Rolling mill stand resin sand gravity casting liquid weight calculation method

Abstract

The invention discloses a rolling mill stand resin sand gravity casting liquid weight calculation method, and relates to the technical field of equipment manufacturing, and the method comprises the following steps: selecting the linear shrinkage rate epsilon L of a casting in different directions according to the wall thickness and length of the casting; obtaining a resin sand box expansion rate fv based on measured data; adjusting the process blank model based on the linear shrinkage rate epsilon L and the resin sand box expansion rate fv; a pouring pipeline model and a riser model are designed based on the process blank model, and the volume of the process blank model, the volume of a pouring pipeline and the volume of a riser are obtained based on three-dimensional design software; and calculating the mass of molten iron required for pouring based on the adjusted volume of the process blank model, the volume of the pouring pipeline and the volume of the riser. According to the method, epsilon L and fv are obtained through a standardization method, cost reduction, energy conservation and zero mold testing are achieved, and the problems that in an existing rolling mill stand resin sand gravity casting technology, the precision of an empirical coefficient method is low, the difference of linear shrinkage in different directions is not considered, the box expansion rate is not quantized, and the accuracy is poor are solved.

Description

Technical Field

[0001] This invention relates to the field of equipment manufacturing technology, and in particular to a method for calculating the weight of resin sand gravity casting liquid in rolling mill stands. Background Technology

[0002] The rolling mill stand is the "skeleton" component of a metallurgical rolling mill unit, bearing the rolling force and ensuring the accuracy of the roll system. A single piece typically weighs 100-450 tons, has a profile dimension exceeding 10 meters, and a wall thickness of 600-1000 mm. Its structure is a closed box or archway shape, with a large moment of inertia and extremely high rigidity requirements. Because its geometry exceeds the usable range of forging, welding, or low-pressure casting, it is globally used for one-time molding using resin self-hardening sand gravity casting. Existing rolling mill stand casting processes have the following drawbacks:

[0003] 1) Current formula for calculating liquid weight: G 总 =G 铸件 +G 浇注系统 +G 冒口 +G 其他损耗 The latter three items are all based on the gross weight of the casting, G. 铸件 The empirical proportional coefficients (15–30%, 10–25%, 3–10%) are used for estimation; the coefficient range is wide, and human intervention is large. The difference in values ​​taken by different engineers in the same workshop can reach ±8%; once the liquid weight is calculated incorrectly, tens of tons of residual molten steel are directly generated, and the energy consumption of recycling is huge. In actual production, waste of more than 15% frequently occurs.

[0004] 2) Ignoring the difference in directional linear shrinkage, the frame has less resistance from the sand core in the length direction, and the shrinkage rate is 0.1–0.3% higher than that in the height direction;

[0005] 3) The nonlinear relationship between the unquantified expansion rate and the casting weight and sand mold strength was ignored; when furan resin sand was used for castings >100t, the expansion weight gain rate was significantly lower than the manual value.

[0006] 4) Resin sand molds are prone to "expansion" under the combined effects of high-temperature molten steel (≈1500℃) and static pressure (>0.08MPa), resulting in larger cavity dimensions and further amplifying liquid weight deviation.

[0007] Due to the combined effects mentioned above, the calculated values ​​using traditional formulas are generally 20-40 tons higher than the actual demand. In the competitive landscape of the metallurgical industry in recent years, characterized by "low-price bidding and meager profits," surplus molten steel not only directly increases the costs of raw materials, energy consumption, refining, and remelting, but also lengthens the production cycle. To mitigate risk, some companies are even forced to perform "secondary casting to compensate for shrinkage," further increasing labor, welding, and finishing costs. Summary of the Invention

[0008] In view of the above analysis and in view of the shortcomings of the prior art, the present invention aims to provide a method for calculating the liquid weight of resin sand gravity casting of rolling mill stands, and to solve at least one of the following problems in the existing resin sand gravity casting process of rolling mill stands: low accuracy of empirical coefficient method, failure to consider the difference of linear shrinkage in different directions, neglect of high temperature static pressure expansion effect, and poor accuracy of expansion rate.

[0009] The objective of this invention is mainly achieved through the following technical solutions:

[0010] This invention discloses a method for calculating the weight of resin sand gravity casting liquid in rolling mill stands, comprising:

[0011] S1: Select the linear shrinkage rate ε of the casting in different directions based on the casting wall thickness and length. L The expansion rate f of the resin sand chamber was obtained based on measured data. v ;

[0012] S2: Based on linear shrinkage rate ε L , resin sand expansion rate f v Adjust the process blank model;

[0013] S3: Design the gating pipe model and riser model based on the process blank model, and obtain the volume of the process blank model, the volume of the gating pipe and the riser based on the 3D design software;

[0014] S4: Calculate the required molten iron mass for pouring based on the adjusted process blank model volume, pouring pipeline volume, and riser volume.

[0015] Preferably, step S1 includes:

[0016] S101: Directly obtain the linear shrinkage rate ε in different directions by looking up the tool table according to the wall thickness-length grade. L ;

[0017] S102: Retrieve the actual resin sand expansion rate table based on the casting weight range, and read f. v .

[0018] Preferably, step S101 includes:

[0019] S1011: Read the maximum wall thickness and maximum length of the casting from the 3D model;

[0020] S1012: Based on the correspondence between the wall thickness to length ratio range and the linear shrinkage rate given in GB / T 9439, the linear shrinkage rate ε in different directions is obtained by looking up a table. l Linear shrinkage ε along the length of the frame casting 长 Linear shrinkage rate ε in the width direction of the frame casting 宽 Linear shrinkage ε in the height direction of the frame casting 高 .

[0021] Preferably, step S102 includes:

[0022] S1021: Calculate the weight G of the casting by weighing or by multiplying the volume and density. c ;

[0023] S1022: Based on weight G c Preliminary classification of expansion rate based on molding sand type;

[0024] S1023: Further refine the initial graded expansion rate of resin sand based on the measured expansion rate data of resin sand.

[0025] Preferably, step S2 includes:

[0026] S201: ε obtained based on step S1 v f v Calculate the correction factor k = (1 + ε) 长 )×(1+ε 宽 )×(1+εheight)×(1+f v );

[0027] S202: Based on the correction factor k, the process blank model GV0 is scaled proportionally. The adjusted process blank model GV1 satisfies:

[0028] GV1 = GV0 × k.

[0029] Preferably, step S3 includes:

[0030] S301: Arrange the straight runner, horizontal runner, and inner runner on the adjusted blank according to the single or multiple package, bottom injection / top injection scheme to obtain the casting pipeline model;

[0031] S302: Determine the feeding position corresponding to the process blank model according to the modular method or the hot spot circle method, call the standard riser series, automatically generate the light and dark riser entities, and obtain the riser model;

[0032] S303: Software Boolean operations merge the blank, gating system, and riser into a closed volume package, confirming no interference and no gaps, forming an overall three-dimensional process model of the process blank model, gating system, and riser model.

[0033] S304: Select the model to be inspected and use the volume segment measurement under the quality attribute of the 3D software to obtain the volume of the process blank model.

[0034] Preferably, step S4 includes: detecting and correcting the density of the casting raw material molten steel at the casting temperature; the detection and correction can be performed using the weighing-volume method (Archimedes' method).

[0035] Preferably, the total mass G of molten steel required for castingL ,satisfy:

[0036] G L =V v ×k×ρ L +(V A +V R )×ρ L ;

[0037] Where, ρ L Where V is the density of molten steel, k is a correction factor, and V is the density of molten steel. v V is the volume of the process blank model. A V is the volume of the casting pipe model. R This represents the volume of the riser model.

[0038] Preferably, the linear shrinkage rate ε L Satisfy: 0.5≤ε L ≤5.

[0039] Preferably, the box expansion rate f v Satisfy: 0.8≤f v ≤5.

[0040] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0041] (1) This invention obtains ε through a standardized method. L f v This technology enables the extraction of measured volumes, allowing for precise calculation of molten iron quality with a single click, achieving "one-click precise casting." Data from the 3D model to the total molten iron volume is sourced uniformly, eliminating empirical coefficients and the differences in manual coefficient selection. This results in improved process design efficiency and reduced steel consumption; residual molten steel is ≤4%, with optimal values ​​≤2%, material utilization exceeding 52%, and yield exceeding 61%. Each piece of molten steel saves 7-20 tons, and material utilization increases by 4-12 percentage points, achieving cost reduction, energy saving, and zero trial casting.

[0042] (2) The present invention uses the measured expansion rate of resin sand, which avoids the problem of excessive difference between the expansion rates of silica sand and resin sand, reduces the deviation of the expansion rate of the upper casting, improves the calculation accuracy, and avoids the problems of excessive deviation and excessive liquid weight caused by the use of general manual values ​​and silica sand expansion rates in the existing technology.

[0043] (3) This invention achieves accurate volume measurement by constructing riser and pouring pipeline models instead of using empirical coefficients, thus improving the poor accuracy caused by the high temperature static pressure expansion box effect in the prior art.

[0044] (4) The present invention adopts three linear shrinkage rates in the direction of the length of the frame casting ε_long, the direction of the width of the frame casting ε_wide, and the direction of the height of the frame casting ε_high. This takes into account the difference in linear shrinkage of the casting in different directions and achieves more accurate measurement. Attached Figure Description

[0045] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0046] Figure 1 This is a schematic diagram of the casting blank of Embodiment 1 of the present invention.

[0047] Figure 2 This is a schematic diagram of the casting blank of Embodiment 2 of the present invention.

[0048] Figure 3 This is a schematic diagram of the casting blank of Embodiment 3 of the present invention. Detailed Implementation

[0049] To make the technical problems solved, the technical solutions, and the beneficial effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0050] This invention discloses a method for calculating the weight of resin sand gravity casting liquid in a rolling mill stand, comprising:

[0051] S1: Select the linear shrinkage rate ε of the casting in different directions based on the casting wall thickness and length. L The expansion rate f of the resin sand chamber was obtained based on measured data. v ;

[0052] S2: Based on linear shrinkage rate ε L , resin sand expansion rate f v Adjust the process blank model;

[0053] S3: Design the gating pipe model and riser model based on the process blank model, and obtain the volume of the process blank model, the volume of the gating pipe and the riser based on the 3D design software;

[0054] S4: Calculate the required molten iron mass for pouring based on the adjusted process blank model volume, pouring pipeline volume, and riser volume.

[0055] During implementation, step S1 outputs ε L f vThe quantitative value provides a unique "enlargement-reduction" benchmark in step S2, ensuring that the dimensions of the billet and gating riser are laid out in one go, eliminating the need for repeated trial molding in the traditional method. The process billet model provides a basis for the gating pipe and riser model, and together with the adjusted process billet model obtained in step S2, they can form a complete and closed three-dimensional volume package, providing the volume of each part that can be extracted with one click in step S3, without the need for additional surface patching or estimation, ensuring that the volume data is from the same source and without manual intervention. The three sets of measured volumes output in step S3 can be used as direct variables in the formula of step S4, with a volume accuracy of ≤1%, which reduces the final molten iron calculation error to ±1.5% and completely eliminates the "coefficient reversal" step. The accurate total amount of molten iron output in step S4 can be poured with one batching, achieving a residual molten steel of ≤1.6%, increasing the yield by 3-8 percentage points, and achieving comprehensive benefits of cost reduction, energy saving, and shortening the cycle.

[0056] It should be noted that the actual size of the process blank obtained during casting is not equal to the theoretical size. This is because, firstly, the molten metal shrinks after solidification, resulting in a smaller volume of the casting compared to the theoretical value; secondly, after the high-temperature molten iron is poured into the resin sand mold, the heat strength of the mold wall decreases, and the cavity expands outward under the static pressure of the molten metal, leading to an increase in the actual weight of the casting compared to the theoretical weight. Different linear shrinkage rates ε are introduced. L , resin sand expansion rate f v The above two factors represent the effects mentioned above, indicating that the actual dimensions of the process blank are affected by these two factors.

[0057] Compared with existing technologies, this invention obtains ε through a standardized method. L f v This technology enables the extraction of measured volumes, allowing for precise calculation of molten iron quality with a single click, achieving "one-click precise casting." Data from the 3D model to the total molten iron volume is sourced uniformly, eliminating empirical coefficients and the differences in manual coefficient selection. This results in improved process design efficiency and reduced steel consumption; residual molten steel is ≤4%, with optimal values ​​≤2%, material utilization exceeding 52%, and yield exceeding 61%. Each piece of molten steel saves 7-20 tons, and material utilization increases by 4-12 percentage points, achieving cost reduction, energy saving, and zero trial casting.

[0058] Specifically, step S1 includes:

[0059] S101: Directly obtain the linear shrinkage rate ε in different directions by looking up the tool table according to the wall thickness-length grade. L ;

[0060] S102: Retrieve the actual resin sand expansion rate table based on the casting weight range, and read f. v .

[0061] Specifically, step S101 includes:

[0062] S1011: Read the maximum wall thickness and maximum length of the casting from the 3D model;

[0063] S1012: Based on the correspondence between the wall thickness to length ratio range and the linear shrinkage rate given in GB / T 9439, the linear shrinkage rate ε in different directions is obtained by looking up a table. l Linear shrinkage ε along the length of the frame casting 长 Linear shrinkage rate ε in the width direction of the frame casting 宽 Linear shrinkage ε in the height direction of the frame casting 高 .

[0064] Compared with the prior art, the present invention adopts the linear shrinkage rate ε in the length direction of the frame casting. 长 Linear shrinkage rate ε in the width direction of the frame casting 宽 Linear shrinkage ε in the height direction of the frame casting 高 The linear shrinkage rate in three directions takes into account the differences in linear shrinkage of the casting in different directions, enabling more accurate measurement.

[0065] Specifically, step S102 includes:

[0066] S1021: Calculate the weight G of the casting by weighing or by multiplying the volume and density. c ;

[0067] S1022: Based on weight G c Preliminary classification of expansion rate based on molding sand type;

[0068] S1023: Further refine the initial graded expansion rate of resin sand based on the measured expansion rate data of resin sand.

[0069] During implementation, the measured data of the resin sand expansion rate of this invention are shown in Table 1:

[0070] Table 1. Measured Increase Rate of Casting Weight Due to Expansion

[0071] <![CDATA[Calculated weight G of the casting C / t]]> Handmade styling / % 10-20 2.0 20-50 1.5 50-100 1.0 ﹥100 0.8

[0072] It should be noted that the existing technology for increasing the box weight is based on measurements using silica sand, which differs significantly from the measured box weight increase rate using resin sand in this invention, as shown in Table 2:

[0073] Table 2 Casting Handbook: Casting Expansion Weight Increase Rate

[0074]

[0075] Compared with the prior art, the present invention uses the measured expansion rate of resin sand, which avoids the problem of excessive difference between the expansion rates of silica sand and resin sand, reduces the deviation of the expansion rate of the upper casting, improves the calculation accuracy, and avoids the problems of excessive deviation and excessive liquid weight caused by the prior art using general manual values ​​and silica sand expansion rates for expansion rate.

[0076] Specifically, the linear shrinkage rate ε L Satisfy: 0.5≤ε L ≤5.

[0077] Specifically, step S2 includes:

[0078] S201: ε obtained based on step S1 v f v Calculate the correction factor k = (1 + ε) 长 )×(1+ε 宽 )×(1+εheight)×(1+f v );

[0079] S202: Based on the correction factor k, the process blank model GV0 is scaled proportionally. The adjusted process blank model GV1 satisfies:

[0080] GV1 = GV0 × k.

[0081] Specifically, the linear shrinkage rate ε L Satisfy: 0.5≤ε L ≤5.

[0082] Specifically, the box expansion rate f v Satisfy: 0.8≤f v ≤5.

[0083] Specifically, step S3 includes:

[0084] S301: Arrange the straight runner, horizontal runner, and inner runner on the adjusted blank according to the single or multiple package, bottom injection / top injection scheme to obtain the casting pipeline model;

[0085] S302: Determine the feeding position corresponding to the process blank model according to the modular method or the hot spot circle method, call the standard riser series, automatically generate the light and dark riser entities, and obtain the riser model;

[0086] S303: Software Boolean operations merge the blank, gating system, and riser into a closed volume package, confirming no interference and no gaps, forming an overall three-dimensional process model of the process blank model, gating system, and riser model.

[0087] S304: Select the model to be inspected and use the volume segment measurement under the quality attribute of the 3D software to obtain the volume of the process blank model.

[0088] Compared with existing technologies, this invention achieves accurate volume measurement by constructing riser and pouring pipeline models instead of using empirical coefficients, thus improving the poor accuracy caused by the high-temperature static pressure expansion box effect in existing technologies.

[0089] Specifically, step S4 includes: detecting and correcting the density of the molten steel raw material at the casting temperature; the detection and correction can be performed using the weighing-volume method (Archimedes' method).

[0090] As an example, the corrected liquid densities of several types of steel at 1500℃ according to the present invention are shown in Table 3 below:

[0091] Table 3 Common Chemical Compositions and Liquid Density ρ of Commonly Used Castings L calculate

[0092]

[0093] Specifically, the total mass of molten steel required for casting, G L ,satisfy:

[0094] G L =V v ×k×ρ L +(V A +V R )×ρ L ;

[0095] Where, ρ L Where V is the density of molten steel, k is a correction factor, and V is the density of molten steel. v V is the volume of the process blank model. A V is the volume of the casting pipe model. R This represents the volume of the riser model.

[0096] The following embodiments are provided to better illustrate the present invention:

[0097] Example 1

[0098] This embodiment discloses a method for calculating the weight of resin sand gravity casting liquid in a rolling mill stand, used for preparing... Figure 1 The side frame blank shown measures 12070×4940×840mm, weighs 232 tons, and is made of G20Mn5 material. It includes:

[0099] S1: Select the linear shrinkage rate ε of the casting in different directions based on the casting wall thickness and length. L The expansion rate f of the resin sand chamber was obtained based on measured data. v ;

[0100] S101: Directly obtain the linear shrinkage rate ε in different directions by looking up the tool table according to the wall thickness-length grade. L ;

[0101] S1011: Read the maximum wall thickness and maximum length of the casting from the 3D model;

[0102] S1012: Based on the correspondence between the wall thickness to length ratio range and the linear shrinkage rate given in GB / T9439, the linear shrinkage rate ε in different directions is obtained by looking up a table. l Linear shrinkage ε along the length of the frame casting 长 Linear shrinkage rate ε in the width direction of the frame casting 宽 Linear shrinkage ε in the height direction of the frame casting 高 .

[0103] S102: Retrieve the actual resin sand expansion rate table based on the casting weight range, and read f. v .

[0104] S1021: Calculate the weight G of the casting by weighing or by multiplying the volume and density. c ;

[0105] S1022: Based on weight G c Preliminary classification of expansion rate based on molding sand type;

[0106] S1023: Further refine the initial graded expansion rate of resin sand based on the measured expansion rate data of resin sand.

[0107] S2: Based on linear shrinkage rate ε L , resin sand expansion rate f v Adjust the process blank model;

[0108] S201: ε obtained based on step S1 v f v Calculate the correction factor k = (1 + ε) 长 )×(1+ε 宽 )×(1+εheight)×(1+f v );

[0109] S202: Based on the correction factor k, the process blank model GV0 is scaled proportionally. The adjusted process blank model GV1 satisfies:

[0110] GV1 = GV0 × k.

[0111] S3: Design the gating pipe model and riser model based on the process blank model, and obtain the volume of the process blank model, the volume of the gating pipe and the riser based on the 3D design software;

[0112] S301: Arrange the straight runner, horizontal runner, and inner runner on the adjusted blank according to the single or multiple package, bottom injection / top injection scheme to obtain the casting pipeline model;

[0113] S302: Determine the feeding position corresponding to the process blank model according to the modular method or the hot spot circle method, call the standard riser series, automatically generate the light and dark riser entities, and obtain the riser model;

[0114] S303: Software Boolean operations merge the blank, gating system, and riser into a closed volume package, confirming no interference and no gaps, forming an overall three-dimensional process model of the process blank model, gating system, and riser model.

[0115] S304: Select the model to be inspected and use the volume segment measurement under the quality attribute of the 3D software to obtain the volume of the model to be inspected.

[0116] S4: Calculate the required mass of molten iron for casting based on the adjusted volume of the process blank model, the volume of the gating pipe, and the riser volume; G: Total mass of molten steel required for casting. L ,satisfy:

[0117] G L =V v ×k×ρ L +(V A +V R )×ρ L k = (1 + ε) 长 )×(1+ε 宽 )×(1+ε 高 )×(1+f v );

[0118] Where, ρ L The liquid density is taken as 0.8% from Table 3, which is 7130 kg / m³. 3 , ε 长 =2.0%; ε 宽 =2.1%; ε 高 =2.1%; Referring to Table 1, we know that... Figure 1 As shown, red represents risers, orange represents castings, and blue represents chills. This machine frame casting is designed with four risers: one open riser and three closed risers. The open riser measures 1740×2290×2640 (pour height) mm with a radius of R200. One closed riser measures 1700×2200×2200 (pour height) mm; two closed risers of the same size measure 1600×1900×2000 (pour height) mm. This machine frame uses a 3-well, 6-hole combined gating system, with both the sprue and runner employing [missing information - likely a specific design element]. Ceramic tile pipes, with 28 internal gating channels. The straight runner is 24m long, the horizontal runner is 37m long, and the ingate is 19m long. The total volume of the pouring piping is V. A 1.034×10 9 mm 3 After the process design was completed, the measured casting volume Vv was 3.37 × 10⁻⁶. 10 mm3 Riser volume V R It is 2.499×10 10 mm 3 .

[0119] According to calculations, G L = 33.75 × 1.02 × 1.021 × 1.021 × 1.008 × 7130 + (1.03 + 25) × 7130

[0120] =443508kg.

[0121] The total gross weight was 444t, the total weight was 267t, the casting yield was 60.1%, and the material utilization rate was 52.25%.

[0122] The overall plan was to pour 388 tons of molten steel in three ladles initially, with the remaining 56 tons poured in two separate pours using risers. In actual production, considering the combined pouring of the three ladles and the crane's lifting capacity, a two-large-one-small pouring method was adopted. The two large ladles each had a planned steel volume of 139 tons, and the small ladle had a planned steel volume of 110 tons. To ensure no slag ingress at the end of the pouring process, each of the two large ladles had an excess of 2 tons. The small ladle had a remaining 20.7 tons of molten steel, resulting in a calculated weight exceeding the actual required weight by 16.7 tons, accounting for 3.76% of the total molten steel weight.

[0123] Calculation of molten steel using typical existing technical methods:

[0124] G 总 =G 铸件 +G 浇注管路 +G 冒口 G 铸件 =G V ×(1+f V ), f V Refer to Table 2 and get 2.5;

[0125] G 浇注系统 =G 铸件 ×k1 (k1 = 0.15);

[0126] G 冒口 =G 铸件 ×k2 (k2=0.15); density of molten steel 7.830kg / m³ 3

[0127] Calculations show that existing technologies require approximately 460 tons of molten steel. This embodiment saves 16 tons of molten steel compared to traditional methods, increases material utilization from 50.8% to 52.25%, and increases casting yield to 60.1%.

[0128] Example 2

[0129] This embodiment discloses a method for calculating the weight of resin sand gravity casting liquid in a rolling mill stand, used for preparing... Figure 2 The side frame blank shown measures 9663×4450×575mm, weighs 93.6 tons, and is made of ZG230-450 material. Figure 2 As shown, the casting process is designed as follows:

[0130] Total mass of molten steel required for casting (G) L ,satisfy:

[0131] G L =V v ×k×ρ L +(V A +V R )×ρ L k = (1 + ε) 长 )×(1+ε 宽 )×(1+ε 高 )×(1+f v The rest is the same as in Example 1;

[0132] Where, ρ L The liquid density is 7075 kg / m³ (from Table 3). 3 , ε 长 =2.0%; ε 宽 =2.1%; ε 高 =2.1%; such as Figure 2 As shown, red represents risers and orange represents castings. This machine frame casting is designed with 4 risers: 2 open risers and 2 closed risers. The first open riser is a waist-shaped open riser with a center distance of 300mm, measuring 1500×1800×1680 (pouring height) mm, with a riser radius of R150. The second open riser is also a waist-shaped open riser with a center distance of 300mm, measuring 1320×1520×1680 (pouring height) mm, with a riser radius of R150. Two identical closed risers are waist-shaped closed risers with a center distance of 300mm, measuring 1040×1340×1300 (pouring height) mm. This machine frame uses a 2-bundle, 4-hole combined casting method, with both the sprue and runner employing... Ceramic tile pipes, with 16 internal gating channels. The sprue is 12m long, the gating runner is 28m long, and the ingate is 5m long. The total volume of the gating system is V. A It is 6.4×10 8 mm 3 After the process design is completed, the volume V of the casting is measured. v 1.36×10 10 mm 3 Riser volume V R 1.005×10 10 mm 3 According to Table 3, the liquid density is 7075 kg / m³. 3 .

[0133] According to calculations, G L = 13.64 × 1.02 × 1.021 × 1.021 × 1.008 × 7075 + (0.64 + 10.05)

[0134] ×7075

[0135] =179063kg.

[0136] The solidified liquid weighed 180t, the gross weight was 109t, the casting yield was 60.7%, and the material utilization rate was 52.14%.

[0137] In actual production, two ladles were considered for combined casting, with the first casting weighing 162t and an additional 18t poured through the riser. The initial casting used two ladles, each planned to hold 81t of molten steel. To ensure no slag entered at the end of the casting process, the actual tapped steel was 84t and 82t. The two ladles had 4.6t and 1.2t remaining respectively, for a total of 5.8t of remaining molten steel. The calculated weight exceeded the actual required weight by 1.8t, accounting for 1.11% of the total weight of the initial casting.

[0138] Calculation of molten steel using typical existing technical methods:

[0139] G 总 =G 铸件 +G 浇注管路 +G 冒口 G 铸件 =G V ×(1+f V ), f V Refer to Table 2 and get 3.0;

[0140] G 浇注系统 =G 铸件 ×k1 (k1 = 0.15);

[0141] G 冒口 =G 铸件 ×k2 (k2=0.15); density of molten steel 7.830kg / m³ 3

[0142] Calculations show that existing technologies require approximately 187 tons of molten steel. This embodiment saves 7 tons of molten steel compared to traditional methods, increases material utilization from 50.2% to 52.14%, and increases casting yield to 60.7%.

[0143] Example 3

[0144] This embodiment discloses a method for calculating the weight of resin sand gravity casting liquid in a rolling mill stand, used for preparing... Figure 3 The frame blank shown measures 10735×4580×800mm, weighs 157.8 tons, and is made of G20Mn5 material. Figure 3 As shown, the casting process is designed as follows:

[0145] Total mass of molten steel required for casting (G) L ,satisfy:

[0146] G L =V v ×k×ρ L +(V A +V R )×ρ L k = (1 + ε) 长 )×(1+ε 宽 )×(1+ε 高 )×(1+f v The rest is the same as in Example 1;

[0147] Where, ρ L The liquid density is 7130 kg / m³ (from Table 3). 3 , ε 长 =2.0%; ε 宽 =2.1%; ε 高 =2.1%; such as Figure 3 As shown, red represents risers and gray represents castings. This machine frame casting is designed with 4 risers: 2 open risers and 2 closed risers. The two identical open risers are waist-shaped risers with a center-to-center distance of 650mm, measuring 1540×2190×1930 (pouring height) mm, with a riser radius of R200. The two identical closed risers are waist-shaped closed risers with a center-to-center distance of 420mm, measuring 1240×1660×1600 (pouring height) mm. This machine frame uses a 2-bundle, 4-hole combined casting method, with both the sprue and runner employing [missing information - likely a specific design or method]. Ceramic tile pipes, with 18 internal gating channels. The sprue is 14m long, the gating runner is 33m long, and the ingate is 6m long. The total volume of the gating system is V. A It is 7.53×10 8 mm 3 After the process design is completed, the volume V of the casting is measured. v 2.25×10 10 mm 3 The riser volume VR is 1.73 × 10⁻⁶. 10 mm 3 The liquid density is 7130 kg / m³. 3 .

[0148] According to calculations, G L = 22.52 × 1.02 × 1.021 × 1.021 × 1.008 × 7130 + (0.73 + 17.36) × 7130

[0149] =300909kg.

[0150] The total weight of the solidified liquid was 301t, the gross weight was 185.4t, the casting yield was 61.6%, and the material utilization rate was 52.42%.

[0151] In actual production, two ladles were considered for combined casting, poured in two stages. The first pour weighed 267t, with an additional 34t poured via riser. The initial pour planned for 133.5t of steel from each ladle. To ensure no slag entered at the end of the pour, the actual steel output from both ladles was 135t. The two ladles had 4.6t and 6t remaining, respectively, for a total of 10.6t of remaining steel. The calculated weight exceeded the actual required weight by 7.6t, representing 2.85% of the total weight of the poured steel.

[0152] Calculation of molten steel using typical existing technical methods:

[0153] G 总 =G 铸件 +G 浇注管路 +G 冒口 G 铸件 =G V ×(1+f V ), f V Refer to Table 2 and get 2.5;

[0154] G 浇注系统 =G 铸件 ×k1 (k1 = 0.15);

[0155] G 冒口 =G 铸件 ×k2 (k2=0.15); density of molten steel 7.830kg / m³ 3

[0156] Calculations show that existing technologies require approximately 309 tons of molten steel. This embodiment saves 7 tons of molten steel compared to traditional methods, increases material utilization from 50.2% to 52.42%, and increases casting yield to 61.6%.

[0157] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for calculating the weight of resin sand gravity casting liquid in a rolling mill stand, characterized in that, include: S1: Select the linear shrinkage rate ε of the casting in different directions based on the casting wall thickness and length. L ; The resin sand expansion rate f was obtained based on measured data. v ; S2: Based on linear shrinkage rate ε L , resin sand expansion rate f v Adjust the process blank model; S3: Design the gating pipe model and riser model based on the process blank model, and obtain the volume of the process blank model, the volume of the gating pipe and the riser based on the 3D design software; S4: Calculate the required molten iron mass for pouring based on the adjusted process blank model volume, pouring pipeline volume, and riser volume.

2. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 1, characterized in that, Step S1 includes: S101: Directly obtain the linear shrinkage rate ε in different directions by looking up the tool table according to the wall thickness-length grade. L ; S102: Retrieve the actual resin sand expansion rate table based on the casting weight range, and read f. v .

3. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 2, characterized in that, Step S101 includes: S1011: Read the maximum wall thickness and maximum length of the casting from the 3D model; S1012: Based on the relationship between the wall thickness to length ratio range and the linear shrinkage rate given in GB / T 9439, the linear shrinkage rate ε in different directions is obtained by looking up a table. l Linear shrinkage ε in the length direction of the frame casting 长 Linear shrinkage rate ε in the width direction of the frame casting 宽 Linear shrinkage ε in the height direction of the frame casting 高 .

4. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 2, characterized in that, Step S102 includes: S1021: Calculate the weight G of the casting by weighing or by multiplying the volume and density. c ; S1022: Based on weight G c Preliminary classification of expansion rate based on molding sand type; S1023: Further refine the initial graded expansion rate of resin sand based on the measured expansion rate data of resin sand.

5. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 1, characterized in that, Step S2 includes: S201: ε obtained based on step S1 v f v Calculate the correction factor k = (1 + ε) 长 )×(1+ε 宽 )×(1+εheight)×(1+f v ); S202: Based on the correction factor k, the process blank model GV0 is scaled proportionally. The adjusted process blank model GV1 satisfies: GV1 = GV0 × k.

6. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 1, characterized in that, Step S3 includes: S301: Arrange the straight runner, horizontal runner, and inner runner on the adjusted blank according to the single or multiple package, bottom injection / top injection scheme to obtain the casting pipeline model; S302: Determine the feeding position corresponding to the process blank model according to the modular method or the hot spot circle method, call the standard riser series, automatically generate the light and dark riser entities, and obtain the riser model; S303: Software Boolean operations merge the blank, gating system, and riser into a closed volume package, confirming no interference and no gaps, forming an overall three-dimensional process model of the process blank model, gating system, and riser model. S304: Select the model to be inspected and use the volume segment measurement under the quality attribute of the 3D software to obtain the volume of the process blank model.

7. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 1, characterized in that, Step S4 includes: detecting and correcting the density of the molten steel raw material at the casting temperature; the detection and correction adopts the weighing-volume method.

8. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 1, characterized in that, Total mass of molten steel required for casting (G) L ,satisfy: G L =V v ×k×ρ L +(V A +V R )×ρ L ; Where, ρ L Where V is the density of molten steel, k is a correction factor, and V is the density of molten steel. v V is the volume of the process blank model. A V is the volume of the casting pipe model. R This represents the volume of the riser model.

9. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to claim 1, characterized in that, linear shrinkage ε L Satisfy: 0.5≤ε L ≤5.

10. The method for calculating the weight of resin sand gravity casting liquid in rolling mill stands according to any one of claims 1-9, characterized in that, Box expansion rate f v Satisfy: 0.8≤f v ≤5.

Images