CN113621750A - Method for producing vermicular cast iron - Google Patents
Method for producing vermicular cast iron Download PDFInfo
- Publication number
- CN113621750A CN113621750A CN202010374558.1A CN202010374558A CN113621750A CN 113621750 A CN113621750 A CN 113621750A CN 202010374558 A CN202010374558 A CN 202010374558A CN 113621750 A CN113621750 A CN 113621750A
- Authority
- CN
- China
- Prior art keywords
- iron
- molten iron
- equal
- mass
- less
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C1/00—Refining of pig-iron; Cast iron
- C21C1/08—Manufacture of cast-iron
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
Abstract
The invention provides a production method of vermicular cast iron, which comprises the following steps: weighing 10-30% of pig iron, 20-40% of scrap steel, 40-50% of return iron and 0.8-1.8% of carburant according to the mass percentage; sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; weighing Mg according to the mass ratio of Mg to molten iron6Re20.3 to 0.5 percent of nodulizer, 0.2 to 0.5 percent of silicon-strontium inoculant, 0.8 to 1.2 percent of 75Si-Fe and 0.5 to 0.7 percent of ductile iron scrap iron are mixed evenly to obtain a mixture; providing a molten iron treatment package, and preheating the molten iron treatment package to more than 600 ℃; raising the temperature of the molten iron to 1480-1500 ℃, then pouring the molten iron into a molten iron treatment package, and simultaneously enabling the mixture to flow into the molten iron treatment package from top to bottom along an inclined chute; and (5) casting and molding, wherein the casting time is less than or equal to 8 minutes, and the vermicular graphite cast iron is obtained after molding.
Description
Technical Field
The invention relates to the technical field of cast iron processing, in particular to a production method of vermicular cast iron.
Background
Vermicular cast iron is vermicular, lumpy or globular graphite which is distributed in different proportions and obtained through vermicular treatment and inoculation treatment, and the mechanical property of the cast iron is effectively improved. The material performance index is between that of gray cast iron and ball-milled cast iron, has certain elongation and good heat dissipation performance while ensuring higher tensile strength and wear resistance, and is widely applied to parts of automobiles which are complex in stress and have higher requirements on strength, toughness, wear resistance and heat dissipation performance.
At present, vermicular cast iron is generally obtained by melting metals such as common pig iron, scrap steel, foundry returns and the like at high temperature and then carrying out vermicular treatment by using a vermicular agent. The production process of the vermicular cast iron has the advantages that the addition amount of the vermiculizer is high, the vermicular rate is unstable, the production cost is increased, and the mass production of products is restricted.
Disclosure of Invention
The invention aims to provide a method for producing vermicular cast iron with stable vermicular rate, which aims to solve the problems in the prior art.
In order to solve the technical problem, the invention provides a production method of vermicular cast iron, which comprises the following steps:
weighing 10-30% of pig iron, 20-40% of scrap steel, 40-50% of return iron and 0.8-1.8% of carburant according to the mass percentage;
sequentially adding the pig iron, the scrap steel, the return iron and the recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein, the mass percent of C in the molten iron is 3.3-3.7%, the mass percent of Si is 1.3-1.6%, the mass percent of Mn is 0.3-0.5%, the mass percent of P is less than or equal to 0.05%, and the mass percent of Sn is less than or equal to 0.02%;
weighing Mg according to the mass ratio of the Mg to the molten iron6Re2Nodulizer 0.3-05%, silicon-strontium inoculant 0.2-0.5%, 75Si-Fe 0.8-1.2% and ductile iron scrap 0.5-0.7%, and mixing uniformly to obtain a mixture;
providing a molten iron treatment package, and preheating the molten iron treatment package to above 600 ℃;
raising the temperature of the molten iron to 1480-1500 ℃, then pouring the molten iron into the preheated molten iron treatment package, and simultaneously enabling the mixture to flow into the preheated molten iron treatment package from top to bottom along an inclined chute, wherein the time for pouring the molten iron into the molten iron treatment package is the same as the time for flowing the mixture into the molten iron treatment package and is 50-60 s;
and (5) casting and molding, wherein the casting time is less than or equal to 8 minutes, and the vermicular graphite cast iron is obtained after molding.
In one embodiment, the step of raising the temperature of the molten iron to 1480-1500 ℃, then pouring the molten iron into the molten iron processing package while allowing the mixture to flow into the molten iron processing package along an inclined chute, wherein the time for pouring the molten iron into the molten iron processing package is 50-60s, and the time for flowing the mixture into the molten iron processing package is 50-60s comprises:
the molten iron is poured from one side of the molten iron treatment bag, and the mixture flows in from the other side opposite to the molten iron pouring end.
In one embodiment, the upper end of the chute is provided with a funnel through which the mixture flows into the upper end of the chute.
In one embodiment, the Mg6Re2The nodulizer comprises, by mass, 5.0-7.0% of Mg, 1.5-2.5% of Re, 35-44% of Si, 2.0-3.0% of Ca, less than or equal to 4.0% of Mn, less than or equal to 0.5% of Al and the balance of Fe.
In one embodiment, the Si content of the silicon-strontium inoculant is 46 percent by mass
50 percent below zero, 0.6 to 1.0 percent of Sr, less than or equal to 0.1 percent of Ca, less than or equal to 0.5 percent of Al and the balance of Fe.
In one embodiment, the 75Si-Fe alloy comprises, by mass, 72% to 80% of Si, not more than 1.0% of Ca, not more than 1.0% of Al, not more than 0.5% of Mn, not more than 0.5% of Cr, not more than 0.04% of P, not more than 0.02% of S, and the balance Fe.
In one embodiment, the ductile iron scrap comprises 3.5-3.6% by mass of C, 2.4-3.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.03% by mass of P, less than or equal to 0.02% by mass of S, and the balance of Fe.
In one embodiment, the pig iron contains C more than or equal to 4.2 wt%, Ti less than or equal to 0.05 wt%, Mn less than or equal to 0.2 wt%, P less than or equal to 0.05 wt%, S less than or equal to 0.02 wt%, and the balance Fe;
the mass percent of C in the scrap steel is less than or equal to 0.5 percent, the mass percent of Si is less than or equal to 0.5 percent, the mass percent of Mn is less than or equal to 0.5 percent, the mass percent of P is less than or equal to 0.045 percent, the mass percent of S is less than or equal to 0.035 percent, the mass percent of Al is less than or equal to 0.05 percent, the mass percent of Cr is less than or equal to 0.06 percent, and the balance is Fe;
the mass percent of C in the re-melted iron is 3.5-3.6%, the mass percent of Si is 2.4-3.6%, the mass percent of Mn is 0.3-0.5%, the mass percent of P is less than or equal to 0.03%, the mass percent of S is less than or equal to 0.02%, and the balance is Fe;
the recarburizing agent contains more than or equal to 92% of fixed C, less than or equal to 0.1% of volatile matter, less than or equal to 5% of ash, less than or equal to 0.15% of S, less than or equal to 0.5% of water and 200-2000ppm of N.
In one embodiment, in the step of sequentially adding the pig iron, the scrap, the returning iron, and the recarburizer to an electric furnace to melt, and adjusting the composition to obtain molten iron, the method for adjusting the composition comprises the steps of:
taking a mixture of the molten pig iron, the molten scrap steel, the molten recycled iron and the recarburizer, manufacturing the mixture into a spectrum test block, detecting element components in the spectrum test block by adopting a rapid direct-reading spectrometer, and then adjusting according to the difference between the detected components and preset components of the molten iron.
In one embodiment, when the composition of the element C in the spectrum test block is higher than the preset composition in the molten iron, adding a corresponding amount of scrap steel; when the components of the C element in the spectrum test block are lower than the preset components in the molten iron, adding a carburant with corresponding weight; and when the composition of the Si element in the spectrum test block is lower than the preset composition in the molten iron, adding 75Si-Fe with corresponding component.
According to the technical scheme, the invention has the advantages and positive effects that:
the production method of the vermicular graphite cast iron adopts Mg6Re2Is nodulizer, and the mixture of molten iron, nodulizer, silicon-strontium inoculant, 75Si-Fe and ductile iron scrap iron enters the molten iron treatment package at the same time, thereby ensuring the mixing action of the molten iron and the mixture, reducing the addition of the nodulizer and further reducing the production cost. Molten iron and the mixture enter the molten iron treatment package at the same time, and the time of entering the molten iron treatment package is the same, so that the molten iron and the mixture are uniformly mixed, the vermicular graphite cast iron has a good vermicular effect, and the vermicular graphite cast iron is stable and uniform in vermicular efficiency. In the production method, the traditional process of pressing the nodulizer on the ladle bottom of the molten iron processing ladle is omitted, so that the operation process is simple and the operability is strong. The process of pouring molten iron in the molten iron treatment ladle to the pouring ladle is omitted, so that the ladle pouring time is omitted, the temperature loss is reduced, the energy consumption is saved, and the burning loss of alloy elements is reduced. Meanwhile, the number of ladle-to-ladle processing operators is reduced, and the labor intensity of workers is reduced.
Drawings
FIG. 1 is a flow chart of a method of producing compacted graphite iron according to the invention;
FIG. 2 is a sectional view of a molten iron processing ladle according to the present invention;
fig. 3 is a schematic view of the structure of the funnel and the chute in the invention.
FIG. 4 is a metallographic picture of vermicular cast iron according to example 3 of the present invention;
FIG. 5 is a metallographic picture of vermicular cast iron according to example 4 of the present invention.
Description of the drawings:
1. a molten iron treatment package; 2. a chute; 3. a funnel.
Detailed Description
Exemplary embodiments that embody features and advantages of the invention are described in detail below in the specification. It is to be understood that the invention is capable of other embodiments and that various changes in form and details may be made therein without departing from the scope of the invention and the description and drawings are to be regarded as illustrative in nature and not as restrictive.
For further explanation of the principles and construction of the present invention, reference will now be made in detail to the preferred embodiments of the present invention, which are illustrated in the accompanying drawings.
The invention provides a production method of vermicular cast iron, which adopts Mg6Re2And (3) a nodulizer is molded, and when the molten iron is added into the molten iron treatment ladle, a mixture containing the nodulizer, an inoculant and the like simultaneously flows into the molten iron ladle, namely the molten iron and the nodulizer are subjected to sub-spheroidizing treatment in the molten iron treatment ladle, so that the finally obtained vermicular graphite cast iron has stable and uniform vermicular rate and good vermicular effect. The production method does not need ladle to be turned over, effectively shortens the processing time, reduces the temperature loss caused by ladle to be turned over and reduces the production cost.
The principle of the method for producing compacted graphite iron is described in detail below.
The method comprises the following specific steps:
s1, weighing 10-30% of pig iron, 20-40% of scrap steel, 40-50% of return iron and 0.8-1.8% of carburant according to the mass percentage.
Wherein the pig iron contains C more than or equal to 4.2 wt%, Ti less than or equal to 0.05 wt%, Mn less than or equal to 0.2 wt%, P less than or equal to 0.05 wt%, S less than or equal to 0.02 wt%, and Fe in balance.
The mass percentage of C in the scrap steel is less than or equal to 0.5 percent, the mass percentage of Si is less than or equal to 0.5 percent, the mass percentage of Mn is less than or equal to 0.5 percent, the mass percentage of P is less than or equal to 0.045 percent, and the mass percentage of S is less than or equal to
0.035%, Al less than or equal to 0.05%, Cr less than or equal to 0.06%, and the balance Fe.
The mass percent of C in the re-melting iron is 3.5-3.6%, the mass percent of Si is 2.4-3.6%, the mass percent of Mn is 0.3-0.5%, the mass percent of P is less than or equal to 0.03%, the mass percent of S is less than or equal to 0.02%, and the balance is Fe.
The mass percentage of fixed C in the carburant is more than or equal to 92 percent, the mass percentage of volatile matter is less than or equal to 0.1 percent, the mass percentage of ash is less than or equal to 5 percent, the mass percentage of S is less than or equal to 0.15 percent, the mass percentage of water is less than or equal to 0.5 percent, and the mass percentage of N is 200-2000 ppm.
S2, adding pig iron, scrap steel, return iron and a carburant into an electric furnace in sequence for melting, and adjusting components to obtain molten iron; wherein, the molten iron contains 3.3 to 3.7 mass percent of C, 1.3 to 1.6 mass percent of Si, 0.3 to 0.5 mass percent of Mn, less than or equal to 0.05 mass percent of P and less than or equal to 0.02 mass percent of Sn.
Specifically, the electric furnace is a medium frequency induction electric furnace.
The method for adjusting the components is as follows:
taking a mixture of molten pig iron, scrap steel, recycled iron and a recarburizer, preparing the mixture into a spectrum test block, detecting element components in the spectrum test block by using a rapid direct-reading spectrometer, and then adjusting according to the difference between the detected components and preset components of molten iron.
When the components of the element C in the spectrum test block are higher than the preset components in the molten iron, adding scrap steel with corresponding weight; and when the component of the element C in the spectrum test block is lower than the preset component in the molten iron, adding a corresponding amount of carburant.
And when the composition of the Si element in the spectrum test block is lower than the preset composition in the molten iron, adding 75Si-Fe with corresponding component.
S3, weighing Mg according to the weight ratio of the Mg to molten iron6Re20.3-0.5% of nodulizer and strontium-silicon pregnant0.2 to 0.5 percent of breeding agent, 0.8 to 1.2 percent of 75Si-Fe and 0.5 to 0.7 percent of nodular iron filings, and evenly mixing to obtain a mixture.
In particular, Mg6Re2The nodulizer comprises, by mass, 5.0-7.0% of Mg, 1.5-2.5% of Re, 35-44% of Si, 2.0-3.0% of Ca, less than or equal to 4.0% of Mn, less than or equal to 0.5% of Al and the balance of Fe.
The magnesium element and the rhenium element are vermicular elements, the magnesium element has self-boiling capacity and can avoid uneven vermicular formation, but the magnesium element is matched with the rhenium element for use because the magnesium element has strong spheroidizing capacity and the content is not suitable to be too high. The rhenium element can desulfurize, degas and purify molten iron, and simultaneously, the graphite grows from flake to sphere and worm.
The silicon-strontium inoculant contains 46-50 wt% of Si, 0.6-1.0 wt% of Sr, less than or equal to 0.1 wt% of Ca, less than or equal to 0.5 wt% of Al and the balance of Fe. The silicon-strontium inoculant can bring more graphite balls, prolong inoculation time and obviously reduce white cast, thereby effectively saving cost.
In 75Si-Fe, the mass percent of Si is 72-80%, the mass percent of Ca is less than or equal to 1.0%, the mass percent of Al is less than or equal to 1.0%, the mass percent of Mn is less than or equal to 0.5%, the mass percent of Cr is less than or equal to 0.5%, the mass percent of P is less than or equal to 0.04%, the mass percent of S is less than or equal to 0.02%, and the balance is Fe. The 75Si-Fe is used for inoculating molten iron and reducing the chilling tendency, and the price of the 75Si-Fe is lower than that of a silicon-strontium inoculant and is matched with the silicon-strontium inoculant to reduce the cost.
The ductile iron scrap comprises 3.5-3.6% by mass of C, 2.4-3.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.03% by mass of P, less than or equal to 0.02% by mass of S and the balance of Fe.
Mg6Re2After the nodulizer, the silicon-strontium inoculant, the 75Si-Fe and the ductile iron scrap iron are uniformly mixed into a mixture, the situation that various substances exist all the time and are added in the whole adding process can be ensuredThe addition is uniform, and segregation is avoided.
S4, providing a molten iron treatment package, and preheating the molten iron treatment package to above 600 ℃.
The molten iron treatment ladle has a space inside for mixing molten iron with a nodulizer or the like and creeping. Specifically, referring to FIG. 2, one side of the molten iron processing ladle has an inclined surface extending outward from the bottom to the top. The inner part and the outer part are respectively the inner part and the outer part which face the inner part of the molten iron processing package by taking the using state of the molten iron processing package as a reference, and the opposite is the outer part.
S5, raising the temperature of the molten iron to 1480-1500 ℃, then pouring the molten iron into the preheated molten iron treatment package, and simultaneously enabling the mixture to flow into the molten iron treatment package from top to bottom in a preheated manner along an inclined chute, wherein the time of pouring the molten iron into the molten iron treatment package is the same, and is 50-60S.
The method for controlling the pouring time of the molten iron comprises the following steps:
and an operator adjusts the tilting speed of the furnace body according to the timer, so that the whole molten iron pouring process is controlled within 50-60 s. Mg (magnesium)6Re2The mixture of nodulizer, silicon-strontium inoculant, 75Si-Fe and nodular iron filings is fed via a funnel into the chute and then fed into molten iron treating ladle. Specifically, referring to fig. 3 to 5, the chute extends obliquely downward from the upper end, and the lower end of the chute is lapped on the top of the inclined surface of the molten iron treatment ladle. The funnel is located at the upper end of the chute so that the mixture located within the funnel can flow from the upper end to the lower end of the chute and into the molten iron treatment reservoir.
The control knob is arranged below the funnel, the flow rate of the mixture is adjusted by the control knob, the speed of the mixture for discharging molten iron is matched with the alloy adding speed, namely the time for the mixture to flow into the molten iron treatment package is the same as the time for the mixture to flow into the molten iron treatment package, and the time is also 50-60 s.
Further, the lower end of the chute is provided with a valve to control the on-off between the chute and the molten iron processing ladle. Namely, the mixture on the chute can enter the molten iron processing bag by opening the valve; the valve is closed and the mixture on the chute cannot enter the treatment package.
And S6, casting and molding, wherein the casting time is less than or equal to 8 minutes, and the vermicular graphite cast iron is obtained after molding.
The production method of the vermicular cast iron uses Mg6Re2Is nodulizer, and the mixture of molten iron, nodulizer, silicon-strontium inoculant, 75Si-Fe and ductile iron scrap iron enters the molten iron treatment package at the same time, thereby ensuring the mixing action of the molten iron and the mixture, reducing the addition of the nodulizer and further reducing the production cost. Molten iron and the mixture enter the molten iron treatment package at the same time, and the time of entering the molten iron treatment package is the same, so that the molten iron and the mixture are uniformly mixed, the vermicular graphite cast iron has a good vermicular effect, and the vermicular graphite cast iron is stable and uniform in vermicular efficiency. In the production method, the traditional process of pressing the nodulizer on the ladle bottom of the molten iron processing ladle is omitted, so that the operation process is simple and the operability is strong. The process of pouring molten iron in the molten iron treatment ladle to the pouring ladle is omitted, so that the ladle pouring time is omitted, the temperature loss is reduced, the energy consumption is saved, and the burning loss of alloy elements is reduced. Meanwhile, the number of ladle-to-ladle processing operators is reduced, and the labor intensity of workers is reduced.
The inventor of the present application describes the dry milling method through various embodiments below, by strictly designing the process conditions of the various steps in the production method to obtain vermicular cast iron with stable and uniform vermicular rate and good vermicular effect.
Example 1
According to the mass percentage, 10 percent of pig iron, 38.2 percent of scrap steel, 50 percent of return iron and 1.8 percent of carburant are weighed.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing Mg according to the mass ratio of Mg to molten iron6Re20.5 percent of nodulizer, 0.5 percent of silicon-strontium inoculant, 1.2 percent of 75Si-Fe and 0.7 percent of ductile iron scrap iron are evenly mixed to obtain a mixture.
Preheating a molten iron treatment ladle to 800 ℃.
The temperature of the molten iron is raised to 1480 ℃, then the molten iron is poured into the preheated molten iron treatment ladle, and simultaneously the inclined surface of the mixture chute flows into the molten iron treatment ladle from top to bottom. Wherein the time for pouring the molten iron into the molten iron treatment package is 50s, and the time for flowing the mixture into the molten iron treatment package is 50 s.
And (5) casting and molding, wherein the casting is carried out for 7 minutes, and the vermicular cast iron is obtained after molding.
Example 2
30 percent of pig iron, 29.2 percent of scrap steel, 40 percent of return iron and 0.8 percent of carburant according to mass percentage.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing Mg according to the mass ratio of Mg to molten iron6Re20.3 percent of nodulizer, 0.2 percent of silicon-strontium inoculant, 0.8 percent of 75Si-Fe and 0.5 percent of ductile iron scrap iron are evenly mixed to obtain a mixture.
Preheating a molten iron treatment ladle to 600 ℃.
And raising the temperature of the molten iron to 1500 ℃, then pouring the molten iron into the preheated molten iron treatment ladle, and simultaneously enabling the inclined surface of the mixture chute to flow into the molten iron treatment ladle from top to bottom. Wherein the time for pouring the molten iron into the molten iron treatment package is 60s, and the time for flowing the mixture into the molten iron treatment package is 60 s.
And (5) casting and molding, wherein the casting is carried out for 6 minutes, and the vermicular cast iron is obtained after molding.
Example 3
According to the mass percentage, 30 percent of pig iron, 20 percent of scrap steel, 49 percent of return iron and 1.0 percent of carburant.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing Mg according to the mass ratio of Mg to molten iron6Re20.4 percent of nodulizer, 0.3 percent of silicon-strontium inoculant, 1.0 percent of 75Si-Fe and 0.6 percent of ductile iron scrap iron are evenly mixed to obtain a mixture.
Preheating a molten iron treatment ladle to 700 ℃.
And raising the temperature of the molten iron to 1490 ℃, then pouring the molten iron into the preheated molten iron treatment ladle, and simultaneously enabling the inclined surface of the mixture chute to flow into the molten iron treatment ladle from top to bottom. Wherein the time for pouring the molten iron into the molten iron treatment package is 55s, and the time for flowing the mixture into the molten iron treatment package is 55 s.
And (5) casting and molding, wherein the vermicular graphite cast iron is obtained after molding.
Example 4
17.5 percent of pig iron, 40 percent of scrap steel, 41 percent of return iron and 1.5 percent of carburant according to mass percentage.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing Mg according to the mass ratio of Mg to molten iron6Re20.35 percent of nodulizer, 0.4 percent of silicon-strontium inoculant, 1.1 percent of 75Si-Fe and 0.55 percent of ductile iron scrap iron are evenly mixed to obtain a mixture.
Preheating a molten iron treatment ladle to 900 ℃.
The temperature of the molten iron is raised to 1485 ℃, and then the molten iron is poured into the preheated molten iron treatment ladle, and simultaneously the inclined surface of the mixture chute flows into the molten iron treatment ladle from top to bottom. Wherein the time for pouring the molten iron into the molten iron treatment package is 56s, and the time for flowing the mixture into the molten iron treatment package is 56 s.
And (4) casting and molding, wherein the vermicular graphite cast iron is obtained after molding for 4 minutes.
Example 5
According to the mass percentage, 23.8 percent of pig iron, 30 percent of scrap steel, 45 percent of return iron and 1.2 percent of carburant.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing Mg according to the mass ratio of Mg to molten iron6Re20.45 percent of nodulizer, 0.45 percent of silicon-strontium inoculant, 0.9 percent of 75Si-Fe and 0.65 percent of ductile iron scrap iron are mixed evenly to obtain a mixture.
Preheating a molten iron treatment ladle to 1000 ℃.
And raising the temperature of the molten iron to 1495 ℃, then pouring the molten iron into the preheated molten iron treatment ladle, and simultaneously enabling the inclined surface of the mixture chute to flow into the molten iron treatment ladle from top to bottom. Wherein the time for pouring the molten iron into the molten iron treatment package is 58s, and the time for flowing the mixture into the molten iron treatment package is 58 s.
And (5) casting and molding, wherein the casting is carried out for 8 minutes, and the vermicular cast iron is obtained after molding.
Example 6
According to the mass percentage, 20.4 percent of pig iron, 35 percent of scrap steel, 43 percent of return iron and 1.6 percent of carburant.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing Mg according to the mass ratio of Mg to molten iron6Re20.4 percent of nodulizer, 0.4 percent of silicon-strontium inoculant, 1.0 percent of 75Si-Fe and 0.6 percent of ductile iron scrap iron are evenly mixed to obtain a mixture.
Preheating the molten iron treatment package to 1100 ℃.
And raising the temperature of the molten iron to 1500 ℃, then pouring the molten iron into the preheated molten iron treatment ladle, and simultaneously enabling the inclined surface of the mixture chute to flow into the molten iron treatment ladle from top to bottom. Wherein the time for pouring the molten iron into the molten iron treatment bag is 52s, and the time for flowing the mixture into the molten iron treatment bag is 52 s.
And (5) casting and molding, wherein the casting is carried out for 7 minutes, and the vermicular cast iron is obtained after molding.
Comparative example 1
17.5 percent of pig iron, 40 percent of scrap steel, 41 percent of return iron and 1.5 percent of carburant according to mass percentage.
Sequentially adding pig iron, scrap steel, return iron and a recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein the molten iron contains 3.3-3.7% by mass of C, 1.3-1.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.05% by mass of P and less than or equal to 0.02% by mass of Sn.
Weighing FeSiMg according to the mass ratio of the FeSiMg to molten iron4Re171.0 percent of type vermiculizer and 75Si-Fe1.0 percent. Wherein, FeSiMg4Re17The weight percentage content of Re in the vermiculizer is 16.8-17.2%, the weight percentage content of Mg is 3.8-4.2%, the weight percentage content of Si is 38-44%, the weight percentage content of Ca is less than or equal to 3%, and the weight percentage content of MgO is less than or equal to 0.8%.
Preheating a molten iron treatment ladle and a pouring ladle to 900 ℃.
FeSiMg is added4Re17Adding the vermiculizer and 75Si-Fe into the bottom of the molten iron processing ladle in a layered manner, and then covering the surface of the molten iron processing ladle by using crushed steel sheets or scrap iron. Ensuring that the 75Si-Fe and scrap steel or iron scrap are completely compacted to the FeSiMg4Re17 vermicular agent, otherwise, the vermicular effect is influenced because the reaction causes early burning loss of Mg and rare earth.
And raising the temperature of the molten iron to 1540 ℃, pouring the molten iron into a molten iron treatment ladle for vermicularizing treatment, and pouring the molten iron into a pouring ladle after the molten iron in the molten iron treatment ladle is treated (no magnesium light is emitted). In the process, the time for pouring molten iron is controlled to be 45 s. The time exceeds 50s, which causes FeS in the molten iron processing ladleiMg4Re17After the vermiculizer is reacted, the molten iron is not poured into the molten iron treatment ladle, so that the molten iron is abnormal in the later period.
And (4) casting and molding, wherein the vermicular graphite cast iron is obtained after molding for 4 minutes.
The properties of the vermicular cast irons of examples 1-6 and comparative example 1 were compared as shown in table 1:
TABLE 1 Properties of vermicular cast irons
| Rate of creep | Tensile strength MPa | Elongation delta/%) | Hardness HBW | |
| Example 1 | 55％ | 385MPa | 5.2％ | 168HB |
| Example 2 | 70％ | 402MPa | 5.8％ | 172HB |
| Example 3 | 65％ | 392MPa | 6.1％ | 170HB |
| Example 4 | 70％ | 415MPa | 5.5％ | 173HB |
| Example 5 | 65％ | 402MPa | 5.9％ | 170HB |
| Example 6 | 70％ | 410MPa | 5.6％ | 168HB |
| Comparative example 1 | 55％ | 368MPa | 4.9％ | 160HB |
As can be seen from the above table, the vermicular cast irons prepared in examples 1-6 have a vermicular cast rate of 55-70%, a stable and uniform vermicular cast rate and a good vermicular effect. Compared with the comparative example, the tensile strength, the elongation and the hardness of the vermicular cast iron in the examples 1 to 6 are all better than those of the comparative example 1.
Wherein FIG. 4 is a metallographic picture of vermicular cast iron of example 3, having a vermicular cast iron percentage of 65%. FIG. 5 is a metallographic picture of vermicular cast iron of example 4, having a vermicular cast iron percentage of 70%.
According to the technical scheme, the invention has the advantages and positive effects that:
the production method of the vermicular graphite cast iron adopts Mg6Re2Is nodulizer, and the mixture of molten iron, nodulizer, silicon-strontium inoculant, 75Si-Fe and ductile iron scrap iron enters the molten iron treatment package at the same time, thereby ensuring the mixing action of the molten iron and the mixture, reducing the addition of the nodulizer and further reducing the production cost. Molten iron and the mixture enter the molten iron treatment package at the same time, and the time of entering the molten iron treatment package is the same, so that the molten iron and the mixture are uniformly mixed, the vermicular graphite cast iron has a good vermicular effect, and the vermicular graphite cast iron is stable and uniform in vermicular efficiency. In the production method, the traditional process of pressing the nodulizer on the ladle bottom of the molten iron processing ladle is omitted, so that the operation process is simple and the operability is strong. The process of pouring molten iron in the molten iron treatment ladle to the pouring ladle is omitted, so that the ladle pouring time is omitted, the temperature loss is reduced, the energy consumption is saved, and the burning loss of alloy elements is reduced. Meanwhile, the number of ladle-to-ladle processing operators is reduced, and the labor intensity of workers is reduced.
While the present invention has been described with reference to several exemplary embodiments, it is understood that the terminology used is intended to be in the nature of words of description and illustration, rather than of limitation. As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the meets and bounds of the claims, or equivalences of such meets and bounds are therefore intended to be embraced by the appended claims.
Claims (10)
1. A method for producing vermicular cast iron is characterized by comprising the following steps:
weighing 10-30% of pig iron, 20-40% of scrap steel, 40-50% of return iron and 0.8-1.8% of carburant according to the mass percentage;
sequentially adding the pig iron, the scrap steel, the return iron and the recarburizer into an electric furnace for melting, and adjusting components to obtain molten iron; wherein, the mass percent of C in the molten iron is 3.3-3.7%, the mass percent of Si is 1.3-1.6%, the mass percent of Mn is 0.3-0.5%, the mass percent of P is less than or equal to 0.05%, and the mass percent of Sn is less than or equal to 0.02%;
weighing Mg according to the mass ratio of the Mg to the molten iron6Re20.3 to 0.5 percent of nodulizer, 0.2 to 0.5 percent of silicon-strontium inoculant, 0.8 to 1.2 percent of 75Si-Fe and 0.5 to 0.7 percent of ductile iron scrap iron are mixed evenly to obtain a mixture;
providing a molten iron treatment package, and preheating the molten iron treatment package to above 600 ℃;
raising the temperature of the molten iron to 1480-1500 ℃, then pouring the molten iron into the preheated molten iron treatment package, and simultaneously enabling the mixture to flow into the preheated molten iron treatment package from top to bottom along an inclined chute, wherein the time for pouring the molten iron into the molten iron treatment package is the same as the time for flowing the mixture into the molten iron treatment package and is 50-60 s;
and (5) casting and molding, wherein the casting time is less than or equal to 8 minutes, and the vermicular graphite cast iron is obtained after molding.
2. The method for producing compacted graphite iron according to claim 1, wherein the step of raising the temperature of the molten iron to 1480-1500 ℃ and then pouring the molten iron into the molten iron treatment package while allowing the mixture to flow into the molten iron treatment package along an inclined chute, wherein the time for pouring the molten iron into the molten iron treatment package is 50-60s, and the time for flowing the mixture into the molten iron treatment package is 50-60s comprises:
the molten iron is poured from one side of the molten iron treatment bag, and the mixture flows in from the other side opposite to the molten iron pouring end.
3. The method of claim 1, wherein the upper end of the chute is provided with a funnel through which the mixture flows into the upper end of the chute.
4. According to claimProcess for the production of compacted graphite iron according to claim 1, characterized in that the Mg6Re2The nodulizer comprises, by mass, 5.0-7.0% of Mg, 1.5-2.5% of Re, 35-44% of Si, 2.0-3.0% of Ca, less than or equal to 4.0% of Mn, less than or equal to 0.5% of Al and the balance of Fe.
5. The method for producing vermicular cast iron according to claim 1, wherein the silicon-strontium inoculant contains 46-50% by mass of Si, 0.6-1.0% by mass of Sr, less than or equal to 0.1% by mass of Ca, less than or equal to 0.5% by mass of Al, and the balance of Fe.
6. The method for producing vermicular cast iron according to claim 1, wherein the mass percent of Si in 75Si-Fe is 72-80%, the mass percent of Ca is less than or equal to 1.0%, the mass percent of Al is less than or equal to 1.0%, the mass percent of Mn is less than or equal to 0.5%, the mass percent of Cr is less than or equal to 0.5%, the mass percent of P is less than or equal to 0.04%, the mass percent of S is less than or equal to 0.02%, and the balance is Fe.
7. The method for producing vermicular cast iron according to claim 1, wherein the ductile iron scrap comprises 3.5-3.6% by mass of C, 2.4-3.6% by mass of Si, 0.3-0.5% by mass of Mn, less than or equal to 0.03% by mass of P, less than or equal to 0.02% by mass of S, and the balance of Fe.
8. The method for producing vermicular cast iron according to claim 1, wherein the pig iron contains C not less than 4.2% by mass, Ti not more than 0.05% by mass, Mn not more than 0.2% by mass, P not more than 0.05% by mass, S not more than 0.02% by mass, and Fe in balance;
the mass percent of C in the scrap steel is less than or equal to 0.5 percent, the mass percent of Si is less than or equal to 0.5 percent, the mass percent of Mn is less than or equal to 0.5 percent, the mass percent of P is less than or equal to 0.045 percent, the mass percent of S is less than or equal to 0.035 percent, the mass percent of Al is less than or equal to 0.05 percent, the mass percent of Cr is less than or equal to 0.06 percent, and the balance is Fe;
the mass percent of C in the re-melted iron is 3.5-3.6%, the mass percent of Si is 2.4-3.6%, the mass percent of Mn is 0.3-0.5%, the mass percent of P is less than or equal to 0.03%, the mass percent of S is less than or equal to 0.02%, and the balance is Fe;
the recarburizing agent contains more than or equal to 92% of fixed C, less than or equal to 0.1% of volatile matter, less than or equal to 5% of ash, less than or equal to 0.15% of S, less than or equal to 0.5% of water and 200-2000ppm of N.
9. The method for producing compacted graphite iron according to claim 1, wherein in the step of sequentially adding the pig iron, the scrap, the returning iron and the recarburizer to an electric furnace to melt and adjusting the composition to obtain molten iron, the method for adjusting the composition comprises the steps of:
taking a mixture of the molten pig iron, the molten scrap steel, the molten recycled iron and the recarburizer, manufacturing the mixture into a spectrum test block, detecting element components in the spectrum test block by adopting a rapid direct-reading spectrometer, and then adjusting according to the difference between the detected components and preset components of the molten iron.
10. The method for producing vermicular cast iron according to claim 9, wherein when the composition of C element in the spectrum test block is higher than the preset composition in the molten iron, scrap steel with corresponding weight is added;
when the components of the C element in the spectrum test block are lower than the preset components in the molten iron, adding a carburant with corresponding weight;
and when the composition of the Si element in the spectrum test block is lower than the preset composition in the molten iron, adding 75Si-Fe with corresponding component.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010374558.1A CN113621750B (en) | 2020-05-06 | 2020-05-06 | Production method of vermicular cast iron |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010374558.1A CN113621750B (en) | 2020-05-06 | 2020-05-06 | Production method of vermicular cast iron |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN113621750A true CN113621750A (en) | 2021-11-09 |
| CN113621750B CN113621750B (en) | 2023-06-09 |
Family
ID=78376708
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010374558.1A Active CN113621750B (en) | 2020-05-06 | 2020-05-06 | Production method of vermicular cast iron |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN113621750B (en) |
Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2937321A1 (en) * | 1979-02-16 | 1980-08-21 | Inst Cercetari Stiintifice | METHOD FOR PRODUCING CAST IRON WITH VERMICULLARGRAPHITE BY MEANS OF DOUBLE MODIFICATION |
| EP0020819A1 (en) * | 1979-06-28 | 1981-01-07 | Buderus Aktiengesellschaft | Process for manufacturing castings of cast iron with vermicular graphite |
| CA1148723A (en) * | 1980-01-15 | 1983-06-28 | Geoffrey Mannion | Production of cast iron containing vermicular graphite |
| SU1723182A1 (en) * | 1990-06-05 | 1992-03-30 | Производственное объединение "Таганрогский комбайновый завод" | Cast iron with vermicular graphite |
| RU2012108256A (en) * | 2012-03-05 | 2013-09-10 | Открытое акционерное общество "АВТОВАЗ" | METHOD FOR PRODUCING HIGH-STRENGTH CAST IRON WITH VERMICULAR CRAFT IN-TREE MODIFICATION WITH LIGATURES OF THE Fe-Si-PZM SYSTEM |
| CN103589943A (en) * | 2013-11-01 | 2014-02-19 | 内蒙古包钢钢联股份有限公司 | Method for treating cast iron by rare earth |
| CN104532113A (en) * | 2014-12-09 | 2015-04-22 | 四川省富邦钒钛制动鼓有限公司 | Vanadium-titanium vermicular cast iron and production method thereof |
| CN105970075A (en) * | 2016-07-15 | 2016-09-28 | 江苏汽铸造股份有限公司 | Technique for preparing vermicular cast iron material |
| CN110964968A (en) * | 2019-12-10 | 2020-04-07 | 西安工业大学 | Efficient vermiculizer for vermicular graphite cast iron, and preparation and production methods thereof |
-
2020
- 2020-05-06 CN CN202010374558.1A patent/CN113621750B/en active Active
Patent Citations (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2937321A1 (en) * | 1979-02-16 | 1980-08-21 | Inst Cercetari Stiintifice | METHOD FOR PRODUCING CAST IRON WITH VERMICULLARGRAPHITE BY MEANS OF DOUBLE MODIFICATION |
| EP0020819A1 (en) * | 1979-06-28 | 1981-01-07 | Buderus Aktiengesellschaft | Process for manufacturing castings of cast iron with vermicular graphite |
| CA1148723A (en) * | 1980-01-15 | 1983-06-28 | Geoffrey Mannion | Production of cast iron containing vermicular graphite |
| SU1723182A1 (en) * | 1990-06-05 | 1992-03-30 | Производственное объединение "Таганрогский комбайновый завод" | Cast iron with vermicular graphite |
| RU2012108256A (en) * | 2012-03-05 | 2013-09-10 | Открытое акционерное общество "АВТОВАЗ" | METHOD FOR PRODUCING HIGH-STRENGTH CAST IRON WITH VERMICULAR CRAFT IN-TREE MODIFICATION WITH LIGATURES OF THE Fe-Si-PZM SYSTEM |
| CN103589943A (en) * | 2013-11-01 | 2014-02-19 | 内蒙古包钢钢联股份有限公司 | Method for treating cast iron by rare earth |
| CN104532113A (en) * | 2014-12-09 | 2015-04-22 | 四川省富邦钒钛制动鼓有限公司 | Vanadium-titanium vermicular cast iron and production method thereof |
| CN105970075A (en) * | 2016-07-15 | 2016-09-28 | 江苏汽铸造股份有限公司 | Technique for preparing vermicular cast iron material |
| CN110964968A (en) * | 2019-12-10 | 2020-04-07 | 西安工业大学 | Efficient vermiculizer for vermicular graphite cast iron, and preparation and production methods thereof |
Non-Patent Citations (1)
| Title |
|---|
| 陈海军等: "Sn对蠕墨铸铁组织与抗热疲劳性能的影响", 铸造, vol. 64, no. 4, pages 5 - 8 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN113621750B (en) | 2023-06-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN106011610B (en) | A kind of high-strength ductile cast iron QT900 6 and preparation method thereof | |
| EP1887090B1 (en) | Improved method of producing ductile iron | |
| CN110819753B (en) | Smelting process for eliminating broken graphite of thick and large ductile iron piece | |
| CN105132796B (en) | Middle silicon molybdenum alloy vermicular cast iron glass mold material and preparation method thereof | |
| CN105861915A (en) | Ferritic spheroidal graphite cast iron and preparation method thereof | |
| CN105886693B (en) | A kind of method of smelting of moderate strength high-elongation magnesium iron | |
| CN106929750A (en) | Compacted iron brake drum and preparation method thereof | |
| CN101525719B (en) | Nucleating agent used for producing thin-wall malleable iron component by metal mold | |
| CN102400032B (en) | Large-cross-section nodular cast iron | |
| CN105648305B (en) | High-strength gray cast iron material and preparation method thereof | |
| CN104593663B (en) | A kind of wear-resistant white cast iron and preparation method thereof | |
| CN114369756B (en) | As-cast QT700-8 material and casting method and application thereof | |
| CN110983165A (en) | Inoculant for nodular cast iron and preparation method thereof | |
| CN113621750A (en) | Method for producing vermicular cast iron | |
| CN102373365B (en) | Large-section nodular cast iron | |
| CN105238988B (en) | Preparing method and application of gray iron inoculant | |
| CN109468427B (en) | Pretreating agent for cast iron and preparation method thereof | |
| SU1724716A1 (en) | Cast iron for metallic forms | |
| CN113046624A (en) | Method for casting gray iron of GM241 alloy with high matrix hardness | |
| SU1421794A1 (en) | Iron | |
| SU1749294A1 (en) | High strength cast iron | |
| CN115161539B (en) | Isothermal quenching spheroidal graphite cast iron planet carrier blank and preparation process thereof | |
| CN113106184B (en) | Casting method of high-carbon low-silicon titanium-free vermicular graphite cast iron material | |
| CN114293091B (en) | High-strength and high-toughness nodular cast iron and preparation method and application thereof | |
| Janerka et al. | Various aspects of application of silicon carbide in the process of cast iron Melting |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |