1050°C. The finishing rolling is 7 continuous rollings. The finishing rolling is carried out in the austenite single phase region. The finishing rolling end temperature is 900-940°C and the finishing rolling reduction rate is 35%-37%. After finishing rolling, the steel plate convexity is controlled to be ≤0.035mm, the steel plate thickness is 3.0-5.0mm, the laminar cooling adopts front-stage cooling, and the laminar cooling rate is 20-50°C / s. The coiling temperature is 580-620°C to obtain the hot rolled steel coil. The hot rolled steel coil is unrolled again on the unwinding machine, and is subjected to straightening and pickling to obtain a finished hot rolled pickled steel plate, wherein the straightening elongation is 0.40% to 1.20%.

5. The manufacturing method according to claim 4, characterized in that: In the metallographic structure of the hot-rolled pickled steel plate, the proportion of pearlite is less than 5% by area percentage.

6. The manufacturing method according to claim 4, characterized in that: The angle between adjacent tooth tips of the pulley made of the hot-rolled pickled steel plate is 39° to 41°.

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