CN115522136B - Method for controlling carbon manganese steel crystal structure through rare earth lanthanum iron microalloying - Google Patents
Method for controlling carbon manganese steel crystal structure through rare earth lanthanum iron microalloying Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/12—Ferrous alloys, e.g. steel alloys containing tungsten, tantalum, molybdenum, vanadium, or niobium
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0006—Adding metallic additives
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/0075—Treating in a ladle furnace, e.g. up-/reheating of molten steel within the ladle
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/06—Deoxidising, e.g. killing
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/04—Removing impurities by adding a treating agent
- C21C7/064—Dephosphorising; Desulfurising
- C21C7/0645—Agents used for dephosphorising or desulfurising
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- 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
- C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
- C21C7/10—Handling in a vacuum
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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
- C22C33/04—Making ferrous alloys by melting
- C22C33/06—Making ferrous alloys by melting using master alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
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- 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
Abstract
The invention discloses a method for controlling carbon-manganese steel crystal structure through rare earth lanthanum-iron microalloying, when the oxygen and sulfur content in steel is low, adding a proper amount of rare earth alloy, forming rare earth inclusion particles with high melting point and dispersion distribution for rare earth lanthanum deoxidation and desulfurization, wherein the rare earth inclusion particles are used as heterogeneous nucleation cores to refine grains, and on the other hand, the resistance of grain boundaries to dislocation can be improved, and the strength and toughness of steel are improved.
Description
Technical Field
The invention relates to the technical field of steelmaking technology, in particular to a method for controlling a carbon-manganese steel crystal structure through rare earth lanthanum-iron microalloying.
Background
The rare earth alloy is added in trace quantity to form a rare earth deoxidization desulfurization product La with high melting point dispersion distribution, wherein rare earth alloy is used for carrying out segregation or other elements on a grain boundary to cause the change of the structure, the components and the energy of the grain boundary, and also influence the diffusion of certain elements and the nucleation and growth of new phases at the same time, thereby further causing the change of the structure and the performance of steel 2 O 3 、La 2 S 3 、La 2 O 2 S、LaAlO 3 The method has the advantages that the method has smaller lattice mismatch degree with ferrite, creates conditions for effective nucleation of the intra-crystal acicular ferrite, and can effectively prevent cracks from propagating in metal due to the fact that the method has a promoting effect on the nucleation of the acicular ferrite, so that the crack in the metal can be effectively prevented from generating, grains are thinned, and the toughness of steel is improved.
The invention relates to a method for controlling carbon manganese steel crystal structure by rare earth lanthanum iron microalloying, which strictly controls sulfur in each procedure, adopts rare earth lanthanum iron microalloying to treat molten steel in the middle of refining, and adds rare earth + -lanthanum iron alloy into steel to form rare earth deoxidized desulfurization product La with high melting point and dispersed distribution 2 O 3 、La( 2 S 3 、La 2 O 2 S、LaAlO 3 The method has the advantages that the method has smaller lattice mismatch degree with ferrite, creates conditions for effective nucleation of the acicular ferrite in the crystal, and can effectively prevent cracks from propagating in metal due to the fact that the acicular ferrite in the crystal has a promotion effect on the nucleation of the acicular ferrite, thereby inhibiting the generation of cracks in the crystal, refining grains and improving the toughness of steel.
Document 1: a rare earth Ce modified high-strength soluble aluminum alloy and a smelting process thereof are provided, wherein rare earth Ce modified high-strength soluble aluminum alloy and a smelting process thereof are provided, rare earth element Ce is added in the smelting process, and the best smelting parameters are adopted, so that the as-cast grains of the soluble aluminum alloy are refined while the controllable dissolution rate is ensured, and the prepared soluble aluminum alloy material has good mechanical properties and good dissolution performance, and the as-cast grains of the soluble aluminum alloy are effectively refined.
Document 2: the tissue refinement and preparation method of hypereutectic aluminum-iron alloy comprises the following steps: the technological key of the method is that under the ordinary casting condition, when hypereutectic Al-Fe base alloy liquid is pre-treated, a trace amount of compound rare earth modifier is added for modification treatment, so that the primary iron-rich phase of the alloy is changed into fine particles from coarse needle-like shapes, and the particle size of the primary iron-rich phase can reach below 2 mu m. The mechanical property and the wear resistance of the alloy are improved, and the high temperature resistance of the alloy system is fully exerted.
Document 3: a method for refining solidification structure of 800H corrosion resistant alloy cast ingot: the method aims to solve the problem of coarse solidification structure of alloy cast ingot, and comprises the links of melting, deoxidizing alloying, refining, casting and the like of alloy, and is characterized in that the alloy is melted according to chemical components under protective atmosphere, and the temperature is kept for 3min, and the components and the temperature are uniform; adding a proper amount of aluminum wires for deoxidization, refining for 5min, controlling the oxygen content in the melt to be 60-l00ppm and controlling the temperature to be 1500 ℃ of soil; then adding 100-300ppm of rare earth Ce, la, Y and other refiners, refining for 1-2min, cooling the melt, and casting the melt into a metal casting mould when the temperature is reduced to 1430-1440 ℃, thus obtaining the ingot casting tissue with fine solidification structure.
Disclosure of Invention
The invention aims to provide a method for controlling a carbon-manganese steel crystal structure through rare earth lanthanum-iron microalloying, when the oxygen and sulfur content in steel is low, a proper amount of rare earth alloy is added, and high-melting-point dispersed rare earth lanthanum deoxidized and desulfurated rare earth inclusion particles are formed, wherein the rare earth inclusion particles serve as heterogeneous nucleation cores to refine grains on one hand, and on the other hand, the resistance of grain boundaries to dislocation can be improved, and the strength and toughness of the steel are improved.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention discloses a method for controlling a carbon-manganese steel crystal structure through rare earth lanthanum-iron microalloying, which comprises the following steps:
the first step: the main components of the microalloyed structural steel are as follows: c is less than or equal to 0.25 percent, si is less than or equal to 0.15 percent, mn is less than or equal to 1.60 percent, nb+V+Ti is less than or equal to 0.15 percent, and the contents of phosphorus and sulfur and harmful elements meet the national standard requirements of steel grades;
and a second step of: the technological process for producing the low-carbon manganese steel by the 260 ton refining furnace comprises the following steps: the technological route of KR molten iron pretreatment-BOF top-bottom combined blowing converter-LF external refining-RH vacuum refining-CCM slab continuous casting is that the molten iron w S of the converter is less than or equal to 0.005%, the tapping temperature of the converter is 1640+/-20 ℃, the w S of the final molten steel is less than 0.025%, slag is blocked, and white ash is added for tapping;
and a third step of: carrying out rapid slagging operation by using 5kg/t lime and 0.5-5kg/t slag melting agent, deoxidizing aluminum particles or aluminum ingots, and ensuring that LF dislocation wS is less than or equal to 0.005% by adding 0.5-1.5 kg/t;
fourth step: the LF refining treatment is finished, the calcium treatment is carried out, the alkalinity is controlled to be R, feO+MnO is controlled to be less than 1.0% at 4.5-9.0%;
fifth step: the rare earth lanthanum alloy comprises the following components: the content of rare earth lanthanum is more than or equal to 5 percent, the other rare earth elements are iron, and the total content of impurity elements is less than or equal to 1 percent;
sixth step: adding rare earth lanthanum alloy at the end of RH vacuum treatment, wherein 0.5-5kg/t rare earth alloy is added into molten steel, the circulation time is more than or equal to 4min, the argon blowing mode with weak stirring and small flow is adopted after air breaking and pressure recovery, the soft blowing time is more than or equal to 8min, and the sufficient denaturation and floating time of inclusions are ensured;
seventh step: the whole casting process protects casting and prevents flocculation caused by secondary oxidation.
Compared with the prior art, the invention has the beneficial technical effects that:
the invention uses high-melting point dispersed fine rare earth deoxidization and desulfurization product La 2 O 3 、La 2 S 3 、La 2 O 2 S、 LaAlO 3 And precipitated phase particles thereof, wherein ferrite is induced to nucleate on the surface of the ferrite in the process of transforming austenite to ferrite, so that the ferrite is precipitated in the austenite crystal grains to form a disordered and interlocked needle-shaped structure, and meanwhile; the method has the advantages that the method has smaller lattice mismatch degree with ferrite, creates conditions for effective nucleation of the intra-crystal acicular ferrite, and can effectively prevent cracks from propagating in metal due to the fact that the method has a promoting effect on the nucleation of the acicular ferrite, so that the crack in the metal can be effectively prevented from generating, grains are thinned, and the toughness of steel is improved.
The finished product structure is shown in fig. 1 and 2, the finished product structure of the rare earth lanthanum-iron alloy is disordered in fig. 1, small grains are gathered around large grains, and the finished product structure is formed into a disordered and interlocked needle-shaped structure after the rare earth lanthanum-iron alloy is added in fig. 2, so that cracks are effectively prevented from propagating in metal, the generation of intra-crystal cracks is inhibited, the grains are refined, the structure is more uniform, and the toughness of steel is improved.
Drawings
The invention is further described with reference to the following description of the drawings.
FIG. 1 is a finished structure without added rare earth alloy;
fig. 2 is a finished structure with rare earth alloy additions.
Detailed Description
A method for controlling the crystal structure of carbon-manganese steel through rare earth lanthanum-iron microalloying, which comprises the following steps:
the first step: the main components of the microalloyed structural steel are as follows: c is less than or equal to 0.25%, si is less than or equal to 0.15%, mn is less than or equal to 1.60%, nb+V+Ti is less than or equal to 0.15%, and the contents of phosphorus and sulfur and harmful elements meet the national standard requirements of steel grades.
The first step: the technological process for producing the low-carbon manganese steel by the 260 ton refining furnace comprises the following steps: the technological process of KR molten iron pretreatment-BOF top-bottom combined blown converter-LF external refining-RH vacuum refining-CCM plate blank continuous casting includes entering molten iron wS less than or equal to 0.005% in converter, tapping temp. of converter being 1640 + -20 deg.C, w S less than 0.025% in final molten steel, stopping slag and adding white ash to make tapping.
And a second step of: the fast slag forming operation is carried out by using lime 5kg/t and slag melting agent 0.5-5kg/t, aluminum particles or aluminum ingots are deoxidized, the addition amount is 0.5-1.5kg/t, and the LF dislocation wS is ensured to be less than or equal to 0.005%.
And a third step of: and after LF refining treatment, performing calcium treatment, wherein the alkalinity is controlled to be 4.5-9.0% and FeO+MnO is less than 1.0%.
Fourth step: the rare earth lanthanum alloy comprises the following components: the content of rare earth lanthanum is more than or equal to 5 percent, the other elements except rare earth simple substances are iron, and the total content of impurity elements is less than or equal to 1 percent.
Fourth step: rare earth lanthanum alloy is added at the end of RH vacuum treatment, 0.5-5kg/t rare earth alloy is added in molten steel, the circulation time is more than or equal to 4min, a weak stirring and small flow argon blowing mode is adopted after air breaking and pressure recovery, the soft blowing time is more than or equal to 8min, and the sufficient denaturation and floating time of inclusions are ensured.
Fifth step: the whole casting process protects casting and prevents flocculation caused by secondary oxidation.
The finished product structure is shown in fig. 1 and 2, the finished product structure of the rare earth lanthanum-iron alloy is disordered in fig. 1, small grains are gathered around large grains, and the finished product structure is formed into a disordered and interlocked needle-shaped structure after the rare earth lanthanum-iron alloy is added in fig. 2, so that cracks are effectively prevented from propagating in metal, the generation of intra-crystal cracks is inhibited, the grains are refined, the structure is more uniform, and the toughness of steel is improved.
The above embodiments are only illustrative of the preferred embodiments of the present invention and are not intended to limit the scope of the present invention, and various modifications and improvements made by those skilled in the art to the technical solutions of the present invention should fall within the protection scope defined by the claims of the present invention without departing from the design spirit of the present invention.
Claims (1)
1. A method for controlling carbon-manganese steel crystal structure through rare earth lanthanum-iron microalloying is characterized by comprising the following steps: the method comprises the following steps:
the first step: the main components of the microalloyed structural steel are as follows: c is less than or equal to 0.25 percent, si is less than or equal to 0.15 percent, mn is less than or equal to 1.60 percent, nb+V+Ti is less than or equal to 0.15 percent, and the contents of phosphorus and sulfur and harmful elements meet the national standard requirements of steel grades;
and a second step of: the technological process for producing the low-carbon manganese steel by the 260 ton refining furnace comprises the following steps: the technological route of KR molten iron pretreatment-BOF top-bottom combined blowing converter-LF external refining-RH vacuum refining-CCM slab continuous casting is that the molten iron w S of the converter is less than or equal to 0.005%, the tapping temperature of the converter is 1640+/-20 ℃, the w S of the final molten steel is less than 0.025%, slag is blocked, and white ash is added for tapping;
and a third step of: carrying out rapid slagging operation by using 5kg/t lime and 0.5-5kg/t slag melting agent, deoxidizing aluminum particles or aluminum ingots, and ensuring that LF dislocation wS is less than or equal to 0.005% by adding 0.5-1.5 kg/t;
fourth step: the LF refining treatment is finished, and the calcium treatment is carried out, wherein the alkalinity is controlled to be R between 4.5 and 9.0, and FeO+MnO is less than 1.0 percent;
fifth step: the rare earth lanthanum alloy comprises the following components: the content of rare earth lanthanum is more than or equal to 5 percent, the other rare earth elements are iron, and the total content of impurity elements is less than or equal to 1 percent;
sixth step: adding rare earth lanthanum alloy at the end of RH vacuum treatment, wherein 0.5-5kg/t rare earth alloy is added into molten steel, the circulation time is more than or equal to 4min, the argon blowing mode with weak stirring and small flow is adopted after air breaking and pressure recovery, the soft blowing time is more than or equal to 8min, and the sufficient denaturation and floating time of inclusions are ensured;
seventh step: the whole casting process of continuous casting protects casting and prevents flocculation flow caused by secondary oxidation;
the finished tissue forms a disordered interlocking needle-like tissue.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102732685A (en) * | 2012-06-20 | 2012-10-17 | 内蒙古包钢钢联股份有限公司 | Method for adding rare earth into RH refining furnace |
| CN106521293A (en) * | 2016-08-04 | 2017-03-22 | 中国科学院金属研究所 | Method for adding rare earth metal into steel to improve performance |
| CN110129508A (en) * | 2019-05-23 | 2019-08-16 | 包头钢铁（集团）有限责任公司 | A kind of technique improving rare earth high-strength steel impact flexibility |
| WO2019169548A1 (en) * | 2018-03-06 | 2019-09-12 | 高海艇 | Low-strength cast steel micro-alloyed with rare earth |
| CN114716256A (en) * | 2022-03-11 | 2022-07-08 | 钢铁研究总院有限公司 | Refractory material for smelting rare earth steel and method for improving rare earth yield |
| CN114774628A (en) * | 2022-04-20 | 2022-07-22 | 包头钢铁（集团）有限责任公司 | Key production method for processing steel for C-Mn low-temperature container by rare earth Ce or La microalloy |
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- 2022-09-20 CN CN202211145603.1A patent/CN115522136B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102732685A (en) * | 2012-06-20 | 2012-10-17 | 内蒙古包钢钢联股份有限公司 | Method for adding rare earth into RH refining furnace |
| CN106521293A (en) * | 2016-08-04 | 2017-03-22 | 中国科学院金属研究所 | Method for adding rare earth metal into steel to improve performance |
| WO2019169548A1 (en) * | 2018-03-06 | 2019-09-12 | 高海艇 | Low-strength cast steel micro-alloyed with rare earth |
| CN110129508A (en) * | 2019-05-23 | 2019-08-16 | 包头钢铁（集团）有限责任公司 | A kind of technique improving rare earth high-strength steel impact flexibility |
| CN114716256A (en) * | 2022-03-11 | 2022-07-08 | 钢铁研究总院有限公司 | Refractory material for smelting rare earth steel and method for improving rare earth yield |
| CN114774628A (en) * | 2022-04-20 | 2022-07-22 | 包头钢铁（集团）有限责任公司 | Key production method for processing steel for C-Mn low-temperature container by rare earth Ce or La microalloy |
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