CN105039834A - Melting process for low-temperature-resistant nodular cast iron - Google Patents
Melting process for low-temperature-resistant nodular cast iron Download PDFInfo
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- CN105039834A CN105039834A CN201510391933.2A CN201510391933A CN105039834A CN 105039834 A CN105039834 A CN 105039834A CN 201510391933 A CN201510391933 A CN 201510391933A CN 105039834 A CN105039834 A CN 105039834A
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- steel scrap
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Abstract
The invention discloses a melting process for low-temperature-resistant nodular cast iron. The melting process comprises the five procedures of melting, analysis and adjustment, standing for slagging-off, tapping iron nodulizing, and pouring and stream inoculation. Steel scrap is matched with graphitized petroleum coke carburants, so that grain refining is facilitated, and the performance of products is improved. Pre-furnace inoculation is matched with stream inoculation, so that the nodulization degree of castings is high, and the performance of finished products is improved.
Description
[technical field]
The present invention relates to the technical field of casting, the technical field of particularly spheroidal graphite cast iron casting.
[background technology]
Spheroidal graphite cast iron obtains globular graphite by nodularization and inoculation, effectively improves the mechanical property of cast iron, in particular improve plasticity and toughness, thus obtain the intensity also higher than carbon steel.Spheroidal graphite cast iron is 20th century a kind of meehanite cast iron materials of growing up of the fifties, and its over-all properties, close to steel, just based on the performance of its excellence, has been successfully used to cast some stressed complexity, and intensity, toughness, wear resistance require higher part.The lower temperature resistance of common spheroidal graphite cast iron is inadequate, can not effectively use at low ambient temperatures.
[summary of the invention]
Object of the present invention solves the problems of the prior art exactly, proposes a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method, nodular iron casting can be made to have good lower temperature resistance.
For achieving the above object, the present invention proposes a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method, comprise melting, analysis and regulation, skim standing, tap a blast furnace spheroidizing and cast five step operations, operating process and the processing parameter of described five step operations are as follows:
(1) melting: add steel scrap 15-25%, greying refinery coke carburelant 1-3%, steel scrap 15-25%, pig iron 40-50%, foundry returns 10-20% while heated crucible in smelting furnace successively;
(2) analysis and regulation: melted temperature and got spectrum sample to during 1300-1350 DEG C, base iron composition is confirmed after drawing a design, when composition is with when requiring deviation > 0.1%, add the pig iron, steel scrap, greying refinery coke carburelant, foundry returns adjust composition;
(3) skim standing: temperature rises to more than 1500 DEG C, power return to zero, leave standstill carry out taking off Slag treatment;
(4) to tap a blast furnace spheroidizing: temperature is down to 1460-1480 DEG C, adds low rare-earth, Mg, Ca nodulizing agent 1.0-1.4% and carries out tapping a blast furnace spheroidizing; Add barium calcium nucleating agent 0.8-1.2% to carry out stokehold and breed,
(5) pour into a mould: when temperature is down to 1310-1350 DEG C, adds sulphur oxygen agent 0.1% and do current-following inoculation, cast.
As preferably, the described pig iron is high-purity pig iron, and high-purity pig iron satisfies condition Si≤0.5%, Mn≤0.2%, P≤0.04%, S≤0.02%, Ti≤0.035%.
As preferably, described steel scrap is soft steel, and soft steel satisfies condition Ti≤0.03%, other micro-summation≤0.1%.
As preferably, described component requirements is C3.4-4.0%, Si1.6-2.2%, Mn≤0.2%, P≤0.04%, S≤0.01%.
As preferably, steel scrap 25%, greying refinery coke carburelant 3%, steel scrap 20%, the pig iron 40%, foundry returns 12% is added successively in described fusion process, in spheroidizing process, the add-on of barium calcium nucleating agent is 1.2%, and in the spheroidizing process that taps a blast furnace, the add-on of low rare-earth, Mg, Ca nodulizing agent is 1.2%.
As preferably, steel scrap 15%, greying refinery coke carburelant 1%, steel scrap 15%, the pig iron 50%, foundry returns 19% is added successively in described fusion process, in spheroidizing process, the add-on of barium calcium nucleating agent is 1.0%, and in the spheroidizing process that taps a blast furnace, the add-on of low rare-earth, Mg, Ca nodulizing agent is 1.4%.
As preferably, described in water in process the sulphur oxygen nucleating agent adding 0.1% with molten iron stream.
Beneficial effect of the present invention: the present invention, by steel scrap being coordinated greying refinery coke carburelant, adds the agent of sulphur oxygen with stream during cast, is conducive to crystal grain thinning, enhances product performance; Cooperation current-following inoculation is bred in stokehold, and make the spheroidal graphite rate of foundry goods reach 2 grades, matrix ferrite content is greater than 95%, improves end properties.
Feature of the present invention and advantage will be described in detail by embodiment.
[embodiment]
Embodiment one:
A kind of low temperature resistant spheroidal graphite cast iron casting inoculation method of the present invention, comprise melting, analysis and regulation, leave standstill skim, tap a blast furnace spheroidizing and cast five step operations, operating process and the processing parameter of described five step operations are as follows:
(1) melting: add steel scrap 25%, greying refinery coke carburelant 3%, steel scrap 20%, the pig iron 40%, foundry returns 12% while heated crucible in smelting furnace successively;
(2) analysis and regulation: melted temperature and got spectrum sample to during 1300-1350 DEG C, base iron composition is confirmed after drawing a design, when composition is with when requiring deviation > 0.1%, add the pig iron, steel scrap, greying refinery coke carburelant, foundry returns adjust composition;
(3) skim standing: temperature rises to more than 1500 DEG C, power return to zero, leave standstill carry out taking off Slag treatment;
(4) to tap a blast furnace spheroidizing: temperature is down to 1460-1480 DEG C, adds low rare-earth, Mg, Ca nodulizing agent 1.2%, adds barium calcium nucleating agent 1.2% and carries out tapping a blast furnace spheroidizing;
(5) leave standstill skim: cast: when temperature is down to 1310-1350 DEG C, carries out pouring into a mould and add sulphur oxygen agent 0.1% and do current-following inoculation.
The described pig iron is high-purity pig iron, high-purity pig iron satisfies condition Si≤0.5%, Mn≤0.2%, P≤0.04%, S≤0.02%, Ti≤0.035%, described steel scrap is soft steel, soft steel satisfies condition Ti≤0.03%, other micro-summation≤0.1%, described component requirements is C3.4-4.0%, Si1.6-2.2%, Mn≤0.2%, P≤0.04%, S≤0.01%.
Embodiment two:
(1) melting: add steel scrap 15%, greying refinery coke carburelant 1%, steel scrap 15%, the pig iron 50%, foundry returns 19% while heated crucible in smelting furnace successively;
(2) analysis and regulation: melted temperature and got spectrum sample to during 1300-1350 DEG C, base iron composition is confirmed after drawing a design, when composition is with when requiring deviation > 0.1%, add the pig iron, steel scrap, greying refinery coke carburelant, foundry returns adjust composition;
(3) skim standing: temperature rises to more than 1500 DEG C, power return to zero, leave standstill carry out taking off Slag treatment;
(4) to tap a blast furnace spheroidizing: temperature is down to 1460-1480 DEG C, adds low rare-earth, Mg, Ca nodulizing agent 1.2%, adds barium calcium nucleating agent 1.0% and carries out tapping a blast furnace spheroidizing;
(5) leave standstill skim: cast: when temperature is down to 1310-1350 DEG C, adds sulphur oxygen agent 0.1% and do current-following inoculation, and pour into a mould.
Working process of the present invention:
A kind of low temperature resistant spheroidal graphite cast iron casting inoculation method of the present invention in the course of the work, reduce pig iron consumption, a large amount of use steel scrap coordinates greying refinery coke carburelant, because the fusing point of C, Si is higher than the temperature of iron liquid, mode mainly by diffusion dissolution enters iron liquid, and in iron liquid, there is the crystallite of a large amount of [C], this crystallite is the good external forming core substrate of eutectic graphite, be conducive to crystal grain thinning, enhance product performance; Cooperation current-following inoculation is bred in stokehold, can effectively form external crystal grain, add graphite nucleation ability, crystal grain thinning, adds the number of graphite and roundness, adds ferrite content, pregnant effect is good, makes the spheroidal graphite degree of foundry goods good, improves product intensity and low temperature impact properties.
Above-described embodiment is to explanation of the present invention, is not limitation of the invention, anyly all belongs to protection scope of the present invention to the scheme after simple transformation of the present invention.
Claims (7)
1. a low temperature resistant spheroidal graphite cast iron melting technology, is characterized in that: comprise melting, analysis and regulation, skim standing, tap a blast furnace spheroidizing and cast five step operations, operating process and the processing parameter of described five step operations are as follows:
(1) melting: add steel scrap 15-25%, greying refinery coke carburelant 1-3%, steel scrap 15-25%, pig iron 40-50%, foundry returns 10-20% while heated crucible in smelting furnace successively;
(2) analysis and regulation: melted temperature and got spectrum sample to during 1300-1350 DEG C, base iron composition is confirmed after drawing a design, when composition is with when requiring deviation > 0.1%, add the pig iron, steel scrap, greying refinery coke carburelant, foundry returns adjust composition;
(3) skim standing: temperature rises to more than 1500 DEG C, power return to zero, leave standstill and carry out process of skimming:
(4) to tap a blast furnace spheroidizing: temperature is down to 1460-1480 DEG C, add low rare-earth, Mg, Ca nodulizing agent 1.0-1.4% and add barium calcium nucleating agent 0.8-1.2% and carry out tapping a blast furnace spheroidizing;
(5) pour into a mould: when temperature is down to 1310-1350 DEG C, pour into a mould, add sulphur oxygen agent 0.1% and do current-following inoculation.
2. a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method as claimed in claim 1, is characterized in that: the described pig iron is high-purity pig iron, and high-purity pig iron satisfies condition Si≤0.5%, Mn≤0.2%, P≤0.04%, S≤0.02%, Ti≤0.035%.
3. a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method as claimed in claim 1, is characterized in that: described steel scrap is soft steel, and soft steel satisfies condition Ti≤0.03%, other micro-summation≤0.1%.
4. a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method as claimed in claim 1, is characterized in that: described component requirements is C3.4-4.0%, Si1.6-2.2%, Mn≤0.2%, P≤0.04%, S≤0.01%.
5. a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method as claimed in claim 1, it is characterized in that: in described fusion process, add pig iron steel scrap 25%, greying refinery coke carburelant 3%, steel scrap 20%, the pig iron 45%, foundry returns 12% successively, leave standstill and skim, in the spheroidizing process that taps a blast furnace, the add-on of low rare-earth, Mg, Ca nodulizing agent is 1.2%.The add-on of barium calcium nucleating agent is 1.2%.
6. a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method as claimed in claim 1, it is characterized in that: in described fusion process, add steel scrap 15%, greying refinery coke carburelant 1%, steel scrap 15%, the pig iron 50%, foundry returns 19% successively, leave standstill and skim, the add-on of low rare-earth, Mg, Ca nodulizing agent in spheroidizing process of tapping a blast furnace is 1.4%, and the add-on of barium calcium nucleating agent is 1.0%.
7. a kind of low temperature resistant spheroidal graphite cast iron casting inoculation method as claimed in claim 1, is characterized in that: described in water in process the sulphur oxygen nucleating agent adding 0.1% with molten iron stream.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
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| CN201510391933.2A CN105039834A (en) | 2015-07-01 | 2015-07-01 | Melting process for low-temperature-resistant nodular cast iron |
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| CN201510391933.2A CN105039834A (en) | 2015-07-01 | 2015-07-01 | Melting process for low-temperature-resistant nodular cast iron |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105543634A (en) * | 2015-12-21 | 2016-05-04 | 肖宇哲 | Process for preparing nodular cast iron by using carbon steel for recarburization |
| CN107387854A (en) * | 2017-07-14 | 2017-11-24 | 常熟市虞菱机械有限责任公司 | A kind of part of revolving valves manual driving device the operating mode suitable for lower temperature |
| CN113913584A (en) * | 2021-10-09 | 2022-01-11 | 临清市金光机械制造有限公司 | Method for eliminating casting shrinkage cavity defect by using petroleum coke recarburizing agent |
-
2015
- 2015-07-01 CN CN201510391933.2A patent/CN105039834A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105543634A (en) * | 2015-12-21 | 2016-05-04 | 肖宇哲 | Process for preparing nodular cast iron by using carbon steel for recarburization |
| CN107387854A (en) * | 2017-07-14 | 2017-11-24 | 常熟市虞菱机械有限责任公司 | A kind of part of revolving valves manual driving device the operating mode suitable for lower temperature |
| CN113913584A (en) * | 2021-10-09 | 2022-01-11 | 临清市金光机械制造有限公司 | Method for eliminating casting shrinkage cavity defect by using petroleum coke recarburizing agent |
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Application publication date: 20151111 |