Disclosure of Invention
In order to solve the technical problem of high manganese steel continuous casting bleed-out for a low-temperature container, the invention provides a process for effectively controlling high manganese steel slab continuous casting bleed-out, which can effectively control the problem of high manganese steel continuous casting bleed-out for the low-temperature container, so that a slab shell is uniformly cooled, the thickness of the slab shell is increased, and the occurrence of the bleed-out accident is avoided.
The invention is realized by the following technical scheme:
the application provides a process for effectively controlling continuous casting bleed-out of a high-manganese steel slab, which comprises the following steps:
controlling the back taper coefficient of a narrow-face copper plate of the continuous casting crystallizer to be 1.5-1.9%/m;
injecting molten steel of high manganese steel into the continuous casting crystallizer for continuous casting, wherein the binary alkalinity (CaO/SiO) of the covering slag of the continuous casting crystallizer2) 0.75-0.95, and a melting point of 880-950 ℃;
and controlling the continuous casting drawing speed to obtain the high-manganese steel plate blank.
Optionally, the chemical components of the mold flux comprise, by mass:
Cao:24-25.6%、SiO2:27-32%、Al2O3:4.0-6.0%、Fe2O3:0.3-0.8%、MgO:3.2-5.3%、MnO:4-7%、K2O:0.2-0.55%、NaO:6.5-9.8%、F:6.1-9.5%、Li2O:1-3.6%、C: 6.2 to 8.5 percent of the total weight of the alloy and less than or equal to 1 percent of other impurity elements.
Optionally, the continuous casting speed is 0.5-0.75 m/min.
Optionally, the average steel passing amount of the continuous casting is 1.4-2.4 t/min.
Optionally, the width of the plate blank is 1600-1800 mm, and the thickness of the plate blank is 230-300 mm.
Optionally, the manganese content in the high manganese steel is 20-25%.
Optionally, in the continuous casting, the thickness of the blank shell is more than or equal to 10 mm.
One or more technical schemes in the invention at least have the following technical effects or advantages:
1. the invention relates to a process for effectively controlling continuous casting breakout of a high-manganese steel slab, which controls the back taper coefficient of a narrow-face copper plate of a continuous casting crystallizer to be 1.5-1.9%/m, adopts low-alkalinity continuous casting protective slag with binary alkalinity of 0.75-0.95 and melting point of 880 plus materials at 950 ℃, and is matched with a lower continuous casting pulling speed to ensure that a slab shell is uniformly cooled and the thickness is increased in the continuous casting process, thereby avoiding breakout accidents.
2. The invention relates to a process for effectively controlling continuous casting breakout of a high manganese steel plate blank, wherein the back taper coefficient is controlled to be 1.5-1.9%/m, because the shrinkage coefficient of the high manganese steel plate blank for a low-temperature container in the continuous casting process is large, the back taper coefficient larger than that of conventional carbon steel is needed to ensure the close attachment of a copper plate and a casting blank, if the back taper is too small, breakout is easily caused, and if the back taper is too large, the blank shell is stressed too large to cause defects, and the crystallizer casting powder adopts binary alkalinity (Ca 0/SiO)2) The high manganese steel casting powder is 0.75-0.95, the melting point is 880-950 ℃, and the low-alkalinity and low-viscosity covering slag is obtained, because the high manganese steel for the low-temperature container has a small heat conductivity coefficient, the covering slag with strong heat transfer capability and full glass phase needs to be adopted to ensure heat transfer and lubrication, and in addition, the liquidus temperature of the high manganese steel is very low, and the covering slag with lower melting point needs to be used to meet the requirement of covering slag melting in the continuous casting process.
The foregoing description is only an overview of the technical solutions of the present invention, and the embodiments of the present invention are described below in order to make the technical means of the present invention more clearly understood and to make the above and other objects, features, and advantages of the present invention more clearly understandable.
Detailed Description
The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are for the purpose of illustrating the invention and are not to be construed as limiting the invention.
Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.
Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.
It should be further noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
In order to solve the technical problems, the general idea is as follows:
the applicant finds that the reason for the occurrence of bleed-out in the existing continuous casting process of the high manganese steel for the low-temperature container is mainly as follows: 1) because the manganese content is high, the liquidus temperature of the high manganese steel is low, which is about 100 ℃ lower than that of plain carbon steel, and therefore, the melting point of the mold flux is required to be sufficiently low and the melting speed is required to be fast. 2) The increase of the manganese content leads to the reduction of the heat conductivity coefficient of the steel grade, which is about 1/5-1/4 of the traditional carbon steel, so that the mold flux is required to have a very good heat transfer function and very good lubricity; the reduction of heat transfer leads to the thinning of the casting blank shell, and the safety thickness of the casting blank shell out of the crystallizer requires more than 10mm, so the high manganese steel plate blank is produced at a low drawing speed. 3) The high manganese steel for the low-temperature container is fully austenitic steel, the solid-liquid shrinkage effect is far greater than that of plain carbon steel although no phase change shrinkage exists in the high-temperature continuous casting process, the inverted taper of a crystallizer copper plate needs to be increased and is tightly attached to a growing blank shell, steel leakage is easily caused if the taper is too small, the high-temperature strength of the high manganese steel is very low, the surface crack defect is easily caused in the cooling process of a continuous casting crystallizer, and the stress rationality of a casting blank is ensured while the heat transfer uniformity and the lubricating property of the casting blank need to be controlled.
According to an exemplary embodiment of the present invention, there is provided a process for effectively controlling continuous casting breakout of a high manganese steel slab, as shown in fig. 1, the process including:
s1, controlling the back taper coefficient of a narrow-face copper plate of a continuous casting crystallizer to be 1.5-1.9%/m;
s2, injecting molten steel of high manganese steel into the continuous casting crystallizer for continuous casting, wherein the binary alkalinity (CaO/SiO) of the covering slag of the continuous casting crystallizer2) 0.75-0.95, and a melting point of 880-950 ℃;
and S3, controlling the continuous casting drawing speed to obtain a high-manganese steel plate blank.
In the invention, the back taper coefficient of the narrow-face copper plate of the continuous casting crystallizer is controlled to be 1.5-1.9%/m, low-alkalinity continuous casting covering slag with binary alkalinity of 0.75-0.95 and melting point of 880-950 ℃ is adopted, and the lower continuous casting pulling speed is matched, so that the blank shell is uniformly cooled and the thickness is increased in the continuous casting process, and the occurrence of steel leakage accidents is avoided.
According to the invention, the back taper coefficient is controlled to be 1.5-1.9%/m, because the shrinkage coefficient is large in the continuous casting process of the high manganese steel plate blank for the low-temperature container, the back taper coefficient which is larger than that of conventional carbon steel is needed to ensure that the copper plate and the casting blank are tightly attached, steel leakage is easily caused if the back taper is too small, and the blank shell is stressed too much to cause defects if the back taper is too large. The crystallizer covering slag adopts binary alkalinity (CaO/SiO)2) The high manganese steel casting powder is 0.75-0.95, the melting point is 880-950 ℃, and the low-alkalinity and low-viscosity covering slag is obtained, because the high manganese steel for the low-temperature container has a small heat conductivity coefficient, the covering slag with strong heat transfer capability and full glass phase needs to be adopted to ensure heat transfer and lubrication, and in addition, the liquidus temperature of the high manganese steel is very low, and the covering slag with lower melting point needs to be used to meet the requirement of covering slag melting in the continuous casting process.
As an optional embodiment, the chemical composition of the mold flux comprises, in mass fraction:
Gao:24-25.6%、SiO2:27-32%、Al2O3:4.0-6.0%、Fe2O3:0.3-0.8%、MgO:3.2-5.3%、MnO:4-7%、K20:0.2-0.55%、NaO:6.5-9.8%、F:6.1-9.5%、Li2o: 1-3.6%, C: 6.2 to 8.5 percent of the total weight of the alloy and less than or equal to 1 percent of other impurity elements.
In the application, the covering slag adopts the components, and the binary alkalinity (Ca0/Si 0) of the covering slag can be ensured2) 0.75-0.95, and a melting point of 880-950 ℃.
As an optional embodiment, the continuous casting speed is 0.5-0.75 m/min.
As an optional embodiment, the average steel passing amount of the continuous casting is 1.4-2.4 t/min.
In the application, the casting machine pulling speed is controlled to be 0.5-0.75 m/min, because the high manganese steel billet shell for the low-temperature container grows slowly, the crack sensitivity is strong, the steel is high in manganese strength and low in strength, the pulling speed needs to be low, and the unit steel passing amount in the continuous casting process is 1.4-2.4T/min.
As an optional implementation mode, the width of the plate blank is 1600-1800 mm, and the thickness of the plate blank is 230-300 mm.
As an optional implementation mode, the manganese content of the high manganese steel is 20-25%.
The process for effectively controlling the continuous casting bleed-out of the high-manganese steel slab is suitable for the high-manganese steel with the manganese content of 20-25%.
The process for effectively controlling the continuous casting bleed-out of the high manganese steel slab will be described in detail in the following by combining the examples, comparative examples and experimental data.
Example 1
The embodiment of the invention provides a process for effectively controlling continuous casting bleed-out of a high manganese steel slab, which is used for producing high manganese steel with the manganese content of 22%, and comprises the following steps:
(1) controlling the back taper coefficient of a narrow-face copper plate of the continuous casting crystallizer to be 1.5%/m;
(2) injecting molten steel of high manganese steel into the continuous casting crystallizer for continuous casting, wherein the binary alkalinity (CaO/SiO) of the covering slag of the continuous casting crystallizer2) 0.9, melting point 938 ℃;
the chemical components of the mold flux comprise the following components in percentage by mass:
Cao:24.3%、SiO2:28.5%、Al2O3:5.8%、Fe2O3:0.5%、MgO:5.2%、MnO:6.5%、K2O:0.3%、NaO:9.5%、F:9.3%、Li2O:1.9%、C:7.5%。
(3) and controlling the continuous casting drawing speed to be 0.73m/min, and the average steel passing amount to be 2.1t/min to obtain a 230mm 1600mm high manganese steel plate blank.
The high manganese steel casting blank of the embodiment has smooth and stable pouring process and no steel leakage accident.
Example 2
The embodiment of the invention provides a process for effectively controlling continuous casting bleed-out of a high manganese steel slab, which is used for producing high manganese steel with the manganese content of 24%, and comprises the following steps:
(1) controlling the back taper coefficient of a narrow-face copper plate of the continuous casting crystallizer to be 1.7%/m;
(2) injecting molten steel of high manganese steel into the continuous casting crystallizer for continuous casting, wherein the binary alkalinity (CaO/SiO) of the covering slag of the continuous casting crystallizer2) 0.8, and a melting point of 920 ℃;
the chemical components of the mold flux comprise the following components in percentage by mass:
Cao:24.8%、SiO2:31%、Al2O3:5.5%、Fe2O3:0.6%、MgO:4.3%、MnO:6%、K2O:0.43%、NaO:8.5%、F:9%、Li2O:2.3%、C:7%。
(3) and controlling the continuous casting drawing speed to be 0.6m/min, and the average steel passing amount to be 1.9t/min to obtain a 230mm 1800mm high manganese steel plate blank.
The high manganese steel casting blank of the embodiment has smooth and stable pouring process and no steel leakage accident.
Example 3
The embodiment of the invention provides a process for effectively controlling continuous casting bleed-out of a high manganese steel slab, which is used for producing high manganese steel with the manganese content of 25%, and comprises the following steps:
(1) controlling the back taper coefficient of a narrow-face copper plate of the continuous casting crystallizer to be 1.85%/m;
(2) injecting molten steel of high manganese steel into the continuous casting crystallizer for continuous casting, wherein the binary alkalinity (Ca 0/SiO) of the covering slag of the continuous casting crystallizer2) 0.75, melting point 900 ℃;
the chemical components of the mold flux comprise the following components in percentage by mass:
Cao:24%、SiO2:32%、Al2O3:4.8%、Fe2O3:0.5%、MgO:5.0%、MnO:6%、K2O:0.5%、NaO:9.2%、F:7.3%、Li2O:3.5%、C:7%。
(3) and controlling the continuous casting drawing speed to be 0.5m/min, and the average steel passing amount to be 2.3t/min to obtain the high-manganese steel plate blank with the blank shape of 300mm x 1800 mm.
The high manganese steel casting blank of the embodiment has smooth and stable pouring process and no steel leakage accident.
Comparative example 1
The comparative example is a high manganese steel plate blank continuous casting process for producing high manganese steel with the manganese content of 24 percent, and comprises the following steps:
(1) controlling the back taper coefficient of a narrow-face copper plate of the continuous casting crystallizer to be 1.35%/m;
(2) injecting molten steel of high manganese steel into the continuous casting crystallizer for continuous casting, wherein the binary alkalinity (Ca 0/SiO) of the covering slag of the continuous casting crystallizer2) 1.1, melting point 1050 ℃;
the chemical components of the mold flux comprise the following components in percentage by mass:
Cao:35.2%、SiO2:32%、Al2O3:1.8%、Fe2O3:0.6%、MgO:1.9%、MnO:2.5%、K2O:0.3%、NaO:9.5%、F:8.6%、Li2O:0.3%、C:7%。
(3) and controlling the continuous casting drawing speed to be 0.9m/min, and the average steel passing amount to be 2.9t/min to obtain a 230mm 1800mm high manganese steel plate blank.
In the pouring process of the high manganese steel casting blank, in the 8 th minute of pouring, a steel leakage accident occurs, and the steel leakage is caused by the extrusion stress at the foot roll position due to the fact that the blank shell of the crystallizer is too thin and grows unevenly through analysis.
As shown in fig. 2, in each of the examples and comparative examples of the present application, the calculation formula of the back taper coefficient of the narrow-face copper plate of the continuous casting mold is as follows:
T=(Wa-Wb)/Wa/H×100;
t: the coefficient of taper of the narrow face,%/m;
wa: the width of the upper opening of the wide surface of the crystallizer is mm;
wb: the width of the lower opening of the wide surface of the crystallizer is mm;
h: crystallizer length, m;
Tp=(Wa-Wb)。
one or more technical solutions in the present application at least have the following technical effects or advantages:
(1) according to the process for effectively controlling the continuous casting breakout of the high-manganese steel plate blank, the inverse taper coefficient of a narrow-face copper plate of a continuous casting crystallizer is controlled to be 1.5-1.9%/m, low-alkalinity continuous casting protective slag with binary alkalinity of 0.75-0.95 and a melting point of 880 plus materials of 950 ℃ is adopted, and the lower continuous casting pulling speed is matched, so that the blank shell is uniformly cooled and the thickness is increased in the continuous casting process, and the breakout accident is avoided.
(2) The utility model provides a process of effective control high manganese steel sheet billet continuous casting breakout, back taper coefficient control is at 1.5 ~ 1.9%/m, this is because the shrinkage factor is big among the low temperature container high manganese steel sheet billet continuous casting process, need guarantee the inseparable laminating of copper and casting blank with the back taper coefficient that is bigger than conventional carbon steel, if the back taper undersize causes the breakout easily, the back taper is too big then leads to the too big and production defect of blank shell atress. The crystallizer covering slag adopts binary alkalinity (CaO/SiO)2) The high manganese steel casting powder is 0.75-0.95, the melting point is 880-950 ℃, and the low-alkalinity and low-viscosity covering slag is obtained, because the high manganese steel for the low-temperature container has a small heat conductivity coefficient, the covering slag with strong heat transfer capability and full glass phase needs to be adopted to ensure heat transfer and lubrication, and in addition, the liquidus temperature of the high manganese steel is very low, and the covering slag with lower melting point needs to be used to meet the requirement of covering slag melting in the continuous casting process.
Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.