Flat steel for gear racks in engineering machinery and its production method

Abstract

This invention belongs to the field of metallurgical technology, specifically relating to a flat steel for engineering machinery racks and its production method. Higher levels of Mn and Cr are used to improve material strength, while appropriate amounts of Al, N, Nb, V, and Ti are added to refine the grain size, and lower P and S content is used to improve toughness. The smelting process emphasizes H removal control, and the continuous casting process reduces low-magnification defects in the billet through reasonable optimization of superheat, casting speed, and end-stage electromagnetic stirring parameters. The rolling process uses a high-temperature diffusion process to achieve uniform microstructure, and a high-reduction + controlled rolling and cooling process improves the material's mechanical properties. The flat steel for engineering machinery racks is suitable for producing rectangular rack steel with a thickness of 30-40 mm and a width of 60-70 mm for direct turning. It possesses high strength, high toughness, and high wear resistance. The hot-rolled mechanical properties show a tensile strength of over 700 MPa, excellent wear resistance, and a wear loss of ≤2.0 g.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, specifically relating to a flat steel for engineering machinery racks and its production method. Background Technology

[0002] With the development of the construction machinery industry, the demand for rack steel is increasing, characterized by its large thickness, high strength, and high toughness. When flat steel is processed into racks, the stress at the meshing joint is the greatest, often requiring extremely high strength and toughness. This necessitates that the flat steel's microstructure possess high-strength, quenched martensite, which requires machining followed by heat treatment and then further machining. For the offshore and onshore wind power industries, even higher strength and wear resistance are required. However, the construction machinery industry does not have the same wear resistance requirements as offshore and onshore wind power rack steel. For cost considerations, as long as the flat steel's microstructure reaches sorbite and its strength is above 700 MPa, its requirements can be met, offering the highest economic efficiency and ensuring safety performance.

[0003] Ordinary rack steel production basically adopts the TMCP process for sheet metal, which involves flame cutting into strips and then machining. This process is time-consuming, labor-intensive, and costly. Document CN109554632A discloses a 690 MPa grade extra-thick rack steel and its manufacturing process, comprising the following chemical composition by mass percentage: C 0.10%–0.16%, Si 0.15%–0.35%, Mn 0.95%–1.35%, P≤0.015%, S≤0.010%, C 0.50%–0.60%, Ni 2.30%–2.60%, Mo 0.45%–0.55%, V 0.03%–0.05%, Al 0.07%–0.09%, Ti≤0.010%, B 0.0010%–0.0020%, N≤0.010%, with the remainder being Fe and unavoidable impurities; carbon equivalent Cep 0.624–0. The thickness ranges from 152mm to 178mm, with a weld sensitivity coefficient of 0.2655 to 0.3404. The 690MPa grade extra-thick rack steel produced by the process of this invention can reach a thickness of 178mm. Under this thickness, all performance indicators meet product requirements. Its mechanical properties are: yield strength 720-770MPa, tensile strength 800-860MPa, elongation 19.4-21.4%, and impact energy at -40°C 87-165J. This document describes a common production scheme for rack steel, using a higher alloy composition to compensate for insufficient cooling rate in the core of the thick steel plate. Therefore, with a higher Ni alloy content, only rack steel with a maximum thickness of 178mm can be produced.

[0004] Currently, the main research direction for rectangular rack steel for engineering machinery racks, with a thickness of 30-40mm and a width of 60-70mm, is low alloy with high content of Ni, Mo, V, etc. The mechanical properties of the steel for engineering machinery racks are improved by increasing the content of Ni and Mo alloys, and all of them are produced by flame cutting of sheet metal. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention employs a converter, refining, RH (heat recovery), continuous casting, and flat steel wire rod process to produce flat steel for engineering machinery racks. Higher levels of Mn and Cr elements are used to enhance material strength, while appropriate amounts of Al, N, Nb, V, and Ti are added to refine the grain size, and lower P and S content is used to improve toughness. The smelting process emphasizes H removal control, and the continuous casting process optimizes superheat, casting speed, and end-stage electromagnetic stirring parameters to reduce low-magnification defects in the billet. The rolling process utilizes a high-temperature diffusion process to achieve uniform microstructure, and employs a high-reduction + controlled rolling and cooling process to improve the material's mechanical properties. This flat steel for engineering machinery racks is suitable for producing rectangular rack steel with a thickness of 30–40 mm and a width of 60–70 mm for direct turning. It possesses high strength, high toughness, and high wear resistance. The hot-rolled mechanical properties include a tensile strength exceeding 700 MPa, excellent wear resistance, and a wear loss ≤2.0 g. The formula of this invention is reasonable, and it directly uses hot-rolled materials. While ensuring the wear resistance of the rack, it reduces the need for flame cutting of sheet metal, thus controlling production costs. The preparation method is simple and the preparation cost is low. The resulting rack steel is used in engineering machinery, with low wear, long service life, and high cost performance, making it worthy of promotion.

[0006] The technical solution adopted by the present invention is as follows: Firstly, the present invention provides a flat steel for engineering machinery racks, the composition by weight percentage being: C: 0.60%~0.70%, Si: 0.10%~0.40%, Mn: 0.50%~1.00%, Cr: 0.05%~0.10%, Mo: 0.01%~0.05%, Al: 0.020%~0.050%, P≤0.030%, S≤0.030%, Cu≤0.20%, Ni: 0.01%~0.10%, V: 0.01%~0.10%, N: 0.0060%~0.0200%, with the remainder being Fe and unavoidable impurities.

[0007] Furthermore, the flat steel for the gear rack of the engineering machinery is suitable for making rectangular gear rack steel with a thickness of 30-40mm and a width of 60-70mm for direct turning.

[0008] Furthermore, the flat steel used for the engineering machinery rack has a microstructure of sorbite + pearlite + ferrite, and its hot-rolled mechanical properties include a tensile strength of ≥700 MPa and a wear loss of ≤2.0 g.

[0009] Secondly, the present invention also provides a method for producing flat steel for gear racks in engineering machinery, specifically including the following steps: S1: Smelting process, the ratio of molten iron to scrap steel in the converter is controlled at 8:2; the target composition of the molten steel at the end point is controlled as follows: C≥0.10%, P≤0.010%. Steel is left to tap, and the addition of oxidizing slag is prohibited. A composite deoxidizer is added during the tapping process to form slag and deoxidize. S2: Refining process, basicity controlled at 6.0~8.0. Before the end of LF furnace refining, aluminum wire is fed to adjust the aluminum content in the molten steel to 0.030%~0.050%. After soft blowing for 8 minutes, nitrogen wire is fed to adjust the nitrogen content in the molten steel to 0.0080%~0.0120%. Before leaving the station, calcium wire is fed to treat the molten steel with calcium, and then a covering agent is added to protect the molten steel. The RH furnace is evacuated to below 67Pa and held for 15 minutes. After evacuation, the hydrogen content in the molten steel is determined and controlled to be ≤1.5ppm. The RH furnace is then turned on to increase nitrogen through circulation. The soft blowing time before leaving the station is 15~25 minutes. S3: Continuous casting process, using weak cooling, specific water content of 0.6 L / KG, target superheat value of 30℃~40℃ in the tundish, billet size is... ; S4: Rolling process, control the heating temperature of the soaking zone to be 1180~1200℃, and the time to be greater than 60min; the reduction rate of the first and second passes is greater than 60%, the ultra-low temperature final rolling temperature is 700-750℃, and the cumulative reduction rate is greater than 80%; S5: Post-rolling slow cooling process, followed by water cooling, controlling the temperature of the upper cooling bed at 700±30℃, with all insulation covers opened for the steel on the cooling bed, and rapid cooling at a rate controlled at 3.0℃ / s~3.5℃ / s.

[0010] Furthermore, in the refining process, the feed rate of the first continuous casting furnace calcium line is 150 meters, and the feed rate of the continuous casting furnace is 120 meters.

[0011] Furthermore, in the continuous casting process, the water distribution in each zone is finely adjusted by measuring the temperature of the billet when it passes through the straightening machine, and the segregation in the continuous casting is reduced in conjunction with the crystallizer and the end electromagnetic stirring; the temperature of the billet when it passes through the straightening machine is 1050~1100℃.

[0012] The beneficial effects of this invention are: (1) Without significantly increasing the Ni and Mo content, this invention improves the strength of the material by increasing the Mn and Cr elements in the steel, and refines the grains by adding appropriate amounts of Al, N, Nb, V and Ti, and improves the toughness of the material by reducing the P and S element content.

[0013] (2) The present invention adopts the high reduction + ultra-low temperature final rolling technology, and the final rolling temperature is controlled at 750~700℃ to further refine the grains; after rolling, the rapid cooling is controlled at 700~500℃ at a slow cooling rate of 3.0℃ / S~3.5℃ / S to ensure that the original structure is a tough structure such as sorbite + pearlite.

[0014] (3) This invention reduces various easily segregated impurity elements in molten steel by smelting pure steel. During continuous casting, the billet temperature is monitored to control segregation and porosity. This ensures that the steel ingot is fully fed during solidification, improving the core density of the billet. At the same time, it controls the degree of positive segregation inside the billet, making up for the problem of insufficient cooling rate in the core of the flat steel. Under the condition of lower alloy cost, the core density and core toughness of the flat steel after rolling are improved. Using the flat steel rolling process, long strip flat steel is produced. After being machined at the customer's place, the final product can be obtained. It has high efficiency and high economy.

[0015] (4) This invention utilizes existing equipment and process conditions in steel plants to create processes that meet customer needs without significantly increasing investment and production costs. Furthermore, the products of this invention can provide experience for the transformation of some engineering machinery products. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a metallographic image of the flat steel produced by the method in Embodiment 1 of the present invention. Detailed Implementation

[0018] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0019] This invention provides a flat steel for engineering machinery racks and its production method. The steel composition by weight percentage is: C: 0.60%–0.70%, Si: 0.10%–0.40%, Mn: 0.50%–1.00%, Cr: 0.05%–0.10%, Mo: 0.01%–0.05%, Al: 0.020%–0.050%, P≤0.030%, S≤0.030%, Cu≤0.20%, Ni: 0.01%–0.10%, V: 0.01%–0.10%, N: 0.0060%–0.0200%, with the remainder being Fe and unavoidable impurities.

[0020] Key process steps include: (1) Smelting: The ratio of molten iron to scrap steel in the converter is controlled at 8:2; the target composition of the final molten steel is controlled as follows: C≥0.10%, P≤0.010%. Steel is left to tap, and oxidizing slag is prohibited. Composite deoxidizer is added during the tapping process to form slag and deoxidize.

[0021] (2) Refining: The basicity of LF is controlled at 6.0~8.0. Before the end of LF furnace refining, aluminum wire is fed to adjust the aluminum in the molten steel to 0.030%~0.050%. After soft blowing time of 8 minutes, nitrogen wire is fed to adjust the N in the molten steel to 0.0080%~0.0120%. Calcium wire is fed to the molten steel before leaving the station to treat it with calcium. The amount of calcium wire fed in the first continuous casting furnace is 150 meters, and the amount fed in the continuous casting furnace is 120 meters. Then, a covering agent is added to protect the molten steel. The RH is evacuated to below 67Pa and the vacuum time is 15 minutes. After evacuation, the hydrogen content of the molten steel is determined and controlled to be ≤1.5ppm. The RH is turned on to increase nitrogen circulation. The soft blowing time before leaving the station is 15~25 minutes.

[0022] (3) Continuous casting: Weak cooling is adopted, with a specific water volume of 0.6 L / KG and a target superheat value of 30℃~40℃ in the tundish. The water distribution in each zone is finely adjusted by measuring the temperature of the billet passing through the straightening machine, which is 1050~1100℃. Combined with the crystallizer and end electromagnetic stirring, the segregation in continuous casting is reduced. The billet size is... .

[0023] (4) Rolling: control the heating temperature of the soaking section to 1180~1200℃ and the time to be greater than 60min; the reduction rate of the first and second passes is greater than 60%; carry out water-controlled rolling, with the final rolling temperature of ultra-low temperature 700-750℃ and the cumulative reduction rate greater than 80%.

[0024] (5) Slow cooling after rolling: After rolling, water cooling is used to control the temperature of the upper cooling bed to 700±30℃. The steel in the cooling bed is separated by a length, and the insulation cover is fully opened. The flow rate of the fan at the bottom of the cooling bed is adjusted to cool quickly. The cooling rate is controlled at 3.0℃ / s~3.5℃ / s.

[0025] The following examples and comparative examples will provide further explanation.

[0026] Example 1: The chemical composition of the flat steel used for the mechanical rack in this embodiment is as follows: C: 0.62%, Si: 0.35%, Mn: 0.85%, Cr: 0.08%, Mo: 0.04%, Al: 0.035%, P: 0.007%, S: 0.002%, Cu: 0.04%, Ni: 0.08%, V: 0.04%, N: 0.012%, with the remainder being Fe and unavoidable impurities.

[0027] Production follows a process flow of converter—refining—continuous casting—rolling, with key process steps including: The basicity of the final slag from the LF furnace refining process is 6.5; after RH soft blowing for 20 minutes, the outlet temperature is 1545℃.

[0028] The secondary cooling water ratio for continuous casting is 0.60 L / KG, the superheat of the tundish is 34℃, the temperature of the center point of the inner arc surface of the billet is monitored, and the secondary cooling water distribution is finely adjusted to control the temperature of the straightening machine to 1050~1100℃.

[0029] The billet is heated for 240 minutes, the high-temperature section is controlled at 1200℃ for 70 minutes, the first rolling pass has a reduction of 65%, the second rolling pass has a reduction of 62%, and the final rolling temperature is 720℃.

[0030] After rolling, the steel is directly cooled by water and controlled cooling. The temperature of the upper cooling bed is 710℃. The steel is cooled on the cooling bed with the insulation cover fully opened. The flow rate of the fan at the bottom of the cooling bed is adjusted for rapid cooling. The cooling rate is controlled at 3.4℃ / S.

[0031] The metallographic structure of the flat steel produced by the above method is sorbite + pearlite + ferrite, such as... Figure 1 As shown; the yield strength is 750 MPa, and the wear loss is 1.5577 g.

[0032] Example 2: The chemical composition of the flat steel used for the mechanical rack in this embodiment is as follows: C: 0.64%, Si: 0.38%, Mn: 0.88%, Cr: 0.09%, Mo: 0.05%, Al: 0.032%, P: 0.008%, S: 0.001%, Cu: 0.04%, Ni: 0.07%, V: 0.06%, N: 0.013%, with the remainder being Fe and unavoidable impurities.

[0033] Production follows a process flow of converter—refining—continuous casting—rolling, with key process steps including: The basicity of the final slag from the LF furnace refining process is 7.0; after 19 minutes of RH soft blowing, the outlet temperature is 1545℃.

[0034] The secondary cooling water ratio is 0.60 L / KG, the tundish superheat is 32℃, the temperature of the center point of the inner arc surface of the billet is monitored, and the secondary cooling water distribution is finely adjusted to control the temperature of the straightening machine to 1050~1100℃.

[0035] The billet is heated for 240 minutes, the high-temperature section is controlled at 1190℃ for 75 minutes, the first rolling pass has a reduction of 70%, the second rolling pass has a reduction of 62%, and the final rolling temperature is 730℃.

[0036] After rolling, the steel is directly cooled by water and controlled cooling. The temperature of the upper cooling bed is 715℃. The steel is cooled on the cooling bed with the insulation cover fully opened. The flow rate of the fan at the bottom of the cooling bed is adjusted for rapid cooling. The cooling rate is controlled at 3.2℃ / S.

[0037] The flat steel produced by the above method has a metallographic structure of sorbite + pearlite + ferrite, a yield strength of 751 MPa, and a wear loss of 1.9989 g.

[0038] Example 3: The chemical composition of the flat steel used for the mechanical rack in this embodiment is as follows: C: 0.63%, Si: 0.32%, Mn: 0.90%, Cr: 0.09%, Mo: 0.04%, Al: 0.030%, P: 0.010%, S: 0.001%, Cu: 0.04%, Ni: 0.08%, V: 0.06%, N: 0.012%, with the remainder being Fe and unavoidable impurities.

[0039] Production follows a process flow of converter—refining—continuous casting—rolling, with key process steps including: The basicity of the final slag from the LF furnace refining process is 6.8; after RH soft blowing for 20 minutes, the outlet temperature is 1545℃.

[0040] The secondary cooling water ratio is 0.60 L / KG, the tundish superheat is 35℃, the temperature of the center point of the inner arc surface of the billet is monitored, and the secondary cooling water distribution is finely adjusted to control the temperature of the straightening machine to 1050~1100℃.

[0041] The billet is heated for 240 minutes, the high-temperature section is controlled at 1200℃ for 75 minutes, the first rolling pass has a reduction of 65%, the second rolling pass has a reduction of 65%, and the final rolling temperature is 730℃.

[0042] After rolling, the steel is directly cooled by water and controlled cooling. The temperature of the upper cooling bed is 718℃. The steel is cooled on the cooling bed with the insulation cover fully opened. The flow rate of the fan at the bottom of the cooling bed is adjusted for rapid cooling. The cooling rate is controlled at 3.3℃ / S.

[0043] The flat steel produced by the above method has a metallographic structure of sorbite + pearlite + ferrite, a yield strength of 760 MPa, and a wear loss of 1.7125 g.

[0044] Example 4: The chemical composition of the flat steel used for the mechanical rack in this embodiment is as follows: C: 0.62%, Si: 0.38%, Mn: 0.91%, Cr: 0.08%, Mo: 0.04%, Al: 0.035%, P: 0.011%, S: 0.001%, Cu: 0.04%, Ni: 0.08%, V: 0.06%, N: 0.011%, with the remainder being Fe and unavoidable impurities.

[0045] Production follows a process flow of converter—refining—continuous casting—rolling, with key process steps including: The basicity of the final slag from the LF furnace refining process is 7.0; after 15 minutes of RH soft blowing, the outlet temperature is 1545℃.

[0046] The secondary cooling water ratio for continuous casting is 0.60 L / KG, the superheat of the tundish is 31℃, the temperature of the center point of the inner arc surface of the billet is monitored, and the secondary cooling water distribution is finely adjusted to control the temperature of the straightening machine to 1050~1100℃.

[0047] The billet is heated for 240 minutes, with the high-temperature section temperature controlled at 1190℃ for 75 minutes. The first rolling pass has a reduction of 63%, the second rolling pass has a reduction of 65%, and the final rolling temperature is 720℃.

[0048] After rolling, the steel is directly cooled by water and controlled cooling. The temperature of the upper cooling bed is 720℃. The steel is cooled on the cooling bed with the insulation cover fully opened. The flow rate of the fan at the bottom of the cooling bed is adjusted for rapid cooling. The cooling rate is controlled at 3.4℃ / S.

[0049] The flat steel produced by the above method has a metallographic structure of sorbite + pearlite + ferrite, a yield strength of 770 MPa, and a wear loss of 1.8356 g.

[0050] Comparative Example 1: The chemical composition of the steel is the same as in Example 1, but the process steps differ from those in Example 1 as follows: The billet is heated for 240 minutes, the high-temperature section is controlled at 1200℃ for 70 minutes, the first rolling pass has a reduction of 40%, the second rolling pass has a reduction of 50%, and the final rolling temperature is 720℃.

[0051] The flat steel produced by the above method has a metallographic structure of sorbite + pearlite + ferrite, a yield strength of 620 MPa, and a wear loss of 3.1002 g.

[0052] Comparative Example 2: The chemical composition of the steel is the same as in Example 3, but the process steps differ from those in Example 3 as follows: The billet heating time is 240 minutes, the high temperature section temperature is controlled at 1180℃ for 75 minutes, the first rolling reduction is 65%, the second rolling reduction is 65%, and the final rolling temperature is 830℃. After rolling, the steel is slowly cooled. The temperature of the upper cooling bed is 810℃. The steel in the densely packed section of the cooling bed is completely closed with the insulation cover closed, and the cooling is slow, with the cooling rate controlled at 1.0℃ / S.

[0053] The flat steel produced by the above method has a microstructure of pearlite + ferrite, a yield strength of 550 MPa, and a wear loss of 3.8252 g.

[0054] In summary, the yield strength of the flat steel obtained by the method in the embodiment is between 750 and 770 MPa, and the wear weight loss is between 1.5577 and 1.9989 g. In the comparative example, without increasing the reduction amount and low-temperature rolling process, the strength is between 550 and 620 MPa, and the wear weight loss is between 3.8252 and 3.1002 g. The strength is much lower than that of the process of the present invention, and the wear weight loss is much higher than that of the process of the present invention.

[0055] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present technical solution are within the protection scope of the present invention.

[0056] To facilitate understanding by those skilled in the art of the improvements of this invention over the prior art, some of the accompanying drawings and descriptions have been simplified, and for clarity, some other elements have been omitted from this application. Those skilled in the art should realize that these omitted elements may also constitute the content of this invention.

Claims

1. A flat steel bar for a gear rack in engineering machinery, characterized in that, The composition by weight percentage is as follows: C: 0.60%–0.70%, Si: 0.10%–0.40%, Mn: 0.50%–1.00%, Cr: 0.05%–0.10%, Mo: 0.01%–0.05%, Al: 0.020%–0.050%, P≤0.030%, S≤0.030%, Cu≤0.20%, Ni: 0.01%–0.10%, V: 0.01%–0.10%, N: 0.0060%–0.0200%, with the remainder being Fe and unavoidable impurities.

2. The flat steel for a gear rack in engineering machinery as described in claim 1, characterized in that, The flat steel for the gear rack of the engineering machinery is suitable for making rectangular gear rack steel with a thickness of 30-40mm and a width of 60-70mm for direct turning.

3. The flat steel for a gear rack in engineering machinery as described in claim 1, characterized in that, The flat steel used for the gear racks of the engineering machinery has a microstructure of sorbite + pearlite + ferrite, and its hot-rolled mechanical properties include a tensile strength of ≥700 MPa and a wear loss of ≤2.0g.

4. A method for producing flat steel for engineering machinery racks as described in any one of claims 1-3, characterized in that, Specifically, the steps include the following: S1: Smelting process, the ratio of molten iron to scrap steel in the converter is controlled at 8:2; the target composition of the molten steel at the end point is controlled as follows: C≥0.10%, P≤0.010%. Steel is left to tap, and the addition of oxidizing slag is prohibited. A composite deoxidizer is added during the tapping process to form slag and deoxidize. S2: Refining process, basicity controlled at 6.0~8.

0. Before the end of LF furnace refining, aluminum wire is fed to adjust the aluminum content in the molten steel to 0.030%~0.050%. After soft blowing for 8 minutes, nitrogen wire is fed to adjust the nitrogen content in the molten steel to 0.0080%~0.0120%. Before leaving the station, calcium wire is fed to treat the molten steel with calcium, and then a covering agent is added to protect the molten steel. The RH furnace is evacuated to below 67Pa and held for 15 minutes. After evacuation, the hydrogen content in the molten steel is determined and controlled to be ≤1.5ppm. The RH furnace is then turned on to increase nitrogen through circulation. The soft blowing time before leaving the station is 15~25 minutes. S3: Continuous casting process, using weak cooling, specific water content of 0.6 L / KG, target superheat value of 30℃~40℃ in the tundish, billet size is... ; S4: Rolling process, control the heating temperature of the soaking zone to be 1180~1200℃, and the time to be greater than 60min; the reduction rate of the first and second passes is greater than 60%, the ultra-low temperature final rolling temperature is 700-750℃, and the cumulative reduction rate is greater than 80%; S5: Post-rolling slow cooling process, followed by water cooling, controlling the temperature of the upper cooling bed at 700±30℃, with all insulation covers opened for the steel on the cooling bed, and rapid cooling at a rate controlled at 3.0℃ / s~3.5℃ / s.

5. The method for producing flat steel for engineering machinery racks as described in claim 4, characterized in that, In the refining process, the feed rate of the first continuous casting furnace calcium line is 150 meters, and the feed rate of the continuous casting furnace is 120 meters.

6. The method for producing flat steel for engineering machinery racks as described in claim 4, characterized in that, In the continuous casting process, the water distribution in each zone is finely adjusted by measuring the temperature of the billet when it passes through the straightening machine, and the segregation of continuous casting is reduced in conjunction with the crystallizer and the end electromagnetic stirring; the temperature of the billet when it passes through the straightening machine is 1050~1100℃.

Images