WO2013188993A1

WO2013188993A1 - Nodularization-processing method

Info

Publication number: WO2013188993A1
Application number: PCT/CN2012/000861
Authority: WO
Inventors: 刘年路; 刘昌晨
Original assignee: 天津市万路科技有限公司
Priority date: 2012-06-21
Filing date: 2012-06-21
Publication date: 2013-12-27
Also published as: CN102884210B; CN102884210A

Abstract

Provided is a nodularization-processing method for producing nodular cast iron. The method comprises: pouring a melted rare earth ferrosiliconmagnesium nodularizer alloy liquid containing Mg ≤20%, Si≤65%, and RE≤3% into a square steel tube for solidification and cooling; fixing the whole rare earth ferrosiliconmagnesium nodularizer lined on the outside with the square steel tube into a nodularization ladle using the inner and bottom masonry refractory bricks and wedge chocks in the nodularization ladle covered with a ladle cover, nodularization-processing through a pour-over ladle method; controlling the time for the nodularization reaction accurately, the temperature reduction of the molten iron being small during the nodularization-processing and pouring, the absorption rates of Mg, RE and Si becoming high after the nodularization-processing; 15 minutes after the completion of the nodularization reaction no decline in spheroidization occurs, thus improving the production environment during the manufacturing of a nodularizer and use thereof and significantly reducing production costs and increasing the quality of the product. Compared with a traditional rare earth ferrosiliconmagnesium nodularizer containing RE at a content of 2-8%, the nodularization-processing by the above method realizes the reduction of the usage amount of RE by 50-75%.

Description

Spheroidizing treatment method

The invention relates to a spheroidizing treatment method for producing nodular cast iron, and more particularly to a spheroidizing treatment of a spheroidal rare earth magnesium silicate spheroidizing agent in a spheroidized bag. Methods.

Background technique

Rare earth magnesium ferrosilicon alloy is widely used as a spheroidizing agent in enterprises producing ductile iron castings. Rare earth magnesium silicon iron alloy

The spheroidizing agent is the most widely used spheroidizing agent at home and abroad, but in its traditional production process, the energy consumption is high, the melting loss is large, and the environmental pollution is serious. The traditional spheroidizing agent has a large absorption rate due to its high absorption rate. . For a long time, domestic and foreign technicians have made unremitting efforts on the in-package spheroidization process technology and the production process of rare earth magnesium silicon spheroidizer.

Force research.

At present, in the production process of spheroidizing with rare earth magnesium ferrosilicon as the spheroidizing agent, when the iron temperature is above 148 CTC, the spheroidizing treatment package is in the state of continuous use of red hot pack, and the Mg content is At 8%, the spheroidization reaction condition is aggravated with the increase of temperature, and strong magnesium light or even molten iron splash occurs. As a result, the absorption rate of the effective elements Mg and RE decreases, resulting in the late decline of the spheroidized molten iron, spheroidization. The level is down. The traditional solution is to add a certain amount of SiCa alloy to increase the content of Ca in the smelting of the spheroidizing agent to alleviate the explosive reaction. Increasing the SiCa alloy undoubtedly increases the production cost. 2 The content of Mg in the spheroidizing agent is controlled to about 8% or 8% to alleviate the reaction. 3 In the dam of the rare earth magnesium silicon spheroidizing agent put into the ladle, the iron filings are covered and solidified, and the pouring riser and the broken iron block are added into the bag to reduce the reaction temperature of the molten iron in the package. 4 After the spheroidizing agent is put into the bag and the ferrosilicon is inoculated, the perlite slag agent is covered thereon or the iron plate is covered thereon. Although the above measures have an effect on controlling the severe reaction of the magnesium alloy, the reaction is completed, the molten iron is cooled more, and the surface of the molten iron is more scum. The stability of the spheroidization reaction is affected by the temperature of the molten iron, and the effective elements Mg, RE and Si The fluctuation range of the absorption rate is large; when the high-temperature molten iron of the cupola smelting is high in the sulphur content of the original molten iron before spheroidization, only the addition amount of the spheroidizing agent is increased and the content of RE and Ca in the spheroidizing agent is increased, and The current increase in the amount of Mg in the spheroidizing agent under high temperature treatment conditions is very limited.

The Chinese invention patent number CN101029367A, which I applied for, is entitled "Spheroidizing Treatment Device and Spheroidization Treatment Process" and two patent applications entitled "Spheroidizing Agent Production Method" in the publication No. CN101509084A, and all of them have obtained patent rights and solved The problem of violent reaction and low effective element absorption rate when spheroidizing in the bag is also solved, and the reaction of the rare earth magnesium silicate spheroidizing agent in the melting process is severe, the burning loss is large, and the composition of the spheroidizing agent alloy is segregated. The problem that needs to be improved: The spheroidization treatment device is used for spheroidization treatment, and the structure of the dam-type spheroidization treatment package is required. In order to put the rare earth magnesium silicate spheroidizing agent and the inoculant into the dam, the dam must be There is sufficient height, for example, the height of the dam of the newly built 1000kg spheroidizing bag is 23cm. The increase of the height of the dam increases the position of the explosion point of the spheroidizing agent boiling boiling reaction, which is not conducive to the absorption of effective elements and the purification of molten iron. The time for controlling the spheroidization reaction needs to be controlled according to the condition of the observation package to control the position of the ram of the struts, and the time required for the non-magnesia spheroidal treatment is longer. After the dam is spheroidized, the dam is easy to be slag and damaged. These problems will affect the stability of the spheroidization quality. It also increased the workload of repairing ladle.

On October 24, 2011, I applied for an invention patent application with the international application number PCT/CN2011/001762 and the name "smokeless ball processing method". The utility model is characterized in that the third bolt and the nut on the vertical column and the positioning rod are used as the first bolt connecting rod indenter of the steering shaft on the rotating shaft of the rotating shaft or the hook head suspension of the motor driving lifting device is matched. In the manner of the strut of the heavy iron, the whole rare earth magnesium silicon spheroidizing agent of the outer lining square steel pipe is fixed in the spheroidized bag by the ram indenter, and is processed by the punching method. The disadvantage is that the monolithic rare earth magnesium silicon spheroidizing agent for fixing the outer lining square steel tube depends on the struts of the struts, which is not conducive to the spheroidizing method of covering the cover, the damage of the struts and the high temperature ball. During the chemical treatment process, the whole rare earth magnesium silicon iron spheroidizing agent with a square steel pipe will move and float after the melt loss, which will affect the quality of the spheroidizing treatment.

Summary of the invention

The object of the present invention is to provide a spheroidizing treatment method, which utilizes an integral rare earth magnesium silicon iron spheroidizing agent with a square-shaped steel pipe and a spheroidizing treatment bag covering the cover, thereby solving the violent reaction in the spheroidizing treatment in the punching bag. The problem of low absorption rate of effective elements, precise control of spheroidization reaction time, improvement of product quality, reduction of production cost, full use and utilization of resources, and significant improvement of the production environment of the spheroidizing agent production process and use process.

In order to achieve the above purpose, the molten rare earth magnesium silicate spheroidizing agent liquid containing 20% of Mg, 65% of Si and 3% of RE is injected into a square steel pipe, and after being solidified and cooled, it is obtained. The square steel pipe is an integral rare earth magnesium silicon iron spheroidizing agent which is lining and open at both ends; as shown in Fig. 1, the first refractory brick is vertically built at the bottom edge of the spheroidizing package, and the second refractory brick is adjacent to the adjacent horizontal level. Brick, the other end of the second refractory brick is made of a third refractory brick, and the fourth refractory brick is vertically laid next to the third refractory brick, and the fifth refractory brick and the sixth refractory brick are horizontally laid in the fourth fireproof Between the brick and the spheroidal bag wall, the fifth refractory brick is overlaid on the sixth refractory brick, and the third refractory brick built at the bottom of the spheroidal package is lower than the second refractory brick of the horizontal masonry. In the continuous production of spheroidizing treatment, a small amount of dross does not hinder the operation. A cover cover is arranged at the upper end of the spheroidizing bag, and the cover cover is divided into a half cover for mounting the U-shaped pouring cup and a half cover for opening the rotation, for installing the U-shaped gate for the purpose of repairing the package The U-shaped pouring cup on the half of the cup is movable, which can easily remove the U-shaped pouring cup. The U-shaped pouring cup is made of iron plate and steel bar as the outer lining refractory material. The half cover of the pouring cup is welded integrally with the cover fixing sleeve, and the rotating half cover can be welded and integrated with the cover rotating sleeve, and the rotating shaft passes through the cover fixing sleeve and the cover rotating sleeve. The half cover of the U-shaped pouring cup and the half cover that can be opened for rotation are combined into one body, and a through hole is provided in the half cover which can be opened and rotated, and a guiding sleeve is welded on the through hole One end of the paper hollow sleeve is fixed by the fastening bolt on the joint sleeve and inserted into the guide sleeve, so that the liquid level of the molten iron in the package can be determined in time, and the half cover of the U-shaped pouring cup is set on the cover. The first fastening sleeve can open the rotating half cover A second fixing sleeve is arranged, and a cover positioning shaft is welded on the half cover of the U-shaped pouring cup, and the U-shaped pouring cup is installed by the cover positioning sleeve which is connected to the upper end of the spheroidizing bag A half cover is fixed, and the short shaft passes through the second fixed sleeve and the first fixed sleeve to fix the half of the cover which can be opened and rotated, and the finished spheroidizing package and the cover cover are dried and used for the ball. Processing.

In order to further improve the utilization rate of rare earth elements, a rare earth metal with a square-shaped steel pipe lined inside the whole magnesium ferrosilicon spheroidizing agent as shown in Fig. 3 and Fig. 4, and a whole magnesium silicon lined with a square steel pipe were designed and fabricated. Iron spheroidizing agent and external The bismuth rare earth metal lining the square steel tube has the same direction of the exposed opening of the alloy, and the bismuth rare earth metal of the outer lining square steel tube is coupled with the composite outer lining square steel tube accommodating the whole magnesium silicate spheroidizing agent by welding. The molten whole magnesium ferrosilicon spheroidizing agent alloy liquid is injected into the composite outer lining square steel tube for solidification cooling. In order to accelerate the cooling of the spheroidizing agent alloy liquid, cooling iron is added between the square steel pipes which are arranged in the combination of the spheroidizing agent alloy liquid, and the spheroidizing agent alloy liquid upper cover iron plate is provided to reduce the chemical composition segregation of the spheroidizing agent. Melt loss; hot metal rushed into the spheroidizing package, after the spheroidization reaction started, the lanthanum rare earth metal lining the square steel tube began to participate in the spheroidization reaction during the reaction time of less than 50% of the entire spheroidization reaction process, effectively supplementing the The required rare earth element content.

The rare earth element content of the outer-lined square steel pipe is placed inside the whole magnesium ferrosilicon spheroidizing agent by using the lanthanum rare earth metal lined with the square steel pipe inside the whole magnesia spheroidizing agent as shown in FIG. 3 and FIG. 4 . 33% of the whole rare earth magnesium ferrosilicon alloy, the whole magnesium ferrosilicon spheroidizing agent lined with square steel tube and the whole rare earth magnesium ferrosilicon alloy with the rare earth element content of the outer lining square steel tube of 33% have the same direction of the exposed opening of the alloy, so as to be spliced The whole rare earth magnesium ferrosilicon alloy with a rare earth element content of 33% of the outer-lined square steel pipe is combined with the composite outer-lining square steel pipe accommodating the whole magnesium ferrosilicon spheroidizing agent, and the molten whole magnesium silicon iron spheroidizing agent alloy is melted. The liquid is injected into the composite outer lining square steel tube for solidification and cooling, and a cooling iron is added between the square steel tubes which are arranged in the combination of the spheroidizing agent alloy liquid, and the spheroidizing agent alloy liquid upper cover iron plate is set; the molten iron is washed into the spheroidizing package ( 1) After the spheroidization reaction starts, in the reaction time less than 50% of the last spheroidization reaction process, the whole rare earth magnesium ferrosilicon alloy with a rare earth element content of 33% of the outer lining square steel tube begins to participate. Ball reaction, effectively complement the content of rare earth elements required.

The square steel pipe has a neat appearance. After the openings are arranged upwards, the rare earth magnesium silicon iron spheroidizing agent alloy liquid produced by the one-step production of ferrosilicon alloy smelted by the submerged arc furnace or the secondary remelting method of the electric furnace is poured into it. The reason why the cooling iron is added between the square steel pipes which are arranged in the combination of the spheroidizing agent alloy liquid and the spheroidizing agent alloy liquid is covered with the iron plate is accelerated, the cooling solidification of the spheroidizing agent alloy liquid is accelerated, and the spheroidizing agent is reduced. Segregation of chemical components, the integral spheroidizer alloy lined with square steel pipe does not need to be broken and sieved, which is convenient for handling and stacking.

The spheroidizing treatment steps are as follows: a. The half of the cover is rotated, and the whole rare earth magnesium silicate spheroidizing agent of the outer lining square steel pipe is placed in the spheroidized bag to reach a predetermined position, and the refractory brick material is made. Inserting the first wedge plug into the upper cover, inserting the upper cover made of refractory brick material and inserting the second wedge plug made of the material of the refractory brick;

b. Putting a ferrosilicon inoculant into the spheroidizing package;

c. Close the rotating half cover and insert a paper hollow sleeve with a coupling sleeve and fastening bolts on the guiding sleeve;

d. The molten iron is punched into the spheroidized bag by a U-shaped pouring cup for spheroidization reaction;

e. The molten iron that has been moved by the paper hollow casing moves to the predetermined molten iron level and stops rushing into the molten iron; f. After the spheroidization reaction is completed, the remaining amount of molten iron is added, and the rotating half cover is opened;

g. After slag slag, cover the molten iron with a compound inoculant with a content of 0.1% particle size and 5mm composition of Mg3-6%, REl-2%, 40-50% Si, close the rotating half cover and insert the first one with the short axis. The fixing sleeve is locked.

The beneficial effects of the invention: Since the whole rare earth magnesium silicon iron spheroidizing agent is stably fixed to the bottom of the ladle by the wedge plug, the magnesium vapor generated during the spheroidization reaction can be unimpededly diffused at the bottom of the ladle, preventing the whole rare earth magnesium Ferrosilicon The problem that the spheroidizing agent moves up and down after being melted and damaged solves the problem that the molten iron splash and the effective element absorption rate are low when the spheroidizing treatment in the bag is smashed, because the temperature of the tapping water can be reduced by the spheroidizing treatment of the molten iron. ~50 °C, after closing the rotating half of the cover, the installed U-shaped pouring cup is the inlet and outlet of the molten iron and pouring molten iron, so that the exposed area of the molten iron in the package is reduced to 3~ of the original exposed area. 4%, in the spheroidization reaction process and casting process to play a positive role in preventing magnesium loss and escape, can achieve magnesium-free smokeless spheroidization treatment without pursuing the lowest cost spheroidization treatment. The spheroidization reaction time can be precisely controlled. When the temperature of the molten iron water fluctuates by <100°0, the spheroidization reaction time is less than 5 seconds. The conventional spheroidizing agent containing Mg8%, RE5% and Si41% is lining with square steel pipe, and the built-in integral spheroidizing agent containing Mgl5%, containing RE1% and containing Si54 is one-step method. The overall rare earth magnesium silicon spheroidizing agent of the outer lining square steel pipe produced by the production or electric furnace secondary remelting method is compared with the traditional rare earth magnesium silicate spheroidizing agent, and the production cost of the product can be reduced by 25%~30% in the ball. The weight of the whole rare earth magnesium silicate spheroidizing agent including the outer lining square steel tube can be reduced by 25~30% compared with the traditional spheroidizing agent; the repeated test shows that the new process spheroidizing temperature is from 1450'C~1578 When the temperature changes between °C, the amount of the whole rare earth magnesium silicate spheroidizing agent of the square-shaped steel pipe is unchanged, the spheroidization reaction time is basically unchanged, and the spheroidization result is not affected, and the traditional spheroidizing treatment is overcome. As the spheroidization temperature increases, the problem of the addition amount of the spheroidizing agent needs to be increased; the production environment of the spheroidizing agent production process and the use process is improved. Compared with the closest international application number PCT/CN2011./001762, the invention patent entitled "Smokeless spheroidization treatment method", in the same rare earth magnesium silicate spheroidizing agent chemical composition and the same spheroidizing treatment temperature Under the condition, the effective spheroidization reaction time of the whole rare earth magnesium silicate spheroidizing agent with externally lined square steel pipe is more precise, the molten iron is cooled less during the spheroidizing treatment and pouring process, and the spheroidization caused by the loss of magnesium and escape is prevented. The decline has a significant effect. The absorption rates of the effective elements Mg, RE and Si are high. For the rare earth element RE content of 2 to 8% of the conventional rare earth magnesium silicate spheroidizing agent, the amount of rare earth element RE can be used in this process. Reduce 50~75%.

BRIEF DESCRIPTION OF THE DRAWINGS:

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a cross-sectional view showing an integral rare earth magnesium ferrosilicon spheroidizing agent in which a spheroidal steel pipe provided with a U-shaped pouring cup and a covering cover is placed with a square-lined steel pipe.

Figure 2 is a top plan view of the monolithic rare earth magnesium ferrosilicon spheroidizing agent in which a U-shaped sprue cup and a covered spheroidal bag are placed with a square-lined steel tube.

Fig. 3 is a cross-sectional view showing a rare earth metal of a ruthenium-lined steel pipe in which a composite outer lining square steel pipe is provided with a square-lined steel pipe.

Fig. 4 is a left side view of a rare earth metal having an outer-lined square steel tube in which a monolithic magnesium iron spheroidizing agent of a composite outer-lining square steel pipe is placed.

DESCRIPTION OF REFERENCE NUMERALS: 1 is a spheroidized bag, 2 is a whole rare earth magnesium silicon spheroidizing agent with a square-shaped steel pipe, 3 is a first wedge plug, 4 is an upper cover made of refractory brick material, 5 is a second Wedge plug, 6 is the first refractory brick, 7 is the second refractory brick, 8 is the third refractory brick, 9 is the fourth refractory brick, 10 is the fifth refractory brick, 11 is the sixth refractory brick, and 12 is the sixth refractory brick, 12 is U Type sprue cup, 13 is a half cover for installing U-shaped pouring cup, 14 is rotating shaft, 15 is paper hollow sleeve, 16 is rotating half cover, 17 is guiding sleeve, 18 is coupling Casing, 19 is a fastening bolt, 20 is a first fastening sleeve, 21 is a second fastening sleeve, 22 is a short shaft, 23 is a cover fixing sleeve, 24 is a cover rotating sleeve, 25 is a package Cover positioning sleeve, 26 is the cover positioning shaft, 27 is the whole magnesium ferrosilicon spheroidizing agent, 28 is the bismuth rare earth metal lined with square steel tube, and 29 is the composite outer lining square steel tube. detailed description:

The implementation of the present invention will be further described with reference to the accompanying drawings: The square steel tube and the wedge plug of the whole rare earth magnesium silicon iron spheroidizing agent play a key role in controlling the reaction state and effective reaction time of the rare earth magnesium alloy; the wedge plug is adopted Made of refractory brick material, according to the shape and size requirements, the wedge plug can be directly produced by the refractory brick production factory, or the stone cutter can be used to cut the refractory brick according to the requirements, and the gap between the refractory bricks built in the spheroidized package 1 Should be < 3mm, when the spheroidizing package 1 shown in Figure 1 is used for spheroidizing treatment, the upper cover 4 made of the spheroidized bag bottom, the fourth refractory brick 9 and the refractory brick material is the same as the first wedge plug 3 The refractory surface tightly surrounds it, delaying the melting speed of the square steel pipe. Therefore, the wall thickness of the square steel pipe can be selected from 2 to 4 mm to meet the needs of spheroidizing treatment. For the spheroidizing treatment temperature is greater than 1480 Ό, the spheroidization reaction time When it is longer, select the wall thickness of the upper limit. The square steel pipe used above can also be made of cast iron and manufactured by casting. It is known from the experiment that in order to prevent the spheroidizing treatment time from being too short and the reaction is too intense, the height of the whole rare earth magnesium silicate spheroidizing agent 2 lining the square steel pipe is placed in the spheroidizing treatment package to be < 12 (^ is suitable, the ball When the amount of molten iron is large, two or more square steel pipes shall be used in the same direction of side-by-side welding combination; in the opening direction of the square steel pipe, a steel plate having a thickness smaller than the steel pipe shall be welded to seal the part of the open end of the square steel pipe. To control the initial reaction state of the spheroidization reaction. The material used for the outer-lining square steel pipe used above is made of plain carbon steel and not coated. The long-handled iron fixture with the same type of brick clamp clamps the whole of the square-shaped steel pipe. Rare earth magnesium silicon spheroidizing agent 2 or wedge plug is placed in the spheroidizing package 1; after pouring the ductile iron water, the slag on the spheroidal package 1 refractory brick is removed with a long shovel; The paper hollow sleeve 15 tube is made of discarded iron water temperature measuring head paper tube; the composition of the compound is Mg5~8%, RE1~2%, Si40~50%, and its particle size is <5mm.

The upper cover made of cast iron material replaces the upper cover 4 made of refractory brick material and the second wedge type plug 5 made of refractory brick material is removed; only the a in the spheroidizing step is changed: the rotation is turned on a half cover 16 is inserted into the spheroidized package 1 after the spheroidal package 1 is placed in a predetermined position, and the first wedge plug 3 made of the material of the refractory brick is inserted and pushed tightly. The upper rare earth plate made of cast iron material is placed on the whole rare earth magnesium silicon spheroidizing agent 2 with a square steel pipe lined outside; the top of the outer square steel pipe is prevented from being melted prematurely.

Replace the upper cover 4 made of refractory brick material with perlite slag agent and cancel the second wedge type plug 5 made of refractory brick material; only change a in the spheroidizing step: open half of the rotation The cover 16 is inserted into the spheroidizing bag 1 to the predetermined position after the spheroidal bag 1 of the square-shaped steel pipe is placed, and the first wedge-shaped plug 3 made of the material of the refractory brick is inserted and pushed outward. A perlite slag agent is placed on the whole rare earth magnesium silicon spheroidizing agent 2 lining the square steel pipe.

When the amount of molten iron in the spheroidizing treatment is large, in order to reduce the height of the whole rare earth magnesium silicon spheroidizing agent 2 of the outer-lining square steel pipe, a rectangular steel pipe may be used as the outer lining.

When the spheroidizing molten iron is poured for a short time, the spheroidizing treatment method described above can cancel the covering cover, and the spheroidizing treatment is carried out by the method of punching in the package.

When the sulphurization of the molten iron is low, the above-mentioned composite inoculant is removed from the molten iron after the spheroidization reaction is finished; the molten iron is covered with a silicon germanium inoculant having a particle size of 0.2% and a particle size of 5 mm.

Example 1: Under the cold air cupola smelting condition, the melting rate was 2 ton / hr, and the whole rare earth magnesium silicate spheroidizing agent 2 with the outer lining square steel pipe shown in Fig. 1 was stably fixed by the wedge plug. The spheroidizing treatment is carried out in the form of iron-clad bottom, the weight of molten iron per package is 1000kg, and the red hot pack is continuously used. The temperature of the molten iron in the tapping tank is 1485Ό, and the sulfur content of the original molten iron is 0.063%, excluding the whole of the outer-lined square steel pipe. Rare earth magnesium silicon iron spheroidizing agent containing Mgl5%, Containing RE2% and containing 58% of Si, the input of the whole rare earth magnesium silicate spheroidizing agent 2 including the outer lining square steel pipe accounts for 1.15% of the weight of the treated molten iron, and 0.4% of the 72SiFe inoculant package is added during the spheroidization reaction. The iron slag and perlite are not covered. After the spheroidization reaction, the addition amount of the secondary composite inoculant is 0.10%, the spheroidization reaction time is 2 minutes and 35 seconds, and the boiling reaction of the magnesium-free photo-iron is 16 minutes after the spheroidization reaction ends. Sampling in 30 seconds, level 2 of spheroidization.

Example 2: Under the medium frequency electric furnace smelting condition, the whole rare earth magnesium silicate spheroidizing agent 2 with the outer lining square steel pipe shown in Fig. 1 was spheroidized by the wedge plug stably fixed at the bottom of the ladle. Treatment, the weight of molten iron per package is 1000kg, the temperature of the molten iron of the electric furnace is 1568°C, the sulfur content of the original molten iron is 0.025%, and the whole rare earth magnesium silicate spheroidizing agent excluding the square-lined steel pipe contains Mgl 2.5%, including RE1 % and Si 58%, the input of the whole rare earth magnesium silicate spheroidizing agent 2 including the outer lining square steel pipe accounts for 0.75% of the weight of the treated molten iron, and 0.35% of the 72SiFe inoculant package is added. After the spheroidization reaction is finished, the slag is finished. The silicon germanium inoculant with a particle size of 5TM! was used to cover the molten iron, and the addition was 0.2%. In the case of not covering the iron filings and perlite, the spheroidization reaction time was 1 minute 45 seconds, the spheroidization reaction was stable, and there was no splash of molten iron. After the spheroidization reaction, the molten iron content was 0.008%, the magnesium content was 0.045%, and the spheroidization reaction was sampled for 12 minutes, and the spheroidization level was 2 grades.

Claims

claims

1. A spheroidizing treatment method for producing ductile iron. The first part of its characteristics is the spheroidizing agent: spheroidize the melted rare earth magnesium ferrosilicon containing 20% Mg, 65% Si and 3% RE. The spheroidizing agent alloy liquid is injected into the square steel tube for solidification and cooling, and a cooling iron is added between the square steel pipes arranged in combination with the spheroidizing agent alloy liquid and the spheroidizing agent alloy liquid is provided with an upper cover iron plate; the second characteristic part is the covering Covered spheroidizing package: A first refractory brick (6) is laid vertically at the bottom edge of the spheroidizing package (1), a second refractory brick (7) is laid horizontally adjacent to it, and a second refractory brick (7) is laid horizontally adjacent to it. The other end of 7) is built with the third refractory brick (8), and the fourth refractory brick (9), the fifth refractory brick (10) and the sixth refractory brick are built vertically next to the third refractory brick (8). (11) The average level is laid between the fourth refractory brick (9) and the wall of the spheroidized bag (1). The fifth refractory brick (10) is overlapped and laid on the sixth refractory brick (11). The height of the third refractory brick (8) at the bottom of the spheroidizing package (1) is lower than the second refractory brick (7) built horizontally, and a covering cover is provided at the upper end of the spheroidizing package (1). It is divided into two parts: a half cover (13) for installing the U-shaped sprue cup and a half cover (16) that can be opened and rotated. The U-shaped half cover (13) for installing the U-shaped sprue cup The sprue cup (12) is movable. The installed U-shaped sprue cup (12) is the inlet and outlet for flushing and pouring molten iron. The U-shaped sprue cup (12) is made of iron plates and steel bars as the skeleton and is lined with fire-resistant material, the half cover (13) of the U-shaped sprue cup is connected to the cover fixed sleeve (23), and the rotating half cover (16) and the cover rotating sleeve (24) can be opened Welded together, the rotating shaft (14) passes through the cover fixed sleeve (23) and the cover rotating sleeve (24) to install the half cover (13) of the U-shaped sprue cup and the half cover (13) that can be opened and rotated. The cover (16) is combined into a whole, and a through hole is provided on the half cover (16) that can be opened and rotated. A guide sleeve (17) is connected to the through hole, and the paper hollow sleeve (15) is One end is fixed by the fastening bolt (19) on the coupling sleeve (18) and then inserted into the guide sleeve (17). A first fastening sleeve is provided on the half cover (13) where the U-shaped sprue cup is installed. (20), the half cover (16) that can be opened and rotated is provided with a second fixed sleeve (21), and a cover positioning shaft (13) is welded to the half cover (13) where the U-shaped sprue cup is installed. 26), fix the half cover (13) of the U-shaped sprue cup through the cover positioning sleeve (25) welded to the upper end of the spheroidizing package (1), and the short axis (22) passes through the second fixed sleeve The tube (21) and the first fixed sleeve (20) fix the half cover (16) that can be opened and rotated, and the constructed spheroidizing package and the covering cover are dried and used for spheroidizing;

The spheroidization process steps are as follows:

a. Open the rotating half cover (16), put the integral rare earth magnesium ferrosilicon spheroidizing agent (2) lined with square steel pipes into the spheroidizing bag (1) and reach the predetermined position, and then make the refractory brick material The first wedge-shaped plug block (3) is inserted and pushed tightly, the upper cover plate (4) made of refractory brick material is put in, and the second wedge-shaped plug block (5) made of refractory brick material is inserted and pushed tight;

b. Put ferrosilicon inoculant into the spheroidizing bag (1);

c. Close the rotating half cover (16), and insert the paper hollow sleeve (15) with the connecting sleeve (18) and the fastening bolt (19) on the guide sleeve (17);

d. The molten iron is poured into the spheroidizing bag (1) from the U-shaped sprue cup (12) to perform the spheroidizing reaction;

e. Stop pouring in the molten iron when the paper hollow casing (15) moves and floats and reaches the predetermined height of the molten iron; f. After the spheroidization reaction is completed, add the remaining amount of molten iron and open the rotating half cover (16);

g. After removing the slag, use 0.1% compound inoculant with a particle size of 5mm and a composition of Mg3-6%, RE 1-2%, and 40-50% Si to cover the molten iron. Close the rotating half cover (16) and use a short The shaft (22) is inserted into the first fixing sleeve (20) and locked.

2. The spheroidizing treatment method according to claim 1, characterized in that the ferrosilicon spheroidizing agent alloy liquid produced by the one-step method of smelting the submerged arc furnace or the rare earth magnesium ferrosilicon spheroidizing agent alloy produced by the electric furnace secondary remelting method is poured into the square. in steel pipe.

3. The spheroidizing treatment method according to claim 1, characterized in that the upper cover plate (4) made of refractory brick material is replaced with an upper cover plate made of cast iron material, and the insertion of the second wedge made of refractory brick material is cancelled. type plug block (5); only change a in the spheroidizing step: open the rotating half cover (16), and put the integral rare earth magnesium ferrosilicon spheroidizing agent (2) lined with a square steel pipe into the spheroidizing After the bag (1) reaches the predetermined position, insert and push the first wedge-shaped plug (3) made of refractory brick material, and place cast iron on the integral rare earth magnesium ferrosilicon nodulizing agent (2) lined with square steel pipes. Top cover made of material.

4. The spheroidizing treatment method according to claim 1, characterized in that the upper cover plate (4) made of refractory brick material is replaced with perlite slag aggregating agent and the insertion of the second wedge-shaped plug made of refractory brick material is cancelled. Block (5); only change a in the spheroidizing step: open the rotating half cover (16), and put the integral rare earth magnesium ferrosilicon spheroidizing agent (2) lined with a square steel pipe into the spheroidizing bag ( 1) After reaching the predetermined position, insert and push the first wedge-shaped plug block (3) made of refractory brick material, and place the perlite slag aggregate on the integral rare earth magnesium ferrosilicon nodulizing agent (2) lined with square steel pipes. agent.

5. The spheroidizing treatment method according to claim 1, characterized by adopting a structure in which two or more square steel pipes have the same opening direction and are welded side by side; in the opening direction of the square steel pipe, a steel plate smaller than the thickness of the steel pipe is used to block the opening direction in a hard-jointed manner. A part of the openings at both ends of the square steel pipe is lined to control the initial reaction state of the spheroidization reaction.

6. The spheroidizing method according to claim 1, characterized in that the spheroidizing method of covering the bag cover by pouring into the bag is cancelled.

7. The spheroidizing method according to claim 1, characterized by changing g in the spheroidizing step, canceling the slag removal and using an added amount of 0.1%, particle size 5, and the ingredients are Mg3-6%, RE1-2%. , 40-50% Si composite inoculant is used to cover the molten iron, change to slag removal, close the rotating half cover (16), and insert the short shaft (22) into the first fixed sleeve (20) to lock.

8. The spheroidizing treatment method according to claims 1, 2, 3, 4, 5, 6, and 7, characterized in that the square steel pipe is replaced by a rectangular steel pipe.

9. The spheroidizing treatment method according to claims 1, 2, 3, 4, 5, 6, and 7, characterized in that a lanthanum-cerium spheroid lined with a square steel pipe is placed inside the integral magnesium ferrosilicon spheroidizing agent (27). The rare earth metal (28), the integral magnesium ferrosilicon nodulizing agent (27) lined with the square steel pipe and the lanthanum rare earth metal (28) lined with the square steel pipe have the same alloy exposed opening direction, and the square steel pipe lined with the outside is welded The lanthanum cerium rare earth metal (28) is connected with the composite lined square steel pipe (29) containing the integral magnesium ferrosilicon nodulizing agent (27), and the melted integral magnesium ferrosilicon nodulizing agent (27) alloy liquid is Inject into the composite lined square steel pipe (29) for solidification and cooling; add a cooling iron between the square steel pipes arranged in a combination and flush the spheroidizing agent alloy liquid and set an upper iron plate for the spheroidizing agent alloy liquid; the molten iron is flushed into the spheroidizing Package (1), after the spheroidization reaction starts, in the last less than 50% of the reaction time of the entire spheroidization reaction process, the lanthanum cerium rare earth metal (28) lined with the square steel pipe begins to participate in the spheroidization reaction, effectively supplementing the required Rare earth element content.

10. The spheroidizing treatment method according to claims 1, 2, 3, 4, 5, 6 and 7, characterized in that a square steel pipe lined with a rare earth element content of 33% is placed inside the integral magnesia ferrosilicon spheroidizing agent. The integral rare earth magnesium ferrosilicon alloy, the integral magnesium ferrosilicon spheroidizing agent lined with square steel pipes and the integral rare earth magnesium ferrosilicon alloy with 33% rare earth element content lined with square steel pipes have the same direction of the alloy exposed opening, and the outer alloy is welded. The overall rare earth element content of the square steel pipe is 33%. The earth-magnesium ferrosilicon alloy is connected with the composite lined square steel pipe that contains the integral magnesium ferrosilicon spheroidizing agent. The melted integral magnesium ferrosilicon spheroidizing agent alloy liquid is injected into the composite lined square steel pipe for solidification and cooling. Add a cooling iron between the square steel tubes arranged in combination with the spheroidizing agent alloy liquid and install an iron plate to cover the spheroidizing agent alloy liquid; the molten iron rushes into the spheroidizing bag (1), and after the spheroidizing reaction starts, the entire spheroidizing reaction At the end of the process, less than 50% of the reaction time, the overall rare earth magnesium ferrosilicon alloy with a rare earth element content of 33% lined with the square steel pipe begins to participate in the spheroidization reaction, effectively supplementing the required rare earth element content.