Production method of peritectic steel continuous casting billet and peritectic steel continuous casting billet

Abstract

The invention discloses a production method of a peritectic steel continuous casting billet and the peritectic steel continuous casting billet. The production method comprises the following steps: transferring refined and outbound molten steel to a tundish to obtain tundish molten steel with the carbon content of 0.07-0.08%; the tundish molten steel is subjected to continuous casting and cooling shaping through a crystallizer, and a peritectic steel continuous casting billet is obtained; wherein the molten steel in the crystallizer meets the condition that T1 = T2 + k, the temperature range of k is 15-35 DEG C, T1 represents the pouring temperature of the molten steel in the crystallizer, and T2 represents the liquidus temperature of the tundish molten steel. According to the production method, the surface quality of the peritectic steel continuous casting billet can be effectively improved, the offline coping amount of the continuous casting billet is reduced, the hot charging and hot delivery proportion is increased, and the production cost is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of peritectic steel preparation, and specifically relates to a production method of a peritectic steel continuous casting billet and a peritectic steel continuous casting billet. Background Art

[0002] The surface quality of peritectic steel continuous casting ingot has a great influence on the yield rate of subsequent casting ingots.

[0003] Generally speaking, iron-carbon alloys with a carbon content of 0.08% to 0.16% will undergo peritectic reactions during solidification, and will obtain a non-equilibrium structure containing δ phase at the end of crystallization, resulting in local air gaps and local "hot spots" in crack-sensitive areas. At this time, the heat output is small, the shell is thin, and depressions are easily generated on the surface. Moreover, the cooling and solidification speeds of the depressed parts are slower than those of other parts, resulting in uneven thickness of the primary shell. At the same time, it will also cause uneven distribution of temperature gradients and stress gradients in the solidified shell, which promotes the formation of cracks and seriously affects the surface quality of the peritectic steel continuous casting billet. Summary of the invention

[0004] The present application provides a production method of peritectic steel continuous casting billets and peritectic steel continuous casting billets, which can effectively improve the surface quality of peritectic steel continuous casting billets, reduce the amount of offline grinding of continuous casting billets, increase the hot charging and hot delivery ratio, and reduce production costs.

[0005] In a first aspect, an embodiment of the present application provides a method for producing a peritectic steel continuous casting billet, comprising:

[0006] Transferring the refined molten steel out of the station to a tundish to obtain tundish molten steel, wherein the carbon content of the molten steel is 0.07% to 0.08%;

[0007] The molten steel in the middle package is continuously cast through a crystallizer and cooled to form a peritectic steel continuous casting billet;

[0008] The molten steel in the crystallizer satisfies the condition: T1=T2+k, the temperature range of k is 15-35°C, T1 represents the pouring temperature of the molten steel in the crystallizer, and T2 represents the liquidus temperature of the molten steel in the middle package.

[0009] According to an embodiment of one aspect of the present application, the temperature range of k is 20-25°C.

[0010] According to an embodiment of one aspect of the present application, the continuous casting speed is 0.8 m / min to 1.4 m / min; the production method further comprises:

[0011] When the molten steel in the middle ladle passes through a crystallizer to be transformed into a solidified shell of a cast billet, the wide surface of the peritectic steel slab obtained by the crystallizer is water-cooled to thicken the solidified shell of the cast billet and reduce bulging, wherein the release rate of cooling water on the wide surface of the crystallizer is 4100L / min to 4300L / min.

[0012] According to an embodiment of one aspect of the present application, after water cooling the wide surface of the peritectic steel slab produced by the crystallizer, the method further includes:

[0013] The peritectic steel slab is subjected to secondary cooling, and the specific water volume of the secondary cooling is 0.7-0.8 L / kg.

[0014] According to an embodiment of one aspect of the present application, the tundish molten steel includes, in mass percentage, 0.07% to 0.08% C, 0.015% to 0.025% P, 0.03% to 0.06% Al, 0.80% to 0.90% Mn, 0.15% to 0.25% Si, 0.008% to 0.012% S, 0.02% to 0.04% Ti, and the remainder is Fe and unavoidable impurities.

[0015] According to an embodiment of one aspect of the present application, the pouring temperature T1 of the molten steel in the crystallizer is 1535°C to 1559°C; the liquidus temperature T2 of the molten steel in the tundish is 1520°C to 1524°C.

[0016] According to an embodiment of one aspect of the present application, the step of continuously casting and cooling the tundish molten steel through a crystallizer comprises:

[0017] The molten steel in the tundish is continuously cast through a crystallizer to obtain a peritectic steel slab;

[0018] The peritectic steel slab is cooled and shaped, wherein when the slab passes through the continuous casting sector, a predetermined sector is pressed down.

[0019] According to an embodiment of one aspect of the present application, the method further includes:

[0020] Real-time detection of the liquid level of molten steel in the crystallizer;

[0021] According to the plurality of liquid levels, a liquid level fluctuation value of the molten steel in the crystallizer is obtained;

[0022] When the liquid level fluctuation value is greater than the first threshold, when the slab passes through the continuous casting sector, the next sector of the predetermined sector is pressed down to reduce the squeezing of the liquid steel at the solidification end of the continuous casting slab by the downward-pressed peritectic steel.

[0023] In a second aspect, an embodiment of the present application provides a peritectic steel continuous casting billet, which is produced by the production method of the first aspect.

[0024] According to an embodiment of one aspect of the present application, the surface quality qualification rate of the peritectic steel continuous casting billet is 99.5%, the abnormal off-line grinding amount of the peritectic steel continuous casting billet is ≤0.5%, and the hot charging and hot delivery ratio is ≥95%.

[0025] This application has at least the following beneficial effects:

[0026] The production method provided by the present application is that during the process of solidifying peritectic steel in a crystallizer to produce cast billets, since peritectic steel is prone to peritectic reaction, which affects the quality fluctuation of the cast billets, the present application adopts a carbon content of 0.07% to 0.08% in the molten steel leaving the refined station, and controls the difference k between the pouring temperature of the molten steel in the crystallizer and the liquidus temperature of the molten steel in the middle of the peritectic steel to be between 15 and 35°C, thereby achieving stable production of peritectic steel continuous casting billets, controlling the crystallizer liquid level fluctuation, improving the surface quality of the peritectic steel continuous casting billets, reducing the abnormal offline grinding amount of the peritectic steel continuous casting billets, increasing the hot charging and hot delivery ratio, and reducing production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solution of the implementation regulations of this application, the following is a brief introduction to the drawings required for use in the embodiments of this application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0028] Figure 1 A schematic diagram of the structure of the middle ladle and the crystallizer in an embodiment of the present application is shown.

[0029] Figure 2 A schematic diagram of the sector segments that the peritectic steel continuous casting billet passes through in the method for producing the peritectic steel continuous casting billet in an embodiment of the present application is shown.

[0030] Figure 3 The appearance of the peritectic steel continuous casting billet according to the embodiment of the present application is shown.

[0031] Figure 4 The figure shows the appearance of the peritectic steel continuous casting billet of the comparative example of the present application.

[0032] Description of the accompanying drawings:

[0033] Among them, 10, the middle ladle; 20, the crystallizer; 1, the first fan-shaped area; 2, the second fan-shaped area; 3, the third fan-shaped area; 4, the fourth fan-shaped area; 5, the fifth fan-shaped area; 6, the sixth fan-shaped area; 7, the seventh fan-shaped area; 8, the eighth fan-shaped area; 9, the ninth fan-shaped area; 10, the tenth fan-shaped area; 11, the eleventh fan-shaped area; 12, the twelfth fan-shaped area; 13, the thirteenth fan-shaped area; 14, the fourteenth fan-shaped area; 15, the fifteenth fan-shaped area; 16, the sixteenth fan-shaped area; 17, the seventeenth fan-shaped area. DETAILED DESCRIPTION

[0034] In order to make the application purpose, technical solution and beneficial technical effect of this application clearer, the application is further described in detail below in conjunction with the embodiments. It should be understood that the implementation regulations described in this specification are only for explaining this application, not for limiting this application.

[0035] For simplicity, the present application only explicitly discloses some numerical ranges. However, any lower limit can be combined with any upper limit to form an unclearly recorded range; and any lower limit can be combined with other lower limits to form an unclearly recorded range, and any upper limit can be combined with any other upper limit to form an unclearly recorded range. In addition, although not clearly recorded, each point or single value between the range endpoints is included in the range. Thus, each point or single value can be combined with any other point or single value as its own lower limit or upper limit or with other lower limits or upper limits to form an unclearly recorded range.

[0036] In the description of the present application, it should be noted that, unless otherwise specified, “above” and “below” are inclusive of the number, and the “multiple” in “one or more” means two or more than two.

[0037] The above application content of the present application is not intended to describe each disclosed embodiment or each implementation in the present application. The following description more specifically illustrates exemplary embodiments. In many places throughout the application, guidance is provided through a series of embodiments, and these implementation regulations can be used in various combinations. In each example, enumeration is only used as a representative group and should not be interpreted as exhaustive.

[0038] Production method of continuous casting billet of peritectic steel

[0039] In a first aspect, an embodiment of the present application provides a method for producing a peritectic steel continuous casting billet, comprising:

[0040] Transferring the refined molten steel out of the station to a tundish to obtain tundish molten steel, wherein the carbon content of the molten steel is 0.07% to 0.08%;

[0041] The molten steel in the middle package is continuously cast through a crystallizer and cooled to form a peritectic steel continuous casting billet;

[0042] Among them, the molten steel in the crystallizer meets the condition: T1=T2+k, the temperature range of k is 15-35°C, and can be optionally 20-25°C, T1 represents the pouring temperature of the molten steel in the crystallizer, and T2 represents the liquidus temperature of the molten steel in the middle package.

[0043] Peritectic Steel refers to a type of steel that undergoes peritectic reaction during solidification. Usually, the composition of this type of steel is in the peritectic reaction zone in the phase diagram, especially the carbon content and other alloying elements that cause the liquid phase to react with the solid phase during solidification to form a new solid phase. Generally speaking, the carbon content is generally around 0.08% to 0.16%, and peritectic reaction will occur, the solidification shrinkage is large, and the incidence of surface cracks is high.

[0044] Peritectic reaction is a phase change reaction in alloy system. At a specific temperature, the liquid phase reacts with a solid phase to generate another new solid phase. The complexity and instability of crystal growth during the solidification of molten steel will lead to large solidification shrinkage, which is easy to form cracks on the surface or inside of the ingot, especially in areas where stress is difficult to release. Defects such as surface cracks, center cracks or intergranular cracks are often related to this, resulting in fluctuations in ingot quality.

[0045] According to the embodiment of the present application, the mass content of carbon in the molten steel after refining is controlled at 0.07% to 0.08%, which can weaken the peritectic reactivity, reduce the shrinkage of the solidified shell, and improve the quality of the ingot. Optionally, the mass content of carbon in the molten steel after refining can be any value or a range composed of 0.070%, 0.071%, 0.072%, 0.073%, 0.074%, 0.075%, 0.076%, 0.077%, 0.078%, 0.079%, 0.080%.

[0046] In some optional embodiments, the temperature range of k can be any value or a range composed of 15°C, 16°C, 17°C, 18°C, 19°C, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, and 35°C. According to the embodiment of the present application, k is controlled within the above range to increase the thickness of the solidified shell of the continuous casting billet, reduce the bulging phenomenon of the casting billet in the fan-shaped segment, and improve the quality of the peritectic steel continuous casting billet.

[0047] For example, the temperature range of k can be determined comprehensively based on the first loss temperature determined by the ladle use frequency, the second loss temperature determined by the molten steel transfer time, the third loss temperature of converting the large ladle used for refined molten steel into the medium ladle used for pouring, and the outlet temperature of the refined molten steel. The first loss temperature can be determined by the ladle temperature control correction model; the second loss temperature can be determined by the molten steel transfer time correction compensation model; the third loss temperature can be determined by the ladle conversion temperature model or by empirical value; the outlet temperature of the refined molten steel can be directly measured.

[0048] As an example, k=T1-T2, T2 represents the liquidus temperature of the molten steel in the middle package. When the type of the molten steel in the middle package is determined, T2 can be determined as a constant value; T1=temperature of refined molten steel-first loss temperature-second loss temperature-third loss temperature.

[0049] The range of K is greater than 35°C, which can be understood as the superheat of the molten steel in the tundish is too high, which will cause the solidified billet shell to become thinner, aggravate the bulging of the continuous casting billet, and cause liquid level fluctuations.

[0050] like Figure 1 As shown, during the production process of peritectic steel continuous casting, the relative position relationship between the intermediate steel ladle 10 and the crystallizer 20 is as shown in FIG. Figure 1 .

[0051] In some optional embodiments, the continuous casting speed is 0.8 m / min to 1.4 m / min; the production method further comprises:

[0052] When the molten steel in the middle ladle passes through a crystallizer to be transformed into a solidified shell of a cast billet, the wide surface of the peritectic steel slab obtained by the crystallizer is water-cooled to thicken the solidified shell of the cast billet and reduce bulging, wherein the release rate of cooling water on the wide surface of the crystallizer is 4100L / min to 4300L / min, which can be selected as any value among 4100L / min, 4150L / min, 4200L / min, 4250L / min, and 4300L / min.

[0053] Wide surface water cooling refers to the water cooling of the wide surface of the continuous casting billet during the continuous casting process, not the thick or narrow surface of the continuous casting billet. The release rate of the cooling water on the wide surface of the crystallizer is within the above range, and the wide surface can be effectively cooled by external water spray or water flow, which helps the surface of the billet to solidify quickly and form a solidified shell, thereby ensuring the stability of the billet in the crystallizer and subsequent stages.

[0054] In the related art, the cooling water release rate of the wide face of the crystallizer can be 3900±100L / min. The present application adopts a cooling water release rate of 4200±100L / min on the wide face of the crystallizer (which can be understood as the wide face of the peritectic steel slab prepared by the crystallizer). The water volume on the wide face is increased by about 7.7%, which can further increase the thickness of the slab shell, improve the quality of the peritectic steel continuous casting slab, and reduce the bulging phenomenon of the peritectic steel continuous casting slab. The water volume on the narrow face can remain unchanged, further increasing the thickness of the slab shell and reducing bulging.

[0055] The pulling speed of continuous casting can be any value among 0.8m / min, 0.9m / min, 1.0m / min, 1.1m / min, 1.2m / min, 1.3m / min, 1.4m / min or the range composed thereof. When the pulling speed of continuous casting is in the above range, the amount of molten steel flowing into the crystallizer is more appropriate, which reduces the large fluctuation of the liquid level in the crystallizer and avoids the ripple defects or inclusions on the surface of the billet caused by the violent fluctuation of the liquid level. If the pulling speed of continuous casting is too low, the production efficiency will be reduced, and the surface thermal cracking problem of the billet may be caused. Increasing the release rate of cooling water for wide surface water cooling can improve the cooling efficiency of the billet, so that the surface of the billet solidifies faster and adapts to the above pulling speed. However, too much water may cause the surface temperature of the billet to drop rapidly, generate thermal stress, and then cause surface cracks or internal stress problems. Therefore, the release rate of the wide surface cooling water of the crystallizer is in the above range, which improves the surface quality of the continuous casting billet. Generally speaking, the width of the continuous casting billet is 1250mm to 2050mm.

[0056] In some optional embodiments, the cooling water release rate of the narrow face cooling may be 420 L / min to 450 L / min. Generally speaking, the thickness of the continuous casting billet is 230 mm.

[0057] In some optional embodiments, after water cooling the wide surface of the peritectic steel slab produced by the crystallizer, the method further comprises:

[0058] The peritectic steel slab is subjected to secondary cooling, and the specific water volume of the secondary cooling is 0.7-0.8 L / kg. The specific water volume of 0.7-0.8 L / kg can be understood as that for each kilogram of the peritectic steel slab, 0.7-0.8 L of water can be used for cooling.

[0059] When the water content of the secondary cooling is within the above range, the thickness can be further increased, the strength of the solidified shell can be improved, the bulging of the slab can be reduced, the thickness of the solidified shell in the fan-shaped segment can be increased as a whole, and a peritectic steel continuous casting slab with better surface quality can be prepared.

[0060] In some optional embodiments, the middle clad molten steel comprises, by mass percentage, 0.07% to 0.08% C, 0.015% to 0.025% P, 0.03% to 0.06% Al, 0.80% to 0.90% Mn, 0.15% to 0.25% Si, 0.008% to 0.012% S, 0.02% to 0.04% Ti, and the remainder is Fe and unavoidable impurities. The above-mentioned middle clad molten steel, by the above-mentioned preparation method, can prepare a peritectic steel continuous casting billet with better surface quality and reduce the amount of grinding.

[0061] In some optional embodiments, the pouring temperature T1 of the molten steel in the crystallizer is 1535°C to 1559°C; the liquidus temperature T2 of the molten steel in the middle package is 1520°C to 1524°C. The liquidus temperature T2 of the molten steel in the middle package of the above type is within the above range, and the pouring temperature T1 of the molten steel in the crystallizer is within the above range, which can increase the thickness of the solidified shell of the continuous casting billet, reduce the bulging phenomenon of the casting billet in the fan-shaped segment, and improve the surface quality of the peritectic steel continuous casting billet.

[0062] In some optional embodiments, the step of continuously casting and cooling the tundish molten steel through a crystallizer comprises:

[0063] The molten steel in the tundish is continuously cast through a crystallizer to obtain a peritectic steel slab;

[0064] The peritectic steel slab is cooled and shaped, wherein when the slab passes through the continuous casting sector, a predetermined sector is pressed down.

[0065] According to the embodiment of the present application, the force for pressing down the predetermined sector is generally between 40 and 50 Bar. The thickness of the slab is generally about 230 mm. By using the above pressure to press down the predetermined sector with a thickness of about 230 mm, the extrusion of the liquid molten steel at the end of the solidification of the continuous casting billet can be reduced, the liquid level fluctuation of the molten steel in the crystallizer can be reduced, and the surface quality of the peritectic steel continuous casting billet can be improved.

[0066] In some optional embodiments, the method further includes:

[0067] Real-time detection of the liquid level of molten steel in the crystallizer;

[0068] According to the plurality of liquid levels, a liquid level fluctuation value of the molten steel in the crystallizer is obtained;

[0069] When the liquid level fluctuation value is greater than the first threshold, when the slab passes through the continuous casting sector, the next sector of the predetermined sector is pressed down to reduce the squeezing of the liquid steel at the solidification end of the continuous casting slab by the downward-pressed peritectic steel.

[0070] Downward pressure can be understood as dynamic light pressure that squeezes the molten steel inside the continuous casting billet. During the continuous casting process, when the molten steel solidifies, due to concentration differences, solute elements (such as carbon, phosphorus, sulfur, etc.) will be enriched in the liquid phase, especially in the center of the billet. This will lead to central segregation, that is, the composition of the center of the billet is different from that of the outside, resulting in uneven chemical composition. Dynamic light pressure promotes the flow and uniform distribution of molten steel by squeezing the internal molten steel that has not yet fully solidified, thereby reducing the formation of segregation, improving the chemical uniformity of the billet, compensating for the volume shrinkage in the center of the billet, and reducing defects caused by shrinkage. However, downward pressure will cause fluctuations in the liquid level of the crystallizer. Pressing down on the next sector of the predetermined sector can not only improve the quality of the peritectic steel continuous casting billet, but also reduce the fluctuation of the crystallizer liquid level, thereby improving the surface quality of the peritectic steel continuous casting billet.

[0071] Exemplarily, the crystallizer may have 1-17 sectors when continuous casting is carried out, namely, the first sector 1; the second sector 2; the third sector 3; the fourth sector 4; the fifth sector 5; the sixth sector 6; the seventh sector 7; the eighth sector 8; the ninth sector 9; the tenth sector 10; the eleventh sector 11; the twelfth sector 12; the thirteenth sector 13; the fourteenth sector 14; the fifteenth sector 15; the sixteenth sector 16; and the seventeenth sector 17. When the continuous casting billet is continuously cast at a pulling speed of 0.8-1.4m / min, if the next sector of the predetermined sector is pressed down, the predetermined sector is the fifth sector 5; the liquid level fluctuation value is 4mm, which is greater than the first threshold value of 2mm. The sixth sector 6 is pressed down to reduce the squeezing of the liquid molten steel at the solidification end of the continuous casting billet by the peritectic steel, reduce the liquid level fluctuation of the molten steel in the crystallizer, and thus improve the surface quality of the peritectic steel continuous casting billet.

[0072] The liquid level of molten steel in the crystallizer can be detected by a position sensor.

[0073] Compared with the production method of related technology, the surface quality of peritectic steel continuous casting billet is improved, the grinding amount of continuous casting billet is reduced, and the grinding amount of offline continuous casting billet is reduced from the original 5.6% to 0.5% and below, and the hot charging and hot delivery ratio is increased by ≥95%. In addition, the production method of this application reduces production costs and has obvious economic benefits.

[0074] Peritectic steel continuous casting

[0075] In a second aspect, an embodiment of the present application provides a peritectic steel continuous casting billet, which is produced by the production method of the first aspect.

[0076] In some optional embodiments, the surface quality qualification rate of the peritectic steel continuous casting billet is 99.5%, the abnormal off-line grinding amount of the peritectic steel continuous casting billet is ≤0.5%, and the hot charging and hot delivery ratio is ≥95%.

[0077] In the embodiments of the present application, the standard for qualified surface quality of the peritectic steel continuous casting billet is based on the surface vibration mark rules in the "Regulations on Inspection, Judgment and Acceptance Management of Continuous Casting Billet Surface Quality", and the inspection is carried out without obvious quality defects such as heavy skin and double casting. The billet surface vibration mark rules, without defects such as heavy skin and double casting are qualified, and the billet surface with obvious defects such as heavy skin and double casting are unqualified.

[0078] Example

[0079] The following examples describe the disclosure of the present application in more detail, and these examples are intended for illustrative purposes only, as it will be apparent to those skilled in the art that various modifications and variations may be made within the scope of the disclosure of the present application. Unless otherwise stated, all parts, percentages, and ratios reported in the following examples are by weight, and all reagents used in the examples are commercially available or synthesized according to conventional methods and can be used directly without further processing, and the instruments used in the examples are commercially available.

[0080] Example 1

[0081] The present application provides a method for producing a peritectic steel continuous casting billet, comprising:

[0082] 10. Transfer the molten steel from the refined station to the tundish to obtain tundish molten steel, wherein the tundish molten steel comprises, by mass percentage, 0.07% to 0.08% C, 0.015% to 0.025% P, 0.03% to 0.06% Al, 0.80% to 0.90% Mn, 0.15% to 0.25% Si, 0.008% to 0.012% S, 0.02% to 0.04% Ti, and the balance is Fe and unavoidable impurities.

[0083] The molten steel in the middle package is continuously cast and cooled and shaped through a crystallizer to obtain a peritectic steel continuous casting billet; the continuous casting pulling speed is 1.2m / min; when the molten steel in the middle package is passed through a crystallizer to be transformed into a solidified shell of the casting billet, the wide surface of the peritectic steel slab obtained by the crystallizer is water-cooled to thicken the solidified shell of the casting billet and reduce bulging, wherein the release rate of cooling water on the wide surface of the crystallizer is 4200L / min, and the actual fluctuation range is ±50L / min.

[0084] The peritectic steel slab is subjected to secondary cooling, wherein the specific water volume of the secondary cooling is 0.76 L / kg. There are 17 peritectic steel segments, and the seventh peritectic steel segment is subjected to light pressing.

[0085] The molten steel in the crystallizer satisfies the condition: T1=T2+k, k is 21°C, T1 represents the pouring temperature of the molten steel in the crystallizer, and T2 represents the liquidus temperature of the molten steel in the tundish.

[0086] Example 2

[0087] The difference between this embodiment and embodiment 1 is that the composition of the molten steel in the tundish is different, which includes, by mass percentage, 0.075% C, 0.020% P, 0.045% Al, 0.85% Mn, 0.20% Si, 0.010% S, 0.03% Ti, and the remainder is Fe and unavoidable impurities.

[0088] Example 3

[0089] The difference between this embodiment and embodiment 1 is that the continuous casting speed is 1.4 m / min.

[0090] Example 4

[0091] The difference between this embodiment and embodiment 1 is that the continuous casting speed is 2.1 m / min.

[0092] Example 5

[0093] The difference between this embodiment and embodiment 1 is that the release rate of cooling water on the wide surface of the crystallizer is 4100 L / min.

[0094] Example 6

[0095] The difference between this embodiment and embodiment 1 is that the release rate of cooling water on the wide surface of the crystallizer is 4300 L / min.

[0096] Example 7

[0097] The difference between this embodiment and embodiment 1 is that the release rate of cooling water on the wide surface of the crystallizer is 3900 L / min.

[0098] Example 8

[0099] The difference between this embodiment and embodiment 1 is that the peritectic steel slab is subjected to secondary cooling, and the specific water volume of the secondary cooling is 0.8 L / kg.

[0100] Example 9

[0101] The difference between this embodiment and embodiment 1 is that the peritectic steel slab is subjected to secondary cooling, and the specific water volume of the secondary cooling is 0.6 L / kg.

[0102] Example 10

[0103] The difference between this embodiment and embodiment 1 is that the peritectic steel slab is subjected to secondary cooling, and the specific water volume of the secondary cooling is 0.9 L / kg.

[0104] Embodiment 11

[0105] The difference between this embodiment and embodiment 1 is that the molten steel in the crystallizer meets the condition that k is 15°C.

[0106] Example 12

[0107] The difference between this embodiment and embodiment 1 is that the molten steel in the crystallizer meets the condition that k is 35°C.

[0108] Example 13

[0109] The difference between this embodiment and embodiment 1 is that: the method further comprises: continuously casting the molten steel in the middle package through a crystallizer to obtain a peritectic steel slab;

[0110] Cooling and shaping the peritectic steel slab, wherein when the slab passes through the continuous casting sector, a predetermined sector is pressed down;

[0111] Real-time detection of the liquid level of molten steel in the crystallizer;

[0112] According to the plurality of liquid levels, a liquid level fluctuation value of the molten steel in the crystallizer is obtained;

[0113] When the liquid level fluctuation value is greater than the first threshold value, when the slab passes through the continuous casting sector, the next sector of the predetermined sector is pressed down to reduce the squeezing of the liquid molten steel at the solidification end of the continuous casting slab by the downward pressing peritectic steel. Under the target pulling speed of 1.2m / min, the original light pressing end position is at the 7th sector of the sector. The liquid level fluctuation value is detected to be 3mm, which is greater than the predetermined value of 2mm. The downward pressing is postponed by one sector and adjusted to the 8th sector.

[0114] Comparative Example 1

[0115] The difference between this comparative example and Example 1 is that the molten steel in the crystallizer meets the condition that k is 42°C.

[0116] Test Section

[0117] The surface quality of the peritectic steel continuous casting billets prepared in the examples and comparative examples was tested, as well as the grinding amount and the hot charging and hot delivery ratio.

[0118] The surface quality of peritectic steel continuous casting billets shall be inspected according to the surface vibration mark rules in the enterprise's internal "Regulations on Inspection, Judgment and Acceptance Management of Continuous Casting Billets". The billets shall be inspected if there are no obvious quality defects such as heavy skin and double casting. The billets shall be qualified if there are regular surface vibration marks and no defects such as heavy skin and double casting. The billets shall be unqualified if there are obvious defects such as heavy skin and double casting on the surface.

[0119] The standard of grinding is subject to the internal "Continuous Casting Billet Surface Quality Inspection, Judgment and Acceptance Management Regulations" of the enterprise. Grinding is qualified when the surface of the continuous casting billet is double-cast and smooth without obvious edges and corners.

[0120] Grinding amount = grinding removal surface quality after grinding / total production quality of ingot

[0121] The hot charging and hot delivery ratio indicates the proportion of the number of peritectic steel continuous casting billets that do not require downward trimming to the total number of peritectic steel continuous casting billets.

[0122] Table 1 Test results of peritectic steel continuous casting billets of the embodiment and comparative example.

[0123]

[0124]

[0125] The above measured performance parameters are average values.

[0126] Figure 3 The appearance of the peritectic steel continuous casting billet of Example 1 of the present application is shown; Figure 4 The appearance of the peritectic steel continuous casting billet of comparative example 1 of the present application is shown, which illustrates that the surface quality of the peritectic steel continuous casting billet produced by the production method of the present application is good, the surface quality qualification rate can be improved, and the grinding amount can be reduced.

[0127] The above are only specific implementations of the present application, but the protection scope of the present application is not limited thereto, and any familiarity with the present technology or replacement should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for producing a peritectic steel continuous casting billet, characterized in that: include: Transferring the refined molten steel out of the station to a tundish to obtain tundish molten steel, wherein the carbon content of the molten steel is 0.07% to 0.08%; The molten steel in the middle package is continuously cast through a crystallizer and cooled to form a peritectic steel continuous casting billet; The molten steel in the crystallizer satisfies the condition: T1=T2+k, the temperature range of k is 15-35°C, T1 represents the pouring temperature of the molten steel in the crystallizer, and T2 represents the liquidus temperature of the molten steel in the middle package.

2. The production method according to claim 1, characterized in that The temperature range of k is 20~25℃.

3. The production method according to claim 1, characterized in that The continuous casting speed is 0.8m / min to 1.4m / min; the production method further comprises: When the molten steel in the middle ladle passes through a crystallizer to be transformed into a solidified shell of a cast billet, the wide surface of the peritectic steel slab obtained by the crystallizer is water-cooled to thicken the solidified shell of the cast billet and reduce bulging, wherein the release rate of cooling water on the wide surface of the crystallizer is 4100L / min to 4300L / min.

4. The production method according to claim 3, characterized in that: After water cooling the wide surface of the peritectic steel slab produced by the crystallizer, the method further comprises: The peritectic steel slab is subjected to secondary cooling, and the specific water volume of the secondary cooling is 0.7-0.8 L / kg.

5. The production method according to any one of claims 1 to 4, characterized in that: The tundish molten steel comprises, by mass percentage, 0.07% to 0.08% C, 0.015% to 0.025% P, 0.03% to 0.06% Al, 0.80% to 0.90% Mn, 0.15% to 0.25% Si, 0.008% to 0.012% S, 0.02% to 0.04% Ti, and the remainder is Fe and unavoidable impurities.

6. The production method according to any one of claims 1 to 4, characterized in that: The pouring temperature T1 of the molten steel in the crystallizer is 1535°C to 1559°C; the liquidus temperature T2 of the molten steel in the tundish is 1520°C to 1524°C.

7. The production method according to any one of claims 1 to 4, characterized in that: The method of continuously casting and cooling the molten steel in the tundish through a crystallizer comprises: The molten steel in the tundish is continuously cast through a crystallizer to obtain a peritectic steel slab; The peritectic steel slab is cooled and shaped, wherein when the slab passes through the continuous casting sector, a predetermined sector is pressed down.

8. The production method according to claim 7, characterized in that: The method further comprises: Real-time detection of the liquid level of molten steel in the crystallizer; According to the plurality of liquid levels, a liquid level fluctuation value of the molten steel in the crystallizer is obtained; When the liquid level fluctuation value is greater than the first threshold, when the slab passes through the continuous casting sector, the next sector of the predetermined sector is pressed down to reduce the squeezing of the liquid steel at the solidification end of the continuous casting slab by the downward-pressed peritectic steel.

9. A peritectic steel continuous casting billet, characterized in that: It is prepared by the production method according to any one of claims 1 to 8.

10. The peritectic steel continuous casting billet according to claim 9, characterized in that: The surface quality qualification rate of the peritectic steel continuous casting billet is 99.5%, the abnormal off-line grinding amount of the peritectic steel continuous casting billet is ≤0.5%, and the hot charging and hot delivery ratio is ≥95%.

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