A mould for casting an ultra-thick heavy nodular cast iron storage container

Abstract

The application relates to a mold for an ultra-thick large nodular cast iron storage container, and belongs to the technical field of ultra-thick large nodular cast iron manufacturing. The mold comprises a sand box, a metal mold unit and a rapid cooling system. The sand box comprises a bottom box and a plurality of pouring box, a bottom box pouring gate is arranged in the bottom box, a straight pouring channel is arranged in the pouring box, and the pouring boxes are arranged on the bottom box. A core is arranged in the bottom box, the core is sleeved with the metal mold unit, a profiling cavity is formed between the core and the metal mold unit, and the metal mold unit is fixed on the bottom box. A water cooling device is arranged on the metal mold unit. One end of the rapid cooling system is communicated with the core, and the other end is connected with an air extraction / supply device. An anti-expansion locking device is arranged between the metal mold unit and the bottom box. The application not only shortens the eutectic solidification time, improves the compactness of the castings, obtains high-performance and zero-shrinkage products, and meets the requirements of ultrasonic detection, but also prevents the castings from generating defects such as slag inclusion and cold shut, and meets the requirements of magnetic powder detection.

Description

TECHNICAL FIELD

[0001] The present application relates to a mold for a super-thick nodular cast iron storage container, and belongs to the technical field of super-thick nodular cast iron manufacturing. BACKGROUND

[0002] In recent years, with the large-scale development of nuclear power, hydropower, wind power generator sets and the heavy-duty development of other engineering machinery equipment, the demand for super-thick nodular cast iron is becoming more and more urgent. Foreign developed countries have a high level in the production of super-thick nodular cast iron parts. In 1983, the German Siempelkamp company produced a nodular cast iron stamping machine support with a wall thickness of 630mm, and France and Japan have successively developed nodular cast iron parts with a wall thickness of more than 400mm. The nuclear spent fuel nodular cast iron storage container has complex structure, harsh technical conditions and harsh environment, and represents the highest level of nodular cast iron production in the world. The German Thyssen successfully produced a N1300 nuclear spent fuel nodular cast iron tank with a weight of 115 tons and a wall thickness of 400mm.

[0003] At present, the national standard "GB / T 1348-2009 Nodular Cast Iron Parts" and the European standard "DIN EN 1563:2012 Cast Nodular Cast Iron" define the wall thickness specification of nodular cast iron to 200mm, and there is no clear detection requirement for super-thick nodular cast iron with a wall thickness of more than 200mm. The super-thick nodular cast iron at the hot spot or the center position often has organizational defects such as metamorphic graphite, shrinkage, and shrinkage hole due to slow solidification speed and long solidification time, which leads to the decrease of mechanical properties, and the generation of chunky graphite is particularly obvious. For nodular cast iron containers with a wall thickness of more than 500mm, such as nuclear spent fuel containers, the technical requirements for such workpieces are: zero defects of ultrasonic flaw detection and magnetic powder flaw detection; and for the ultrasonic flaw detection of the super-thick nodular cast iron storage container, zero defects are a technical difficulty. SUMMARY

[0004] The technical problem to be solved by the present application is to provide a mold for a super-thick nodular cast iron storage container to avoid the above technical shortcomings and meet the requirements of ultrasonic inspection and magnetic powder inspection.

[0005] The application solves the above problems by adopting the technical scheme of a casting mold of an ultra-thick nodular cast iron storage container, which comprises a sand box, a metal mold unit and a rapid cooling system, the sand box comprises a bottom box and a plurality of pouring boxes, a bottom box pouring gate is arranged in the bottom box, a straight pouring pipe is arranged in each pouring box, and the straight pouring pipes and the bottom box pouring gate are communicated.

[0006] The core comprises a core support and a chill unit, the core support is vertically fixed on the bottom box, a chill support is arranged on the core support, the chill unit is wrapped on the chill support, and sand is filled between the chill support and the core support.

[0007] The bottom of the chill support is provided with a plurality of support blocks in a ring shape for supporting the chill unit, a plurality of installation holes are arranged on the chill support in a ring shape along the shaft, and bolts are arranged in the installation holes to connect the chill support and the chill unit.

[0008] The chill unit comprises a ring-shaped chill and a chill cover, the chill cover is arranged at the top end of the ring-shaped chill, and the chill cover is fixedly connected with the core support.

[0009] The chill cover comprises an outer ring chill and an inner ring chill, the outer ring chill is clamped on the cover plate in a ring shape, and the inner ring chill is arranged on the inner side of the outer ring chill.

[0010] The rapid cooling system comprises an air extraction pipeline and an air supply pipeline, the air extraction pipeline and the air supply pipeline are arranged in the sand box, a plurality of air cooling holes are arranged on the chill support, and the air extraction pipeline and the air supply pipeline are communicated with the corresponding air cooling holes.

[0011] The water cooling device comprises a water cooling pipe and a nozzle, the water cooling pipe is wrapped on the metal mold unit, the nozzle is arranged on the water cooling pipe in a ring shape, and a valve for adjusting the water flow is arranged on the water cooling pipe.

[0012] The anti-expansion locking device comprises a pressing iron and a clamp, the pressing iron is arranged at the top end of the metal mold unit, and the clamp is fixedly connected with the bottom box and the metal mold unit.

[0013] The metal mold unit comprises a plurality of metal molds, the metal molds are arranged in a stack and are fixedly connected, and a casting body riser is arranged on the top metal mold.

[0014] The seat bag is communicated with the straight gate of the gate.

[0015] Compared with the prior art, the application has the advantages that: a casting mold of the super-thick large nodular cast iron storage container cools the cold iron unit and the metal mold unit respectively, improves the continuous chilling capacity of the cold iron and the metal mold, shortens the eutectic solidification time, and improves the compactness of the casting; the pressing iron is placed on the top layer of the metal mold, the clamp fastens the bottom box and the metal mold unit firmly, prevents the graphite expansion from lifting the box during pouring, and avoids the problems of shrinkage and shooting of the super-thick large nodular cast iron storage container, so as to obtain a high-performance and zero-shrinkage product that meets the requirements of ultrasonic detection. The two bottom-pouring systems are used to pour the profiled chamber at the same time, which not only makes the molten iron stand still sufficiently, facilitates the floating of the slag, reduces the use of filter sheets, and reduces the production cost, but also stabilizes the pouring process, prevents the casting from producing defects such as slag inclusion and cold shut, and meets the requirements of magnetic powder detection. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 It is a schematic diagram of a hundred-ton spent fuel nodular cast iron container;

[0017] Figure 2 It is a schematic diagram of a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application (without the pressing iron and the clamp);

[0018] Figure 3 It is a schematic diagram of a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application;

[0019] Figure 4 It is a longitudinal sectional view of a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application;

[0020] Figure 5 It is a schematic diagram of a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application (without the sand box);

[0021] Figure 6 It is a top view of a bottom box in a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application;

[0022] Figure 7 It is a schematic diagram of a cold iron support in a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application;

[0023] Figure 8 It is a schematic diagram of a core support in a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application;

[0024] Figure 9 It is a top view of a water cooling device in a casting mold of a super-thick large nodular cast iron storage container of an embodiment of the application;

[0025] Figure 10 This is a schematic diagram of a cooling iron cover (excluding the cover plate) in a casting mold of an ultra-thick large ductile iron storage and transportation container according to an embodiment of the present invention;

[0026] In the figure, 1 is the base box, 2 is the runner box, 3 is the metal mold unit, 4 is the seat bag, 5 is the water cooling device, 5.1 is the water cooling pipe, 5.2 is the nozzle, 6 is the core bracket, 7 is the chiller bracket, 7.1 is the air cooling hole, 7.2 is the support block, 8 is the sprue pipe, 9 is the ingrowth, 10 is the nest, 11 is the horizontal runner, 12 is the exhaust pipe, 13 is the air supply pipe, 14 is the weight, 15 is the clamp, 16 is the body riser, 17 is the outer ring chiller, and 18 is the inner ring chiller. DETAILED DESCRIPTION

[0027] The present invention will be described in further detail below with reference to the accompanying drawings and embodiments.

[0028] like Figure 1 As shown in the figure, the outer diameter of the 100-ton spent fuel container is 2550mm, the inner diameter is 1565mm, the height is 4860mm, the wall thickness is 500mm, and the weight is 120T. Figure 2 、 3 As shown, the casting mold for the 100-ton spent fuel container includes a sand box, a metal mold unit 3, and a rapid cooling system. The sand box includes a base box 1 and a sprue box 2. The base box 1 is equipped with a base box runner, and the sprue box 2 is equipped with a sprue pipe 8. Sprue boxes 2 are installed on both sides of the base box 1 to connect the sprue pipe 8 with the base box runner. The base box 1 is equipped with a clay core, which is covered by a metal mold unit 3. The metal mold unit 3 covers the clay core within its inner cavity, forming a contoured cavity for the 100-ton spent fuel container between the outer surface of the clay core and the inner cavity of the metal mold unit 3. The metal mold unit 3 is fixed to the base box 1, connecting the contoured cavity with the base box runner. The sprue box 2 is equipped with two 50T seat bags 4, each of which is connected to the sprue pipe 8 on the corresponding side. The rapid cooling system includes an air supply pipe 13 and an exhaust pipe 12. The air supply pipe 13 and the exhaust pipe 12 are respectively pre-buried in the sand box. One end of the air supply pipe 13 and one end of the exhaust pipe 12 are respectively connected to the clay core. The other end of the air supply pipe 13 is connected to the blower to blow in natural wind. The other end of the exhaust pipe 12 is connected to the exhaust fan to promptly extract the hot air in the profiling chamber.

[0029] The above-mentioned 100-ton spent fuel storage and transportation container has a pouring weight of approximately 150 tons and is cast using two sets of 50-ton ladles plus a 30-ton ladle. The advantages are: sufficient static stagnation of the molten iron facilitates the floating of slag inclusions, reduces the use of filters, and reduces costs; maintains a stable pouring process, prevents defects such as slag inclusions and cold shuts in the casting; and facilitates rapid pouring and mold filling, reducing slag inclusions in the casting.

[0030] In order to prevent the graphite expansion from lifting the box, the weight of the theoretical weight iron 14 needs to be more than 450T. However, the top surface area of the top layer metal mold is small, and it is impossible to place so many weight irons 14. Figure 3 As shown in the drawings, the weight iron 14 and the hoop 15 are combined and locked to prevent the graphite expansion from lifting the box during the solidification process. After the box is combined, four 25T weight irons 14 are placed on the top layer metal mold, and then the bottom box 1 and the metal mold unit 3 are tightly fastened through the hoop 15 to prevent the graphite expansion from lifting the box during the pouring process, which causes the hundred-ton spent fuel storage and transportation container to produce shrinkage, shooting box and other problems.

[0031] As shown in the drawings, Figure 5 , 6 The bottom box sprue includes a left bottom box sprue system and a right bottom box sprue system arranged symmetrically. The left bottom box sprue system is communicated with the straight sprue pipe 8 in the left sprue box, and the right bottom box sprue system is communicated with the straight sprue pipe 8 in the right sprue box. The left and right bottom box sprue systems respectively include nine inner sprues 9, and the nine inner sprues 9 are communicated with the cross sprue 11 through the nest 10. The multiple inner sprues 9 make the filling stable and avoid turbulence to cause defects such as slag inclusion and gas entrapment in the castings. The above straight sprue pipe 8, inner sprue 9 and cross sprue 11 are respectively wrapped with refractory pipe. Considering that the wall thickness of the hundred-ton spent fuel container is about 500mm, the low-temperature fast pouring process is selected, the pouring temperature is 1300-1350℃, the pouring time is 100-150s, and the inner sprue 9 iron feeding line speed is 0.7-1.0m / s, which can reduce the liquid shrinkage of the metal and prevent the generation of shrinkage.

[0032] As shown in the drawings, Figure 4 , 7 , 8, the core includes a core support 6, a ring cold iron and a cold iron cover. The core support 6 is made of 6 steel plates by ring type reinforcing rib welding and processing, and the bottom plane is required to be flat and the structure is non-closed type for easy assembly of the cold iron. The cold iron support 7 is a cylindrical body welded by steel plates. The core support 6 is vertically fixed on the core support nest of the bottom box 1, and the core support 6 is sleeved with a plurality of stacked cold iron supports 7. The ring cold iron is wrapped outside the corresponding cold iron support 7, so that the plurality of stacked cold iron supports 7 are respectively provided with ring cold irons. The bottom cold iron support 7 is provided with 12 support blocks 7.2 in the ring for supporting the ring cold iron. The cold iron support 7 is provided with a plurality of evenly arranged mounting holes along the axis, and the mounting holes are provided with bolts, and the other ends of the bolts are provided with ring cold irons, so that the ring cold irons have a connection relationship with the cold iron support 7. The cold iron support 7 and the core support 6 are filled with chromite sand, which has good thermal conductivity and can effectively reduce the temperature of the cold iron. The cold iron cover is supported on the top end of the ring cold iron, and the cold iron cover is fixedly connected with the core support 7 through bolts to form a core that meets the requirements.

[0033] As shown in the drawings, Figure 10As shown, the above-mentioned cold iron cover includes an outer ring cold iron 17 and an inner ring cold iron 18, the bottom of the outer ring cold iron 17 is provided with a T-shaped groove, and the cover plate is uniformly provided with a T-shaped convex groove in the circumferential direction, the T-shaped groove is matched with the T-shaped convex groove, so that the outer ring cold iron 17 is clamped on the cover plate in the circumferential direction, the inner ring cold iron 18 is laid on the inner side of the outer ring cold iron 17, and the cover plate is covered by the outer ring cold iron 17 and the inner ring cold iron 18. After the outer ring cold iron 17 and the inner ring cold iron 18 are installed in position, the gap between the two cold irons is filled with sand. Due to thermal expansion and contraction after casting, the outer ring cold iron 17 is assembled with a T-shaped groove to prevent the outer ring cold iron 17 from sticking to the casting after the box is opened. When the casting shrinks, the outer ring cold iron 17 will slide inward along the T-shaped groove, and will not stick to the inner wall of the casting, avoiding the difficulty of cleaning.

[0034] As shown in Figure 6 , 7 , the cold iron support 7 is provided with four air cooling holes 7.1 in the circumferential direction at the bottom, the rapid cooling system includes three air supply pipelines 13 and one air exhaust pipeline 12, and the air supply pipeline 13 and the air exhaust pipeline 12 are respectively communicated with the four air cooling holes 7.1. After casting, the temperature of the cold iron rises, which will cause the temperature of the air in the core support 6 to rise. Three air blowers are used to blow natural wind into the three air supply pipelines 13 respectively, and the blown natural wind can reduce the temperature in the cavity. One air extractor is used to extract hot air from the top of the cavity through the air exhaust pipeline 12, so as to improve the cooling environment of the hot spot area. By blowing natural wind and extracting hot air, the temperature in the cavity can be effectively reduced, the continuous chilling effect of the cold iron can be strengthened, and the solidification time of the hundred-ton spent fuel container can be shortened, so as to obtain a high-performance and zero-shrinkage product.

[0035] As shown in Figure 2 , 9 , the metal mold unit 3 includes six layers of metal molds, and the six layers of metal molds are stacked and connected by bolts between adjacent two metal molds. The metal mold unit is wrapped with a water-cooled pipe 5.1, and a plurality of nozzles 5.2 are arranged on the water-cooled pipe 5.1 in the circumferential direction. After water is supplied to the water-cooled pipe 5.1, the water is sprayed through the nozzles to cool the metal mold unit 3 and strengthen the continuous chilling capacity of the metal mold unit 3. A plurality of valves are arranged on the water-cooled pipe 5.1, and each valve can adjust the water outlet state of the nozzle: spray or water. After casting, the valves are opened, so that the water supplied to the water-cooled pipe 5.1 is sprayed or watered on the metal mold unit 3 through the nozzles 5.2, the temperature of the metal mold unit 3 is reduced, and the solidification time of the hundred-ton spent fuel storage and transportation container is shortened.

[0036] When the wall thickness of the casting is super large, the structure is prone to problems such as graphite floating, graphite blooming, flaky graphite, insufficient number of graphite balls and coarse graphite size. When the casting is cooled by cold iron and metal mold, the chilling capacity of the cold iron and metal mold will be greatly reduced after being heated, and the continuous cooling effect cannot be achieved, and even the heat preservation effect is reversed. The method of cooling the casting by ordinary cold iron and metal mold cannot solve such metallurgical structure problems. The cold iron and metal mold are cooled respectively in the application, the continuous chilling capacity of the cold iron and metal mold is improved, and a hundred-ton-class spent fuel storage and transportation container with dense structure is obtained.

[0037] As shown in Figure 4 The body riser 6 can not only collect dirt and cold iron, but also can play a feeding effect to prevent the super-thick nodular cast iron storage and transportation container from producing defects such as slag inclusion and shrinkage.

[0038] The cold iron and metal mold unit 3 are cooled respectively in the application, the continuous chilling capacity of the cold iron and metal mold is improved, the eutectic solidification time is shortened, and the density of the casting is improved; the cold iron 14 is placed on the top metal mold, the clamp 15 tightly fastens the bottom box 1 and the metal mold unit 3, prevents the graphite expansion from lifting the box during pouring, and avoids problems such as shrinkage and shooting of the super-thick nodular cast iron storage and transportation container, so as to obtain a high-performance, zero-shrinkage product that meets the ultrasonic detection requirements. Two bottom-pouring systems are used to pour the profiled chamber at the same time, which not only makes the iron liquid stand still fully, facilitates the floating of slag inclusion, reduces the use of filter sheets, and reduces the production cost; and the pouring process is stable, which prevents the casting from producing defects such as slag inclusion and cold shut, and meets the magnetic powder detection requirements.

[0039] In addition to the above embodiments, the application also includes other implementation manners, and any technical solution formed by equivalent transformation or equivalent replacement shall fall within the protection scope of the claims of the application.

Claims

1. A mold for a super-thick ductile iron storage container, characterized in that: The sand box, the metal mold unit and the rapid cooling system, the sand box includes a bottom box and a plurality of runner boxes, a bottom box runner is arranged in the bottom box, a straight runner pipeline is arranged in the runner box, a plurality of runner boxes are arranged on the bottom box, and the straight runner pipeline and the bottom box runner are communicated; a core is arranged in the bottom box, a metal mold unit is sleeved on the core, an ultra-thick large nodular cast iron storage container profiling chamber is formed between the core and the metal mold unit, the metal mold unit is fixed on the bottom box, and the profiling chamber and the bottom box runner are communicated; a water cooling device is arranged on the metal mold unit to cool the metal mold unit; one end of the rapid cooling system is communicated with the core, the other end is connected with an air suction / supply device, and the core is cooled; an anti-expansion locking device is arranged between the metal mold unit and the bottom box; The core includes a core support and a chill unit, the core support is vertically fixed on the bottom box, a chill support is sleeved on the core support, the chill unit is covered on the chill support, and sand is filled between the chill support and the core support; A plurality of support blocks are arranged on the bottom of the chill support in a ring shape to support the chill unit; a plurality of installation holes are arranged on the chill support in a ring shape at intervals, bolts are arranged in the installation holes, and the chill support and the chill unit are connected; The rapid cooling system includes an air suction pipeline and an air supply pipeline, the air suction pipeline and the air supply pipeline are arranged in the sand box, a plurality of air cooling holes are formed in the chill support, and the air suction pipeline and the air supply pipeline are communicated with the corresponding air cooling holes; The water cooling device includes a water cooling pipe and a nozzle, the water cooling pipe is sleeved on the metal mold unit, the nozzle is arranged on the water cooling pipe in a ring shape, and a valve for adjusting water flow is arranged on the water cooling pipe; The anti-expansion locking device includes a pressing iron and a clamp, the pressing iron is arranged on the top end of the metal mold unit, and the clamp is fixedly connected with the bottom box and the metal mold unit.

2. A mould for a super-thick ductile iron storage container according to claim 1, characterized in that: The chill unit includes a ring-shaped chill and a chill cover, the chill cover is arranged on the top end of the ring-shaped chill, and the chill cover is fixedly connected with the core support.

3. A mould for a super-thick ductile iron storage container according to claim 2, characterized in that: The chill cover includes an outer ring chill and an inner ring chill, the outer ring chill is clamped on the cover plate in a ring shape, and the inner ring chill is arranged on the inner side of the outer ring chill.

4. A mould for a super-thick ductile iron storage container according to claim 1, characterized in that: The metal mold unit includes a plurality of metal molds, the metal molds are arranged in a stack and are fixedly connected, and a casting body riser is arranged on the top metal mold.

5. A mould for the casting of an ultra-thick ductile iron storage container according to claim 1, characterized in that: A seat bag is arranged on the runner box, and the seat bag is communicated with the runner straight runner.

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