A method for eliminating edge cracks of high carbon steel in an esp production line

Abstract

The present application relates to the technical field of ESP production line high-carbon steel, and particularly to a method for eliminating edge cracks of high-carbon steel in an ESP production line, which comprises the following steps: electric furnace steelmaking, continuous casting, edge heater, rough rolling, electromagnetic induction heating, descaling, finish rolling, layer cooling, flying shear and coiler; in the electric furnace steelmaking, the raw materials are controlled according to mass percentage, including 0.30-0.70% of C, 0.15-0.40% of Si, 0.4-1.20% of Mn, ≤0.003% of S, ≤0.035% of P, ≤0.25% of Cu, ≤0.008% of N, and the rest is iron element; in the continuous casting, the thickness of the casting blank is 90-110 mm, the pulling speed is 4.0-4.3 m / min, the thickness of the intermediate blank is 10-20 mm, and the wedge-shaped control of the intermediate blank is within 30 μm; in the rough rolling, the edge heating power is set to 300 KW, and the edge depth coverage is 50-97 mm; the present application avoids the edge crack defects on both sides of the produced steel coil, provides a prerequisite for the development of thin slab continuous casting and rolling production line steel, improves the product quality of medium and high-carbon steel and micro-alloy high-carbon steel, and increases the benefit of steel and market competitiveness of the enterprise.

Description

Technical Field

[0001] This invention relates to the field of high carbon steel technology for ESP production lines, and in particular to a method for eliminating edge cracks in high carbon steel for ESP production lines. Background Technology

[0002] The ESP headless rolling production line is a continuous rolling line. The cast billet undergoes no heating or holding process. Furthermore, it uses scrap steel from electric arc furnace steelmaking as raw material, resulting in high levels of harmful elements such as phosphorus, sulfur, copper, and nitrogen in the molten steel, significantly impacting billet quality. After exiting the fan-shaped section, the billet directly undergoes roughing, induction furnace, descaling, finishing, laminar flow cooling, high-speed flying shear, and coiling processes. This is advantageous for the mass production of thin-gauge low-carbon mild steel. The produced thin-gauge hot-rolled products can replace some cold-rolled products, achieving "hot-rolling instead of cold-rolling." It offers significant energy-saving and emission-reduction effects, aligning with the steel industry's development direction of simplicity, efficiency, and green ecology, which is the current trend in the steel industry.

[0003] Because the ESP headless rolling production line uses thin slab continuous casting and rolling technology, with a rigid link between the casting machine and the rolling mill, it has higher technical requirements for slab quality and temperature uniformity. This imposes certain limitations on the rolling of medium and high carbon steel and low alloy high-strength steel, especially for high carbon steel production. Since the slab exiting the fan-shaped section does not undergo heating and heat preservation processes, the temperature difference across the slab cross-section is large, and the slab shell temperature is low. In particular, the temperature drop at the edge of the slab is significant after secondary cooling with cold water. High carbon steel has a high carbon content, and the temperature drop has a significant impact on the thermoplasticity of the strip edge. The roughing compression ratio is large, and edge cracks occur during low-temperature rolling. These defects cannot be eliminated through subsequent production processes and tend to increase, thus limiting the mass production of high carbon steel. Downstream customers are prone to strip breakage during slitting and rolling, and re-threading increases production costs and reduces operational efficiency. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for eliminating edge cracks in high-carbon steel used in ESP production lines.

[0005] This invention is achieved using the following technical solution: a method for eliminating edge cracks in high-carbon steel produced in ESP production lines, the method comprising the following steps: 1. Electric furnace steelmaking → continuous casting → edge heater → rough rolling → electromagnetic induction heating → descaling → finish rolling → laminar cooling → flying shear → coiler;

[0006] Electric arc furnace steelmaking: Raw materials are controlled by mass percentage, including: 0.30% to 0.70% C, 0.15% to 0.40% Si, 0.4% to 1.20% Mn, ≤0.003% S, ≤0.035% P, ≤0.25% Cu, ≤0.008% N, with the remainder being iron.

[0007] Continuous casting: billet thickness 90-110mm, casting speed 4.0-4.3m / min, intermediate billet thickness 10-20mm, intermediate billet wedge shape controlled within 30μm;

[0008] Edge heater: Edge heating power set at 300KW, covering edge depth 50-97mm;

[0009] Roughing: The maximum rolling force of the three roughing mills is 3500T;

[0010] Electromagnetic induction heating: The outlet temperature of electromagnetic induction heating is set to 1150-1180℃;

[0011] Descaling: Descaling chamber pressure set to 250 bar - 350 bar;

[0012] Finishing mill: The finishing mill exit temperature is controlled at 810-840℃. When the finishing mill final rolling temperature is lower than 815℃, adjust the dephosphorization pressure and the amount of anti-oxidation and spalling water at the F1 inlet, and adjust them with the finishing mill exit temperature as the target.

[0013] Laminar cooling: There are a total of 34 sets of upper and lower manifolds, with sets 1-12 being the coarse adjustment section, sets 13-30 being the fine adjustment section, and sets 31-34 being the precision adjustment section;

[0014] Flying shear: There are two sets of pinch rollers, one at the front and one at the back, to ensure high-speed flying shear micro-tension shearing and winding;

[0015] Winding machines: 3 underground winding machines to ensure continuous production.

[0016] Preferably, the billet thickness in continuous casting is 90-110 mm, and the casting speed is 4.0-4.3 m / min.

[0017] Preferably, the electromagnetic induction heating outlet temperature is set to 1150-1180℃, the edge offset value is adjusted within the range of -10mm to 10mm, and the upper and lower electromagnetic mold width offset value is 15mm.

[0018] Preferably, the dephosphorization pressure is adjusted to 250 bar-350 bar during finishing rolling.

[0019] Preferably, the winding process uses air cooling by closing the upper and lower manifolds and side water valves, with a winding temperature of 630-690℃.

[0020] The beneficial effects of this invention are as follows: This invention provides a method for eliminating edge cracks in high-carbon steel produced on ESP production lines, which avoids edge crack defects on both sides of the produced steel coils. This provides a prerequisite for the development of specialty steels in thin slab continuous casting and rolling production lines, improves the quality of medium and high carbon steels and micro-alloyed high-carbon steel products, and increases the efficiency and market competitiveness of enterprises in specialty steel production. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the temperature difference in the cross-section of the billet at the continuous casting outlet;

[0022] Figure 2 This is a schematic diagram illustrating the effect of temperature on the plasticity of carbon steel.

[0023] Figure 3 This is a schematic diagram comparing the temperatures before and after the side heaters were put into use;

[0024] Figure 4 This is a schematic diagram of the steel coil with the edge heater in operation;

[0025] Figure 5 This is a schematic diagram comparing the side heaters in operation and not in operation. Detailed Implementation

[0026] The invention will now be further described with reference to the accompanying drawings.

[0027] This invention provides an embodiment: a method for eliminating edge cracks in high-carbon steel in an ESP production line, the method comprising the following steps: electric arc furnace steelmaking → continuous casting → edge heater → rough rolling → electromagnetic induction heating → descaling → finish rolling → laminar cooling → flying shear → coiler;

[0028] Electric arc furnace steelmaking: Raw materials are controlled by mass percentage, including: 0.30% to 0.70% C, 0.15% to 0.40% Si, 0.4% to 1.20% Mn, ≤0.003% S, ≤0.035% P, ≤0.25% Cu, ≤0.008% N, with the remainder being iron.

[0029] Continuous casting: billet thickness 90-110mm, casting speed 4.0-4.3m / min, intermediate billet thickness 10-20mm, intermediate billet wedge shape controlled within 30μm;

[0030] Edge heater: Edge heating power set at 300KW, covering edge depth 50-97mm;

[0031] Roughing: The maximum rolling force of the three roughing mills is 3500T;

[0032] Electromagnetic induction heating: The outlet temperature of electromagnetic induction heating is set to 1150-1180℃;

[0033] Descaling: Descaling chamber pressure set to 250 bar - 350 bar;

[0034] Finishing mill: The finishing mill exit temperature is controlled at 810-840℃. When the finishing mill final rolling temperature is lower than 815℃, adjust the dephosphorization pressure and the amount of anti-oxidation and spalling water at the F1 inlet, and adjust them with the finishing mill exit temperature as the target.

[0035] Laminar cooling: There are a total of 34 sets of upper and lower manifolds, with sets 1-12 being the coarse adjustment section, sets 13-30 being the fine adjustment section, and sets 31-34 being the precision adjustment section;

[0036] Flying shear: There are two sets of pinch rollers, one at the front and one at the back, to ensure high-speed flying shear micro-tension shearing and winding;

[0037] Winding machines: 3 underground winding machines to ensure continuous production.

[0038] The billet thickness in continuous casting is 90-110 mm, and the casting speed is 4.0-4.3 m / min.

[0039] The power of the edge heater is set to 300KW, covering an edge depth of 50-97mm.

[0040] The electromagnetic induction heating outlet temperature is set to 1150-1180℃, the edge offset value is adjustable within a range of -10mm to -10mm, and the upper and lower electromagnetic mold width offset value is 15mm.

[0041] Adjust the dephosphorization pressure to 250 bar-350 bar during finishing rolling.

[0042] The winding process uses air cooling by closing the upper and lower manifolds and side water valves, with a winding temperature of 630-690℃.

[0043] Steelmaking process: Controlled by mass percentage, including the following steel composition: C 0.30%-0.70%, Si 0.15%-0.40%, Mn 0.40%-1.20%, S ≤0.003%, P ≤0.035%, Cu ≤0.25%, N ≤0.008%, with the remainder being Fe. This ensures qualified molten steel for steelmaking. A C content of 0.30%-0.70% is crucial for solid solution strengthening, increasing material strength, and reducing elongation. A well-designed composition helps control the pace and cost of steelmaking. Excessive C content leads to rapid billet temperature drop during casting due to the strong cooling effect of the secondary cooling water. As the billet temperature decreases, C precipitation in austenite decreases, and carbides accumulate at austenite grain boundaries, reducing the plasticity of the matrix. Rapid cooling at the billet edges also leads to cracks during bending and straightening. The silicon (Si) content is 0.15%-0.40%. Si mainly plays a role in deoxidation and solid solution strengthening of molten steel. However, excessive Si will reduce the plasticity and toughness of the steel, and excessive silicon can easily form banded structures in the steel, making the transverse properties lower than the longitudinal properties. The manganese (Mn) content is 0.40%-1.20%. Manganese can act as a deoxidizer, improving the deoxidation effect of silicon and aluminum. Manganese combines with sulfur to form MnS, reducing the harmful effects of sulfur in steel. However, excessive manganese can coarsen the grains, reduce the total area of ​​grain boundaries, weaken the intergranular bonds, and reduce the plasticity of the steel.

[0044] Please see Figure 1 , Figure 2 Continuous casting process: Billet thickness 90-110mm, casting speed controlled within the range of 4.0-4.3m / min. Controlling the casting speed to 4.0-4.3m / min is crucial because high-carbon steel has a high C content, resulting in high secondary cooling intensity during casting. The resulting billet skin in the crystallizer is thin, with low thermoplasticity, making it prone to cracking. Cracks extend towards the core, leading to leakage accidents. At the exit of the fan-shaped section, the billet surface temperature is low with a large temperature difference, while the billet core temperature is high. The billet surface temperature undergoes a warming process, with the warming process decreasing from the middle to the edges of the billet cross-section. The edge temperature drops significantly and is low, so the warming effect is minimal. The C content in the Fe matrix precipitates as temperature decreases, mostly as carbides at grain boundaries, reducing matrix bonding. When the billet temperature is 950-1000℃, the edge temperature is 850-900℃.

[0045] Please continue reading. Figures 3 to 5 In the roughing rolling process: the edge heater power is set to 200-400KW, with a coverage depth of 50-97mm. The intermediate billet thickness is 12-20mm, and the wedge shape of the intermediate billet is controlled within 30um. The edge heater coverage depth of 50-97mm is to increase the edge temperature by 100-150℃, compensate for the heat loss at the edge of the cast billet, increase the edge plasticity during the roughing rolling stage, and prevent edge cracking. This provides high-quality feedstock for downstream rolling. After the edge heater function was put into use, the strip quality was significantly improved.

[0046] Electromagnetic induction heating and descaling processes: The electromagnetic induction heating furnace and descaling process consist of 10 modules, each with a maximum set power of 35KW. The furnace outlet temperature is set at 1150-1180℃, and the edge temperature is individually adjustable, with the edge temperature 30-50℃ higher than the set outlet temperature. The descaling pressure is selected between 250bar and 350bar. Increasing the set temperature and edge temperature of the electromagnetic furnace, while lowering the descaling pressure, is intended to better increase the intermediate slab temperature, improve strip plasticity, reduce mill load, and decrease the tendency for edge cracking.

[0047] Finishing rolling process: In the finishing rolling process, the finishing mill exit temperature is controlled between 810-840℃. When the finishing rolling temperature is lower than 815℃, the descaling pressure, the amount of anti-oxidation and spalling water at the F1 inlet, and the electromagnetic induction furnace temperature are adjusted to target the finishing mill exit temperature. A low finishing rolling temperature results in high strip deformation resistance, excessive mill load, and increased mill vibration, affecting the strip surface quality and reducing equipment precision.

[0048] In the continuous casting process, the billet thickness is 90-110mm, and the casting speed is controlled within the range of 4.0-4.3m / min. The reason for controlling the continuous casting speed at 4.0-4.3m / min is that the carbon content in high-carbon steel is high, the cooling intensity of the secondary cooling water during casting is high, the billet skin formed in the crystallizer is thin, the skin has low thermoplasticity, and it is prone to cracking; the cracks extend to the core, resulting in steel leakage accidents.

[0049] In the roughing rolling process, the edge heater power is set at 200-400KW, covering the edge depth of 50-97mm. This is to increase the edge temperature by 100-150℃, compensate for heat loss at the edge of the cast billet, increase edge plasticity during the roughing rolling stage, and prevent edge cracking. This provides high-quality feedstock for downstream rolling, and the strip quality has been significantly improved after the edge heater function was put into operation.

[0050] In the finishing rolling process, the finishing mill exit temperature is controlled at 810-840℃. When the finishing mill final rolling temperature is lower than 815℃, it is to reduce the deformation resistance of the strip steel, reduce the mill load, avoid mill vibration, and avoid affecting the surface quality of the strip steel.

[0051] The winding process uses air cooling by closing the upper and lower manifolds and the side-blowing solenoid valves for cooling, with a winding temperature of 630-690℃.

[0052] The induction heating outlet temperature is set to 1150℃-1180℃, the offset value of the heating position on the side of the heating module is -10-15mm, and the opening of the upper and lower electromagnetic modules is 15mm.

[0053] Without heat treatment, the billet cross-section experiences large temperature differences and low temperatures, especially at the edges and corners. The roughing rolling speed is affected by the continuous casting speed, resulting in slow rolling, low deformation rate, and low strip thermoplasticity. The core temperature of the billet is high, while the surface temperature undergoes a warming process. The warming process decreases from the middle to the edges of the billet cross-section, with a large temperature drop at the edges and no warming. The carbon content in the Fe matrix precipitates as temperature decreases, mainly as carbides at grain boundaries, reducing matrix bonding. When the billet enters the roughing rolling stage, its temperature is precisely in the third hot brittle zone. Using edge heaters increases the edge temperature of the billet, reducing the influence of the hot brittle zone and decreasing edge cracks in the intermediate plates during roughing, thus eliminating edge cracking problems in high-carbon steel on the ESP production line and achieving stable rolling of high-carbon steel grades. Example 1:

[0054] In the embodiment, the process flow for producing 2.5mm high-carbon steel 60Mn through thin slab continuous casting and rolling is as follows: scrap steel → electric furnace → LF refining → continuous casting → rough rolling → electromagnetic induction heating → descaling → finish rolling → coiling → finished product.

[0055] In this embodiment, raw materials such as scrap steel are sequentially smelted in an electric arc furnace and refined in an LF furnace. The composition of the molten steel is controlled as follows: C: 0.61%, Si: 0.23%, Mn: 0.80%, S: ≤0.003%, P: ≤0.012%, Cu: ≤0.25%, Al: 0.015%, with the balance being Fe and impurities.

[0056] 1. Hot-rolled steel coils with a rolling stroke of 2.5mm are produced by continuously casting, roughing, finishing, coiling, and slow cooling processes of LF-refined molten steel through a continuous casting and rolling production line.

[0057] 2. Continuous casting speed: 4.2 m / min; billet thickness: 105 mm;

[0058] 3. The 105mm billet is rolled in three passes of rough rolling. The thickness of the intermediate billet is 18mm. The power of the edge heater at the entrance of the rough rolling mill is set to 300KW, the edge coverage depth is 85mm, and the exit temperature of the rough rolling mill is 930-960℃.

[0059] 4. The intermediate billet after three passes of rough rolling is heated by an electromagnetic induction furnace. The induction heating outlet temperature is set to 1170℃, the OFFSET value of the heating position at the edge of the heating module is -10 to 15mm, and the opening of the upper and lower electromagnetic modules is 15mm.

[0060] 5. The intermediate billet in the induction heating furnace is then descaled by water pressure of 300 bar, with the upper and lower manifolds for descaling 36 mm away from the surface of the strip.

[0061] 6. The dephosphorized intermediate billet is rolled into 2.5mm thick hot-rolled strip steel through 5 passes of finishing rolling, with 5% F1 inlet anti-oxidation and spalling water, and a final rolling temperature of 815-840℃;

[0062] 7. The strip steel is cooled by laminar flow cooling using air cooling method, with a laminar cooling outlet temperature of 660-690℃. It then enters the coiler through a high-speed flying shear to coil the strip steel into a steel coil.

[0063] 8. The steel coils formed by the coiler are transported from the transportation area to the finished product warehouse, which is under closed management to allow the steel strip to cool slowly.

[0064] Results: No edge cracks were found on both sides of the steel coil, and the finished product quality was good.

[0065] Comparative Example 1

[0066] In the embodiment, the process flow for producing 2.5mm high-carbon steel 60Mn through thin slab continuous casting and rolling is as follows: scrap steel → electric furnace → LF refining → continuous casting → rough rolling → electromagnetic induction heating → descaling → finish rolling → coiling → finished product.

[0067] In this embodiment, raw materials such as scrap steel are sequentially smelted in an electric furnace and refined in an LF furnace. The composition of the molten steel is controlled as follows: C: 0.60%, Si: 0.23%, Mn: 0.80%, S: ≤0.003%, P: ≤0.012%, Cu: ≤0.25%, Al: 0.015%, with the balance being Fe and impurities.

[0068] 1. Hot-rolled steel coils with a rolling stroke of 2.5mm are produced by continuously casting, roughing, finishing, coiling, and slow cooling processes of LF-refined molten steel through a continuous casting and rolling production line.

[0069] 2. Continuous casting speed: 4.2 m / min; billet thickness: 105 mm;

[0070] 3. The 105mm billet is rolled in three passes of rough rolling. The thickness of the intermediate billet is 18mm. The edge heater function at the entrance of the rough rolling mill is not in use. The exit temperature of the rough rolling mill is 930-960℃.

[0071] 4. The intermediate billet after three passes of rough rolling is heated by an electromagnetic induction furnace. The induction heating outlet temperature is set to 1170℃, the OFFSET value of the heating position at the edge of the heating module is -10 to 15mm, and the opening of the upper and lower electromagnetic modules is 15mm.

[0072] 5. The intermediate billet in the induction heating furnace is then descaled by water pressure of 300 bar, with the upper and lower manifolds for descaling 36 mm away from the surface of the strip.

[0073] 6. The dephosphorized intermediate billet is rolled into 2.5mm thick hot-rolled strip steel through 5 passes of finishing rolling, with 5% F1 inlet anti-oxidation and spalling water, and a final rolling temperature of 815-840℃;

[0074] 7. The strip steel is cooled by laminar flow cooling using air cooling method, with a laminar cooling outlet temperature of 660-690℃. It then enters the coiler through a high-speed flying shear and is coiled into a steel coil.

[0075] 8. The steel coils formed by the coiler are transported from the transportation area to the finished product warehouse, which is under closed management to allow the steel strip to cool slowly.

[0076] Results: Edge cracks appeared on both sides of the all-steel coil, there were many burrs on both sides, and the edges were uneven. Example 2:

[0077] In the embodiment, the process flow for producing 3.0mm high carbon steel 50Mn through thin slab continuous casting and rolling is as follows: scrap steel → electric furnace → LF refining → continuous casting → rough rolling → electromagnetic induction heating → descaling → finish rolling → coiling → finished product.

[0078] In this embodiment, raw materials such as scrap steel are sequentially smelted in an electric arc furnace and refined in an LF furnace. The composition of the molten steel is controlled as follows: C: 0.48%, Si: 0.25%, Mn: 0.78%, S: ≤0.002%, P: ≤0.006%, Cu: ≤0.20%, Al: 0.02%, with the balance being Fe and impurities.

[0079] 1. Hot-rolled steel coils with a rolling stroke of 3.0mm are produced by continuously casting, roughing, finishing, coiling, and slow cooling processes of LF-refined molten steel through a continuous casting and rolling production line.

[0080] 2. Continuous casting speed: 4.15 m / min; billet thickness: 105 mm;

[0081] 3. The 105mm billet is rolled in three passes of rough rolling. The thickness of the intermediate billet is 16mm. The power of the edge heater at the entrance of the rough rolling mill is set to 300KW, the edge coverage depth is 85mm, and the exit temperature of the rough rolling mill is 930-960℃.

[0082] 4. The intermediate billet after three passes of rough rolling is heated by an electromagnetic induction furnace. The induction heating outlet temperature is set to 1180℃, the OFFSET value of the heating position at the edge of the heating module is between -10 and 15mm, and the opening of the upper and lower electromagnetic modules is 15mm.

[0083] 5. The intermediate billet in the induction heating furnace is then descaled by water pressure of 250 bar, with the upper and lower manifolds for descaling 36 mm away from the surface of the strip.

[0084] 6. The dephosphorized intermediate billet is rolled into 3.0mm thick hot-rolled strip steel through 5 passes of finishing rolling, with 5% anti-oxidation and spalling water at the F1 inlet and a final rolling temperature of 815-830℃;

[0085] 7. The strip steel is cooled by laminar flow cooling using air cooling method, with a laminar cooling outlet temperature of 650-670℃. It then enters the coiler through a high-speed flying shear and is coiled into a steel coil.

[0086] 8. The steel coils formed by the coiler are transported from the transportation area to the finished product warehouse, which is under closed management to allow the steel strip to cool slowly.

[0087] Results: No notches or cracks appeared on the sides of the hot-rolled steel coils, and the finished product quality was good.

[0088] Comparative Example 2

[0089] In the embodiment, the process flow for producing 3.0mm high carbon steel 50Mn through thin slab continuous casting and rolling is as follows: scrap steel → electric furnace → LF refining → continuous casting → rough rolling → electromagnetic induction heating → descaling → finish rolling → coiling → finished product.

[0090] In this embodiment, raw materials such as scrap steel are sequentially smelted in an electric arc furnace and refined in an LF furnace. The composition of the molten steel is controlled as follows: C: 0.48%, Si: 0.25%, Mn: 0.75%, S: ≤0.002%, P: ≤0.006%, Cu: ≤0.20%, Al: 0.02%, with the balance being Fe and impurities.

[0091] 1. Hot-rolled steel coils with a rolling stroke of 3.0mm are produced from LF-refined molten steel through continuous casting, roughing, finishing, coiling, and slow cooling processes on the continuous casting and rolling production line.

[0092] 2. Continuous casting speed: 4.15 m / min; billet thickness: 105 mm;

[0093] 3. The 105mm billet is rolled in three passes of rough rolling. The thickness of the intermediate billet is 16mm. The edge heater function at the entrance of the rough rolling mill is not in use. The exit temperature of the rough rolling mill is 930-960℃.

[0094] 4. The intermediate billet after three passes of rough rolling is heated by an electromagnetic induction furnace. The induction heating outlet temperature is set to 1180℃, the OFFSET value of the heating position at the edge of the heating module is between -10 and 15mm, and the opening of the upper and lower electromagnetic modules is 15mm.

[0095] 5. The intermediate billet in the induction heating furnace is then descaled by water pressure of 250 bar, with the upper and lower manifolds for descaling 36 mm away from the surface of the strip.

[0096] 6. The dephosphorized intermediate billet is rolled into 3.0mm thick hot-rolled strip steel through 5 passes of finishing rolling, with 5% anti-oxidation and spalling water at the F1 inlet and a final rolling temperature of 815-830℃;

[0097] 7. The strip steel is cooled by laminar flow cooling using air cooling method, with a laminar cooling outlet temperature of 650-670℃. It then enters the coiler through a high-speed flying shear and is coiled into a steel coil.

Claims

1. A method of eliminating edge cracking in high carbon steel in an ESP production line, characterized by: The method comprises the following steps: electric furnace steelmaking → continuous casting → edge heater → rough rolling → electromagnetic induction heating → descaling → finish rolling → layer cooling → flying shear → coiler; The electric furnace steelmaking controls the raw materials in mass percentage, wherein the raw materials include: 0.30%-0.70% of C, 0.15%-0.40% of Si, 0.4%-1.20% of Mn, ≤0.003% of S, ≤0.035% of P, ≤0.25% of Cu, ≤0.008% of N, and the rest is iron element; The continuous casting has a billet thickness of 90-110 mm and a drawing speed of 4.0-4.3 m / min, and an intermediate billet thickness of 10-20 mm and a wedge-shaped control within 30 μm; The edge heater has an edge heating power set to 300 kW and a covering edge depth of 50-97 mm; The rough rolling has a maximum rolling force of 3500 T; The electromagnetic induction heating has an electromagnetic induction heating outlet temperature set to 1150-1180 ℃, and an edge OFFSET value of-10 mm-10 mm and an upper and lower electromagnetic module width opening OFFSET value of 15 mm; The descaling has a descaling box pressure set to 250 bar-350 bar; The finish rolling has a finish rolling outlet temperature controlled at 810-840 ℃, and when the finish rolling final rolling temperature is lower than 815 ℃, the descaling pressure and F1 inlet anti-oxidation peeling water amount are adjusted to adjust the finish rolling outlet temperature as the target; the descaling pressure is adjusted to 250 bar-350 bar in the finish rolling; The layer cooling has a total of 34 upper and lower headers, 1-12 groups of which are coarse adjustment sections, 13-30 groups of which are fine adjustment sections, and 31-34 groups of which are fine adjustment sections; The flying shear has one group of front and rear pinch rollers to ensure high-speed flying shear micro-tension shearing and dividing; The coiler has three underground coilers to ensure the continuity of production; when coiling, the layer cooling closes the upper and lower headers and the side blowing water valve, and adopts air cooling mode to cool, and the coiling temperature is 630-690 ℃.

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