Steel ingot, pouring method thereof and heat preservation type chassis

Abstract

The invention relates to a steel ingot, a pouring method thereof and a heat preservation type chassis, and belongs to the technical field of smelting technologies. The steel ingot is poured through a heat preservation type base plate, and the steel ingot sequentially comprises a water gap, an ingot body and a dead head from bottom to top. The pouring speed of the water gap part is 7-9t / min; the pouring speed of the ingot body is 5-6 t / min; the pouring speed of the riser part is 2-4 t / min; the heat preservation type chassis comprises a chassis body, a steel sleeve, heat preservation materials, filling materials, a bottom steel plate and an upper steel plate. Under the cooperation of the heat preservation type base plate and the pouring speed, within a certain period of time, liquid metal with a large proportion is kept at the water gap part in the steel ingot, solidification of the water gap part of the steel ingot can be slowed down, the deposition cone problem can be relieved, the time is long enough to enable inclusions and isometric crystals to enter the water gap part, it is guaranteed that the interior of an ingot body is clean, and the metallurgical quality is improved.

Description

Technical Field

[0001] The invention relates to the technical field of smelting, and is a steel ingot and a pouring method thereof, and a heat-insulating chassis. Background Art

[0002] In recent years, with the surge in electricity consumption and the increasing demand for large rolling mills in the steel industry, the size of forgings such as rotors and rolls has also increased accordingly, which has directly led to an increase in the weight of the required forging steel ingots.

[0003] Large steel ingots are generally prepared by gravity casting. They are in a vertical state and mainly consist of a nozzle, an ingot body and a riser, of which the riser is located at the upper end of the ingot body. During the solidification process of the steel ingot, the molten steel enters the chassis. Since the temperature at the nozzle position of the chassis is relatively low, the high-temperature molten steel is quickly cooled and solidified. The equiaxed crystals formed during the solidification process sink, and the tip of the columnar crystal breaks and sinks, forming a sedimentation cone at the nozzle. During the solidification process of the ingot body, the sedimentation cone generated at the nozzle gradually grows toward the ingot body and gathers at the part of the ingot body close to the nozzle, affecting the use of the ingot body.

[0004] Therefore, there is an urgent need for a casting method that can effectively alleviate the sedimentation cone problem and ensure that the number of inclusions in the ingot body is low, thereby ensuring the flaw detection results. Summary of the invention

[0005] In view of the above analysis, the present invention aims to provide a steel ingot and a casting method thereof, and an insulating chassis, which can effectively alleviate the problem of sedimentation cones in the steel ingot and do not affect the flaw detection results of the final product.

[0006] In a first aspect, the present invention provides a method for casting a steel ingot, which uses a heat-insulating chassis to cast the steel ingot, wherein the steel ingot comprises a nozzle, an ingot body and a riser from bottom to top;

[0007] The pouring speed of the water inlet is 7-9 t / min; the pouring speed of the ingot body is 5-6 t / min; the pouring speed of the riser is 2-4 t / min;

[0008] The heat-insulated chassis includes a chassis, a steel sleeve, heat-insulating materials, filling materials, a bottom steel plate and an upper steel plate;

[0009] The steel sleeve is placed in a groove opened on the chassis, the insulation material is wrapped around the outer circumference of the steel sleeve, the filling material is placed on the side of the insulation material away from the steel sleeve, the bottom steel plate is placed inside the steel sleeve and connected to the chassis, and the upper steel plate covers the filling material.

[0010] Furthermore, the thermal insulation material is selected from asbestos and rock wool.

[0011] Furthermore, the thickness of the thermal insulation material is 50-100 mm.

[0012] Furthermore, the filling material is selected from steel balls, broken steel blocks and steel nail scraps.

[0013] Furthermore, the steel ball is made of ordinary carbon steel or stainless steel, and has a diameter of 5-10 mm.

[0014] Furthermore, the thickness of the bottom steel plate is 50-60 mm.

[0015] Furthermore, the casting method of the steel ingot comprises the following steps:

[0016] S1: Assembly of the insulated chassis;

[0017] S2: placing a heat-insulating chassis on the ground, then placing a steel ingot mold on the heat-insulating chassis, and finally placing a riser sleeve on the steel ingot mold;

[0018] S3: pouring the molten steel into an ingot mold, adjusting the pouring speed, and obtaining a steel ingot after cooling.

[0019] In a second aspect, the present invention provides a steel ingot prepared by the casting method of the steel ingot described in the present invention.

[0020] Furthermore, the steel ingot comprises a nozzle, an ingot body and a riser from bottom to top, and the weight ratio of the nozzle to the ingot body is 1:(16-34).

[0021] In a third aspect, the present invention provides a heat-insulating chassis for implementing the casting method of the steel ingot described in the present invention.

[0022] The heat-insulating chassis comprises a chassis, a steel sleeve, a heat-insulating material, a filling material, a bottom steel plate and an upper steel plate;

[0023] The steel sleeve is placed in a groove opened on the chassis, the insulation material is wrapped around the outer circumference of the steel sleeve, the filling material is placed on the side of the insulation material away from the steel sleeve, the bottom steel plate is placed inside the steel sleeve and connected to the chassis, and the upper steel plate covers the filling material.

[0024] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0025] 1. The present invention uses an insulating chassis to cast steel ingots. The water inlet of the steel ingot is insulated under the action of insulating materials and filling materials, and the pouring speed during the pouring process is controlled. The pouring speed of the water inlet is 7-9t / min; the pouring speed of the ingot body is 5-6t / min; and the pouring speed of the riser part of the steel ingot is 2-4t / min. With the cooperation of the insulating chassis and the pouring speed, a large proportion of liquid metal is maintained in the water inlet of the steel ingot within a certain period of time, which can slow down the solidification of the water inlet of the steel ingot, help alleviate the sedimentation cone problem, and have enough time for inclusions and equiaxed crystals to enter the water inlet, ensuring that the inside of the ingot body is relatively clean.

[0026] 2. The heat-insulating chassis of the present invention includes a chassis, a steel sleeve, a heat-insulating material, a filling material, a bottom steel plate and an upper steel plate. The steel sleeve is placed in a groove opened on the chassis, and the heat-insulating material and the filling material are wrapped on the outer circumference of the steel sleeve in sequence. The diameter of the bottom steel plate is the same as the inner diameter of the steel sleeve, and the bottom steel plate is placed at the bottom of the steel sleeve and connected to the chassis. The cavity formed by the bottom steel plate and the steel sleeve is the water inlet. During the pouring process, the water inlet is insulated under the action of the heat-insulating material and the filling material, so that the solidification of the water inlet of the steel ingot slows down.

[0027] 3. The heat-insulating material in the present invention is made of asbestos or rock wool, and the thickness is above 50 mm, which can better insulate the nozzle area and effectively slow down the speed of temperature drop of molten steel in the nozzle area.

[0028] 4. The filling material in the present invention is a steel ball with a diameter of 5-10 mm, which is compacted; on the one hand, the steel ball fixes the position of the thermal insulation material to ensure good contact between the thermal insulation material and the steel sleeve; on the other hand, the small air gap between the steel balls forms a multi-layer air insulation wall, further enhancing the insulation effect of the water inlet.

[0029] 5. The chassis, steel sleeve, bottom steel plate and upper steel plate in the present invention need to be ground or polished before use, and no visible rust is allowed on the surface to prevent slag inclusions from entering the ingot body during the casting process and affecting the quality of the steel ingot.

[0030] In the present invention, the above-mentioned technical solutions can also be combined with each other to achieve more preferred combination solutions. Other features and advantages of the present invention will be described in the subsequent description, and some advantages can become obvious from the description, or can be understood by practicing the present invention. The purpose and other advantages of the present invention can be realized and obtained through the contents particularly pointed out in the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings are only for the purpose of illustrating particular embodiments and are not to be considered limiting of the present invention. Like reference symbols denote like components throughout the drawings.

[0032] Figure 1 This is a schematic diagram of the heat-insulating chassis structure;

[0033] Figure 2 It is a schematic diagram of the assembly of the heat-insulating chassis, the ingot mold and the riser sleeve during the ingot pouring process;

[0034] Figure 3 The samples are from the nozzle area and the nozzle side of the ingot body in Example 1;

[0035] Figure 4 The samples of the nozzle part and the nozzle side of the ingot body in comparative example 1;

[0036] In the figure, 1. chassis; 2. upper steel plate; 3. filling material; 4. insulation material; 5. steel sleeve; 6. bottom steel plate; 7. steel ingot mold; 8. riser sleeve. DETAILED DESCRIPTION

[0037] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0038] With the rapid development of industry, the size of forgings such as rotors and rolls has also increased accordingly, which has directly led to the increase in the size of forging ingots. However, during the preparation of ingots, the water inlet often produces a sedimentation cone problem.

[0039] In order to alleviate the sedimentation cone problem, the present invention provides a method for casting a steel ingot, which uses a heat-insulating chassis to cast the steel ingot, wherein the steel ingot includes a water inlet, an ingot body and a riser from bottom to top;

[0040] The pouring speed of the water inlet is 7-9 t / min; the pouring speed of the ingot body is 5-6 t / min; the pouring speed of the riser is 2-4 t / min;

[0041] The heat-insulated chassis includes a chassis, a steel sleeve, heat-insulating materials, filling materials, a bottom steel plate and an upper steel plate;

[0042] The steel sleeve is placed in a groove opened on the chassis, the thermal insulation material is wrapped around the outer circumference of the steel sleeve, the filling material is placed on the side of the thermal insulation material away from the steel sleeve, the bottom steel plate is placed inside the steel sleeve and connected to the chassis, and the upper steel plate covers the filling material.

[0043] Compared with the prior art, the present invention adopts an insulating bottom plate and controls the pouring speed during the pouring process, thereby prolonging the solidification time of the water inlet, allowing inclusions and equiaxed crystals on the water inlet side of the ingot body to enter the water inlet, effectively alleviating the sedimentation cone problem on the water inlet side of the ingot body.

[0044] The heat-insulating chassis includes a steel sleeve placed on the chassis, and a bottom steel plate of a certain thickness is placed at the bottom of the steel sleeve. The space formed by the steel sleeve and the bottom steel plate is the nozzle. The steel sleeve is wrapped with insulation material and filling material on the outer circumference of the steel sleeve in sequence. Under the joint action of the insulation material and the filling material, the molten steel in the steel sleeve can be insulated, and the cooling rate and solidification rate of the molten steel can be slowed down. Under the influence of gravity, inclusions and equiaxed crystals on the nozzle side of the ingot body enter the nozzle, ensuring the metallurgical quality of the ingot body.

[0045] During the pouring process, the pouring speed at different positions of the ingot is controlled. The pouring speed at the water inlet is 7-9t / min, which can ensure that the water inlet is at a higher temperature, which is conducive to the inclusions and equiaxed crystals on the water inlet side of the ingot body entering the water inlet. The pouring speed at the riser is 2-4t / min, which makes the liquid level in the ingot body rise steadily, thereby promoting the floating of inclusions on the riser side of the ingot body and ensuring the metallurgical quality of the ingot body.

[0046] Specifically, in order to facilitate lifting and assembly, a plurality of lifting ears are evenly fixed on the outer peripheral surface of the chassis.

[0047] Specifically, the thermal insulation material is selected from asbestos and rock wool.

[0048] Specifically, the thickness of the thermal insulation material is 50-100 mm.

[0049] Specifically, the filling material is selected from steel balls, steel sand, and steel nail scraps.

[0050] Preferably, the steel ball is made of ordinary carbon steel or stainless steel, and has a diameter of 5-10 mm.

[0051] The solidification rate of the molten steel in the nozzle can be reduced by the combined effect of the insulation material and the filling material. The insulation material is selected from asbestos or rock wool with a thickness of 50-100mm and good insulation effect. When the thickness of the insulation material is less than 50mm, the insulation effect is poor and the sedimentation cone problem cannot be effectively solved; when the thickness of the insulation material is greater than 100mm, the insulation effect will not increase with the increase of thickness, but it will affect the supporting strength of the subsequent filling material on the steel sleeve.

[0052] The insulation material is wrapped on the outer circumference of the steel sleeve, and then the filling material is placed on the side of the insulation material away from the steel sleeve. The filling material can not only fit the insulation material tightly on the steel sleeve, but also has a certain insulation effect. In particular, the filling material is selected from steel balls with a diameter of 5-10mm, and the small air gaps between the steel balls form a multi-layer air insulation wall, which further strengthens the insulation of the water outlet.

[0053] Specifically, the chassis is a cylinder, and a groove is provided on the upper surface of the chassis. Generally, the groove provided on the commonly used chassis is in the shape of a truncated cone, and the cross-axial section is in the shape of an inverted trapezoid.

[0054] The insulation material, the upper steel plate and the chassis form an area with a right triangle cross section, which is the insulation material area. The two right-angled sides of the right triangle are parallel to or coincide with the insulation material and the upper steel plate, respectively. In other words, during the pouring and solidification of the molten steel, under the joint action of the insulation material and the filling material in the triangular area, the molten steel in the steel sleeve forms a gradient solidification when solidifying, and solidifies gradually from the bottom to the top, ensuring that impurities such as inclusions enter the nozzle.

[0055] Specifically, the thickness of the bottom steel plate is 50-60 mm.

[0056] The function of the bottom steel plate is to prevent the molten steel from impacting the chassis for a long time, which will soften the chassis and cause adhesion, making it impossible to effectively separate the steel ingot and the chassis. When the thickness of the bottom steel plate is too large, the proportion of the ingot water outlet will decrease, reducing the probability of inclusions entering the water outlet and easily causing material waste; when the thickness of the bottom steel plate is too small, it is easy to lose the protective effect on the chassis.

[0057] Specifically, the height of the steel sleeve is 1200 mm and the diameter is 1000-2000 mm.

[0058] Specifically, the thickness of the upper steel plate is 20-50 mm.

[0059] The upper steel plate is circular and has a through hole in the center. The diameter of the through hole is the same as the outer diameter of the steel sleeve, or the diameter of the through hole is equal to the outer diameter of the steel sleeve and twice the thickness of the insulation material. The outer diameter of the upper steel plate matches the inner diameter of the ingot mold water inlet side. Its main function is to cover the filling material to prevent the filling material from entering the ingot body, and to ensure that the ingot and the chassis do not stick together during demoulding, so as to facilitate demoulding.

[0060] Specifically, the casting method of the steel ingot comprises the following steps:

[0061] S1: Assembly of the insulated chassis;

[0062] S2: placing a heat-insulating chassis on the ground, then placing a steel ingot mold on the heat-insulating chassis, and finally placing a riser sleeve on the steel ingot mold;

[0063] S3: pouring the molten steel into an ingot mold, adjusting the pouring speed, and obtaining a steel ingot after cooling.

[0064] Reference Figure 1 , place the chassis 1 on the ground. The chassis 1 is a cylinder, and a groove is opened in the center of the chassis 1; a circular bottom steel plate 6 is placed in the groove, and the central axis of the bottom steel plate 6 is collinear with the central axis of the chassis 1; a steel sleeve 5 is placed on the bottom steel plate 6, and the inner diameter of the steel sleeve 5 is the same as the diameter of the bottom steel plate 6; then a certain thickness of thermal insulation material 4 is wrapped on the outer circumference of the steel sleeve 5, and a filling material 3 is placed on the side of the thermal insulation material 4 away from the steel sleeve 5, and the filling material 3 is flush with the upper surface of the chassis 1; finally, the upper steel plate 2 is placed on the filling material 3, and a through hole is opened in the center of the upper steel plate 2, and the diameter of the through hole is equal to the outer diameter of the steel sleeve 5 plus twice the thickness of the thermal insulation material 4. The assembly of the thermal insulation chassis 1 is completed and is ready for use.

[0065] Reference Figure 2 , place the insulated chassis 1 on the ground, then place the ingot mold 7 on the insulated chassis 1, and then place the riser sleeve 8 on the side of the ingot mold 7 away from the insulated chassis 1, wherein the central axes of the insulated chassis 1, the ingot mold 7 and the riser sleeve 8 are located in the same straight line, finally, pour the molten steel into the ingot mold 7, adjust the pouring speed so that the ingot fills the insulated chassis 1, the ingot mold 7 and the riser sleeve 8, and demould after cooling to obtain the ingot.

[0066] It should be noted that the steel ingot is made by the casting method of the present invention, and the steel ingot includes a nozzle, an ingot body and a riser from bottom to top, and the weight ratio of the nozzle to the ingot body is 1:(16-34), and can be used to prepare super-large steel ingots of 96-363t.

[0067] In order to explain the present invention clearly, the following examples and comparative examples are provided for illustration.

[0068] Example 1

[0069] Take 211t steel ingot as an example.

[0070] The preparation of steel ingots includes the following steps:

[0071] S1: Assembly of the insulated chassis

[0072] S11: placing the chassis on the ground, and placing a bottom steel plate in the groove of the chassis, wherein the bottom steel plate has a thickness of 50 mm and a diameter of 1500 mm;

[0073] S12: Put a steel sleeve on the bottom steel plate, and then wrap the insulation material asbestos board along the outer circumference of the steel sleeve, wherein the inner diameter of the steel sleeve is 1500mm, the outer diameter is 1520mm, and the height is 1200mm; the thickness of the asbestos board is 50mm, and the height is 1200mm;

[0074] S13: Then place a filling material on the side of the asbestos board away from the steel sleeve. The height of the filling material is flush with the upper surface of the chassis. The filling material is a steel ball with a diameter of 5 mm.

[0075] S14: Finally, a circular upper steel plate with a thickness of 20 mm is covered on the steel ball, the upper steel plate is flush with the steel sleeve, and the diameter of the through hole opened in the upper steel plate is 1520 mm;

[0076] S2: placing a heat-insulating chassis on the ground, then placing a steel ingot mold on the heat-insulating chassis, and finally placing a riser sleeve on the steel ingot mold;

[0077] Specifications of the ingot mold: The ingot mold is a 24-sided concentric cylinder with a height of 3435mm, an upper outer diameter of 3917mm, an upper inner diameter of 3017mm, a lower outer diameter of 3708mm, a lower inner diameter of 2708mm, a taper of 9.0%, and a height-to-diameter ratio of 1.2.

[0078] Specifications of the riser sleeve: insulation riser height 2020mm, inner diameter of riser lower flange 2917mm, inner diameter of riser lower edge 3517mm, inner diameter of insulation riser upper flange 2720mm, outer diameter of insulation riser upper end 3320mm, thickness of upper and lower flanges are both 100mm, thickness of insulation riser outer wall 120mm, taper of insulation riser 9.8%, height-to-diameter ratio 0.39.

[0079] S3: Before pouring, all positions in contact with molten steel need to be polished and air suctioned, and no visible rust is allowed on the polished bright surface; during pouring, the pouring speed is controlled by controlling the opening and closing degree of the argon blowing slide. The pouring speed at the water inlet is 8t / min, the pouring speed at the ingot body is 5t / min, and the pouring speed at the riser is 3t / min.

[0080] After cooling, a steel ingot is obtained.

[0081] Example 2

[0082] Take 242t steel ingot as an example.

[0083] The preparation of steel ingots includes the following steps:

[0084] S1: Assembly of the insulated chassis

[0085] S11: placing the chassis on the ground, and placing a bottom steel plate in the groove of the chassis, wherein the bottom steel plate has a thickness of 50 mm and a diameter of 1600 mm;

[0086] S12: Put a steel sleeve on the bottom steel plate, and then wrap the insulation material asbestos board along the outer circumference of the steel sleeve, wherein the inner diameter of the steel sleeve is 1500mm, the outer diameter is 1520mm, and the height is 1200mm; the thickness of the asbestos board is 50mm, and the height is 1200mm;

[0087] S13: Then place a filling material on the side of the asbestos board away from the steel sleeve. The height of the filling material is flush with the upper surface of the chassis. The filling material is a steel ball with a diameter of 5 mm.

[0088] S14: Finally, a circular upper steel plate with a thickness of 20 mm is covered on the steel ball, the upper steel plate is flush with the steel sleeve, and the diameter of the through hole opened in the upper steel plate is 1520 mm;

[0089] S2: placing a heat-insulating chassis on the ground, then placing a steel ingot mold on the heat-insulating chassis, and finally placing a riser sleeve on the steel ingot mold;

[0090] Specifications of the ingot mold: The ingot mold is a 24-sided concentric cylinder with a height of 3458mm, an upper outer diameter of 4062mm, an upper inner diameter of 3162mm, a lower outer diameter of 3851mm, a lower inner diameter of 2851mm, a taper of 9.0%, and a height-to-diameter ratio of 1.15.

[0091] Specifications of the riser sleeve: insulation riser height 2020mm, inner diameter of riser lower flange 3082mm, inner diameter of riser lower edge 3682mm, inner diameter of insulation riser upper flange 2890mm, outer diameter of insulation riser upper end 3490mm, thickness of upper and lower flanges are both 100mm, thickness of insulation riser outer wall 120mm, taper of insulation riser 9.5%, height-to-diameter ratio 0.37.

[0092] S3: Before pouring, all positions in contact with molten steel need to be polished and air suctioned, and no visible rust is allowed on the polished bright surface; during pouring, the pouring speed is controlled by controlling the opening and closing degree of the argon blowing slide. The pouring speed at the water inlet is 9t / min, the pouring speed at the ingot body is 6t / min, and the pouring speed at the riser is 4t / min.

[0093] After cooling, a steel ingot is obtained.

[0094] Example 3

[0095] The preparation process of the steel ingot in Example 3 is substantially the same as that in Example 1, except that the weight of the steel ingot in Example 3 is 185 t.

[0096] Specifications of the ingot mold: The ingot mold is a 24-sided concentric cylinder with a height of 3249mm, an upper outer diameter of 3685mm, an upper inner diameter of 2845mm, a lower outer diameter of 3509mm, a lower inner diameter of 2569mm, a taper of 8.5%, and a height-to-diameter ratio of 1.2.

[0097] Specifications of the riser sleeve: insulation riser height 2020mm, inner diameter of riser lower flange 2760mm, inner diameter of riser lower edge 3360mm, inner diameter of insulation riser upper flange 2565mm, outer diameter of insulation riser upper end 3165mm, thickness of upper and lower flanges are both 100mm, thickness of insulation riser outer wall 120mm, taper of insulation riser 9.7%, height-to-diameter ratio 0.39.

[0098] After cooling, a steel ingot is obtained.

[0099] Comparative Example 1

[0100] Take 211t steel ingot as an example.

[0101] The preparation methods of the steel ingots of Comparative Example 1 and Example 1 are substantially the same, except that the casting of Comparative Example 1 is performed according to the conventional operation:

[0102] Step 1: Place the chassis on the ground, and place a bottom steel plate in the groove of the chassis, where the thickness of the bottom steel plate is 50 mm and the diameter is 1500 mm;

[0103] Step 2: Place the insulation chassis on the ground, then place the ingot mold on the insulation chassis, and finally place the riser sleeve on the ingot mold;

[0104] Step 3: Before pouring, all the places in contact with the molten steel need to be polished and air sucked, and no visible rust is allowed on the polished surface;

[0105] Step 4: During pouring, the pouring speed is controlled by opening the argon blowing slide, and the pouring speed is 6t / min.

[0106] After cooling, a steel ingot is obtained.

[0107] Comparative Example 2

[0108] The preparation methods of the steel ingots in Comparative Example 2 and Example 1 are substantially the same, except that the casting speed of the entire process in Comparative Example 2 is 5 t / min.

[0109] After cooling, a steel ingot is obtained.

[0110] Performance Testing

[0111] The steel ingots obtained in Examples 1-3 and Comparative Examples 1-2 were forged using the same forging process, which was as follows: first, the nozzle was clamped, and then the riser was cut off; then upsetting was performed, and then stretching was performed; and then upsetting and stretching were performed again. After forging, a HS511 digital ultrasonic flaw detector was used to perform flaw detection, and the flaw detection position was the nozzle side of the ingot body. The test results are shown in Table 1. The steel ingots obtained in Example 1 and Comparative Example 1 were sampled to observe whether there was a sediment pile problem at the nozzle position and the nozzle side of the ingot body. Figure 3 and Figure 4 .

[0112] Table 1 Flaw detection results

[0113]

[0114]

[0115] Referring to Examples 1-3 and Comparative Examples 1-3 and combined with Table 1, it can be seen that the inclusions on the water inlet side of the ingot body after forging are more fully settled by using the steel ingots prepared by Examples 1-3, and the size of the inclusions is less than Φ4 mm. This indicates that the use of the casting method and the heat-insulating chassis can effectively alleviate the sedimentation cone problem.

[0116] Reference Figure 3 and Figure 4 Comparative Example 1 is an existing casting method, and the steel ingot produced has a serious sedimentation cone problem, which is mainly concentrated on the ingot body water inlet side and water inlet position. However, Example 1 adopts an insulating chassis and controls the casting speed of each part, which can effectively alleviate the sedimentation cone problem.

[0117] 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 changes or substitutions that can be easily conceived by any technician familiar with the technical field within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for casting a steel ingot, characterized in that: A heat-insulating bottom plate is used to cast a steel ingot, wherein the steel ingot comprises a water nozzle, an ingot body and a riser from bottom to top; The pouring speed of the water inlet is 7-9 t / min; the pouring speed of the ingot body is 5-6 t / min; the pouring speed of the riser is 2-4 t / min; The heat-insulated chassis includes a chassis, a steel sleeve, heat-insulating materials, filling materials, a bottom steel plate and an upper steel plate; The steel sleeve is placed in a groove opened on the chassis, the insulation material is wrapped around the outer circumference of the steel sleeve, the filling material is placed on the side of the insulation material away from the steel sleeve, the bottom steel plate is placed inside the steel sleeve and connected to the chassis, and the upper steel plate covers the filling material.

2. The method for casting a steel ingot according to claim 1, characterized in that: The thermal insulation material is selected from asbestos and rock wool.

3. The method for casting a steel ingot according to claim 2, characterized in that: The thickness of the thermal insulation material is 50-100 mm.

4. The method for casting a steel ingot according to claim 1, characterized in that: The filling material is selected from steel balls, broken steel blocks and steel nail scraps.

5. The method for casting a steel ingot according to claim 4, characterized in that: The steel ball is made of ordinary carbon steel or stainless steel, and has a diameter of 5-10 mm.

6. The method for casting a steel ingot according to claim 1, characterized in that: The thickness of the bottom steel plate is 50-60 mm.

7. The method for casting a steel ingot according to any one of claims 1 to 6, characterized in that: The following steps are involved: S1: Assembly of the insulated chassis; S2: placing a heat-insulating chassis on the ground, then placing a steel ingot mold on the heat-insulating chassis, and finally placing a riser sleeve on the steel ingot mold; S3: pouring the molten steel into an ingot mold, adjusting the pouring speed, and obtaining a steel ingot after cooling.

8. A steel ingot, characterized in that: The steel ingot is prepared by the casting method of any one of claims 1 to 7.

9. The steel ingot according to claim 8, characterized in that: The steel ingot comprises a nozzle, an ingot body and a riser from bottom to top, and the weight ratio of the nozzle to the ingot body is 1:(16-34).

10. A heat-insulating chassis for implementing the casting method of the steel ingot according to any one of claims 1 to 7, characterized in that: The heat-insulating chassis comprises a chassis, a steel sleeve, a heat-insulating material, a filling material, a bottom steel plate and an upper steel plate; The steel sleeve is placed in a groove opened on the chassis, the insulation material is wrapped around the outer circumference of the steel sleeve, the filling material is placed on the side of the insulation material away from the steel sleeve, the bottom steel plate is placed inside the steel sleeve and connected to the chassis, and the upper steel plate covers the filling material.

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