Process for manufacturing spheroidal graphite cast iron anti-settling well lid

Abstract

The application relates to the field of nodular cast iron well covers, in particular to a nodular cast iron anti-settling intelligent well cover preparation process, which comprises the following steps: step S1: nodular cast iron raw materials are added into a feeding bin according to the raw material proportion and heated; step S2: a central control unit starts a transmission device to pour cast iron liquid into a well cover mold; step S3: the central control unit sends the well cover mold after pouring to cooling liquid for cooling; step S4: the strength of the nodular cast iron well cover is detected; and step S5: the well cover with qualified strength is polished. Through the preparation process, the preparation process of the nodular cast iron well cover can be accurately controlled, manual participation is reduced, the production process of the nodular cast iron well cover is more intelligent, the production efficiency of the nodular cast iron well cover is improved, the strength of the nodular cast iron well cover can be guaranteed, and defective products are reduced.

Description

Technical Field

[0001] This invention relates to the field of ductile iron manhole cover technology, and in particular to a manufacturing process for ductile iron anti-settlement manhole covers. Background Technology

[0002] Ductile iron is produced by spheroidizing and inoculating to obtain spheroidal graphite, which effectively improves the mechanical properties of cast iron, especially its plasticity and toughness, resulting in strength higher than carbon steel. Ductile iron manhole covers are a type of ductile iron product. One advantage of ductile iron manhole covers is that, due to the high strength and good toughness of ductile iron, they are about 30% lighter than similar gray cast iron manhole covers. Ductile iron manhole covers are generally divided into round and square shapes. In urban road administration, round covers are generally used because they are less prone to tilting, better protecting the safety of pedestrians and vehicles. The use of round shapes is mainly due to the fact that every diameter of a round manhole cover is the same length. This means that if a vehicle runs over the cover, regardless of how it is lifted, its diameter will always be slightly wider than the manhole opening below, preventing the cover from falling into the manhole.

[0003] During the production of ductile iron manhole covers, it is necessary to ensure that the pouring speed of the molten iron is within a reasonable range to prevent the pouring speed from being too fast or too slow, which would affect the pouring quality of the ductile iron manhole cover. In the existing technology, the pouring process usually requires manual control, which results in low pouring efficiency, large errors, and insufficient precision in the pouring process. Summary of the Invention

[0004] Therefore, the present invention provides a manufacturing process for a ductile iron anti-settlement smart manhole cover, which overcomes the problems of the existing technology where the casting process usually requires manual control, resulting in low casting efficiency, large errors, and insufficient precision in the casting process.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a manufacturing process for a ductile iron anti-settlement manhole cover, comprising the following steps:

[0006] Step S1: Add ductile iron raw materials to the feed hopper according to the raw material ratio and heat them;

[0007] Step S2: The central control unit starts the transmission device to inject molten iron into the well cover mold;

[0008] Step S3: The central control unit transports the cast manhole cover mold to the coolant for cooling;

[0009] Step S4: Test the strength of the ductile iron manhole cover;

[0010] Step S5: Grind the surface of the manhole cover that meets the strength requirements;

[0011] In the process of preparing ductile iron anti-settlement manhole covers using this technology, a detection unit and a central control unit are set up. The detection unit includes a first detector, a second detector, a third detector, a fourth detector, and a ductile iron manhole cover strength detector. The first detector is used to detect the volume of the mold cavity; the second detector is used to detect the inner surface area of ​​the mold. The central control unit calculates the surface-to-body ratio of the ductile iron manhole cover based on the inner surface area and the volume of the mold cavity, and determines the planned injection speed of molten iron at the casting port of the ductile iron manhole cover mold based on the calculated surface-to-body ratio. The third detector is used to detect the liquid level height at the pouring port of the ductile iron manhole cover mold; the fourth detector is used to detect the volume of molten cast iron flowing into the pouring port; the central control unit determines the final pouring speed based on the liquid level height at the pouring port of the ductile iron manhole cover mold and the volume of molten cast iron flowing into the pouring port; the ductile iron strength detector is used to detect the strength of the ductile iron manhole cover. If the strength of the ductile iron manhole cover meets the standard, the central control unit determines that the ductile iron manhole cover is completed. If the strength of the ductile iron manhole cover does not meet the standard, the proportion of ductile iron raw materials is further adjusted.

[0012] Further, in step S2, the first detector detects the volume of the mold cavity, denoted as Z, and uploads it to the central control unit. The central control unit records the initial pouring speed of the molten iron, denoted as V. The central control unit calculates the estimated pouring time of the molten iron as T, where T = Z ÷ V. The central control unit has preset minimum pouring time Tmin, where Tmin = Z ÷ Vmax, and Vmax is the maximum pouring speed of the molten iron. It also has preset maximum pouring time Tmax, where Tmax = Z ÷ Vmin, and Vmin is the minimum pouring speed of the molten iron. The central control unit compares the estimated pouring time T with the minimum pouring time Tmin and the maximum pouring time Tmax, and determines whether the pouring time of the molten iron for the ductile iron manhole cover is within a reasonable range based on the comparison results.

[0013] When T < Tmin, the central control unit determines that the pouring speed is too fast and adjusts the pouring speed to Vmax;

[0014] When Tmin≤T<Tmax, the central control unit determines that the pouring speed is within a reasonable range and does not adjust the initial pouring speed of the molten iron.

[0015] When T > Tmax, the central control unit determines that the pouring speed is too slow and adjusts the pouring speed to Vmin.

[0016] Furthermore, when the central control unit determines that the pouring speed is not within a reasonable range, the second detector detects the inner surface area of ​​the mold, denoted as S, and uploads the data to the central control unit. The central control unit calculates the surface-to-body ratio B of the ductile iron manhole cover based on the inner cavity volume and inner surface area of ​​the mold, where B = S / Q. The central control unit is equipped with a first preset surface-to-body ratio B1 and a second preset surface-to-body ratio B2, a first preset proposed pouring speed adjustment coefficient α1, a second preset proposed pouring speed adjustment coefficient α2, and a third preset proposed pouring speed adjustment coefficient α3. The central control unit compares the surface-to-body ratio B of the ductile iron manhole cover with the first preset surface-to-body ratio B1 and the second preset surface-to-body ratio B2, and selects the corresponding pouring speed adjustment coefficient based on the comparison result, thereby determining the proposed pouring speed.

[0017] When B < B1, the central control unit selects α1 as the proposed pouring speed adjustment coefficient;

[0018] When B1≤B≤B2, the central control unit selects α2 as the proposed pouring speed adjustment coefficient;

[0019] When B > B2, the central control unit selects α3 as the proposed pouring speed adjustment coefficient;

[0020] When the central control unit selects αi as the adjustment coefficient for the proposed pouring speed, i = 1, 2, 3, the central control unit records the adjusted proposed pouring speed as V', then V' = V × αi; the central control unit compares the adjusted proposed pouring speed with the minimum pouring speed Vmin and the maximum pouring speed Vmax;

[0021] When V' < Vmin, the central control unit will adjust the planned pouring speed to Vmin;

[0022] When Vmin≤V'≤Vmax, the central control unit does not adjust the planned pouring speed;

[0023] When V' > Vmax, the central control unit will adjust the planned pouring speed to Vmax.

[0024] Furthermore, after the central control unit determines the planned pouring speed V', the third detector detects the liquid level height at the pouring port of the ductile iron manhole cover mold and records it as H. The central control unit has preset maximum liquid level height Hmax and minimum liquid level height Hmin at the pouring port. The central control unit determines the final pouring speed by comparing the liquid level height H at the pouring port of the ductile iron manhole cover mold with the preset maximum liquid level height Hmax and preset minimum liquid level height Hmin.

[0025] When H < Hmin, the central control unit determines the final pouring speed based on the volume of molten cast iron flowing into the pouring port and the volume of the mold cavity.

[0026] When Hmin < H < Hmax, the central control unit determines the final pouring speed as the planned pouring speed V'.

[0027] When H > Hmax, the central control unit determines the final pouring speed based on the volume of molten cast iron flowing into the pouring port and the volume of the mold cavity.

[0028] Further, when H < Hmin, the volume of molten cast iron flowing into the pouring port detected by the fourth detector is recorded as Q', and the ratio of the mold cavity volume Q to the volume of molten cast iron flowing into the pouring port Q' is K, K = Q ÷ Q'. The central control unit has a first preset volume ratio K1, a second preset volume ratio K2, a first preset final pouring speed adjustment coefficient γ1, and a second preset final pouring speed adjustment coefficient γ2. The central control unit compares the ratio of the mold cavity volume Q to the volume of molten cast iron flowing into the pouring port Q', K, with the first preset volume ratio K1 and the second preset volume ratio K2.

[0029] When K < K1, the central control unit selects γ1 as the adjustment coefficient for the final pouring speed;

[0030] When K1≤K≤K2, the central control unit selects γ2 as the adjustment coefficient for the final pouring speed;

[0031] When K > K2, the central control unit determines that the ductile iron mold is leaking and issues a warning signal.

[0032] Furthermore, when H > Hmax, the central control unit has a third preset volume ratio K3, a fourth preset volume ratio K4, a third preset final pouring speed adjustment coefficient γ3, and a fourth preset final pouring speed adjustment coefficient γ4. The central control unit compares the ratio K of the mold cavity volume Q to the volume Q' of the molten cast iron flowing into the pouring port with the third preset volume ratio K3 and the fourth preset volume ratio K4.

[0033] When K < K3, the central control unit determines that too many voids are generated during the casting process of the ductile iron manhole cover and issues a warning signal.

[0034] When K3≤K≤K4, the central control unit selects γ4 as the adjustment coefficient for the final pouring speed;

[0035] When K > K4, the central control unit selects γ3 as the adjustment coefficient for the final pouring speed.

[0036] Furthermore, when the central control unit selects γi as the adjustment coefficient for the injection speed of molten iron in the ball mill cast iron manhole cover, i = 1, 2, then the final pouring speed after adjustment is V1', V1' = V' + V' × γi;

[0037] When the central control unit selects γj as the adjustment coefficient for the injection speed of molten iron in the ball mill cast iron manhole cover, i = 3, 4, then the final molten iron injection speed after adjustment is V2', V2' = V' - V' × γj.

[0038] Furthermore, when the central control unit selects Vi' as the final pouring speed of the ductile iron manhole cover mold, i = 1, 2, the central control unit compares the final pouring speed Vi' with the minimum pouring speed Vmin and the maximum pouring speed Vmax;

[0039] When Vi' < Vmin, the central control unit will adjust the final pouring speed to Vmin;

[0040] When Vmin≤Vi'≤Vmax, the central control unit does not adjust the final pouring speed;

[0041] When Vi' > Vmax, the central control unit will adjust the final pouring speed to Vmax.

[0042] Furthermore, when the central control unit determines that the final pouring speed meets the standard, in step S4, the ductile iron manhole cover strength testing device further tests the strength D of the ductile iron manhole cover. The central control unit has a preset reference strength Dc for the ductile iron manhole cover. The central control unit compares the strength D of the ductile iron manhole cover detected by the ductile iron manhole cover strength testing device with the reference strength Dc of the ductile iron manhole cover:

[0043] When D≥Dc, the central control unit determines that the strength of the ductile iron manhole cover meets the standard;

[0044] When D < Dc, the central control unit determines that the strength of the ductile iron manhole cover does not meet the standard, and controls and adjusts the proportion of ductile iron raw materials.

[0045] Preferably, the raw materials for the ductile iron manhole cover include virgin iron, scrap steel, recycled materials, ferrosilicon, carbon raiser, nickel, spheroidizing agent, and inoculant.

[0046] Compared with the prior art, the beneficial effect of the present invention is that, in the process of preparing ductile iron manhole covers using this process, the central control unit controls the molten iron to pour into the ductile iron manhole cover mold at an initial pouring speed. The first detector detects the volume of the mold cavity and uploads the data to the central control unit. The central control unit calculates the estimated pouring time based on the mold cavity volume and the initial pouring speed. The central control unit has preset minimum and maximum pouring times. By comparing the calculated pouring time with the preset minimum and maximum pouring times, it is determined whether the pouring speed of the molten iron is within a reasonable range. When the injection speed of the molten iron is not within a reasonable range, the central control unit adjusts the pouring speed of the molten iron to a reasonable range. In this way, the injection speed of the molten iron is controlled within a reasonable range, avoiding the molten iron being poured too fast or too slow, which would affect the pouring quality.

[0047] Furthermore, when the central control unit determines that the pouring speed of the molten iron is within a reasonable range, the second detector detects the inner surface area of ​​the mold and uploads the data to the central control unit. The central control unit calculates the surface-to-body ratio of the ductile iron manhole cover based on the inner cavity volume and inner surface area of ​​the mold, determines the planned injection speed of the molten iron based on the surface-to-body ratio of the ductile iron manhole cover, and determines the planned pouring speed of the molten iron based on the surface-to-body ratio of the ductile iron manhole cover, making the pouring process more refined and further improving the pouring quality of the ductile iron manhole cover.

[0048] Furthermore, after the central control unit determines the planned pouring speed of the molten iron based on the surface-to-body ratio of the ductile iron manhole cover, the third detector detects the liquid level at the pouring port of the ductile iron manhole cover mold, and the fourth detector detects the volume of molten iron flowing into the pouring port. The central control unit is equipped with the highest and lowest liquid level at the pouring port. By comparing the detected liquid level at the pouring port of the ductile iron manhole cover mold with the highest and lowest liquid level at the pouring port, the pouring speed is finally determined. When the liquid level at the pouring port is at the highest... When the liquid level is within the range of the highest and lowest liquid level, the central control unit controls the molten iron to be poured into the ductile iron manhole cover mold at a predetermined injection rate. When the liquid level at the pouring port is not within the range of the highest and lowest liquid level, the central control unit determines that the pouring rate of the molten iron needs to be determined by combining the ratio between the volume of the molten iron flowing into the pouring port and the volume of the mold cavity. By combining the ratio between the volume of the molten iron flowing into the pouring port and the volume of the mold cavity to determine the pouring rate, the pouring process is made more precise and the pouring quality is improved.

[0049] Furthermore, in step S4, the ductile iron manhole cover strength detector is used to test the strength of the produced ductile iron manhole cover. If the strength of the ductile iron manhole cover is unqualified, the proportion of ductile iron raw materials is adjusted. In this way, the quality of the produced ductile iron manhole cover is improved.

[0050] Working principle: When using the ductile iron anti-settlement manhole cover prepared by this method, it is equipped with an adjusting ring, anti-fall device, manhole shaft, manhole cover plate, and upper flange. The manhole seat of the ductile iron anti-settlement manhole cover adopts a flange-type upper plate structure, and the upper plate is flush with the road surface elevation. The ductile iron manhole cover transfers the vehicle load it bears to the road structure layer around the manhole shaft through the upper flange and is connected to the manhole shaft by a socket connection, reducing the uneven settlement between the manhole cover and the road surface.

[0051] The flange width is not less than 150mm, and the outer edge of the flange face is provided with a reverse snap structure so that the manhole base and the road structure form an integral whole;

[0052] The manhole cover support surface is equipped with a trapezoidal elastic buffer rubber pad to reduce noise and improve driving comfort. A trapezoidal groove is also provided to ensure a firm connection between the gasket and the manhole seat. The rubber gasket has good wear resistance, corrosion resistance, oil resistance and weather resistance.

[0053] The ductile iron manhole cover and the manhole base are equipped with anti-theft and locking devices to ensure that the manhole cover and the manhole base are fastened together when closed, preventing the manhole cover from falling off the manhole base. Attached Figure Description

[0054] Figure 1 This is a process flow diagram of the manufacturing process of the ductile iron anti-settlement manhole cover described in this invention. Detailed Implementation

[0055] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0056] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0057] It should be noted that in the description of this invention, the terms "upper", "lower", "left", "right", "inner", "outer", etc., which indicate directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and is not intended to indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation of this invention.

[0058] Furthermore, it should be noted that, in the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0059] Please see Figure 1 The diagram shown is a process flow chart of the manufacturing process of the ductile iron anti-settlement manhole cover according to the present invention, including the following steps:

[0060] Step S1: Add ductile iron raw materials to the feed hopper according to the raw material ratio and heat them;

[0061] Step S2: The central control unit starts the transmission device to inject molten iron into the well cover mold;

[0062] Step S3: The central control unit transports the cast manhole cover mold to the coolant for cooling;

[0063] Step S4: Test the strength of the ductile iron manhole cover;

[0064] Step S5: Grind the surface of the manhole cover that meets the strength requirements;

[0065] In the process of preparing ductile iron anti-settlement manhole covers using this technology, a detection unit and a central control unit are set up. The detection unit includes a first detector, a second detector, a third detector, a fourth detector, and a ductile iron manhole cover strength detector. The first detector is used to detect the volume of the mold cavity; the second detector is used to detect the inner surface area of ​​the mold. The central control unit calculates the surface-to-body ratio of the ductile iron manhole cover based on the inner surface area and the volume of the mold cavity, and determines the planned injection speed of molten iron at the casting port of the ductile iron manhole cover mold based on the calculated surface-to-body ratio. The third detector is used to detect the liquid level height at the pouring port of the ductile iron manhole cover mold; the fourth detector is used to detect the volume of molten cast iron flowing into the pouring port; the central control unit determines the final pouring speed based on the liquid level height at the pouring port of the ductile iron manhole cover mold and the volume of molten cast iron flowing into the pouring port; the ductile iron strength detector is used to detect the strength of the ductile iron manhole cover. If the strength of the ductile iron manhole cover meets the standard, the central control unit determines that the ductile iron manhole cover is completed. If the strength of the ductile iron manhole cover does not meet the standard, the proportion of ductile iron raw materials is further adjusted.

[0066] Further, in step S2, the first detector detects the volume of the mold cavity, denoted as Z, and uploads it to the central control unit. The central control unit records the initial pouring speed of the molten iron, denoted as V. The central control unit calculates the estimated pouring time of the molten iron as T, where T = Z ÷ V. The central control unit has preset minimum pouring time Tmin, where Tmin = Z ÷ Vmax, and Vmax is the maximum pouring speed of the molten iron. It also has preset maximum pouring time Tmax, where Tmax = Z ÷ Vmin, and Vmin is the minimum pouring speed of the molten iron. The central control unit compares the estimated pouring time T with the minimum pouring time Tmin and the maximum pouring time Tmax, and determines whether the pouring time of the molten iron for the ductile iron manhole cover is within a reasonable range based on the comparison results.

[0067] When T < Tmin, the central control unit determines that the pouring speed is too fast and adjusts the pouring speed to Vmax;

[0068] When Tmin≤T<Tmax, the central control unit determines that the pouring speed is within a reasonable range and does not adjust the initial pouring speed of the molten iron.

[0069] When T > Tmax, the central control unit determines that the pouring speed is too slow and adjusts the pouring speed to Vmin.

[0070] Specifically, in the process of manufacturing ductile iron manhole covers using this technology, the central control unit controls the molten iron to pour into the ductile iron manhole cover mold at an initial pouring speed. The first detector detects the volume of the mold cavity and uploads the data to the central control unit. The central control unit calculates the estimated pouring time based on the mold cavity volume and the initial pouring speed. The central control unit has preset minimum and maximum pouring times. By comparing the calculated pouring time with the preset minimum and maximum pouring times, it is determined whether the pouring speed of the molten iron is within a reasonable range. When the pouring speed of the molten iron is not within a reasonable range, the central control unit adjusts the pouring speed of the molten iron to a reasonable range. In this way, the pouring speed of the molten iron is controlled within a reasonable range, avoiding pouring speeds that are too fast or too slow, which would affect the pouring quality.

[0071] Furthermore, when the central control unit determines that the pouring speed is not within a reasonable range, the second detector detects the inner surface area of ​​the mold, denoted as S, and uploads the data to the central control unit. The central control unit calculates the surface-to-body ratio B of the ductile iron manhole cover based on the inner cavity volume and inner surface area of ​​the mold, where B = S / Q. The central control unit is equipped with a first preset surface-to-body ratio B1 and a second preset surface-to-body ratio B2, a first preset proposed pouring speed adjustment coefficient α1, a second preset proposed pouring speed adjustment coefficient α2, and a third preset proposed pouring speed adjustment coefficient α3. The central control unit compares the surface-to-body ratio B of the ductile iron manhole cover with the first preset surface-to-body ratio B1 and the second preset surface-to-body ratio B2, and selects the corresponding pouring speed adjustment coefficient based on the comparison result, thereby determining the proposed pouring speed.

[0072] When B < B1, the central control unit selects α1 as the proposed pouring speed adjustment coefficient;

[0073] When B1≤B≤B2, the central control unit selects α2 as the proposed pouring speed adjustment coefficient;

[0074] When B > B2, the central control unit selects α3 as the proposed pouring speed adjustment coefficient;

[0075] When the central control unit selects αi as the adjustment coefficient for the proposed pouring speed, i = 1, 2, 3, the central control unit records the adjusted proposed pouring speed as V', then V' = V × αi; the central control unit compares the adjusted proposed pouring speed with the minimum pouring speed Vmin and the maximum pouring speed Vmax;

[0076] When V' < Vmin, the central control unit will adjust the planned pouring speed to Vmin;

[0077] When Vmin≤V'≤Vmax, the central control unit does not adjust the planned pouring speed;

[0078] When V' > Vmax, the central control unit will adjust the planned pouring speed to Vmax.

[0079] Specifically, when the central control unit determines that the pouring speed of the molten iron is within a reasonable range, the second detector detects the inner surface area of ​​the mold and uploads the data to the central control unit. The central control unit calculates the surface-to-body ratio of the ductile iron manhole cover based on the inner cavity volume and inner surface area of ​​the mold, and determines the planned injection speed of the molten iron based on the surface-to-body ratio of the ductile iron manhole cover. This makes the pouring process more refined and further improves the pouring quality of the ductile iron manhole cover.

[0080] Furthermore, after the central control unit determines the planned pouring speed V', the third detector detects the liquid level height at the pouring port of the ductile iron manhole cover mold and records it as H. The central control unit has preset maximum liquid level height Hmax and minimum liquid level height Hmin at the pouring port. The central control unit determines the final pouring speed by comparing the liquid level height H at the pouring port of the ductile iron manhole cover mold with the preset maximum liquid level height Hmax and preset minimum liquid level height Hmin.

[0081] When H < Hmin, the central control unit determines the final pouring speed based on the volume of molten cast iron flowing into the pouring port and the volume of the mold cavity.

[0082] When Hmin < H < Hmax, the central control unit determines the final pouring speed as the planned pouring speed V'.

[0083] When H > Hmax, the central control unit determines the final pouring speed based on the volume of molten cast iron flowing into the pouring port and the volume of the mold cavity.

[0084] Further, when H < Hmin, the volume of molten cast iron flowing into the pouring port detected by the fourth detector is recorded as Q', and the ratio of the mold cavity volume Q to the volume of molten cast iron flowing into the pouring port Q' is K, K = Q ÷ Q'. The central control unit has a first preset volume ratio K1, a second preset volume ratio K2, a first preset final pouring speed adjustment coefficient γ1, and a second preset final pouring speed adjustment coefficient γ2. The central control unit compares the ratio of the mold cavity volume Q to the volume of molten cast iron flowing into the pouring port Q', K, with the first preset volume ratio K1 and the second preset volume ratio K2.

[0085] When K < K1, the central control unit selects γ1 as the adjustment coefficient for the final pouring speed;

[0086] When K1≤K≤K2, the central control unit selects γ2 as the adjustment coefficient for the final pouring speed;

[0087] When K > K2, the central control unit determines that the ductile iron mold is leaking and issues a warning signal.

[0088] Furthermore, when H > Hmax, the central control unit has a third preset volume ratio K3, a fourth preset volume ratio K4, a third preset final pouring speed adjustment coefficient γ3, and a fourth preset final pouring speed adjustment coefficient γ4. The central control unit compares the ratio K of the mold cavity volume Q to the volume Q' of the molten cast iron flowing into the pouring port with the third preset volume ratio K3 and the fourth preset volume ratio K4.

[0089] When K < K3, the central control unit determines that too many voids are generated during the casting process of the ductile iron manhole cover and issues a warning signal.

[0090] When K3≤K≤K4, the central control unit selects γ4 as the adjustment coefficient for the final pouring speed;

[0091] When K > K4, the central control unit selects γ3 as the adjustment coefficient for the final pouring speed.

[0092] Furthermore, when the central control unit selects γi as the adjustment coefficient for the injection speed of molten iron in the ball mill cast iron manhole cover, i = 1, 2, then the final pouring speed after adjustment is V1', V1' = V' + V' × γi;

[0093] When the central control unit selects γj as the adjustment coefficient for the injection speed of molten iron in the ball mill cast iron manhole cover, i = 3, 4, then the final molten iron injection speed after adjustment is V2', V2' = V' - V' × γj.

[0094] Furthermore, when the central control unit selects Vi' as the final pouring speed of the ductile iron manhole cover mold, i = 1, 2, the central control unit compares the final pouring speed Vi' with the minimum pouring speed Vmin and the maximum pouring speed Vmax;

[0095] When Vi' < Vmin, the central control unit will adjust the final pouring speed to Vmin;

[0096] When Vmin≤Vi'≤Vmax, the central control unit does not adjust the final pouring speed;

[0097] When Vi' > Vmax, the central control unit will adjust the final pouring speed to Vmax.

[0098] Specifically, after the central control unit determines the planned pouring speed of molten iron based on the surface-to-body ratio of the ductile iron manhole cover, the third detector detects the liquid level at the pouring port of the ductile iron manhole cover mold, and the fourth detector detects the volume of molten iron flowing into the pouring port. The central control unit is equipped with the highest and lowest liquid level at the pouring port. By comparing the detected liquid level at the pouring port of the ductile iron manhole cover mold with the highest and lowest liquid level at the pouring port, the pouring speed is finally determined. When the liquid level at the pouring port is at the highest... When the liquid level is within the range of the highest and lowest liquid level, the central control unit controls the molten iron to be poured into the ductile iron manhole cover mold at a predetermined injection rate. When the liquid level at the pouring port is not within the range of the highest and lowest liquid level, the central control unit determines that the pouring rate of the molten iron needs to be determined by combining the ratio between the volume of the molten iron flowing into the pouring port and the volume of the mold cavity. By combining the ratio between the volume of the molten iron flowing into the pouring port and the volume of the mold cavity to determine the pouring rate, the pouring process is made more precise and the pouring quality is improved.

[0099] Furthermore, when the central control unit determines that the final pouring speed meets the standard, in step S4, the ductile iron manhole cover strength testing device further tests the strength D of the ductile iron manhole cover. The central control unit has a preset reference strength Dc for the ductile iron manhole cover. The central control unit compares the strength D of the ductile iron manhole cover detected by the ductile iron manhole cover strength testing device with the reference strength Dc of the ductile iron manhole cover:

[0100] When D≥Dc, the central control unit determines that the strength of the ductile iron manhole cover meets the standard;

[0101] When D < Dc, the central control unit determines that the strength of the ductile iron manhole cover does not meet the standard, and controls and adjusts the proportion of ductile iron raw materials.

[0102] Specifically, in step S4, the ductile iron manhole cover strength detector is used to test the strength of the produced ductile iron manhole cover. If the strength of the ductile iron manhole cover is not up to standard, the proportion of ductile iron raw materials is adjusted. In this way, the quality of the produced ductile iron manhole cover is improved.

[0103] Preferably, the raw materials for the ductile iron manhole cover include virgin iron, scrap steel, recycled materials, ferrosilicon, carbon raiser, nickel, spheroidizing agent, and inoculant.

[0104] Preferably, the raw materials for the ductile iron manhole cover include virgin iron, scrap steel, recycled materials, ferrosilicon, carbon raiser, nickel, spheroidizing agent, and inoculant.

[0105] Working principle: When using the ductile iron anti-settlement manhole cover prepared by this method, it is equipped with an adjusting ring, anti-fall device, manhole cylinder, manhole cover plate, and upper flange. The manhole seat of the ductile iron anti-settlement manhole cover adopts a flange-type upper plate structure, and the upper plate is flush with the road surface elevation. The ductile iron manhole cover transfers the vehicle load it bears to the road structure layer around the manhole cylinder through the upper flange and is connected to the manhole cylinder by a socket connection, reducing the uneven settlement between the manhole cover and the road surface.

[0106] The flange width is not less than 150mm, and the outer edge of the flange face is provided with a reverse snap structure so that the manhole base and the road structure form an integral whole;

[0107] The manhole cover support surface is equipped with a trapezoidal elastic buffer rubber pad to reduce noise and improve driving comfort. A trapezoidal groove is also provided to ensure a firm connection between the gasket and the manhole seat. The rubber gasket has good wear resistance, corrosion resistance, oil resistance and weather resistance.

[0108] The ductile iron manhole cover and the manhole base are equipped with anti-theft and locking devices to ensure that the manhole cover and the manhole base are fastened together when closed, preventing the manhole cover from falling off the manhole base.

[0109] Therefore, the technical solution of the present invention has been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

[0110] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A process for producing a spheroidal graphite cast iron anti-settling well lid, characterized by, It comprises the following steps, Step S1: according to the proportion of raw materials, the ductile iron raw materials are added into the feeding bin for heating; Step S2: the central control unit starts the transmission device to pour the cast iron liquid into the manhole cover mold; Step S3: the central control unit transports the poured manhole cover mold to the cooling liquid for cooling; Step S4: detect the strength of the ductile iron manhole cover; Step S5: polish the surface of the manhole cover with qualified strength; In the process of preparing the ductile iron anti-settling manhole cover, a detection unit and a central control unit are provided, the detection unit comprises a first detector, a second detector, a third detector, a fourth detector, a ductile iron manhole cover strength detector, the first detector is used to detect the cavity volume of the mold; the second detector is used to detect the inner surface area of the mold, the central control unit calculates the surface-body ratio of the ductile iron manhole cover according to the inner surface area of the mold and the cavity volume of the mold, and determines the tentative pouring speed of the cast iron liquid at the pouring opening of the ductile iron manhole cover mold according to the calculated surface-body ratio; The third detector is used to detect the liquid level of the pouring opening of the ductile iron manhole cover mold; The fourth detector is used to detect the volume of the cast iron liquid flowing into the pouring opening; the central control unit determines the final pouring speed according to the liquid level of the pouring opening of the ductile iron manhole cover mold and the volume of the cast iron liquid flowing into the pouring opening; the ductile iron strength detector is used to detect the strength of the ductile iron manhole cover, if the strength of the ductile iron manhole cover meets the standard, the central control unit determines that the preparation of the ductile iron manhole cover is completed, if the strength of the ductile iron manhole cover does not meet the standard, the proportioning of the ductile iron raw materials is further adjusted.

2. The manufacturing process of ductile iron anti-settlement manhole cover according to claim 1, characterized in that, In the step S2, the first detector detects the cavity volume of the mold, denoted as Z, and uploads it to the central control unit, the central control unit records the initial pouring speed of the cast iron liquid, denoted as V, the central control unit calculates the expected pouring time of the cast iron liquid as T, T=Z÷V, the central control unit is pre-set with the shortest pouring time Tmin of the cast iron liquid, Tmin=Z÷Vmax, wherein Vmax is the maximum pouring speed of the cast iron liquid, and the longest pouring time Tmax of the cast iron liquid is pre-set, Tmax=Z÷Vmin, wherein Vmin is the minimum pouring speed of the cast iron liquid; the central control unit compares the expected pouring time T of the cast iron liquid with the shortest pouring time Tmin and the longest pouring time Tmax, and judges whether the pouring time of the ductile iron manhole cover cast iron liquid is within a reasonable range according to the comparison result; When T When Tmin≤T When T When T 3. The manufacturing process of ductile iron anti-settlement manhole cover according to claim 2, characterized in that, When the central control unit determines that the pouring speed is not within a reasonable range, the second detector detects the inner surface area of the mold, denoted as S, and uploads data information to the central control unit, the central control unit calculates the surface-volume ratio B of the ductile iron manhole cover according to the volume of the mold cavity and the inner surface area of the mold, B=S / Q, the central control unit is provided with a first preset surface-volume ratio B1, a second preset surface-volume ratio B2, a first preset pouring speed adjustment coefficient α1, a second preset pouring speed adjustment coefficient α2, and a third preset pouring speed adjustment coefficient α3, the central control unit compares the surface-volume ratio B of the ductile iron manhole cover with the first preset surface-volume ratio B1 and the second preset surface-volume ratio B2, and selects the corresponding pouring speed adjustment coefficient according to the comparison result, so as to determine the tentative pouring speed: When B When B1≤B≤B2, the central control unit selects α2 as the pouring speed adjustment coefficient; When B>B2, the central control unit selects α3 as the pouring speed adjustment coefficient; When the central control unit selects αi as the pouring speed adjustment coefficient, i=1, 2, 3, the central control unit adjusts the tentative pouring speed to V', then V'=V×αi; the central control unit compares the adjusted tentative pouring speed with the minimum pouring speed Vmin and the maximum pouring speed Vmax; When V'<Vmin, the central control unit adjusts the tentative pouring speed to Vmin; When Vmin≤V'≤Vmax, the central control unit does not adjust the tentative pouring speed; When V'>Vmax, the central control unit adjusts the tentative pouring speed to Vmax.

4. The manufacturing process of ductile iron anti-settlement manhole cover according to claim 3, characterized in that, When the central control unit determines the tentative pouring speed V', the third detector detects the liquid level of the pouring port of the ductile iron manhole cover mold, denoted as H, the central control unit is provided with a preset maximum liquid level Hmax of the pouring port and a preset minimum liquid level Hmin of the pouring port, the central control unit compares the liquid level H of the pouring port of the ductile iron manhole cover mold with the preset maximum liquid level Hmax of the pouring port and the preset minimum liquid level Hmin of the pouring port to determine the final pouring speed; When H When Hmin<H<Hmax, the central control unit determines the final pouring speed as the tentative pouring speed V'; When H>Hmax, the central control unit determines the final pouring speed according to the volume of the ductile iron liquid flowing into the pouring port and the volume of the mold cavity.

5. The manufacturing process of ductile iron anti-settlement manhole cover according to claim 4, characterized in that, When H When K When K When K 6. The manufacturing process of ductile iron anti-settlement manhole cover according to claim 5, characterized in that, When K When the control unit selects γi as the adjustment coefficient of the pouring speed of the ductile iron liquid, i = 1, 2, the adjusted final pouring speed is V1', V1' = V' + V' × γi. When the control unit selects γj as the adjustment coefficient of the pouring speed of the ductile iron liquid, i = 3, 4, the adjusted final pouring speed of the ductile iron liquid is V2', V2' = V' - V' × γj. When the control unit selects Vi' as the final pouring speed of the ductile iron manhole cover mold, i = 1, 2, the control unit compares the final pouring speed Vi' with the minimum pouring speed Vmin and the maximum pouring speed Vmax.

7. The manufacturing process of ductile iron anti-settlement manhole cover according to claim 6, characterized in that, When Vi' < Vmin, the control unit adjusts the final pouring speed to Vmin. When Vmin≤Vi'≤Vmax, the control unit does not adjust the final pouring speed.

8. The process for the preparation of a nodular cast iron anti-settling intelligent manhole cover according to claim 7, characterized in that, When Vi' > Vmax, the control unit adjusts the final pouring speed to Vmax. When the control unit determines that the final pouring speed meets the standard, the strength detection device of the ductile iron manhole cover further detects the strength D of the ductile iron manhole cover during step S4, and the control unit has a reference strength Dc of the ductile iron manhole cover preset therein. The control unit compares the strength D of the ductile iron manhole cover detected by the strength detection device of the ductile iron manhole cover with the reference strength Dc of the ductile iron manhole cover: ​ ​ 9. The process for the preparation of a nodular cast iron anti-settling intelligent manhole cover according to claim 8, characterized in that, ​ When D≥Dc, the central control unit determines that the strength of the ductile iron manhole cover meets the standard; When D 10. The process for the preparation of nodular cast iron anti-settling intelligent manhole cover as claimed in claim 1 wherein, The raw materials of the ductile iron manhole cover include virgin iron, scrap steel, recycled material, ferrosilicon, carburizer, nickel, spheroidizing agent, and inoculant.

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