Submersed nozzle for thin slab continuous casting

Abstract

The utility model relates to a sheet billet continuous casting submersed nozzle which comprises a nozzle body, a flow dividing body and a flow guiding body. Molten metal channels which are symmetrically through in the axial direction are arranged in the nozzle body, and the nozzle body is composed of a molten metal inflow section, an expansion section and an outflow section which are sequentially connected from top to bottom. The flow dividing body comprises a central flow dividing body with a side surface groove and a pair of axisymmetric outer side flow dividing bodies which are arranged in the outflow section, so that five dispersion liquid outflow ports are formed in the water gap; the flow guide bodies are a pair of axially symmetrical flow guide bodies arranged in the outflow section and automatically guide and distribute the flow quantity of molten metal flowing out of the main outflow channel and the outer auxiliary outflow channel. Through the mutual matching effect of the flow dividing body and the flow guiding body which are arranged in the outflow section of the water gap, the water gap can meet the requirement of producing high-quality casting blanks under the condition of different metal liquid flows at high and low pulling speeds when an MCCR thin slab continuous casting machine is used for casting large-section and small-section casting blanks.

Description

Technical Field

[0001] The utility model relates to the technical field of thin slab continuous casting, in particular to an MCCR thin slab continuous casting method for producing large and small section castings and a flexible and universal submerged nozzle at high and low drawing speeds. Background Art

[0002] In the continuous casting of molten metal (especially molten steel), molten metal with a certain degree of superheat needs to be poured from the continuous casting tundish into the continuous casting crystallizer through a submerged entry nozzle (SEN) made of refractory materials to achieve protective pouring and prevent secondary oxidation of the molten metal; at the same time, the structure and size of the submerged entry nozzle (SEN) directly affect the flow field and temperature field of the molten metal flowing into the crystallizer, thereby affecting the internal and external quality of the continuous casting billet and the continuous casting production efficiency.

[0003] Multi-mode Continuous Casting and Rolling (MCCR) is a new generation of thin slab continuous casting and rolling production line. The cross-sectional width of MCCR continuous casting slabs can range from 900mm to more than 1500mm, the cross-sectional thickness of the casting slabs can reach more than 110mm, and the maximum drawing speed of continuous casting production can reach more than 5.5m / min. On the one hand, during the normal casting process of the MCCR thin slab continuous casting machine, stable and high-quality production is normally required at a casting slab drawing speed of up to 5.0m / min (molten metal flux up to 6 tons / min) or more, while in the middle of a continuous casting casting, stable and high-quality production is required at a lower casting speed (such as 3.5m / min) and a lower molten metal flux; on the other hand, the width of the casting slab section selected by the MCCR thin slab continuous casting machine ranges from 900mm to more than 1500mm. Therefore, the flux of molten metal flowing through the submerged nozzle during continuous casting varies greatly under different sizes of billet sections and different drawing speeds. The actual requirement is that the submerged nozzle can adapt to the production of large and small section billets by the MCCR thin slab continuous casting machine, and ensure the stability of the metal liquid level in the funnel-shaped crystallizer of the thin slab continuous casting machine under different conditions of high and low drawing speeds or high and low metal liquid fluxes, and the liquid level fluctuation amplitude is small, and the "liquid surface slag rolling" phenomenon cannot occur; at the same time, the temperature of the metal liquid surface is required to be relatively high, which is conducive to the melting of the protective slag and the performance of its metallurgical functions, and the liquid surface "cold steel" phenomenon cannot occur. Finally, the purpose of stable continuous casting to produce high-quality continuous casting billets inside and outside can be achieved.

[0004] At present, in actual production, only two submerged nozzles with different structural sizes can be used to adapt to the casting production of continuous casting billets with different cross-sections, which brings difficulties and waste to the actual continuous casting production organization. Fig. 9 and Fig.10 As shown, when they are used in MCCR thin slab continuous casting machine production, prior art 1 ( Fig. 9 The nozzle shown in the figure is used in the continuous casting production of small and medium section width (900mm-1350mm) ingots, and is not suitable for the stable production of continuous casting ingots with a section width of more than 1350mm under high billet drawing speed continuous casting conditions; the prior art 2 ( Fig.10 The sprue (as shown) is used in the continuous casting production of medium and large cross-section (greater than 1350mm) billets, and is not suitable for the stable production of continuous casting billets with a cross-section width below 1350mm at a lower billet drawing speed. These two types of sprues will cause problems such as excessive fluctuations in the metal liquid level in the crystallizer or excessively low local temperature of the metal liquid level in the crystallizer and cold steel formation during the continuous casting production process due to the billet cross-section width and the corresponding billet drawing speed that they cannot adapt to, and cannot meet the requirements of high-quality and stable continuous casting production. Therefore, actual production needs to provide an immersion sprue (SEN) with a structural size that can meet the needs of MCCR thin slab continuous casting machines for casting large and small cross-section billets and flexible and universal continuous casting production of "high-quality billets" under different process conditions such as high and low drawing speeds. Summary of the invention

[0005] The utility model aims at the problems existing in the prior art and provides a MCCR thin slab continuous casting machine which can be used in different situations of producing large and small cross-section castings and high and low casting speed continuous casting, so that the molten metal in the crystallizer has better dispersion, stable flow and temperature distribution, and meets the requirements of realizing MCCR thin slab continuous casting under various process conditions by using a single submerged nozzle to stably produce high-quality castings. To achieve this purpose, the utility model is realized by adopting a technical solution of the configuration of the molten metal channel in the nozzle and the cross-sectional area of ​​the channel.

[0006] A thin slab continuous casting immersion nozzle, comprising a nozzle body, a flow divider and a flow guide; a molten metal channel is provided in the nozzle body and runs along the central vertical axis, the cross section perpendicular to the axis is symmetrical, and the molten metal channel has an inlet; the nozzle body is composed of an inflow section, an expansion section and an outflow section connected in sequence from top to bottom, and the molten metal channels in each section are smoothly transitionally connected. The nozzle of the utility model is characterized in that a central flow divider, a pair of axisymmetric outer flow dividers and a pair of axisymmetric flow guides are provided in the outflow section of the nozzle body, so that the end surface of the outflow section of the molten metal channel in the nozzle forms five dispersed outlets; wherein:

[0007] The central distributor body is arranged on the bottom central axis of the outflow section of the nozzle body, and the central distributor body has an upper top surface and a lower bottom surface, a pair of axisymmetric side surfaces and a central outflow channel. The upper top surface and the lower bottom surface of the central distributor body are both horizontal planes, and a pair of axisymmetric grooves are arranged on the two side surfaces of the central distributor body.

[0008] The pair of axisymmetric outer flow dividers are located between the central flow divider body and the corresponding side walls of the water inlet on both sides. The outer flow dividers have a flow guide arc top surface, an inner flow guide inclined plane, an outer flow guide inclined plane and a downward inclined bottom surface; the inner flow guide inclined plane of the outer flow divider, the side surface of the central flow divider on the same side and the wide surface of the channel in the water inlet outflow section constitute the main outflow channel of the water inlet; the outer flow guide inclined plane of the outer flow divider, the side arc surface of the metal liquid channel near the water inlet outlet located in the expansion section on the same side and the wide surface of the channel in the water inlet outflow section constitute two outer auxiliary outflow channels of the water inlet;

[0009] The pair of axisymmetric guide bodies are arranged at the upper part of the outflow section of the nozzle body, and the guide body has a top surface, a bottom surface, an outer inclined plane and an inner inclined plane. The top surface and the bottom surface of the guide body are horizontal planes, and the inner inclined plane and the outer inclined plane of each guide body are parallel to each other; the inclination angles of the inner inclined plane and the outer inclined plane of the guide body are the same as the inclination angle of the inner guide inclined plane of the outer flow distributor on the same side.

[0010] Furthermore, a pair of axially symmetrical grooves are provided on the two sides of the central divider body, and the depth of the bottom surface of the grooves is from deep to shallow from top to bottom. The upper part of the bottom surface of the grooves is an arc surface and then transitions to a diversion inclined plane in the lower part. The diversion inclination angle of the middle and lower diversion inclined plane of the side groove of the central divider body is from 5 degrees and inclusive to 8 degrees and inclusive; the width of the groove set on the side of the central divider body is 1 / 3 to 3 / 4 of the maximum width of the cross section of the molten metal channel in the outflow section of the nozzle body.

[0011] Furthermore, the width of the bottom surface of the central divider body is 70 mm and includes 70 mm to 80 mm and includes 80 mm; the maximum width of the top surface of the central divider body is 100% and includes 100% to 150% and includes 150% of the width of the bottom surface of the central divider body; the height of the central divider body is greater than 1 / 2 of the distance between the bottom surface of the guide body and the bottom end surface of the nozzle body, and is less than 2 / 5 of the length of the outflow section of the nozzle body.

[0012] Furthermore, the diversion inclination angle of the outer diversion inclined plane of the pair of axisymmetric outer diverter bodies is from 25 degrees and inclusive to 35 degrees and inclusive, and the diversion inclination angle of the inner diversion inclined plane is from 12 degrees and inclusive to 18 degrees and inclusive; the downward inclined bottom surface of the outer diverter body constitutes a part of the bottom outer inclined end surface of the outflow section of the nozzle body, and the horizontal inclination angle of the end surface is from 40 degrees and inclusive to 50 degrees and inclusive.

[0013] Furthermore, the radius of curvature of the top surface of the guide arc of the pair of axisymmetric outer diverter bodies is from 10 mm to 15 mm; the minimum spacing between the pair of axisymmetric outer diverter bodies is 70% to 80% of the maximum length of the cross-section of the molten metal channel in the outflow section of the nozzle body; the distance between the highest point of the top surface of the guide arc of the outer diverter body and the bottom end surface of the nozzle body is 80 to 90% of the length of the outflow section of the nozzle body.

[0014] Furthermore, the minimum spacing between the pair of axisymmetric flow guides is 25% to 30% of the maximum length of the cross-section of the molten metal channel in the outflow section of the nozzle body, and is less than 50% of the minimum spacing between the pair of axisymmetric outer flow guides; the length of the outer inclined plane of the flow guide is greater than or equal to the length of its bottom surface, and less than 150% of the length of its bottom surface.

[0015] Furthermore, the height position of the top surface of the guide body is 0 to 10 mm lower than the upper edge of the auxiliary outflow channel hole, that is, the entrance position of the outflow section of the nozzle body, and is higher than the highest point position of the arc top surface of the external distributor body; the distance between the bottom surface of the guide body and the bottom end surface of the nozzle body is 65% to 70% of the length of the outflow section of the nozzle body, and is lower than the highest point position of the guide arc top surface of the external distributor body.

[0016] Furthermore, the horizontal top surfaces of the pair of axisymmetric flow guide bodies and the inner inclined planes thereof can be connected by a small arc surface or a small vertical surface.

[0017] Furthermore, the molten metal channel in the inlet section of the nozzle body is a circular channel with a bowl-shaped inlet, the diameter of the circular cross-section of the inlet is 80mm~95mm, and the circular cross-sectional area at the inlet is 190%~210% of the circular cross-sectional area at the outlet, and the length of the inlet section is 1 / 8~1 / 7 of the total length of the nozzle body.

[0018] Furthermore, the inlet of the molten metal channel in the expansion section of the nozzle body is consistent with the circular cross-section of the outlet of the molten metal channel in the inflow section. Then, the cross-section of the molten metal channel in the expansion section is a flat cross-section, and its cross-sectional area gradually expands and is controlled by three cross-sectional dimensions. The cross-sectional area at the outlet of the molten metal channel in the expansion section is 255% to 265% of the cross-sectional area at its inlet; the length of the expansion section is 5 / 7 to 7 / 9 of the total length of the nozzle body.

[0019] Furthermore, the maximum length of the cross section of the molten metal channel in the outflow section of the nozzle body is 360mm to 400mm, the length of the bottom middle horizontal end surface of the outflow section of the nozzle body is 50% to 60% of the maximum length of the cross section of the molten metal channel in the outflow section of the nozzle body, and the length of the outflow section of the nozzle body is 1 / 9 to 1 / 8 of the total length of the nozzle body.

[0020] Furthermore, the basic wall thickness of the refractory material of the nozzle body is 25 to 40 mm, the material wall thickness of the side surface of the nozzle body near the outlet of the expansion section gradually decreases along the radius of curvature of the side expansion arc, and the material wall thickness of the wide surface of the nozzle body in the outflow section gradually decreases to 2 / 3 of the wall thickness at the inlet, and the total length of the nozzle body is the sum of the lengths of its three sections (inflow section, expansion section, outflow section).

[0021] Compared with the prior art, the beneficial effects of the utility model are:

[0022] The utility model discloses an immersed water nozzle for continuous casting of thin slabs, which can automatically disperse and divert the molten metal better, so that the molten metal in the crystallizer of the thin slab continuous casting machine can have a more reasonable flow and a better temperature distribution in the crystallizer when producing different large and small section castings and continuous casting at different drawing speeds. The utility model realizes a universal immersed water nozzle to meet the needs of stably producing high-quality continuous casting billets under various process conditions, brings convenience to the continuous casting production organization and improves production efficiency.

[0023] The utility model discloses a thin slab continuous casting submerged nozzle which can adapt to the thin slab continuous casting machine to stably produce castings with full-size cross-sections at a pulling speed of 3.0-5.0 m / min or above, and avoid the occurrence of the "liquid surface slag rolling" phenomenon in the crystallizer.

[0024] The utility model discloses a thin slab continuous casting submerged nozzle which can adapt to the thin slab continuous casting machine to stably continuously cast the casting slabs with sections in the full range of sizes and avoid the occurrence of the "cold steel" phenomenon in the crystallizer in various drawing speed continuous casting states. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation on the present invention. In the accompanying drawings:

[0026] Attached Figure 1 It is a schematic diagram of a vertical cross-section of the main central portion of the nozzle of the utility model;

[0027] Attached Figure 2 It is a side view of the central vertical section of the nozzle described in the utility model;

[0028] Attached Figure 3 It is an enlarged perspective view of the central flow divider of the water outlet of the utility model;

[0029] Attached Figure 4 It is a detailed identification view of the outflow section of the nozzle of the utility model;

[0030] Attached Figure 5 It is a dimensioned view of the outflow section structure of the nozzle of the utility model;

[0031] Attached Figure 6 The water outlet described in the utility model is Figure 1 Horizontal cross-section at AA;

[0032] Attached Figure 7 The water outlet described in the utility model is Figure 1 Horizontal cross-section at the middle BB;

[0033] Attached Figure 8 The water outlet described in the utility model is Figure 1 Horizontal cross section at mid-CC;

[0034] Attached Fig. 9 It is a structural schematic diagram of an immersed nozzle for thin slabs of prior art 1;

[0035] Attached Fig.10 It is a schematic structural diagram of an immersion nozzle for thin slabs of prior art 2;

[0036] Attached Fig.11 Yes Fig. 9 A comparison diagram of velocity simulation data of the submerged nozzle of the prior art 1 and the nozzle of the utility model is shown;

[0037] Attached Fig.12 Yes Fig.10 The speed simulation data comparison diagram of the submerged water nozzle of the prior art 2 and the water nozzle described in the utility model is shown.

[0038] Description of reference numerals:

[0039] In the figure: 1. nozzle body 2. inflow section 3. expansion section 4. outflow section 5. central diverter body 6. outer diverter body 7. guide body 11. middle end face of nozzle body 22. outer oblique end face of bottom of nozzle body 33. main outlet channel of nozzle 44. auxiliary outlet channel of nozzle 51. upper top face of central diverter body 52. ​​bottom face of groove of central diverter body 61. inner guide oblique plane of outer diverter body 62. outer guide oblique plane of outer diverter body 63. guide arc top face of outer diverter body 71. inner oblique plane of guide body 72. outer oblique plane of guide body 73. top face of guide body 74. bottom face of guide body O. central vertical axis of nozzle body DETAILED DESCRIPTION

[0040] In order to make the purpose, technical scheme and technical effect of the utility model clearer, the utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0041] like Figures 1 to 8 As shown, the utility model describes an immersion nozzle for continuous casting of thin slabs, comprising a nozzle body 1, a central flow divider 5, an outer flow divider 6 and a flow guide 7; the nozzle body 1 is composed of an inflow section 2, an expansion section 3, and an outflow section 4 which are sequentially connected from top to bottom; the nozzle body 1 is provided with a molten metal channel which passes through along the vertical center axis O, and the cross-sections of the molten metal channels are symmetrical, and the molten metal channels of each section are smoothly transitionally connected, and the molten metal channel in the nozzle body 1 is provided with an inlet and five outlets.

[0042] The molten metal channel in the inflow section 2 is a circular channel with a bowl-shaped entrance. The diameter of the circular cross-section of the outlet of the molten metal channel in the inflow section 2 is set to 90mm, or can be from 80mm to 90mm, or from 85mm to 95mm; the circular cross-sectional area at its inlet is 198% of the circular cross-sectional area at its outlet; the length H1 of the circular cross-sectional inflow section 2 is set to 165mm, or 1 / 8 to 1 / 7 of the total length of the nozzle body 1.

[0043] The inlet of the molten metal channel in the expansion section 3 is the circular outlet of the molten metal channel in the inflow section 2, and the cross sections are the same, and then the length of the cross section gradually expands and the width gradually decreases. The flat cross section is basically a rectangular surface with semicircular surfaces at both ends, and the flat cross section area gradually expands and is controlled by the sizes of the three cross sections AA, BB and CC. In one embodiment, the distance between the AA cross section and the inlet of the molten metal channel in the expansion section 3 is 420mm, or can be from 400mm to 430mm; the distance between the AA cross section and the BB cross section is 310mm, and can be from 300mm to 320mm; the distance between the BB cross section and the CC cross section is 250mm, and can be from 240mm to 260mm; the length H2 of the expansion section 3 is 980mm, or 5 / 7 to 7 / 9 of the total length of the nozzle body 1.

[0044] Figure 6-8 yes Figure 1-2 The AA, BB and CC cross-sectional views of the expansion section 3 of the nozzle body 1 of the utility model are shown in the figure. In one embodiment, the ratio of the inner length a11 to the inner width b11 in the AA cross-sectional view is set to 2.4, or can be from 2.3 to 2.5; the cross-sectional area of ​​the molten metal channel in the AA cross-sectional view is 140% of the cross-sectional area of ​​the molten metal channel at the inlet of the expansion section 3, or from 135% to 145%; the ratio of the inner length a21 to the inner width b21 in the BB cross-sectional view can be set to 4.85, from 4.75 to 4.95; the cross-sectional area of ​​the molten metal channel in the BB cross-sectional view is 180% of the cross-sectional area of ​​the molten metal channel at the inlet of the expansion section 3, or from 170% to 185%; the inner length a31 to the inner width b31 in the CC ...%. The ratio of the inner width b31 can be set to 8.65, from 8.5 to 8.9; the cross-sectional area of ​​the molten metal channel in CC is 260% of the cross-sectional area at the entrance of the molten metal channel in the expansion section 3, or from 255% to 265%; the outer length a12, a22 and outer width b12, b22, b32 of each cross section are the required inner length and inner width plus 2 times the basic wall thickness of the nozzle body material; the inner width b31 of the CC cross section is 40mm, or from 30mm to 50mm; the inner length of the CC cross section is the same as the outer length a31, and its value is 385mm, or from 360mm to 400mm.

[0045] The channel in the outflow section 4 has a flat cross section, and its inlet is the outlet of the expansion section 3; the maximum length of the cross section of the molten metal channel in the outflow section 4 is a31; the maximum width of the cross section of the molten metal channel in the outflow section 4 is b31; the length H3 of the outflow section 4 is 145 mm, or 1 / 9 to 1 / 8 of the total length of the nozzle body.

[0046] A central flow divider 5, a pair of axisymmetric outer flow dividers 6 and a pair of axisymmetric flow guides 7 are arranged in the outflow section 4 of the nozzle body 1, so that the end surface of the outflow section of the molten metal channel in the nozzle forms five dispersed outlets; wherein:

[0047] The central divider body 5 is arranged on the bottom central axis of the outflow section 4 of the nozzle body 1. The central divider body 5 has an upper top surface 51 and a lower bottom surface and a pair of axisymmetric two side surfaces of the central divider body 5 and a vertical circular hole center outflow channel. The upper top surface 51 and the lower bottom surface of the central divider body are both horizontal planes, and a pair of axisymmetric grooves are arranged on the two side surfaces of the central divider body.

[0048] In one embodiment, the depth of the groove bottom surface 52 is from deep to shallow from top to bottom, the upper part of the groove bottom surface 52 is an arc surface, and its radius value is 5mm~10mm, and the middle and lower parts of the groove bottom surface 52 are diversion inclined planes, and its diversion angle γ is 6 degrees; the width of the groove is 20mm, or 1 / 3~3 / 4 of the b31 value.

[0049] The width b of the bottom surface of the central divider 5 is 70 mm and includes 70 mm to 80 mm and includes 80 mm; the maximum width a of the top surface 51 of the central divider 5 is 80 mm, or 100% and includes 100% to 150% and includes 150% of the b value; the height h1 of the central divider 5 can be 60 mm, or 1 / 2 of the h2 value to 2 / 5 of H3.

[0050] A vertical circular hole central outflow channel is arranged in the central flow divider 5 , and the diameter thereof is 19 mm, or ranges from 15 to 25 mm; the lower bottom surface of the central flow divider 5 constitutes the central part of the middle end surface 11 of the nozzle body 1 .

[0051] The pair of axisymmetric outer flow dividers 6 are arranged between the central flow divider body 5 and the side walls of the corresponding nozzle bodies 1 on both sides. The outer flow dividers 6 have a guide arc top surface 63, an inner guide inclined plane 61, an outer guide inclined plane 62 and a lower inclined bottom surface; the inner guide inclined plane 61 of the outer flow divider 6 and the side surface of the central flow divider 5 on the same side and the wide surface of the channel in the outflow section constitute the main outflow channel 33 of the nozzle; the outer guide inclined plane 62 of the outer flow divider 6 and the side arc surface of the metal liquid channel located near the outlet of the expansion section 3 and the wide surface of the channel in the outflow section 4 constitute two outer auxiliary outflow channels 44 of the nozzle.

[0052] In one embodiment, the angle between the outer guide inclined plane 62 of the outer diverter body 6 and the central vertical axis O, i.e., the guide inclination angle α, is 30 degrees, or 25 degrees to 35 degrees; the guide inclination angle β of the inner guide inclined plane 61 of the outer diverter body 6 is 15 degrees, or 12 degrees to 18 degrees; the curvature radius r of the guide arc top surface 63 of the outer diverter body 6 is 13 mm, or 10 mm to 15 mm; the lower inclined bottom surface of the outer diverter body 6 constitutes the A portion of the bottom outer oblique end surface 22 of the outflow section 4 of the nozzle body 1, the horizontal inclination angle θ of the bottom outer oblique end surface 22 is 45 degrees, or 40 degrees to 50 degrees; the minimum spacing d between the pair of axisymmetric outer diverter bodies 6 is 285 mm, or 70% to 80% of a31; the distance h3 between the highest point of the guide arc top surface 63 of the outer diverter body 6 and the bottom end surface 11 of the nozzle body 1 is 120 mm, or 80% to 90% of the H3 value;

[0053] The pair of axisymmetric guide bodies 7 are arranged at the upper part of the outflow section 4 of the nozzle body 1, and the guide body 7 has an inner inclined plane 71, an outer inclined plane 72, a top surface 73 and a bottom surface 74; the top surface 73 and the bottom surface 74 of each guide body are both horizontal planes.

[0054] In one embodiment, the minimum spacing e between the pair of axisymmetric guide bodies 7 is 105 mm, or 25% to 30% of the value of a31, and less than 50% of the value of d; the length of the outer inclined plane 72 of the guide body 7 is 40 mm, or from 35 mm to 50 mm; the length of the bottom surface 74 of the guide body 7 can be 33 mm, or from 30 mm to 40 mm; the height position of the top surface 73 of the guide body 7 is lower than the upper edge of the auxiliary outflow channel hole, that is, the upper edge of the nozzle body. The inlet position of the outflow section 4 is 5mm, or 0-10mm, and is higher than the highest point of the arc top surface of the external flow divider; the distance h2 between the bottom surface 74 of the guide body 7 and the bottom end surface 11 of the nozzle body 1 is 100mm, or 65%-70% of the H3 value, and is lower than the highest point of the guide arc top surface 63 of the external flow divider 6; the length B of the bottom middle horizontal end surface 11 of the outflow section 4 of the nozzle body 1 is 210mm, or 50-60% of a31.

[0055] The included angles between the inner inclined plane 71 and the outer inclined plane 72 of the guide body 7 and the central vertical axis O are the same as the guide angle β of the inner guide inclined plane 61 of the outer flow divider 6 on the same side.

[0056] In one embodiment, the top surface 73 of the pair of axisymmetric flow guide bodies 7 and their inner inclined plane 71 are connected by a small arc surface, the radius of which can be 8 mm, or from 5 mm to 10 mm; or by a small vertical surface, the vertical length of which is 8 mm, or from 5 mm to 10 mm.

[0057] In one embodiment, the basic wall thickness of the material of the nozzle body 1 is 30 mm, the wall thickness of the narrow surface of the nozzle body 1 near the outlet of its expansion section 3 gradually decreases to zero according to the curvature radius R of the side expansion arc of 75 mm, and the wall thickness of the wide surface of the nozzle body 1 in the outflow section 4 gradually decreases to 20 mm. The total length of the nozzle body 1 is 1285 mm, which can be from 1270 mm to 1300 mm depending on the continuous casting equipment.

[0058] The beneficial effects of the submerged nozzle for thin slabs described in the utility model will be further described below through flow field simulation tests in the embodiments.

[0059] Fig.11 It is a comparison diagram of the speed of the molten metal distributed along the width direction on the horizontal section at the nozzle outlet of the crystallizer when casting at a high pulling speed during MCCR continuous casting to produce large-section ingots using the nozzle of the prior art 1 and the nozzle described in the utility model.

[0060] As shown in the figure, the metal liquid velocity distribution in the width direction of the crystallizer at the outlet of the water nozzle described in the utility model (data indicated by the dotted line) is relatively more uniform and dispersed, so that its maximum speed is about 30% lower than the maximum speed of the submerged water nozzle for thin slabs provided by the prior art 1 on the horizontal section of the crystallizer at the water nozzle outlet (data indicated by the solid line), and the upward swirling flow velocity near the narrow surface of the crystallizer on both sides of the curve is also reduced, and the speed on both sides is also relatively uniform, so that the flow velocity on the liquid surface of the crystallizer is controlled and the liquid surface is more stable, thereby avoiding the occurrence of "liquid surface slag rolling" phenomenon in the crystallizer.

[0061] Fig.12 The velocity of the molten metal on the horizontal section at the nozzle outlet of the crystallizer is compared when casting is performed at a lower pulling speed during MCCR continuous casting production of small-section ingots using the nozzle of the prior art 2 and the nozzle of the utility model.

[0062] As shown in the figure, the molten metal flow rate in the width direction of the crystallizer at the outlet of the water nozzle described in the utility model (data indicated by the dotted line) is relatively more uniform and dispersed, and its maximum speed is about 20% higher than the maximum speed of the submerged water nozzle for thin slabs provided by the prior art 2 on the horizontal section of the crystallizer at the water nozzle outlet (data indicated by the solid line), and the upward swirling flow rate near the narrow surface of the crystallizer on both sides of the curve is also improved, which is beneficial to bring the high-temperature molten metal to the crystallizer liquid surface, which is very important for promoting the melting of protective slag and the role of its metallurgical function, and at the same time ensures that the crystallizer liquid surface can avoid the occurrence of "cold steel" phenomenon when the crystallizer liquid level is in a stable state.

[0063] Therefore, the submerged nozzle for MCCR thin slabs described in the utility model is superior to the submerged nozzle for thin slabs provided by prior arts 1 and 2 in terms of flow velocity and temperature distribution in the crystallizer.

[0064] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements, changes or combinations according to the technical scheme and concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A thin slab continuous casting immersion nozzle, comprising a nozzle body, a flow divider and a flow guide, wherein a molten metal channel is provided in the nozzle body and passes through along the central vertical axis, and the cross section thereof is symmetrical, the molten metal channel has an inlet, and the molten metal channel has at least one outlet; the nozzle body is composed of an inflow section, an expansion section and an outflow section connected in sequence from top to bottom, and the molten metal channels in each section are smoothly transitionally connected, and the characteristics are: A central flow divider, a pair of axially symmetrical outer flow dividers and a pair of axially symmetrical flow guides are arranged in the outflow section of the nozzle body; wherein: The central dividing body is arranged on the bottom central axis of the outflow section of the nozzle body, and the central dividing body has an upper top surface and a lower bottom surface, a pair of axisymmetric side surfaces and a central outflow channel. The upper top surface and the lower bottom surface of the central dividing body are both horizontal planes, and a pair of axisymmetric grooves are arranged on both sides of the central dividing body; The pair of axisymmetric outer flow dividers are located between the central flow divider body and the corresponding side walls of the water inlet on both sides. The outer flow dividers have a flow guide arc top surface, an inner flow guide inclined plane, an outer flow guide inclined plane and a lower inclined bottom surface; the inner flow guide inclined plane of the outer flow divider, the side surface of the central flow divider on the same side and the wide surface of the inner channel of the outflow section constitute the main outflow channel of the water inlet, and the outer flow guide inclined plane of the outer flow divider, the side arc surface of the metal liquid channel located on the same side of the expansion section near its outlet and the wide surface of the inner channel of the outflow section constitute the two outer auxiliary outflow channels of the water inlet; The pair of axisymmetric guide bodies are arranged at the upper part of the outflow section of the nozzle body. The guide body has a top surface, a bottom surface, an outer inclined plane and an inner inclined plane. The top surface and the bottom surface of the guide body are horizontal planes.

2. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: A pair of axially symmetrical grooves are provided on the two sides of the central divider body, and the depth of the bottom surface of the grooves is from deep to shallow from top to bottom. The upper part of the bottom surface of the grooves is an arc surface and then transitions to the middle and lower diversion inclined plane. The diversion inclination angle (γ) of the middle and lower diversion inclined plane of the side grooves of the central divider body is from 5 degrees and inclusive to 8 degrees and inclusive; the width of the grooves set on the side of the central divider body is 1 / 3 to 3 / 4 of the maximum width of the cross section of the molten metal channel in the outflow section of the nozzle body.

3. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The width (b) of the bottom surface of the central divider body is 70 mm and includes 70 mm to 80 mm and includes 80 mm; the maximum width (a) of the top surface of the central divider body is 100% and includes 100% to 150% and includes 150% of the width (b) of the bottom surface of the central divider body; the height (h1) of the central divider body is greater than 1 / 2 of the distance (h2) between the bottom surface of the guide body and the bottom end surface of the nozzle body, and is less than 2 / 5 of the length (H3) of the outflow section of the nozzle body.

4. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The value of the diversion angle (α) of the outer diversion inclined plane of the pair of axisymmetric outer diverter bodies is from 25 degrees and includes 25 degrees to 35 degrees and includes 35 degrees; the value of the diversion angle (β) of the inner diversion inclined plane of the outer diverter body is from 12 degrees and includes 12 degrees to 18 degrees and includes 18 degrees; the curvature radius (r) of the top surface of the diversion arc of the outer diverter body is 13 mm, from 10 mm to 15 mm; the lower inclined bottom surface of the outer diverter body constitutes a part of the bottom outer inclined end surface of the outflow section of the nozzle body, and the horizontal inclination angle (θ) of the bottom outer inclined end surface is from 40 degrees and includes 40 degrees to 50 degrees and includes 50 degrees.

5. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The minimum spacing (d) between the pair of axisymmetric outer flow dividers is 70% to 80% of the maximum length of the cross section of the molten metal channel in the outflow section of the nozzle body; the distance (h3) between the highest point of the top surface of the guide arc of the outer flow divider and the bottom end surface of the nozzle body is 80% to 90% of the length of the outflow section of the nozzle body.

6. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The minimum spacing (e) between the pair of axisymmetric flow guides is 25% to 30% of the maximum length of the cross-section of the molten metal channel in the outflow section of the nozzle body, and is less than 50% of the minimum spacing (d) between the pair of axisymmetric outer flow guides; the length of the outer inclined plane of the flow guide is greater than or equal to the length of its bottom surface, and less than 150% of the length of its bottom surface.

7. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The height position of the top surface of the guide body is 0 to 10 mm lower than the upper edge of the auxiliary outflow channel hole, that is, the entrance position of the outflow section of the nozzle body, and is higher than the highest point position of the arc top surface of the external distributor body; the distance (h2) between the bottom surface of the guide body and the bottom end surface of the nozzle body is 65% to 70% of the length (H3) of the outflow section of the nozzle body, and is lower than the highest point position of the guide arc top surface of the external distributor body.

8. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The inclination angles of the inner inclined plane and the outer inclined plane of the guide body are the same as the guide inclination angle (β) of the inner guide inclined plane of the outer flow divider on the same side.

9. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The cross-sectional area at the outlet of the molten metal channel in the expansion section is 255% to 265% of the cross-sectional area at the inlet; the length (H2) of the expansion section is 5 / 7 to 7 / 9 of the total length of the nozzle body.

10. The thin slab continuous casting submerged nozzle according to claim 1, characterized in that: The length (B) of the bottom middle horizontal end surface of the outflow section of the nozzle body is 50% to 60% of the maximum length (a31) of the cross section of the molten metal channel in the outflow section of the nozzle body, and the length (H3) of the outflow section of the nozzle body is 1 / 9 to 1 / 8 of the total length of the nozzle body.

Images