High-strength decrement wind power steel with yield strength larger than or equal to 420 MPa and manufacturing method of high-strength decrement wind power steel

Abstract

The invention relates to the technical field of steel plate production, in particular to high-strength decrement wind power steel with the yield strength larger than or equal to 420 MPa. The high-strength decrement wind power steel comprises, by mass, 0.15%-0.175% of C, 0.2%-0.3% of Si, 1.45%-1.55% of Mn, 0.015%-0.025% of Nb, 0-0.001% of Ti, 0.015%-0.035% of Al, 0.40%-0.45% of Ceq and the balance Fe and inevitable impurities. The manufacturing method of the high-strength decrement wind power steel comprises the following steps of secondary cutting of a thick plate, heating of the thick plate, rolling of the thick plate, water cooling of the thick plate, hot straightening of the thick plate, shearing of the thick plate, jet printing of the thick plate and shape combining and warehousing of the thick plate. The method has the beneficial effects that the steel plate strength of the high-strength decrement wind power steel is improved, the performance of the steel plate tends to be stable, the production quality of the high-strength decrement wind power steel is improved, and the production quality qualification rate of the high-strength decrement wind power steel is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of steel plate production, and in particular to a high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa and a manufacturing method thereof. Background Art

[0002] In recent years, with the continuous aggravation of global energy consumption and environmental problems, many countries have begun to turn to the development of sustainable energy, and wind power generation is an important choice. Based on the current vigorous development of wind power technology, the demand for wind power steel has gradually increased and gradually oriented towards high-strength reduced wind power. Wind power steel is a special steel plate widely used in the manufacture of wind power equipment, and high-strength reduced wind power steel is a medium-high strength and lightweight type of wind power steel. It has excellent properties such as impact resistance and fatigue resistance, and plays a vital role in the production process of wind power equipment. Due to the high performance requirements, the production process difficulty of high-strength reduced wind power steel is relatively increased. Its demand mainly involves Q420ND, Q420NE, Q420MD and other steel grades, and the steel mark requirements are JT5Q6AP1 and JT5P31P2. The traditional production process of high-strength reduced wind power steel includes the following: 1. Secondary cutting of thick plates: mainly cutting and segmenting the steelmaking mother billet according to instructions; 2. Thick plate heating: mainly used to heat the slabs loaded into the furnace; 3. Thick plate rolling: mainly rolling the incoming slab into the required specifications and dimensions according to the process design requirements, and obtaining the required rolling temperature; 4. Thick plate shearing: mainly cutting the steel plate into the required size according to the instructions; 5. Thick plate straightening: straighten the steel plate after heat treatment according to the actual needs of the plate shape; 6. Thick plate printing: Print the steel plate information on the surface and side of the steel plate according to the instructions; 7. Thick plates are put into storage after they are in good shape: Confirm the appearance, size and shape of the steel plates, and put them into storage after they meet the technical requirements.

[0003] Based on the above-mentioned steel plate demand and its traditional production process, in the actual production process of high-strength reduced-weight wind power steel, firstly, due to the fluctuations in chemical composition and production process, there is instability in steel plate performance; secondly, due to the fluctuations in process parameters of the rolling process, there is instability in steel plate production quality. Summary of the invention

[0004] The purpose of the present invention is to provide a high-strength reduced-weight wind power steel with a yield strength ≥420MPa and a manufacturing method thereof, so as to solve the problems of unstable steel plate performance and unstable steel plate production quality commonly existing in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solution: A high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa, wherein the chemical composition is as follows by mass percentage: C: 0.15-0.175%, Si: 0.2-0.3%, Mn: 1.45-1.55%, Nb: 0.015-0.025%, Ti: 0-0.001%, Al: 0.015-0.035%, and Ceq: 0.40-0.45%.

[0006] Preferably, the thickness of the high-strength reduced-weight wind power steel is in the range of 20 to 55 mm.

[0007] Preferably, the grade of the high-strength reduced-weight wind power steel is Q420ND.

[0008] The present invention also provides a method for manufacturing high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa, comprising the following steps: S1. Secondary cutting of thick plates: The slabs are heated by hot delivery and hot loading process, and the hot delivered slabs are cut into short slabs according to the design instructions, and the burrs are removed online to ensure that the size and surface quality of the slabs are normal and meet the requirements of furnace loading; S2. Thick plate heating: The furnace temperature is controlled at 1130-1170℃. The time in the furnace is divided into cold charging and hot charging for control. The cold charging time in the furnace is controlled at ≥210min, and the hot charging time in the furnace is controlled at ≥180min. S3. Thick plate rolling: The steel plate is rolled using a low temperature controlled rolling process, and the key rolling process parameters are controlled as follows: (1) The rolling temperature is controlled at 770-800℃; (2) The final rolling temperature is controlled at 730-760°C; (3) The rolling point thickness is controlled according to 1.8T, where T represents the rolled thickness of the steel plate; (4) The rough rolling mill adopts 9 passes, the finishing mill adopts 7 passes, the rough rolling dephosphorization is 2 passes, and the finishing rolling dephosphorization is 1 pass; (5) The reduction rate of the 1st to 3rd passes is controlled at 5-10%, the reduction rate of the 4th to 8th passes is controlled at 15-20%, the reduction rate of the 9th pass is 0%, the reduction rate of the 10th pass is controlled at 15-20%, the reduction rate of the 11th to 14th passes is controlled at 10-15%, the reduction rate of the 15th pass is controlled at 5-10%, and the reduction rate of the 16th pass is 0%; (6) The reduction of the 1st and 6th passes is controlled within 20-25 mm, the reduction of the 2nd and 7th passes is controlled within 15-20 mm, the reduction of the 3rd and 8th passes is controlled within 10-15 mm, the reduction of the 4th and 5th passes is controlled within 25-30 mm, the reduction of the 9th pass is 0 mm, the reduction of the 10th to 12th passes is controlled within 5-10 mm, the reduction of the 13th to 15th passes is controlled within 1-5 mm, and the reduction of the 16th pass is 0 mm; (7) The rolling force of the 1st to 8th passes is controlled within the range of 20-50 MN, the rolling force of the 9th pass is 0 MN, the rolling force of the 10th to 15th passes is controlled within the range of 30-70 MN, and the rolling force of the 16th pass is 0 MN; (8) The torque of the 1st to 8th passes is controlled within the range of 500 to 3500 kNm, the torque of the 9th pass is 0 kNm, the torque of the 10th to 15th passes is controlled within the range of 500 to 3500 kNm, and the torque of the 16th pass is 0 kNm; (9) The roller shifting position of the 1st to 9th passes is 0, the roller shifting position of the 10th to 12th passes is controlled at 100-150, the roller shifting position of the 13th to 14th passes is controlled at 80-130, the roller shifting position of the 15th pass is controlled at 50-100, and the roller shifting position of the 16th pass is 0; (10) The biting speed of the 1st to 8th passes is controlled at 0.5-1.5 m / s, the biting speed of the 9th pass is 0 m / s, the biting speed of the 10th to 15th passes is controlled at 1.5-3 m / s, and the biting speed of the 16th pass is 0 m / s; (11) The maximum rolling speed of the 1st to 8th passes is controlled at 1 to 3.5 m / s, the maximum rolling speed of the 9th pass is 0 m / s, the maximum rolling speed of the 10th to 15th passes is controlled at 4 to 6.5 m / s, and the maximum rolling speed of the 16th pass is 0 m / s; S4, thick plate water cooling: ACC process is used for cooling, the start cooling temperature is controlled at 750-810℃, the final cooling temperature is controlled at 570-630℃, and the cooling rate is controlled at 10-14℃ / s; S5. Hot straightening of thick plates: The steel plates are straightened in one pass, the straightening speed is controlled at 2.0-2.2 m / s, and the straightening force is controlled at 300-350 t; S6, Thick Plate Shearing: Shear the head, tail and edge of the steel plate according to the production size requirements; S7, Thick Plate Printing: Print the steel plate information on the surface and side of the steel plate; S8. Thick plates are put into storage after being in good shape: the appearance, size and shape of the steel plates are confirmed and they are put into storage after meeting the production requirements.

[0009] Beneficial effects of the present invention: 1. The present invention rationally designs and adjusts the chemical composition of the steel plate to improve the strength of the high-strength reduced-weight wind power steel plate. The yield strength of the steel plate can be increased to above 420 MPa, making the performance of the steel plate tend to be stable.

[0010] 2. The present invention optimizes and adjusts the production process parameters, ensures the stability of steel plate performance, improves the production quality of high-strength reduced-weight wind power steel, and increases the production quality qualification rate of high-strength reduced-weight wind power steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a table diagram of steel plate rolling process parameters provided according to an embodiment of the present invention. DETAILED DESCRIPTION

[0012] The technical solutions in the embodiments of the present invention will be described below with reference to the accompanying drawings.

[0013] The present invention provides a high-strength reduced-weight wind power steel and a manufacturing method thereof. The yield strength of the high-strength reduced-weight wind power steel can be increased to above 420 MPa, so that the performance of the steel plate tends to be stable and the production quality of the high-strength reduced-weight wind power steel is improved.

[0014] To achieve the above effects, the technical solutions adopted are: The manufacturing method of the high-strength reduced wind power steel with a yield strength ≥420MPa described in the present invention adopts the following component ratio, and the specific chemical composition is calculated by mass percentage: C: 0.165%, Si: 0.255%, Mn: 1.455%, Nb: 0.020%, Ti: 0.001%, Al: 0.020%, Ceq: 0.41%; the thickness of the high-strength reduced wind power steel is 28.3mm; the steel grade of the high-strength reduced wind power steel is Q420ND.

[0015] A method for manufacturing high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa, comprising the following steps: S1. Secondary cutting of thick plates: The slabs are heated by hot delivery and hot loading process, and the hot delivered slabs are cut into short slabs according to the design instructions, and the burrs are removed online to ensure that the size and surface quality of the slabs are normal and meet the requirements of furnace loading; S2. Thick plate heating: the furnace temperature is controlled at 1130-1170℃, and the furnace time is controlled at 200-220min; S3. Thick plate rolling: The steel plate is rolled using a low temperature controlled rolling process, and the key rolling process parameters are controlled as follows: the starting rolling temperature is controlled at 770-800°C; the final rolling temperature is controlled at 730-760°C; the rolling point thickness is controlled according to 1.8T, where T represents the rolling thickness of the steel plate; the rough rolling mill adopts 9 passes, the finishing mill adopts 7 passes, the rough rolling dephosphorization is 2 passes, and the finishing rolling dephosphorization is 1 pass; the reduction rate, reduction amount, rolling force, torque, roll shifting position, steel biting speed, and maximum rolling speed of each rolling pass are as follows: Figure 1 As shown; S4, thick plate water cooling: ACC process is used for cooling, the starting cooling temperature is 770℃, the final cooling temperature is 590℃, and the cooling rate is 12℃ / s; S5, thick plate hot straightening: the steel plate is straightened in one pass, the straightening speed is 2.1m / s, and the straightening force is 320t; S6, Thick Plate Shearing: Shear the head, tail and edge of the steel plate according to the production size requirements; S7, Thick Plate Printing: Print the steel plate information on the surface and side of the steel plate; S8. Thick plates are put into storage after being in good shape: the appearance, size and shape of the steel plates are confirmed and they are put into storage after meeting the production requirements.

[0016] Implementation results: The formed high-strength reduced-weight wind power steel has good quality after inspection, and the steel plate inspection performance is qualified, meeting various technical requirements.

Claims

1. A high-strength reduced-weight wind power steel with a yield strength of ≥420MPa, characterized in that: Its chemical composition by mass percentage is: C: 0.15-0.175%, Si: 0.2-0.3%, Mn: 1.45-1.55%, Nb: 0.015-0.025%, Ti: 0-0.001%, Al: 0.015-0.035%, Ceq: 0.40-0.45%.

2. The high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa according to claim 1, characterized in that: The thickness of the high-strength reduced-weight wind power steel ranges from 20 to 55 mm.

3. The high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa according to claim 1, characterized in that: The grade of the high-strength reduced-weight wind power steel is Q420ND.

4. A method for manufacturing high-strength reduced-weight wind power steel with a yield strength of ≥420 MPa according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Secondary cutting of thick plates: The slabs are heated by hot delivery and hot loading process, and the hot delivered slabs are cut into short slabs according to the design instructions, and the burrs are removed online to ensure that the size and surface quality of the slabs are normal and meet the requirements of furnace loading; S2. Thick plate heating: The furnace temperature is controlled at 1130-1170℃. The time in the furnace is divided into cold charging and hot charging for control. The cold charging time in the furnace is controlled at ≥210min, and the hot charging time in the furnace is controlled at ≥180min. S3. Thick plate rolling: The steel plate is rolled using a low temperature controlled rolling process, and the key rolling process parameters are controlled as follows: (1) The rolling temperature is controlled at 770-800℃; (2) The final rolling temperature is controlled at 730-760°C; (3) The rolling point thickness is controlled according to 1.8T, where T represents the rolled thickness of the steel plate; (4) The rough rolling mill adopts 9 passes, the finishing mill adopts 7 passes, the rough rolling dephosphorization is 2 passes, and the finishing rolling dephosphorization is 1 pass; (5) The reduction rate of the 1st to 3rd passes is controlled at 5-10%, the reduction rate of the 4th to 8th passes is controlled at 15-20%, the reduction rate of the 9th pass is 0%, the reduction rate of the 10th pass is controlled at 15-20%, the reduction rate of the 11th to 14th passes is controlled at 10-15%, the reduction rate of the 15th pass is controlled at 5-10%, and the reduction rate of the 16th pass is 0%; (6) The reduction of the 1st and 6th passes is controlled within 20-25 mm, the reduction of the 2nd and 7th passes is controlled within 15-20 mm, the reduction of the 3rd and 8th passes is controlled within 10-15 mm, the reduction of the 4th and 5th passes is controlled within 25-30 mm, the reduction of the 9th pass is 0 mm, the reduction of the 10th to 12th passes is controlled within 5-10 mm, the reduction of the 13th to 15th passes is controlled within 1-5 mm, and the reduction of the 16th pass is 0 mm; (7) The rolling force of the 1st to 8th passes is controlled within the range of 20-50 MN, the rolling force of the 9th pass is 0 MN, the rolling force of the 10th to 15th passes is controlled within the range of 30-70 MN, and the rolling force of the 16th pass is 0 MN; (8) The torque of the 1st to 8th passes is controlled within the range of 500 to 3500 kNm, the torque of the 9th pass is 0 kNm, the torque of the 10th to 15th passes is controlled within the range of 500 to 3500 kNm, and the torque of the 16th pass is 0 kNm; (9) The roller shifting position of the 1st to 9th passes is 0, the roller shifting position of the 10th to 12th passes is controlled at 100-150, the roller shifting position of the 13th to 14th passes is controlled at 80-130, the roller shifting position of the 15th pass is controlled at 50-100, and the roller shifting position of the 16th pass is 0; (10) The biting speed of the 1st to 8th passes is controlled at 0.5-1.5 m / s, the biting speed of the 9th pass is 0 m / s, the biting speed of the 10th to 15th passes is controlled at 1.5-3 m / s, and the biting speed of the 16th pass is 0 m / s; (11) The maximum rolling speed of the 1st to 8th passes is controlled at 1 to 3.5 m / s, the maximum rolling speed of the 9th pass is 0 m / s, the maximum rolling speed of the 10th to 15th passes is controlled at 4 to 6.5 m / s, and the maximum rolling speed of the 16th pass is 0 m / s; S4, thick plate water cooling: ACC process is used for cooling, the start cooling temperature is controlled at 750-810℃, the final cooling temperature is controlled at 570-630℃, and the cooling rate is controlled at 10-14℃ / s; S5. Hot straightening of thick plates: The steel plates are straightened in one pass, the straightening speed is controlled at 2.0-2.2 m / s, and the straightening force is controlled at 300-350 t; S6, Thick Plate Shearing: Shear the head, tail and edge of the steel plate according to the production size requirements; S7, Thick Plate Printing: Print the steel plate information on the surface and side of the steel plate; S8. Thick plates are put into storage after being in good shape: the appearance, size and shape of the steel plates are confirmed and they are put into storage after meeting the production requirements.

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