CN116878272A - Gray cast iron smelting furnace and smelting process - Google Patents

Abstract

The application provides a gray cast iron smelting furnace and a smelting process, and relates to the field of gray cast iron manufacturing. The device comprises a bracket and a shell rotationally arranged on the bracket, wherein a crucible heated by a heating coil is arranged in the shell, an opening of the crucible is communicated with the top of the shell, a heat preservation sleeve is arranged in the shell, the heating coil and the crucible are both positioned in the heat preservation sleeve, and a preheating space is formed between the inner wall of the shell and the outer wall of the heat preservation sleeve; the top of the shell is provided with at least one pair of material conveying openings communicated with the preheating space, and the material to be melted enters and exits the preheating space through the material conveying openings. The application has the effects of reducing the waste of heat in the smelting process and improving the energy utilization rate.

Description

Gray cast iron smelting furnace and smelting process

Technical Field

The application relates to the field of gray cast iron manufacture, in particular to a gray cast iron smelting furnace and a smelting process.

Background

Gray cast iron refers to cast iron having flake graphite, and is called gray cast iron because the fracture appears dark gray at the time of fracture. The main components are iron, carbon, silicon, manganese, sulfur and phosphorus, and the cast iron has the most widely applied, and the yield of the cast iron accounts for more than 80 percent of the total yield of the cast iron. Gray cast iron has good casting performance, good vibration damping performance and good wear resistance, and therefore, the gray cast iron is widely applied to a plurality of industries.

At present, in the production process of gray cast iron, raw materials such as scrap steel, pig iron, furnace returns and the like and processing aids are required to be placed into a smelting furnace for smelting, then the molten materials are poured into a mould for casting, and the gray cast iron is formed after cooling.

However, in the smelting process of the smelting furnace, a large amount of heat is generated, most of the heat is used for heating various raw materials in the smelting furnace, the raw materials are ensured to be changed into a molten state, and a small amount of heat is radiated outwards, so that heat is wasted, the utilization rate of energy sources in the gray cast iron smelting process is reduced, and the production cost of enterprises is increased.

Disclosure of Invention

In order to solve the problem of serious heat waste in the smelting process, the application provides a gray cast iron smelting furnace and a smelting process.

In a first aspect, the application provides a gray cast iron smelting furnace, which adopts the following technical scheme:

the gray cast iron smelting furnace comprises a bracket and a shell rotationally arranged on the bracket, wherein a crucible heated by a heating coil is arranged in the shell, an opening of the crucible is communicated with the top of the shell, a heat preservation sleeve is arranged in the shell, the heating coil and the crucible are both positioned in the heat preservation sleeve, and a preheating space is formed between the inner wall of the shell and the outer wall of the heat preservation sleeve;

the top of the shell is provided with at least one pair of material conveying openings communicated with the preheating space, and the material to be melted enters and exits the preheating space through the material conveying openings.

Through adopting above-mentioned technical scheme, the heat that heating coil produced mostly transmits to the crucible and is used for the heating of waiting the melt in the crucible, little part heat passes the insulation cover through the mode of thermal radiation and enters into preheating space in, thereby form the preheating effect to waiting the melt in the preheating space, after waiting the melt to become in molten state's melt in the crucible and pour into the mould, waiting the melt through preheating can shift to in the crucible through the material conveying mouth, thereby the temperature when waiting the melt to get into the crucible has been improved, be convenient for heating coil can be with less energy with waiting the melt through preheating to the molten state, the invalid loss of heat has been reduced, the utilization ratio of the energy has been improved.

Optionally, the top of casing is equipped with out liquid subassembly, go out liquid subassembly and include guard ring and mouth of a river, the guard ring is established at the top of casing and is set up with the crucible is coaxial, the mouth of a river is located the outer wall of guard ring and is linked together with the inboard of guard ring, the melt in the crucible passes the guard ring and outwards discharges from the mouth of a river.

Through adopting above-mentioned technical scheme, when casing and crucible rotate around the support, the molten liquid can be through the mouth of a river on the shroud direct outwards flow, can prevent on the one hand that the molten liquid from entering into in the gap between crucible and the casing, on the other hand under the drainage effect at mouth of a river, the molten liquid can concentrate and be columnar inflow to in the mould, effectively prevents that the molten liquid from producing uncontrollable everywhere along the outer wall of casing and flowing, when improving molten liquid dumping efficiency, has ensured the security of operation.

Optionally, a cover body is further arranged at the top of the shell, a containing groove for containing the retainer and the water gap is formed in the bottom of the cover body, and the notch of the containing groove is separated from the top of the water gap.

Through adopting above-mentioned technical scheme, the lid can be closing cap crucible ground opening, reduces the heating coil and treats the heat loss of melt in-process, improves the melting speed of treating the melt.

Optionally, a cavity and a material conveying channel are further arranged in the cover body, the cross section of the cavity is T-shaped, the transverse part of the cavity is close to the top of the cover body, and the vertical part of the cavity is communicated with the bottom of the accommodating groove and is in butt joint with the opening of the crucible;

one end of the material conveying channel is communicated with the transverse part of the cavity, and the other end of the material conveying channel is in butt joint with the material conveying opening.

By adopting the technical scheme, in the process of heating the crucible and the to-be-melted material, rising heat flow with higher temperature can be formed at the opening of the crucible, and the rising heat flow can sequentially pass through the vertical part of the cavity and the transverse part of the cavity and enter the preheating space, so that the preheating effect on the to-be-melted material in the preheating space is improved, and the energy utilization rate is further improved; moreover, after the molten liquid is poured, the effect that the molten material in the preheating space automatically enters the crucible can be achieved through adjusting the rotation angle of the crucible.

Optionally, a pair of spout that radial cross-section is the shape of falling T in the top of casing, the spout is located the both sides of retainer symmetrically, the bottom of lid is equipped with a pair of draw runner, a pair of draw runner respectively and just slide in a pair of spout with the adaptation.

Through adopting above-mentioned technical scheme, under the cooperation of spout and draw runner, the lid can not break away from at casing pivoted in-process, plays the spacing effect to the lid.

Optionally, the cover body is further provided with a socket, the socket penetrates through two side walls of the cover body, which are oppositely arranged, the socket is located above the accommodating groove and is communicated with the vertical portion of the cavity, the width of the socket is larger than the inner diameter of the guard ring, a pair of sockets are internally provided with a movable plate in an adaptive manner, and the movable plate seals the guard ring.

Through adopting above-mentioned technical scheme, the fly leaf can insert from the one end of socket and outwards wear out from the other end of socket to realize that the fly leaf can the closing cap guard ring, on the one hand reduce the heat loss in the crucible, on the other hand can prevent at the crucible slope, carry out the in-process that the melt emptys, treat in the melt in the preheating space a small amount can automatic slide into the melt, lead to impurity content in the melt too high, just also reduced the yields of finished product.

Optionally, a feeding pipe is arranged at the bottom of the shell, one end of the feeding pipe is communicated with the preheating space, and a hose is detachably arranged at the other end of the feeding pipe;

one end of the hose, which is far away from the feeding pipe, is provided with a feeding pipe, and the to-be-melted material enters the hose through the feeding pipe and is conveyed into the preheating space in an air conveying mode.

Through adopting above-mentioned technical scheme, when the melt emptys, casing and crucible are in the incline condition, cup joint the hose on the inlet pipe, throw into to treat the melt in to the hose through the material feeding pipe, because the mode that adopts the pneumatic conveying carries out to treat the melt for treat in the hose in the melt enters into preheating space with higher speed, and promote to preheat treating in the space the melt and remove to the cavity in, like this, improved the reserve of treating the melt in the cavity, avoid treating the melt to the crucible in multiple addition.

Optionally, the movable plate includes a bottom plate and a top plate, the bottom of the bottom plate is close to the bottom of the cover body, and the bottom of the top plate is attached to the top of the bottom plate;

the top plate is internally provided with a plurality of perforations, the perforations penetrate through two side walls of the top plate which are oppositely arranged, the stretching direction of the perforations is consistent with that of the jack, the top of the top plate is provided with a plurality of air holes, the inner diameter of each air hole is smaller than the outer diameter of the material to be melted, and the air holes are mutually communicated with the perforations.

Through adopting above-mentioned technical scheme, the bottom plate plays the closure effect to the vertical portion of cavity, and the roof plays when holding back to treat the melt, preventing to treat the melt and get into the crucible, is used for treating the air current that the melt carries out the wind and send in the hose and can outwards discharge through gas pocket and perforation, guarantees to treat in the melt can carry to preheating the space reliably.

Optionally, the device further comprises a fan arranged on the mounting frame, wherein the fan is communicated with one end of the hose and blows air towards the inside of the hose, an included angle of 30-60 degrees exists between the axis of the feeding pipe and the air flowing direction, and the feeding pipe is arranged above the mounting frame.

Through adopting above-mentioned technical scheme, the fan blows gas in to the hose, forms high-speed air current, and the material pipe tilt up can be convenient for throw the material, and the waiting molten material of throwing moves to preheating space in the fast under the blowing of high-speed air current.

In a second aspect, the application provides a smelting process of a gray cast iron smelting furnace, which adopts the following technical scheme:

the smelting process of the gray cast iron smelting furnace is characterized by comprising the following steps of:

s1, directly throwing a part of to-be-melted materials into a crucible, throwing the rest part of to-be-melted materials into a preheating space through a material conveying port, covering the top of a shell by a cover body, and inserting a movable plate into a socket;

s2, heating the crucible by the heating coil, and heating the preheating space by heat radiated outwards;

s3, after the molten material in the crucible is changed into molten liquid in a molten state, rotating the shell and the crucible, and enabling the molten liquid to flow out through the water gap;

s4, after the molten liquid is poured, sleeving a hose on a feed pipe, starting a fan, putting new to-be-melted material into the feed pipe, and pushing the to-be-melted material in the preheating space into the cavity by the new to-be-melted material;

s5, reversely rotating the shell and the crucible, pulling out the movable plate after resetting, enabling the to-be-melted material in the cavity to enter the crucible, and then inserting the movable plate;

s6, repeating the steps S2-S5, and thus batch smelting of gray cast iron can be realized.

Through adopting above-mentioned technical scheme, control the rotation direction of casing and crucible, can realize when the molten in the crucible emptys, treat the deposit of melt in the cavity, after the molten in the crucible emptys, can carry out the interpolation of treating the melt to the crucible through preheating immediately, the flow is compacter, and the heat of to the external radiation is then recycled, has improved the utilization ratio of the energy.

In summary, the application has the following beneficial effects:

1. through set up the space of preheating in the outside of insulation cover and the inboard of casing for the heating coil is to the interior heat of treating the outside radiation when the melt heats of crucible can enter into the space of preheating, and is treated the melt absorption in the space of preheating, has realized treating the preheating effect of melt, has effectively reduced thermal loss, has improved the utilization ratio of the energy.

2. Through set up the lid at the top of casing to set up the cavity in the lid, with the rising heat flow that produces from the top of crucible in introducing the preheating space, improved to the preheating effect of waiting the melt in the preheating space, also further reduced thermal loss.

2. Through the plug of fly leaf and the action of fan, can reliably realize the transfer of waiting the melt after preheating in to the crucible and the complement of waiting the melt in the preheating space, improve the continuity of smelting process, the sustainable production of industrialization of being convenient for.

Drawings

FIG. 1 is a schematic top view of the present application;

FIG. 2 is a schematic cross-sectional view taken along section line A-A in FIG. 1;

FIG. 3 is a schematic perspective view of a housing of the present application;

FIG. 4 is a schematic perspective view of the cover of the present application;

FIG. 5 is a schematic perspective view of the present application;

fig. 6 is an operational state reference diagram of fig. 5;

fig. 7 is a schematic perspective view of the movable plate;

in the figure: 1. a bracket; 2. a housing; 21. preheating the space; 22. a material conveying port; 23. a chute; 24. a feed pipe; 3. a heating coil; 4. a crucible; 5. a thermal insulation sleeve; 6. a liquid outlet component; 61. a retainer; 62. a water gap; 7. a cover body; 71. a receiving groove; 72. a cavity; 73. a material conveying channel; 74. a slide bar; 75. a socket; 8. a movable plate; 81. a bottom plate; 82. a top plate; 821. perforating; 822. air holes; 91. a hose; 92. a feeding pipe; 93. a mounting frame; 94. a blower.

Detailed Description

The application is described in further detail below with reference to fig. 1-7.

Fig. 1 is a schematic top view of the present application, and fig. 2 is a schematic cross-sectional view taken along section line A-A in fig. 1. Referring to fig. 1 and 2, a gray cast iron smelting furnace, including support 1 and rotation locate the casing 2 on the support 1, be equipped with the crucible 4 that heats through heating coil 3 in the casing 2, the opening of crucible 4 communicates with the top of casing 2, be equipped with heat preservation cover 5 in the casing 2, heating coil 3 and crucible 4 all are located the inside of heat preservation cover 5, form preheating space 21 between the inner wall of casing 2 and the outer wall of heat preservation cover 5, preheating space 21 communicates with the outside through the material conveying mouth 22 at casing 2 top to realize waiting the business turn over of melt.

Fig. 3 is a schematic perspective view of the housing 2 in the present application. Referring to fig. 3, the top of the housing 2 is provided with a mounting hole, the opening of the crucible 4 is flush with and coaxially arranged with the mounting hole, a liquid outlet assembly 6 is arranged at the outer side of the mounting hole at the top of the housing 2, the liquid outlet assembly 6 comprises a guard ring 61 and a water gap 62, the guard ring 61 seals a gap between the opening of the crucible 4 and the mounting hole, the water gap 62 is arranged on the outer wall of the guard ring 61 and is communicated with the inner side and the outer side of the guard ring 61.

After a sufficient amount of to-be-melted material is placed into the crucible 4, a certain amount of to-be-melted material can be placed into the preheating space 21 through the material conveying opening 22, so that most of heat is isolated at the inner side of the heat preservation sleeve 5 in the process of heating the to-be-melted material in the crucible 4 by the heating coil 3, and is used for heating the to-be-melted material, part of heat can radiate to the outer side of the heat preservation sleeve 5, so that the to-be-melted material is absorbed by the to-be-melted material in the preheating space 21, thereby realizing preheating of the to-be-melted material, after the to-be-melted material in the crucible 4 is changed into a melted material in a melted state, the shell 2 is driven by the motor on the bracket 1 to rotate, and the shell 2 drives the crucible 4 to rotate, so that the melted material flows through the guard ring 61 and is poured out through the water opening 62, so that the stability of the flow in the pouring process of the melted material is improved, and the melted material cannot drop around along the outer wall of the shell 2, and the safety in the operation process is improved; after the molten liquid is poured completely, the shell 2 is continuously rotated along the same direction, so that the material conveying opening 22 is gradually oriented to the ground, the molten material to be melted in the preheating space 21 leaks from the material conveying opening 22, the shell 2 reversely rotates and resets, the molten material to be melted is put into the crucible 4, the initial temperature of the molten material to be melted in the crucible 4 is increased, the heating time of the molten material to be melted in the crucible 4 is shortened, the heat radiated to the outside is secondarily utilized, and the utilization rate of energy sources is effectively improved.

Referring to fig. 2, the top of the housing 2 is further provided with a cover 7 and a pair of sliding grooves 23, by the arrangement of the cover 7, the loss of heat radiated outwards from the top of the crucible 4 is remarkably reduced, the heating time of the molten material to be melted in the crucible 4 is further reduced, the loss of energy is reduced to the greatest extent, the bottom of the cover 7 is provided with a pair of sliding strips 74 and a containing groove 71 for containing the retainer 61 and the water gap 62, the containing groove 71 and the retainer 61 are mutually attached, the tightness is improved, a distance exists between the bottom of the containing groove 71 and the upper side of the water gap 62, and the phenomenon that the molten material cannot stably flow due to contact between the bottom of the containing groove 71 in the process of pouring the molten material is avoided.

Fig. 4 is a schematic perspective view of the cover 7 in the present application. Referring to fig. 4, a material conveying channel 73 and a cavity 72 with a T-shaped section, the number of which corresponds to that of the material conveying openings 22, are arranged in the cover body 7, the preheating space 21 is connected with the cavity 72 through the material conveying openings 22 and the material conveying channel 73, and the vertical part of the cavity 72 is communicated with the accommodating groove 71 and the crucible 4, so that the to-be-melted material in the preheating space 21 can smoothly enter the crucible 4; the sliding strip 74 and the sliding groove 23 are in an inverted T shape which is mutually matched, one end of the sliding groove 23 is communicated with the side wall of the shell 2 and is in an open shape, the extending direction of the sliding groove 23 can be selected at will, the sliding strip 74 is ensured to slide into the sliding groove 23 and can not slide out of the sliding groove 23 in the rotating process of the shell 2, and thus, the cover body 7 can be ensured to be reliably covered on the top of the shell 2.

Further, after the molten liquid is poured and the opening of the crucible 4 continues to rotate downwards, the to-be-melted material in the preheating space 21 passes through the material conveying opening 22 and the material conveying channel 73 and enters the cavity 72 under the action of gravity, and as the vertical part of the cavity 72 is coaxially arranged with the crucible 4, after the shell 2 and the crucible 4 rotate and reset, most of to-be-melted material in the cavity 72 falls into the crucible 4 and a small part of to-be-melted material flows back into the preheating space 21, so that the to-be-melted material after preheating can automatically enter the crucible 4, and the temperature is reduced after the to-be-melted material after preheating is prevented from completely separating from the cover body 7 and the shell 2, so that the reliability of the preheating effect of the to-be-melted material is ensured.

Fig. 5 is a schematic perspective view of the present application, and fig. 6 is an operation state reference diagram of fig. 5. Referring to fig. 5 and 6, a feeding pipe 24 communicated with the preheating space 21 is arranged at the bottom of the shell 2, a valve is arranged on the feeding pipe 24, a fan 94 and a hose 91 are arranged on the outer side of the shell 2 through a mounting frame 93, the hose 91 is detachably connected with the feeding pipe 24, the fan 94 inputs high-speed air flow into the hose 91, a feeding pipe 92 communicated with the hose 91 is further arranged above the mounting frame 93, an included angle of 30-60 degrees is formed between the feeding pipe 92 and the hose 91, after the valve is opened, the to-be-melted material fed into the hose 91 through the feeding pipe 92 passes through the feeding pipe 24 under the drive of the high-speed air flow and enters the preheating space 21.

After the crucible 4 rotates along with the shell 2 and the molten liquid is poured, the hose 91 can be sleeved on the feed pipe 24, the fan 94 is opened again, the fan 94 forms high-speed flowing air flow in the hose 91, then the molten material is thrown into the feed pipe 24, the molten material is pushed into the preheating space 21 by the air flow, the molten material in the preheating space 21 is pushed into the cavity 72, and after the molten liquid in the crucible 4 is poured, the crucible 4 and the shell 2 can be reset immediately without continuously rotating the crucible 4 due to the pushing action of the air flow, and the gravity action of the molten material is overcome by the pushing action of the air flow, so that the molten material can still enter the preheating space 21 and the cavity 72.

Referring to fig. 2 and 4, a socket 75 extending in a horizontal direction is provided on a side wall of the cover 7, one end of the socket 75 is communicated with the side wall, the other end of the socket 75 is communicated with the other side wall opposite to the side wall, and the socket 75 is located above the accommodating groove 71 and is communicated with a vertical portion of the cavity 72 after penetrating through the cover 7, a movable plate 8 is inserted in the socket 75 in an adapting manner, and the width of the movable plate 8 is larger than the outer diameter of the guard ring 61, and then the guard ring 61 is covered by the movable plate 8.

During the heating process of the heating coil 3 to heat the to-be-melted material in the crucible 4, the movable plate 8 can be pulled away from the insertion opening 75, and the rising heat flow generated at the top of the crucible 4 enters the cavity 72, the material conveying channel 73 and the preheating space 21, so that the preheating effect on the to-be-melted material in the preheating space 21 is improved; at the heating effect of heating coil 3, carry out the molten in-process of empting, insert movable plate 8 in socket 75, prevent to preheat in space 21 wait in the molten material advance enter into cavity 72 and crucible 4 in, cause there to be in the molten material to wait in the molten material, the yields of finished product to reduce.

Fig. 7 is a schematic perspective view of the movable plate 8. Referring to fig. 7, the movable plate 8 includes a top plate 82 and a bottom plate 81 that are attached to each other, the bottom plate 81 faces the top of the cover 7, the top plate 82 faces the top of the cover 7, a plurality of through holes 821 penetrating the top plate 82 in the horizontal direction are formed, two ends of each through hole 821 are respectively and correspondingly communicated with two opposite side walls of the top plate 82, a plurality of air holes 822 corresponding to the plurality of through holes 821 in a one-to-one manner are formed in the top of the top plate 82, and the inner diameter of each air hole 822 is smaller than the outer diameter of the material to be melted, so that the material to be melted is trapped at the top of the top plate 82.

When the fan 94 starts to work, the movable plate 8 is kept to be inserted into the insertion opening 75, so that after the air flow entrains the to-be-melted material and enters the preheating space 21, the to-be-melted material in the preheating space 21 is pushed to enter the cavity 72, and the to-be-melted material fills the cavity 72 due to the interception effect of the top plate 82, then the blowing effect of the fan 94 is stopped, the insert plate is pulled out, the to-be-melted material in the cavity 72 enters the crucible 4, the quantity of the to-be-melted material added into the crucible 4 in one operation is improved, the cover body 7 is prevented from being frequently opened, the to-be-melted material is complemented, the heat loss in the opening and closing process of the cover body 7 is reduced, and the utilization rate of energy is further improved; because the top plate 82 is provided with the air holes 822 and the through holes 821 which are mutually communicated, and the inner diameter of the air holes 822 is smaller than the outer diameter of the to-be-melted material, the to-be-melted material can be trapped at the top of the top plate 82, and the air flow can be discharged outwards through the air holes 822 and the through holes 821, so that the air flow can not flow into the crucible 4, the descending speed of the temperature of the crucible 4 can be reduced, and the air flow in the preheating space 21, the material conveying channel 73 and the cavity 72 can be smoother, so that the to-be-melted material in the hose 91 can be reliably conveyed into the preheating space 21, and the preheated to-be-melted material in the preheating space 21 is pushed into the cavity 72, so that the to-be-melted material is concentrated in the cavity 72 and falls into the crucible 4; in order to further improve the smoothness of the air flow, one air hole 822 may be provided corresponding to one through hole 821, so that the air flow can be prevented from forming turbulence after entering the same through hole 821 from the different air holes 822.

A smelting process of a gray cast iron smelting furnace comprises the following steps:

s1, a part of to-be-melted material is directly put into a crucible 4, the rest part of to-be-melted material is put into a preheating space 21 through a material conveying opening 22, a cover body 7 is covered on the top of a shell 2, and a movable plate 8 is inserted into a socket 75;

s2, heating the crucible 4 by the heating coil 3, and heating the preheating space 21 by heat radiated outwards;

s3, after the molten material in the crucible 4 is changed into molten material in a molten state, driving the shell 2 and the crucible 4 to rotate through a motor on the bracket 1, and enabling the molten material to flow into a corresponding mold outwards through the water gap 62;

s4, after the molten liquid is poured, sleeving a hose 91 on the feeding pipe 24, opening a valve on the feeding pipe 24, starting a fan 94, putting new molten material into the feeding pipe 92, enabling air flow to drive the new molten material to enter the preheating space 21, pushing the molten material to enter the preheating space 21 into the cavity 72, filling the cavity 72 under the interception effect of the top plate 82, and enabling the air flow to flow out of the socket 75 through an air hole 822 and a perforation 821 on the top plate 82;

s5, reversely rotating the shell 2 and the crucible 4, after resetting, drawing out the movable plate 8, enabling the to-be-melted material in the cavity 72 to enter the crucible 4, inserting the movable plate 8, supplementing the to-be-melted material into the preheating space 21 through the feeding pipe 92 and the hose 91, pulling out the hose 91, and closing the valve;

s6, repeating the steps S2-S5, and thus batch smelting of gray cast iron can be realized.

When the movable plate 8 is inserted into the insertion opening 75, under the condition that the air flow generated by the fan 94 is not influenced, the preheated to-be-melted material in the preheating space 21 can be pushed into the cavity 72 in the state that the casing 2 and the crucible 4 are at any angle, after the casing 2 and the crucible 4 are reset, sufficient to-be-melted material in the cavity 72 is quickly conveyed into the crucible 4 through the drawing-out of the movable plate 8, the cover 7 is not required to be opened for supplementing to-be-melted material, then the movable plate 8 is inserted into the insertion opening 75, and the to-be-melted material in the preheating space 21 can be supplemented.

The above embodiments are not intended to limit the scope of the present application, so: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.

Claims (10)

1. The utility model provides a gray cast iron smelting furnace, includes support (1) and rotates casing (2) of locating on support (1), be equipped with crucible (4) through heating coil (3) heating in casing (2), the opening of crucible (4) communicates with the top of casing (2), a serial communication port, be equipped with heat preservation cover (5) in casing (2), heating coil (3) and crucible (4) all are located the inside of heat preservation cover (5), form preheating space (21) between the inner wall of casing (2) and the outer wall of heat preservation cover (5);

the top of the shell (2) is provided with at least one pair of material conveying openings (22) communicated with the preheating space (21), and the material to be melted enters and exits the preheating space (21) through the material conveying openings (22).

2. The gray cast iron smelting furnace according to claim 1, wherein the top of the shell (2) is provided with a liquid outlet assembly (6), the liquid outlet assembly (6) comprises a guard ring (61) and a water gap (62), the guard ring (61) is annularly arranged at the top of the shell (2) and is coaxially arranged with the crucible (4), the water gap (62) is arranged on the outer wall of the guard ring (61) and is communicated with the inner side of the guard ring (61), and molten liquid in the crucible (4) passes through the guard ring (61) and is discharged outwards from the water gap (62).

3. A gray cast iron smelting furnace according to claim 2, characterized in that the top of the shell (2) is further provided with a cover body (7), the bottom of the cover body (7) is provided with a containing groove (71) for containing the retainer (61) and the water gap (62), and the notch of the containing groove (71) is separated from the top of the water gap (62).

4. A gray cast iron smelting furnace according to claim 3, characterized in that a cavity (72) and a material conveying channel (73) are further arranged in the cover body (7), the cross section of the cavity (72) is in a T shape, the transverse part of the cavity (72) is close to the top of the cover body (7), and the vertical part of the cavity (72) is communicated with the bottom of the accommodating groove (71) and is in butt joint with the opening of the crucible (4);

one end of the material conveying channel (73) is communicated with the transverse part of the cavity (72), and the other end of the material conveying channel (73) is in butt joint with the material conveying opening (22).

5. A gray cast iron smelting furnace according to claim 3, characterized in that a pair of sliding grooves (23) with inverted T-shaped radial cross sections are formed in the top of the shell (2), the sliding grooves (23) are symmetrically formed in two sides of the guard ring (61), a pair of sliding strips (74) are arranged at the bottom of the cover body (7), and the sliding strips (74) respectively and adaptively slide in the sliding grooves (23).

6. The gray cast iron smelting furnace according to claim 4, wherein the cover body (7) is further provided with a socket (75), the socket (75) penetrates through two side walls of the cover body (7) which are oppositely arranged, the socket (75) is located above the containing groove (71) and is communicated with the vertical part of the cavity (72), the width of the socket (75) is larger than the inner diameter of the retainer (61), a movable plate (8) is inserted in the pair of sockets (75) in an adapting mode, and the movable plate (8) covers the retainer (61).

7. A gray cast iron smelting furnace according to claim 6, characterized in that the bottom of the housing (2) is provided with a feed pipe (24), one end of the feed pipe (24) is communicated with the preheating space (21), and the other end of the feed pipe (24) is detachably provided with a hose (91);

one end of the hose (91) far away from the feeding pipe (24) is provided with a feeding pipe (92), and the to-be-melted material enters the hose (91) through the feeding pipe (92) and is conveyed into the preheating space (21) in an air conveying mode.

8. The gray cast iron smelting furnace according to claim 7, wherein the movable plate (8) comprises a bottom plate (81) and a top plate (82), the bottom of the bottom plate (81) is close to the bottom of the cover body (7), and the bottom of the top plate (82) is attached to the top of the bottom plate (81);

be equipped with a plurality of perforation (821) in roof (82), perforation (821) run through two lateral walls of roof (82) that set up relatively, the direction of extension of perforation (821) with the direction of extension of socket (75) is unanimous, the top of roof (82) is equipped with a plurality of gas pockets (822), the internal diameter of gas pocket (822) is less than wait the external diameter of melt, gas pocket (822) and perforation (821) intercommunication each other.

9. The gray cast iron smelting furnace according to claim 7, further comprising a fan (94) arranged on the mounting frame (93), wherein the fan (94) is communicated with one end of the hose (91) and blows air into the hose (91), an included angle of 30-60 degrees exists between the axis of the feeding pipe (92) and the air flowing direction, and the feeding pipe (92) is arranged above the mounting frame (93).

10. A smelting process for a gray cast iron smelting furnace according to claim 1, comprising the steps of:

s1, directly throwing a part of to-be-melted material into a crucible (4), throwing the rest part of to-be-melted material into a preheating space (21) through a material conveying opening (22), covering a cover body (7) on the top of a shell (2) and inserting a movable plate (8) into a socket (75);

s2, heating the crucible (4) by the heating coil (3), and heating the preheating space (21) by heat radiated outwards;

s3, after the molten material in the crucible (4) is changed into molten material in a molten state, the shell (2) and the crucible (4) are rotated, and the molten material flows outwards through the water gap (62);

s4, after the molten liquid is poured, sleeving a hose (91) on a feeding pipe (24), starting a fan (94), putting new molten material to be melted into the feeding pipe (92), and pushing the molten material to be melted into a cavity (72) in a preheating space (21) by the new molten material to be melted;

s5, reversely rotating the shell (2) and the crucible (4), and after resetting, pulling out the movable plate (8) to enable the to-be-melted material in the cavity (72) to enter the crucible (4), and then inserting the movable plate (8);

s6, repeating the steps S2-S5, and thus batch smelting of gray cast iron can be realized.