CN110904380B - High-hardness nodular cast iron roller sheet and casting method thereof - Google Patents
High-hardness nodular cast iron roller sheet and casting method thereof Download PDFInfo
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- CN110904380B CN110904380B CN201911226790.4A CN201911226790A CN110904380B CN 110904380 B CN110904380 B CN 110904380B CN 201911226790 A CN201911226790 A CN 201911226790A CN 110904380 B CN110904380 B CN 110904380B
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/10—Cast-iron alloys containing aluminium or silicon
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D3/00—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts
- B21D3/02—Straightening or restoring form of metal rods, metal tubes, metal profiles, or specific articles made therefrom, whether or not in combination with sheet metal parts by rollers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D15/00—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor
- B22D15/005—Casting using a mould or core of which a part significant to the process is of high thermal conductivity, e.g. chill casting; Moulds or accessories specially adapted therefor of rolls, wheels or the like
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/08—Making cast-iron alloys
- C22C33/10—Making cast-iron alloys including procedures for adding magnesium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/04—Cast-iron alloys containing spheroidal graphite
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C37/00—Cast-iron alloys
- C22C37/06—Cast-iron alloys containing chromium
- C22C37/08—Cast-iron alloys containing chromium with nickel
Abstract
The invention relates to the technical field of mechanical casting, and particularly discloses a high-hardness nodular cast iron roller sheet and a casting method thereof. The high-hardness nodular cast iron material comprises the following chemical components in percentage by mass: 2.9 to 3.4 percent of C, 1.35 to 1.7 percent of Si, 0.55 to 0.85 percent of Mn, less than or equal to 0.06 percent of P, less than or equal to 0.02 percent of S, 0.35 to 0.85 percent of Cr, 0.25 to 0.8 percent of Mo, 0.3 to 0.7 percent of Ni, less than or equal to 0.02 percent of Ba, 0.04 to 0.07 percent of Mg, 0.01 to 0.03 percent of RE, and the balance of Fe and inevitable impurities. The high-hardness nodular cast iron roller sheet has the advantages that the hardness of the working layer is high, the toughness inside the roller sheet is strong, the service performance of the roller sheet is obviously improved, and the service life of the roller sheet is obviously prolonged.
Description
Technical Field
The invention relates to the technical field of mechanical casting, in particular to a high-hardness nodular cast iron roller sheet and a casting method thereof.
Background
In recent years, with the successive production of steel sheet pile production lines in iron and steel enterprises, the market demand of the roller sheet of the tooth-shaped straightener serving as a main accessory is also rapidly increased, at present, the straightening roller sheet is mainly centrifugally cast and is mainly simple cylindrical or annular in shape, most of the roller sheet of the straightener used for the steel sheet pile is tooth-shaped, only the simple cylindrical or annular can be cast during the production of a centrifugal machine, the tooth shape is mainly obtained by turning a machine tool, the hardness requirement of a working layer of the roller sheet is generally higher, the roller sheet obtained by turning the machine tool is high in processing difficulty, large in processing amount, time and labor are wasted, the manufacturing cost is always high, and the external working layer of the roller sheet obtained by turning the machine tool is damaged to a certain extent, so that the hardness and the use strength of the roller sheet are seriously influenced.
Disclosure of Invention
The invention provides a high-hardness nodular cast iron roller sheet and a casting method thereof, aiming at the problems that the hardness, the use strength and other properties of the existing toothed roller sheet cannot meet the use requirements, the processing difficulty is high, and the manufacturing cost is high.
In order to achieve the purpose of the invention, the embodiment of the invention adopts the following technical scheme:
a high-hardness nodular cast iron material comprises the following chemical components in percentage by mass:
2.9 to 3.4 percent of C, 1.35 to 1.7 percent of Si, 0.55 to 0.85 percent of Mn, less than or equal to 0.06 percent of P, less than or equal to 0.02 percent of S, 0.35 to 0.85 percent of Cr, 0.25 to 0.8 percent of Mo, 0.3 to 0.7 percent of Ni, less than or equal to 0.02 percent of Ba, 0.04 to 0.07 percent of Mg, 0.01 to 0.03 percent of RE, and the balance of Fe and inevitable impurities.
Compared with the prior art, the high-hardness nodular cast iron material provided by the invention has the advantages that the casting with higher hardness of the working layer can be obtained by a non-centrifugal casting method by adjusting the component proportion of Cr, Ni and Mo, the casting with different hardness and internal hardness of the working layer can be formed by the same component of casting liquid by adjusting the cooling speed of the casting liquid, the hardness of the working layer is improved, the toughness of the inner layer of the roller sheet is increased, the internal crystal structure of the material is uniformly distributed, the service performance of the casting is obviously improved, and the service life of the casting is obviously prolonged.
The invention also provides a casting method of the roller sheet, the roller sheet has the chemical composition of the high-hardness nodular cast iron material, and the casting method of the roller sheet at least comprises the following steps:
a. heating and melting scrap steel, pig iron, a carburant and ferrochrome to obtain molten alloy iron;
b. continuously heating the alloy molten iron to the temperature of 1350-;
c. heating the basic casting liquid to 1410-1450 ℃, and adding rare earth magnesium-silicon alloy to obtain roller piece casting liquid;
d. pouring the roller sheet casting liquid into the roller sheet casting device, simultaneously adding the silicon-barium alloy into the roller sheet casting device along with the liquid column of the casting liquid, and carrying out heat preservation and annealing to obtain the roller sheet.
Compared with the prior art, in the method for casting the roller sheet, the basic casting liquid is heated to 1410-1450 ℃, and then a certain amount of rare earth magnesium-silicon alloy is added to separate out carbon element in the basic casting liquid in a spherical graphite form, so that the cutting action of graphite on a matrix is reduced, and the wear resistance and the strength of the roller sheet are improved; meanwhile, a certain amount of silicon-barium alloy is added into a liquid column formed by the roller sheet casting liquid in the casting process, so that the silicon-barium alloy flows into the roller sheet casting device along with the roller sheet casting liquid, the supercooling degree of the casting liquid can be reduced, a large number of uniformly distributed crystal nuclei are formed in the roller sheet casting liquid, the purpose of refining crystal grains formed in the casting liquid is achieved, fine spherical graphite and carbide are finally formed in the casting liquid, and the structural uniformity and the tensile strength of the roller sheet are improved. Preferably, the method for adding the rare earth magnesium-silicon alloy in the step c comprises the following steps: the rare earth magnesium silicon alloy is placed in a groove at the bottom of a dam bag for casting, the surface of the rare earth magnesium silicon alloy is covered with ferrosilicon, and the basic casting liquid is poured into the dam bag.
Preferably, the method for adding the rare earth magnesium-silicon alloy in the step c comprises the following steps: the rare earth magnesium silicon alloy is placed in a groove at the bottom of a dam bag for casting, the surface of the rare earth magnesium silicon alloy is covered with ferrosilicon, and the basic casting liquid is poured into the dam bag.
By the method, the rare earth magnesium-silicon alloy and the basic casting liquid are subjected to full contact reaction, so that carbon element is precipitated in the form of spherical graphite in the solidification process of the basic casting liquid. The addition of the ferrosilicon alloy can reduce the supercooling degree of the roll sheet casting liquid, and a large number of uniformly distributed crystal nuclei are formed to obtain fine spherical graphite and network carbide.
Preferably, the mass content of Mg in the rare earth magnesium-silicon alloy is 6-8%, and the mass content of RE in the rare earth magnesium-silicon alloy is 0.8-1.2%.
Preferably, the addition amount of the ferrosilicon alloy accounts for 0.4-0.8% of the mass of the basic pouring liquid.
Preferably, the process of pouring the roll sheet casting liquid into the roll sheet casting device in the step d is as follows: and pouring the roller sheet pouring liquid through the pouring gate, and pouring the residual roller sheet pouring liquid into the roller sheet casting device through the riser when the pouring liquid reaches the height of 1/3-1/2 of the riser of the roller sheet casting device.
In the pouring process, a small amount of pouring liquid is poured into the roller sheet casting device through the riser, so that the phenomenon that the condensing speed of the pouring liquid close to the riser is too high and the uniformity of the strength of the roller sheet is influenced can be prevented.
Preferably, the grain diameter of the silicon-barium alloy in the step d is 0.2-0.5 mm; the silicon-barium alloy comprises, by mass, 4.5-5% of Ba, 2.5-3% of Al, 68-70% of Si and the balance Fe.
Preferably, the pouring temperature in the step d is 1300-1350 ℃; the heat preservation time is 10-15h, and in the heat preservation process, when the temperature of the roller sheet is reduced to 200-300 ℃, the riser and the pouring channel are thermally cut.
Preferably, the annealing process in step d is as follows: the roller sheet is heated to 560 ℃ and 600 ℃ at the speed of 50-60 ℃/h, and is cooled to room temperature after heat preservation for 6-8 hours.
The invention also provides a roller sheet obtained by casting by using the casting method.
The invention also provides a roller sheet casting device used in the roller sheet casting method, and the roller sheet casting device comprises a drag flask, a cope flask, a metal cold mold, a pouring channel and a riser; the upper sand box covers the lower sand box; the metal cold mold is positioned between the upper sand box and the lower sand box, the inner contour of the metal cold mold is in accordance with the shape of the outer contour of the roller sheet for pouring, a sand core is arranged in the inner contour of the metal cold mold, and a roller sheet cavity for forming the roller sheet in the pouring process is formed between the metal cold mold and the sand core; the pouring channel penetrates through the upper sand box and the metal cold mold and is communicated with the bottom of the roller sheet cavity through the lower sand box, and a pouring port is formed in one end, located on the upper sand box, of the pouring channel; and the riser is positioned in the cope flask above the roller sheet cavity.
Compared with the prior art, the roller sheet casting device disclosed by the invention can be used for casting a roller sheet with a complex shape and high casting difficulty, and the roller sheet obtained by pouring can be in contact with a metal cold mold by utilizing different heat dissipation effects of different materials of a sand box and the metal cold mold and the supercooling effect of the metal cold mold, so that the metal cold mold can chill casting liquid, a compact pearlite structure, fine spherical graphite and net-shaped carbide are obtained in the roller sheet, the roller sheet has the characteristics of high hardness of an outer working layer, low hardness of a core part and good toughness, and the processing and using requirements of two kinds of hardness of an inner hardness and an outer hardness of one material are met; on the other hand, in the pouring process, the riser is positioned in the cope box, so that the better heat insulation effect is achieved, and the pouring liquid enters from the lower part of the roller sheet cavity through the pouring channel, so that the integral use strength of the roller sheet is ensured not to be influenced by the excessively high condensation speed of the riser; the roll sheet with a complex structure, high working layer hardness and good tensile strength can be obtained, the later processing amount of the roll sheet is small, the cutting step is omitted, the material is saved, the cost is saved by more than 30%, and the casting difficulty is greatly reduced.
Preferably, resin sand is filled in both the cope flask and the drag flask, and the sand core is a resin sand core.
The resin sand has a good heat preservation effect, the heat dissipation process is slow, a strong heat dissipation contrast can be formed with the metal cold type mold, and in the casting process, the casting liquid is chilled in the metal cold type mold, so that a high-hardness working layer is formed on the surface of the roller sheet.
Preferably, the outer walls of the cope flask and the drag flask are welded and formed by adopting steel plates with the thickness of 18-22 mm.
Preferably, the metal cold type die is made of grey cast iron, particularly HT200 grey cast iron, and the wall thickness of the metal cold type die is 200mm-300 mm.
The invention uses gray cast iron as the metal cold mold, and can control the chilling effect on the casting liquid by controlling the wall thickness of the mold, when the wall thickness of the metal cold mold is 200mm-300mm, the chilling effect of the outer contour of the metal cold mold on the casting liquid can obtain compact pearlite structure, fine spherical graphite and net-shaped carbide on the surface of the roller sheet, so that the hardness HSD of the working layer on the surface of the roller sheet can reach more than 63, and the hardness of the core part is kept between 36-44, thus having higher use performance.
Preferably, the outer diameter of the roller sheet is D, and the inner profile diameter of the metal cold-type die is: (1.014-1.015) D +15 mm.
The diameter of the inner contour of the metal cold type die is 1.014-1.015 times of the diameter of the roller sheet and 15mm, the extra 15mm can be used as the processing width of the roller sheet, and the width of the roller sheet which is 0.014-0.015 times of the diameter of the roller sheet reserves a margin for cold contraction generated in the cooling process of the casting liquid.
Preferably, the pouring channel comprises a sprue, a cross gate and an inner gate, the cross gate is positioned in the drag flask, the sprue sequentially penetrates through the cope flask, the metal cold-type mold and the drag flask to be communicated with the cross gate, and the inner gate is arranged in the drag flask and connected between the cross gate and the roller sheet cavity.
Preferably, the pouring channel is a ceramic pipeline, and the pouring liquid enters the roller-type cavity through the ceramic pipeline.
Preferably, the inner side surface of the metal cold mould, the outer side surface of the sand core and the inner wall of the riser are coated with 1.5-3mm of refractory coating, and the refractory coating is zirconium silicate coating.
The zirconium silicate coating has better fire resistance and high temperature resistance, can increase the flatness of the surface of the roller sheet and reduce the workload of polishing in later processing when coated inside the metal cold mold, and cannot influence the chilling effect of the metal cold mold on the casting liquid.
Preferably, the riser is of a funnel-shaped structure with a large opening at the upper end and a small opening at the lower end.
The funnel-shaped structure of rising head can reduce the condensation speed of the casting liquid that is close to the rising head position in the roller piece die cavity, improves the holistic use strength of roller piece.
Drawings
FIG. 1 is a schematic cross-sectional view of a roll sheet casting apparatus according to an embodiment of the present invention;
the casting method comprises the following steps of 1, a cope flask, 2, a drag flask, 3, a metal cold mold, 4, a sand core, 5, a pouring gate, 61, a sprue, 62, a cross gate, 63, an ingate, 7, a riser, 8 and a roller sheet cavity.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
Example 1
A high-hardness nodular cast iron material comprises the following chemical components in percentage by mass:
2.9% of C, 1.35% of Si, 0.55% of Mn, 0.04% of P, 0.01% of S, 0.35% of Cr, 0.25% of Mo, 0.3% of Ni, 0.02% of Ba, 0.04% of Mg, 0.01% of RE, and the balance of Fe and inevitable impurities.
The casting method of the straightening machine roller sheet with the chemical composition of the high-hardness nodular cast iron material comprises the following steps:
a. adding scrap steel, pig iron, a carburant and ferrochrome in a mass ratio of 60:25:1:0.5 into an intermediate frequency electric furnace to be smelted to obtain molten alloy iron;
b. continuously heating the alloy molten iron until the temperature reaches 1350 ℃, and respectively adding ferromolybdenum accounting for 0.5 percent of the mass of the alloy molten iron, metallic nickel accounting for 0.3 percent of the mass of the alloy molten iron and ferromanganese accounting for 0.5 percent of the mass of the alloy molten iron to obtain basic casting liquid;
c. placing rare earth magnesium silicon alloy with the mass of 1.1% of the basic pouring liquid into a groove at the bottom of a dam bag for casting, covering the surface of the rare earth magnesium silicon alloy with silicon iron alloy with the mass of 0.4% of the basic pouring liquid, heating the basic pouring liquid to 1410 ℃, and pouring the basic pouring liquid into the dam bag to obtain roll sheet pouring liquid; wherein the mass content of Mg in the rare earth magnesium-silicon alloy is 6 percent, and the mass content of RE is 0.8 percent;
d. preheating a roller sheet casting device to 150 ℃, when the temperature of the roller sheet casting liquid reaches 1300 ℃, pouring the casting liquid into a roller sheet cavity 8 of the roller sheet casting device through a pouring gate 5, and simultaneously adding a silicon-barium alloy accounting for 0.1 percent of the mass of the roller sheet casting liquid into the roller sheet casting device along with a liquid column of the casting liquid, wherein the granularity of the silicon-barium alloy is 0.2mm, the mass content of Ba in the silicon-barium alloy is 4.5 percent, the mass content of Al is 2.5 percent, the mass content of Si is 69 percent, and the balance is Fe; and when the casting liquid in the roller sheet casting device reaches the height of 1/3 of the riser 7, pouring the residual casting liquid into the roller sheet casting device through the riser 7, preserving heat for 10 hours after pouring is finished, in the heat preservation process, after the temperature of the roller sheet is reduced to 200 ℃, thermally cutting the riser 7 and the pouring channel 6, heating to 560 ℃ along with the furnace at the speed of 50 ℃/, preserving heat for 6 hours, cooling to 200 ℃, and air cooling to room temperature to obtain the roller sheet of the straightener.
In the casting process of the roller sheet of the straightener, the used roller sheet casting device comprises a drag flask 2, an upper flask 1, a metal cold mold 3, a pouring channel and a riser 7;
the cope flask 1 is covered on the drag flask 2; the metal cold mold 3 is positioned between the upper sand box 1 and the lower sand box 2, the inner contour of the metal cold mold 3 is in accordance with the shape of the outer contour of a roller sheet for casting, a sand core 4 is arranged inside the metal cold mold 3, and a roller sheet cavity 8 for forming the roller sheet in the casting process is formed between the metal cold mold 3 and the sand core 4; the pouring channel penetrates through the upper sand box 1 and the metal cold mold 3 and is communicated with the bottom of the roller sheet cavity 8 through the lower sand box 2, and a pouring port 5 is formed in one end, located on the upper sand box 1, of the pouring channel; the riser 7 is positioned in the cope flask 1 above the roller sheet cavity 8.
Wherein the upper sand box 1 and the lower sand box 2 are both filled with resin sand, and the sand core 4 is a resin sand core; the outer walls of the upper sand box 1 and the lower sand box 2 are welded and formed by adopting steel plates with the thickness of 20 mm; the material of the metal cold type die 3 is HT200 grey cast iron, and the wall thickness of the metal cold type die 3 is 200 mm; the internal profile diameter of the metal cold die 3 is 1.015 times the external diameter of the roll sheet plus 15 mm: the pouring channel comprises a straight pouring gate 61, a cross pouring gate 62 and an inner pouring gate 63, the cross pouring gate 62 is positioned in the lower sand box 2, the straight pouring gate 61 sequentially penetrates through the upper sand box 1, the metal cold type mold 3 and the lower sand box 2 to be communicated with the cross pouring gate 62, and the inner pouring gate 63 is arranged in the lower sand box 2 and is connected between the cross pouring gate 62 and the roller piece cavity 8; the pouring channel is a ceramic pipeline, and pouring liquid enters the roller piece cavity 8 through the ceramic pipeline; zirconium silicate paint with the thickness of 1.5mm is coated on the inner side surface of the metal cold mold 3, the outer side surface of the sand core 4 and the inner wall of the riser 7; the riser 7 is of a funnel-shaped structure with a large opening at the upper end and a small opening at the lower end.
Example 2
A high-hardness nodular cast iron material comprises the following chemical components in percentage by mass:
3.2% of C, 1.5% of Si, 0.7% of Mn, 0.05% of P, 0.01% of S, 0.5% of Cr, 0.5% of Mo, 0.5% of Ni, 0.01% of Ba, 0.06% of Mg, 0.02% of RE, and the balance of Fe and inevitable impurities.
The casting method of the straightening machine roller sheet with the chemical composition of the high-hardness nodular cast iron material comprises the following steps:
a. adding scrap steel, pig iron, a carburant and ferrochrome in a mass ratio of 65:30:2:1 into an intermediate frequency electric furnace to be smelted to obtain molten alloy iron;
b. continuously heating the alloy molten iron to 1380 ℃, and respectively adding ferromolybdenum accounting for 1 percent of the mass of the alloy molten iron, metallic nickel accounting for 0.5 percent of the mass of the alloy molten iron and ferromanganese accounting for 0.6 percent of the mass of the alloy molten iron to obtain basic casting liquid;
c. placing rare earth magnesium silicon alloy with the mass of 1.1% of the basic casting liquid into a groove at the bottom of a dam bag for casting, covering the surface of the rare earth magnesium silicon alloy with silicon iron alloy with the mass of 0.6% of the basic casting liquid, heating the basic casting liquid to 1430 ℃, and pouring the basic casting liquid into the dam bag to obtain roll sheet casting liquid; wherein the mass content of Mg in the rare earth magnesium-silicon alloy is 7 percent, and the mass content of RE is 1 percent;
d. preheating a roller sheet casting device to 200 ℃, when the temperature of the roller sheet casting liquid reaches 1320 ℃, pouring the casting liquid into a roller sheet cavity 8 of the roller sheet casting device through a pouring gate 5, and simultaneously adding a silicon-barium alloy accounting for 0.2% of the mass of the roller sheet casting liquid into the roller sheet casting device along with a liquid column of the casting liquid, wherein the granularity of the silicon-barium alloy is 0.3mm, the mass content of Ba in the silicon-barium alloy is 4.8%, the mass content of Al is 2.8%, the mass content of Si is 68%, and the balance is Fe; and when the casting liquid in the roller sheet casting device reaches the height of a riser 1/2, pouring the rest casting liquid into the roller sheet casting device through the riser 7, preserving heat for 12 hours after pouring is finished, in the heat preservation process, after the temperature of the roller sheet is reduced to 300 ℃, thermally cutting the riser 7 and a pouring channel, heating the roller sheet to 580 ℃ at the speed of 55 ℃/h, preserving heat for 7 hours, cooling to 200 ℃, and air cooling to room temperature to obtain the roller sheet of the straightener.
In the casting of the rolls of the leveler, the same roll casting apparatus as that used in example 1 was used.
Example 3
A high-hardness nodular cast iron material comprises the following chemical components in percentage by mass:
3.4% of C, 1.7% of Si, 0.85% of Mn, 0.05% of P, 0.02% of S, 0.85% of Cr, 0.25% of Mo, 0.7% of Ni, 0.02% of Ba0.07% of Mg, 0.03% of RE, and the balance of Fe and inevitable impurities.
The casting method of the straightener roll sheet containing the high-hardness nodular cast iron material comprises the following steps:
a. adding scrap steel, pig iron, a carburant and ferrochrome in a mass ratio of 70:35:3:1.2 into an intermediate frequency electric furnace to be smelted to obtain molten alloy iron;
b. continuously heating the molten alloy iron to 1390 ℃, and respectively adding ferromolybdenum accounting for 0.5 percent of the mass of the molten alloy iron, metallic nickel accounting for 0.7 percent of the mass of the molten alloy iron and ferromanganese accounting for 0.8 percent of the mass of the molten alloy iron to obtain basic pouring liquid;
c. placing rare earth magnesium silicon alloy with the mass of 1.2% of the basic pouring liquid into a groove at the bottom of a dam bag for casting, covering the surface of the rare earth magnesium silicon alloy with silicon iron alloy with the mass of 0.8% of the basic pouring liquid, heating the basic pouring liquid to 1450 ℃, and pouring the basic pouring liquid into the dam bag to obtain roll sheet pouring liquid; wherein the mass content of Mg in the rare earth magnesium-silicon alloy is 8 percent, and the mass content of RE is 1.2 percent;
d. preheating a roller sheet casting device to 200 ℃, when the temperature of roller sheet casting liquid reaches 1350 ℃, pouring the casting liquid into a roller sheet cavity 8 of the roller sheet casting device through a pouring gate 5, and simultaneously adding silicon-barium alloy accounting for 0.2% of the mass of the roller sheet casting liquid into the roller sheet casting device along with a liquid column of the casting liquid, wherein the granularity of the silicon-barium alloy is 0.5mm, the mass content of Ba in the silicon-barium alloy is 5%, the mass content of Al is 3%, the mass content of Si is 70%, and the balance is Fe; and when the casting liquid in the roller sheet casting device reaches the height of a riser 1/2, pouring the rest casting liquid into the roller sheet casting device through the riser 7, preserving heat for 15 hours after pouring is finished, in the heat preservation process, after the temperature of the roller sheet is reduced to 300 ℃, thermally cutting the riser 7 and a pouring channel, heating the roller sheet to 600 ℃ at the speed of 60 ℃/h, preserving heat for 8 hours, cooling to 200 ℃, and air cooling to room temperature to obtain the roller sheet of the straightener.
In the casting of the rolls of the leveler, the same roll casting apparatus as that used in example 1 was used.
Comparative example 1
The silicon-barium alloy in example 1 was replaced with an equivalent silicon-iron alloy having an equivalent grain size, and the casting method and the casting apparatus were the same as those in example 1 to obtain a leveler roller piece.
The properties of the leveler roller sheets obtained in examples 1 to 3 and comparative example 1 were measured, and the results are shown in the following table:
| detecting items | Example 1 | Example 2 | Example 3 | Comparative example 1 |
| Tensile strength (megapascals) | 475 MPa (pressure) | 480 MPa (MPa) | 480 MPa (MPa) | 420 MPa |
| Hardness of working layer of roller sheet | 60-64 | 60-65 | 61-63 | 52-58 |
| Internal hardness of roller sheet | 36-40 | 38-42 | 39-44 | 32-40 |
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents or improvements made within the spirit and principle of the present invention should be included in the scope of the present invention.
Claims (8)
1. A casting method of a roller sheet, the roller sheet has the chemical composition of a high-hardness nodular cast iron material, and is characterized in that: the high-hardness nodular cast iron material comprises the following chemical components in percentage by mass:
2.9 to 3.4 percent of C, 1.35 to 1.7 percent of Si, 0.55 to 0.85 percent of Mn, less than or equal to 0.06 percent of P, less than or equal to 0.02 percent of S, 0.35 to 0.85 percent of Cr, 0.25 to 0.8 percent of Mo, 0.3 to 0.7 percent of Ni, less than or equal to 0.02 percent of Ba, 0.04 to 0.07 percent of Mg, 0.01 to 0.03 percent of RE, and the balance of Fe and inevitable impurities;
the casting method of the roller sheet comprises the following steps:
a. heating and melting scrap steel, pig iron, a carburant and ferrochrome to obtain molten alloy iron;
b. continuously heating the alloy molten iron to the temperature of 1350-;
c. heating the basic casting liquid to 1410-1450 ℃, and adding rare earth magnesium-silicon alloy to obtain roller piece casting liquid;
d. pouring the roller sheet casting liquid into a roller sheet casting device, simultaneously adding the silicon-barium alloy into the roller sheet casting device along with a liquid column of the casting liquid, and carrying out heat preservation and annealing to obtain a roller sheet;
the roll sheet casting device includes:
a drag flask;
the upper sand box is covered on the lower sand box;
the metal cold-type mould is positioned between the upper sand box and the lower sand box, the inner contour of the metal cold-type mould is in accordance with the shape of the outer contour of the roller sheet for pouring, a sand core is arranged in the inner contour of the metal cold-type mould, and a roller sheet cavity for forming the roller sheet in the pouring process is formed between the metal cold-type mould and the sand core;
the pouring channel penetrates through the upper sand box and the metal cold mold and is communicated with the bottom of the roller sheet cavity through the lower sand box, and a pouring port is formed in one end, located on the upper sand box, of the pouring channel; and
and the riser is positioned in the cope flask above the roller sheet cavity.
2. A method of casting a roll sheet as claimed in claim 1, wherein: the method for adding the rare earth magnesium-silicon alloy in the step c comprises the following steps: the rare earth magnesium silicon alloy is placed in a groove at the bottom of a dam bag for casting, the surface of the rare earth magnesium silicon alloy is covered with ferrosilicon, and the basic casting liquid is poured into the dam bag.
3. A method of casting a roll sheet as claimed in claim 2, wherein: the mass content of Mg in the rare earth magnesium-silicon alloy is 6-8%, and the mass content of RE is 0.8-1.2%.
4. A method of casting a roll sheet as claimed in claim 2, wherein: the addition of the ferrosilicon alloy accounts for 0.4-0.8% of the mass of the basic pouring liquid.
5. A method of casting a roll sheet as claimed in claim 1, wherein: the process of pouring the roller sheet pouring liquid into the roller sheet casting device in the step d is as follows: and pouring the roller sheet pouring liquid through the pouring gate, and pouring the residual roller sheet pouring liquid into the roller sheet casting device through the riser when the pouring liquid reaches the height of 1/3-1/2 of the riser of the roller sheet casting device.
6. A method of casting a roll sheet as claimed in claim 1, wherein: the grain diameter of the silicon-barium alloy in the step d is 0.2-0.5 mm; the silicon-barium alloy comprises, by mass, 4.5-5% of Ba, 2.5-3% of Al, 68-70% of Si and the balance Fe.
7. A method of casting a roll sheet as claimed in claim 1, wherein: the pouring temperature in the step d is 1300-1350 ℃; the heat preservation time is 10-15 h; and/or
The annealing process in the step d is as follows: raising the temperature to 560 ℃ and 600 ℃ at the speed of 50-60 ℃/h, preserving the heat for 6-8 hours, and then cooling to room temperature.
8. A roll sheet obtained by casting according to the casting method described in any one of claims 2 to 7.
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| JPS59130667A (en) * | 1983-01-17 | 1984-07-27 | Kubota Ltd | Production of composite spherioidal graphite cast iron roll |
| CN1070600A (en) * | 1992-08-24 | 1993-04-07 | 冶金工业部钢铁研究总院 | The production method of centrifugally compounded nodular graphite cast iron roller |
| CN102554129A (en) * | 2011-12-26 | 2012-07-11 | 常州凯达重工科技有限公司 | Roll casting process and pouring device adopted by same |
| CN103320676A (en) * | 2013-06-24 | 2013-09-25 | 无锡市彩云机械设备有限公司 | Alloy nodular cast iron roll |
| CN105274423A (en) * | 2014-06-13 | 2016-01-27 | 中国科学院金属研究所 | Carbide-containing austempered ductile iron and preparation method thereof |
| CN110273100A (en) * | 2019-07-09 | 2019-09-24 | 常州市中宇合金轧辊厂 | A kind of modified spheroidal graphite cast-iron beam-and-rail planishing roll and its production method |
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2019
- 2019-12-04 CN CN201911226790.4A patent/CN110904380B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59130667A (en) * | 1983-01-17 | 1984-07-27 | Kubota Ltd | Production of composite spherioidal graphite cast iron roll |
| CN1070600A (en) * | 1992-08-24 | 1993-04-07 | 冶金工业部钢铁研究总院 | The production method of centrifugally compounded nodular graphite cast iron roller |
| CN102554129A (en) * | 2011-12-26 | 2012-07-11 | 常州凯达重工科技有限公司 | Roll casting process and pouring device adopted by same |
| CN103320676A (en) * | 2013-06-24 | 2013-09-25 | 无锡市彩云机械设备有限公司 | Alloy nodular cast iron roll |
| CN105274423A (en) * | 2014-06-13 | 2016-01-27 | 中国科学院金属研究所 | Carbide-containing austempered ductile iron and preparation method thereof |
| CN110273100A (en) * | 2019-07-09 | 2019-09-24 | 常州市中宇合金轧辊厂 | A kind of modified spheroidal graphite cast-iron beam-and-rail planishing roll and its production method |
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