CN113832382A - Preparation method for graphite refining of vermicular graphite cast iron - Google Patents
Preparation method for graphite refining of vermicular graphite cast iron Download PDFInfo
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- CN113832382A CN113832382A CN202111072183.4A CN202111072183A CN113832382A CN 113832382 A CN113832382 A CN 113832382A CN 202111072183 A CN202111072183 A CN 202111072183A CN 113832382 A CN113832382 A CN 113832382A
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- graphite
- cast iron
- vermicular
- temperature
- refining
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 52
- 229910002804 graphite Inorganic materials 0.000 title claims abstract description 50
- 239000010439 graphite Substances 0.000 title claims abstract description 50
- 229910001018 Cast iron Inorganic materials 0.000 title claims abstract description 27
- 238000007670 refining Methods 0.000 title claims abstract description 18
- 238000002360 preparation method Methods 0.000 title claims abstract description 9
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 36
- 239000010959 steel Substances 0.000 claims abstract description 36
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical group [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 30
- 239000007788 liquid Substances 0.000 claims abstract description 29
- 239000000463 material Substances 0.000 claims abstract description 23
- 229910052742 iron Inorganic materials 0.000 claims abstract description 14
- 238000005266 casting Methods 0.000 claims abstract description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 24
- 239000000956 alloy Substances 0.000 claims description 24
- 239000003795 chemical substances by application Substances 0.000 claims description 16
- 239000002699 waste material Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 10
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims description 6
- 239000013078 crystal Substances 0.000 claims description 6
- 238000002844 melting Methods 0.000 claims description 6
- 230000008018 melting Effects 0.000 claims description 6
- 238000003756 stirring Methods 0.000 claims description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 3
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 3
- 229910001309 Ferromolybdenum Inorganic materials 0.000 claims description 3
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 3
- 229910001200 Ferrotitanium Inorganic materials 0.000 claims description 3
- MBMLMWLHJBBADN-UHFFFAOYSA-N Ferrous sulfide Chemical compound [Fe]=S MBMLMWLHJBBADN-UHFFFAOYSA-N 0.000 claims description 3
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 3
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 claims description 3
- CSDREXVUYHZDNP-UHFFFAOYSA-N alumanylidynesilicon Chemical compound [Al].[Si] CSDREXVUYHZDNP-UHFFFAOYSA-N 0.000 claims description 3
- OOJQNBIDYDPHHE-UHFFFAOYSA-N barium silicon Chemical compound [Si].[Ba] OOJQNBIDYDPHHE-UHFFFAOYSA-N 0.000 claims description 3
- 229910052802 copper Inorganic materials 0.000 claims description 3
- 239000010949 copper Substances 0.000 claims description 3
- 230000006698 induction Effects 0.000 claims description 3
- 239000002054 inoculum Substances 0.000 claims description 3
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 3
- 229910052759 nickel Inorganic materials 0.000 claims description 3
- 238000004321 preservation Methods 0.000 claims description 3
- 229910052710 silicon Inorganic materials 0.000 claims description 3
- 239000010703 silicon Substances 0.000 claims description 3
- 239000002893 slag Substances 0.000 claims description 3
- 229910052717 sulfur Inorganic materials 0.000 claims description 3
- 239000011593 sulfur Substances 0.000 claims description 3
- 229910000805 Pig iron Inorganic materials 0.000 abstract description 4
- 238000003723 Smelting Methods 0.000 abstract description 4
- 238000005516 engineering process Methods 0.000 abstract description 3
- 229910001562 pearlite Inorganic materials 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 abstract description 2
- 239000002994 raw material Substances 0.000 abstract description 2
- 239000007787 solid Substances 0.000 abstract description 2
- 229910001060 Gray iron Inorganic materials 0.000 description 2
- 229910001141 Ductile iron Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
Images
Classifications
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D27/00—Treating the metal in the mould while it is molten or ductile ; Pressure or vacuum casting
- B22D27/08—Shaking, vibrating, or turning of moulds
-
- 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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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (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
A preparation method for graphite refining of vermicular cast iron relates to the technical field of vermicular cast iron, solves the problem that coarse hypereutectic graphite in pig iron is left in a solid cast iron structure from a liquid state, and the shrinkage tendency of molten iron is increased, uses scrap steel as a raw material, breaks formed graphite in a casting by means of vibration, and refines the length of the graphite; the vermicular cast iron product is produced by using the all-scrap steel smelting and physical vibration technology, because the carbon content in steel is lower, the inheritance of coarse graphite is not generated, the shrinkage tendency of the vermicular cast iron is correspondingly reduced, the graphite size in the structure is reduced, the chilling tendency is reduced, and the pearlite rate is increased, so that the strength and the hardness of the material are improved, and meanwhile, the plasticity and the toughness are correspondingly improved.
Description
Technical Field
The invention relates to the technical field of vermicular cast iron, in particular to a preparation method for graphite refinement of vermicular cast iron.
Background
The vermicular graphite cast iron has the strength of nodular cast iron, has similar vibration-proof, heat-conducting and casting performances compared with gray cast iron, and has better plasticity and fatigue resistance compared with gray cast iron. Due to good performance, the composite material is widely applied to engine cylinders, automobile exhaust pipes, supercharger shells and railway train brake discs. At present, vermicular cast iron is manufactured by smelting and casting by taking pig iron as a main raw material, and problems are brought along, such as coarse hypereutectic graphite in the pig iron is transferred to a solid cast iron structure from a liquid state, and the shrinkage tendency of the molten iron is increased.
Disclosure of Invention
In order to solve the problems, the invention provides a preparation method for graphite refining of vermicular cast iron, which is used for refining the size of graphite in the vermicular cast iron and reducing the influence of the graphite on the cutting of material tissues, so that the strength and the hardness of the material are improved, and meanwhile, the plasticity and the toughness are correspondingly improved. In order to achieve the purpose, the invention adopts the technical scheme that: a preparation method for graphite refining of vermicular cast iron comprises the following steps:
1. adding 30% of waste steel materials into a medium-frequency induction furnace, completely melting, adding a graphite carburant according to 2-3% of the weight of molten steel, stirring for 1-2min, immediately adding 50% of waste steel materials, and then continuously melting;
2. after the added waste steel materials are completely melted, adding a graphite carburant according to 2-3% of the weight of the molten steel, stirring for 1-2min, and immediately adding the rest 20% of the waste steel materials;
3. after all the waste steel materials are melted, keeping the temperature of molten iron at 1350-;
4. raising the temperature of the molten steel to 1400 ℃ and 1500 ℃, and sequentially adding 0.4-0.8% of pure nickel, 0.65-0.85% of pure copper, 0.65-0.85% of ferromolybdenum, 0.5-0.9% of ferromanganese and 2.0-3.5% of silicon crystal; after the added alloy is completely melted, adding a deslagging agent to remove slag, covering the whole liquid level with the deslagging agent, waiting for 2-3 minutes, and removing scum on the surface of the alloy liquid;
5. preserving heat at the temperature of 1400 ℃ and 1500 ℃, and scattering a layer of covering agent on the surface of the alloy liquid in the heat preservation process, wherein the thickness of the covering agent is 8-10 mm;
6. after the temperature of the alloy liquid is proper, transferring the alloy liquid, removing a covering agent on the liquid surface by using a tool before transferring, transferring the alloy liquid into a pouring ladle, and when the alloy liquid is transferred by 20-30%, adding an inoculant (0.25-0.40% of ferrosilicon, 0.20-0.40% of silicon-aluminum and 0.20-0.40% of silicon-barium) and a vermiculizer into the pouring ladle, wherein the alloy liquid cannot be transferred in the process of adding;
7. measuring the temperature of molten iron in a pouring ladle, controlling the pouring temperature to be 1360 +/-10 ℃, starting a motor within 3-8 seconds, carrying out micro-vibration on the casting mould, stopping a vibrating machine within 10-20 seconds after the casting is poured, breaking formed graphite in the casting by means of vibration, and refining the length of the graphite.
Further, after the scrap steel in the step 1 is completely melted, 0.05-0.1% of ferrous sulfide is added, the sulfur content is controlled to be 0.02-0.04%, the creep range is enlarged, and the creep rate is accurately controlled.
Further, in the step 2, after the scrap steel is completely melted, the temperature of the molten iron is raised to 1480-1500 ℃, and 0.2-0.8% of ferrotitanium is added for reverse spheroidization, so that the creep rate is improved, and the graphite is refined.
Further, after the furnace burden in the step 4 is melted, molten iron refining is carried out at 1530-1550 ℃, the refining time is 3-5 minutes, graphite crystal nuclei are increased, and graphite is refined.
Further, the vibration frequency of the step 7 micro-vibration was set to 80 HZ.
Compared with the prior art, the invention has the following beneficial effects: the vermicular cast iron product is produced by using the all-scrap steel smelting and physical vibration technology, because the carbon content in steel is lower, the inheritance of coarse graphite is not generated, the shrinkage tendency of the vermicular cast iron is correspondingly reduced, the graphite size in the structure is reduced, the chilling tendency is reduced, and the pearlite rate is increased, so that the strength and the hardness of the material are improved, and meanwhile, the plasticity and the toughness are correspondingly improved.
Drawings
The present invention is described in further detail below with reference to the attached drawings.
FIG. 1 is a metallographic picture of graphite magnified 100 times in a vermicular cast iron material prepared using pig iron;
FIG. 2 is a metallographic picture of graphite at 100 times magnification of a vermicular cast iron material prepared using a whole scrap steel material.
Detailed Description
In order to make the technical solutions of the present invention better understood by those skilled in the art, the present invention will be further described with reference to fig. 1 and 2 and specific examples.
As shown in the attached figures 1 and 2, the preparation method of the graphite refining of the vermicular cast iron comprises the following steps:
1. adding 30% of waste steel materials into a medium-frequency induction furnace, completely melting, adding 0.05-0.1% of ferrous sulfide, controlling the sulfur content to be 0.02-0.04%, enlarging the creep range, and accurately controlling the creep rate; adding a graphite carburant according to 2-3% of the weight of the molten steel, stirring for 1-2min, immediately adding 50% of waste steel materials, and then continuously melting;
2. after the added waste steel materials are completely melted, adding a graphite recarburizing agent according to 2-3% of the weight of the molten steel, stirring for 1-2min, immediately adding the rest 20% of the waste steel materials, after the waste steel is completely melted, raising the temperature of the molten iron to 1480-1500 ℃, adding 0.2-0.8% of ferrotitanium, performing anti-spheroidization treatment, improving the creep rate and refining graphite;
3. after all the waste steel materials are melted, keeping the temperature of molten iron at 1350-;
4. raising the temperature of the molten steel to 1400 ℃ and 1500 ℃, and sequentially adding 0.4-0.8% of pure nickel, 0.65-0.85% of pure copper, 0.65-0.85% of ferromolybdenum, 0.5-0.9% of ferromanganese and 2.0-3.5% of silicon crystal; after the added alloy is completely melted, adding a deslagging agent to remove slag, covering the whole liquid level with the deslagging agent, waiting for 2-3 minutes, and removing scum on the surface of the alloy liquid;
5. after the furnace burden is melted, molten iron refining is carried out at 1530-1550 ℃, the refining time is 3-5 minutes, graphite crystal nuclei are increased, and graphite is refined;
6. preserving heat at the temperature of 1400 ℃ and 1500 ℃, and scattering a layer of covering agent on the surface of the alloy liquid in the heat preservation process, wherein the thickness of the covering agent is 8-10 mm;
7. after the temperature of the alloy liquid is proper, transferring the alloy liquid, removing a covering agent on the liquid surface by using a tool before transferring, transferring the alloy liquid into a pouring ladle, and when the alloy liquid is transferred by 20-30%, adding an inoculant (0.25-0.40% of ferrosilicon, 0.20-0.40% of silicon-aluminum and 0.20-0.40% of silicon-barium) and a vermiculizer into the pouring ladle, wherein the alloy liquid cannot be transferred in the process of adding;
8. measuring the temperature of molten iron in a pouring ladle, controlling the pouring temperature to be 1360 +/-10 ℃, controlling the pouring time to be within 3-8 seconds, starting a motor to enable the casting mould to vibrate in a micro mode, wherein the vibration frequency is 80HZ, stopping a vibrating machine within 10-20 seconds after casting pouring is finished, breaking formed graphite in the casting by means of vibration, and refining the length of the graphite.
As can be seen from the attached drawings 1 and 2, the graphite size in the vermicular cast iron produced by using the all scrap steel smelting and physical vibration technology is smaller, and after the vermicular cast iron material smelted and poured by the method is sampled and tested, the tensile strength is more than or equal to 450MPa, the hardness is 210-250MPa, the elongation after fracture is more than or equal to 1.5%, the vermicular rate is more than or equal to 75%, and the pearlite rate is more than or equal to 75%.
Claims (5)
1. A preparation method for graphite refinement of vermicular graphite cast iron is characterized by comprising the following steps:
1) adding 30% of waste steel materials into a medium-frequency induction furnace, completely melting, adding a graphite carburant according to 2-3% of the weight of molten steel, stirring for 1-2min, immediately adding 50% of waste steel materials, and then continuously melting;
2) after the added waste steel materials are completely melted, adding a graphite carburant according to 2-3% of the weight of the molten steel, stirring for 1-2min, and immediately adding the rest 20% of the waste steel materials;
3) after all the waste steel materials are melted, keeping the temperature of molten iron at 1350-;
4) raising the temperature of the molten steel to 1400 ℃ and 1500 ℃, and sequentially adding 0.4-0.8% of pure nickel, 0.65-0.85% of pure copper, 0.65-0.85% of ferromolybdenum, 0.5-0.9% of ferromanganese and 2.0-3.5% of silicon crystal; after the added alloy is completely melted, adding a deslagging agent to remove slag, covering the whole liquid level with the deslagging agent, waiting for 2-3 minutes, and removing scum on the surface of the alloy liquid;
5) preserving heat at the temperature of 1400 ℃ and 1500 ℃, and scattering a layer of covering agent on the surface of the alloy liquid in the heat preservation process, wherein the thickness of the covering agent is 8-10 mm;
6) after the temperature of the alloy liquid is proper, transferring the alloy liquid, removing a covering agent on the liquid surface by using a tool before transferring, transferring the alloy liquid into a pouring ladle, and when the alloy liquid is transferred by 20-30%, adding an inoculant (0.25-0.40% of ferrosilicon, 0.20-0.40% of silicon-aluminum and 0.20-0.40% of silicon-barium) and a vermiculizer into the pouring ladle, wherein the alloy liquid cannot be transferred in the process of adding;
7) measuring the temperature of molten iron in a pouring ladle, controlling the pouring temperature to be 1360 +/-10 ℃, starting a motor within 3-8 seconds, carrying out micro-vibration on the casting mould, stopping a vibrating machine within 10-20 seconds after the casting is poured, breaking formed graphite in the casting by means of vibration, and refining the length of the graphite.
2. The method for preparing graphite refining vermicular cast iron according to claim 1, wherein 0.05-0.1% of ferrous sulfide is added after the scrap steel in the step 1) is completely melted, so that the sulfur content is controlled to be 0.02-0.04%, the vermicular range is enlarged, and the vermicular rate is accurately controlled.
3. The method for preparing graphite refined vermicular cast iron according to claim 1, wherein in the step 2), after the scrap steel is completely melted, the temperature of molten iron is raised to 1480-1500 ℃, and 0.2-0.8% ferrotitanium is added for reverse spheroidization, so that the vermicular rate is improved, and the graphite is refined.
4. The preparation method for graphite refining of vermicular cast iron as claimed in claim 1, wherein after the furnace burden is melted in step 4), molten iron refining is carried out at 1530-1550 ℃ for 3-5 minutes, so as to increase graphite crystal nuclei and refine graphite.
5. The method for preparing compacted vermicular cast iron graphite according to claim 1, wherein the vibration frequency of the micro vibration in the step 7) is set to be 80 Hz.
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|---|---|---|---|
| CN202111072183.4A CN113832382A (en) | 2021-09-14 | 2021-09-14 | Preparation method for graphite refining of vermicular graphite cast iron |
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| CN202111072183.4A CN113832382A (en) | 2021-09-14 | 2021-09-14 | Preparation method for graphite refining of vermicular graphite cast iron |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114990419A (en) * | 2022-06-22 | 2022-09-02 | 吉林省诚鼎精密铸造有限公司 | Method for smelting cast iron from scrap steel |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105483508A (en) * | 2014-09-29 | 2016-04-13 | 常州朗锐铸造有限公司 | Alloy vermicular graphite cast iron for railway vehicle brake disc and smelting method of alloy vermicular graphite cast iron |
| CN110904381A (en) * | 2019-12-30 | 2020-03-24 | 江西久旺汽车配件制造有限公司 | Vermicular graphite cast iron material and preparation method and application thereof |
-
2021
- 2021-09-14 CN CN202111072183.4A patent/CN113832382A/en active Pending
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105483508A (en) * | 2014-09-29 | 2016-04-13 | 常州朗锐铸造有限公司 | Alloy vermicular graphite cast iron for railway vehicle brake disc and smelting method of alloy vermicular graphite cast iron |
| CN110904381A (en) * | 2019-12-30 | 2020-03-24 | 江西久旺汽车配件制造有限公司 | Vermicular graphite cast iron material and preparation method and application thereof |
Non-Patent Citations (1)
| Title |
|---|
| 翟利民等: "振动场对铸造合金凝固结晶的影响", 《山西机械》 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114990419A (en) * | 2022-06-22 | 2022-09-02 | 吉林省诚鼎精密铸造有限公司 | Method for smelting cast iron from scrap steel |
| CN114990419B (en) * | 2022-06-22 | 2023-10-27 | 吉林省诚鼎精密铸造有限公司 | Method for smelting cast iron by using scrap steel |
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Application publication date: 20211224 |