Summary of the invention
Object of the present invention will provide high-sulfur phosphorus high-strength steel continuously cast bloom production method for a kind of fractured connecting rod exactly, and the method is easy to control steel grades, has avoided Cracks In Continuous Cast Billets, and technique is simple, and production cost is low.
For achieving the above object, the technical solution used in the present invention is: high-sulfur phosphorus high-strength steel continuously cast bloom production method for a kind of fractured connecting rod, comprises the following steps:
1) electrosmelting: adopt molten iron and steel scrap to smelt as starting material, the weight ratio of molten iron and steel scrap is (6~8): 1, at initial smelting period, adopt and be rapidly heated decarburization and flow less slag operation; And control oxidation terminal temperature is: 1630~1650 ℃, end point carbon weight percent content is 0.30~0.40%, and terminal phosphorus weight percent content is 0.030~0.045%;
2) heart of the inclined to one side end of electric furnace tapping: tapping adopts stays steel remaining slag operation, tap and in ladle, add quickened lime 3.0~4.0kg/t, Iron sulfuret 2.0~2.5kg/t, aluminium block 1.0~1.5kg/t at 1/3 o'clock, and Si-Ca-Ba 2.0~2.5kg/t carries out deoxidation, increases sulphur and alloying; And to control steel oxygen content in water be 0~80ppm, sulphur weight percent content is 0.050~0.060%;
3) LF stove refining: adopt CaO-SiO
2-MgO low basicity slag system carries out refining, and refining slag basicity is 1.2~1.8; And utilize deoxidation material to carry out diffusive deoxidation, and controlling steel oxygen content in water is 0~20ppm, sulphur weight percent content is 0.040~0.050%;
4) continuous casting: continuous casting adopts full guard cast; in crystallisation process, adopt induction stirring and continuously cast bloom carried out weak but cold; can obtain phosphorus weight percent content is 0.030~0.050%, the high-strength steel continuously cast bloom of the motor car engine fractured connecting rod that sulphur weight percent content is 0.035~0.045%.
Further, described step 3) in, after entering refining furnace, molten steel adds magnesia 3.0~3.5kg/t, and quartz sand 3.0~3.5kg/t carries out slag making, and the main component of this refining slag and weight percent content thereof are: CaO:35~45%, SiO
2: 25~30%, Al
2o
3: 10~15%, MgO:15~20%, MnO:2~5%, CaF
2: 3~8%.
Further, described step 3) in, power transmission is fed aluminum steel 1.0~1.5m/t after 8~12 minutes, adopt silicon carbide, carbon dust, ferrosilicon powder simultaneously, with and calcium powder carry out diffusive deoxidation, deaeration time is 30~40min, and controlling carbon weight percent content is 0.4~0.6%, and adjusts sulphur content in steel with sulphur line.
Further, described step 3) in, before casting, molten steel is carried out to soft blow after molten steel composition adjustment completes, the soft blow time is 8~12min.
Further, described step 4) in, continuous casting of molten steel adopt large bag-long nozzle-tundish-crystallizer-strand two cold-strand aligning-cutting-retarded cooling process.
Further, described step 4) in, described conical degree of crystallizer is 0.8~0.95, and the crystallizer water yield is 1700~1800L/min, and crystallizer protecting residue basicity is 0.7~0.9; Crystallizer adopts induction stirring, and induction stirring electric current is 500~600A, and frequency is 3~4Hz.
Further, described step 4) in, described strand secondary cooling zone adopts four sections of types of cooling, and wherein, first paragraph and second segment adopt water-cooling pattern, and the 3rd section and the 4th section adopts the aerosol type of cooling, and secondary cooling water specific water is 0.25~0.28L/kg.
Further, described step 4) in, strand aligning adopts multi-point straightening mode, and entering straightening section temperature is 950~1000 ℃.
Further, described step 4) in, after entering cold bed, the continuously cast bloom after employing flame cutting hangs in rapidly burial pit, and to control strand and cut to hanging in burial pit time≤10min, it is 600~800 ℃ that strand enters burial pit temperature.
Further, described step 4) in, long nozzle and tundish adopt the protection of argon envelope, and argon seal pressure is 0.10~0.15MPa.
Compared with prior art, the present invention has the following advantages:
One, in earlier stage adopts and is rapidly heated decarburization and flows less slag operation at electrosmelting, when guaranteeing in molten steel phosphorus content, makes need not add ferrophosphorus in steel, has saved alloy.
Its two, in refining period, adopt CaO-SiO
2-MgO low basicity slag system has not only guaranteed the stable of sulphur composition but also has reduced the etch of ladle lining, and then makes S composition be easy to control, and the recovery rate of S is high.
They are three years old; continuous casting is poured into a mould by protection; induction stirring; and and the weak cold strand crackle that but reduced, guarantee to produce qualified phosphorous, sulphur high-strength steel continuously cast bloom, in continuously cast bloom, P stable content is controlled at 0.030~0.050%; sulphur content is stable is controlled at 0.035~0.045%; low power rank≤1.0 grade of strand, oxygen level≤20ppm, and cc billet surface quality is good.
Its four, the inventive method technique circuit is simple, workable, be easy to control, and production cost is low, has significantly saved the energy.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, be convenient to more clearly understand the present invention, but they do not form restriction to the present invention.Except as otherwise noted, the percentage ratio adopting in the present invention is weight percentage.
Embodiment 1:
Produce high-sulfur phosphorus high-strength steel continuously cast bloom for a kind of motor car engine fractured connecting rod, the production method step of this continuously cast bloom is as follows:
1) electrosmelting: adopt molten iron and steel scrap as starting material, the weight ratio of molten iron and steel scrap is 6:1; Be rapidly heated decarburization and flow less slag of initial smelting period, and control oxidation terminal temperature and be: 1630 ℃, endpoint carbon content is 0.30%, and end phosphorus content is 0.030%;
2) heart of the inclined to one side end of electric furnace tapping: tapping adopts and stays steel remaining slag operation, taps and adds quickened lime 4.0kg/t, Iron sulfuret 2.0kg/t at 1/3 o'clock in ladle, aluminium block 1.5kg/t, Si-Ca-Ba 2.5kg/t, controlling and entering oxygen level in follow-up LF refining furnace is 80ppm, sulphur content is 0.050%;
3) LF refining furnace: molten steel adds magnesia 3.0kg/t after entering refining furnace, quartz sand 3.0kg/t makes low basicity refining slag, and refining slag main component is: CaO:40%, SiO
2: 30%, Al
2o
3: 10%, MgO:15%, MnO:2%, CaF
2: 3%, refining slag basicity is 1.3; Power transmission is fed aluminum steel 1.5m/t after 10 minutes, adopt the deoxidation materials such as silicon carbide, carbon dust, ferrosilicon powder and silicon calcium powder to carry out diffusive deoxidation, and deaeration time is 40min, with sulphur line, adjusts sulphur content in steel, and while guaranteeing on bull ladle continuous casting platform, in steel, sulphur content is 0.040%; After composition and temperature adjustment complete, molten steel carries out soft blow, and the soft blow time is 8min;
4) continuous casting: continuous casting of molten steel adopt large bag-long nozzle-tundish-crystallizer-bis-cold-aligning-cutting-retarded cooling process, wherein, long nozzle and tundish adopt argon to seal and protect, argon seal pressure is 0.10MPa; Conical degree of crystallizer is 0.95, and the crystallizer water yield is 1800L/min, and crystallizer adopts induction stirring, and induction stirring electric current is 600A, and frequency is 3Hz, and the basicity of crystallizer protecting residue is 0.80, and fusing point is 1080 ℃; Strand secondary cooling zone adopts four sections of types of cooling, and wherein first and second section is water-cooling pattern, and third and fourth section is the aerosol type of cooling, and secondary cooling water specific water is 0.28L/kg; Strand aligning adopts multi-point straightening mode, and entering straightening section temperature is 950 ℃; After continuously cast bloom after employing flame cutting enters cold bed, hang in rapidly burial pit, it is 9min that strand has cut to hanging in the burial pit time, and strand enters 650 ℃ of burial pit temperature.
Chemical composition and the content thereof of gained continuously cast bloom are as follows: C:0.40%, and Si:0.70%, Mn:1.20%, P:0.030%, S:0.035, N:0.0160%, all the other are Fe, trace element and inevitable impurity; The low power of this continuously cast bloom, oxygen, phosphorus, and the control situation of sulphur sees the following form 1.
Embodiment 2:
Produce high-sulfur phosphorus high-strength steel continuously cast bloom for a kind of motor car engine fractured connecting rod, the production method step of this continuously cast bloom is as follows:
1) electrosmelting: adopt molten iron and steel scrap as starting material, the weight ratio of molten iron and steel scrap is 8:1; Be rapidly heated decarburization and flow less slag of initial smelting period, and control oxidation terminal temperature and be: 1645 ℃, endpoint carbon content is 0.35%, and end phosphorus content is 0.045%;
2) heart of the inclined to one side end of electric furnace tapping: tapping adopts and stays steel remaining slag operation, taps and adds quickened lime 3.0kg/t, Iron sulfuret 2.5kg/t at 1/3 o'clock in ladle, aluminium block 1.2kg/t, Si-Ca-Ba 2.3kg/t, controlling and entering oxygen level in follow-up LF refining furnace is 60ppm, sulphur content is 0.060%;
3) LF refining furnace: molten steel adds magnesia 3.5kg/t after entering refining furnace, quartz sand 3.5kg/t makes low basicity refining slag, and refining slag main component is: CaO:35%, SiO
2: 30%, Al
2o
3: 10%, MgO:20%, MnO:2%, CaF
2: 3%, refining slag basicity is 1.2; Power transmission is fed aluminum steel 1.0m/t after 10 minutes, adopt the deoxidation materials such as silicon carbide, carbon dust, ferrosilicon powder and silicon calcium powder to carry out diffusive deoxidation, and deaeration time is 35min, with sulphur line, adjusts sulphur content in steel, and while guaranteeing on bull ladle continuous casting platform, in steel, sulphur content is 0.050%; After composition and temperature adjustment complete, molten steel carries out soft blow, and the soft blow time is 12min;
4) continuous casting: continuous casting of molten steel adopt large bag-long nozzle-tundish-crystallizer-bis-cold-aligning-cutting-retarded cooling process, wherein, long nozzle and tundish adopt argon to seal and protect, argon seal pressure is 0.12MPa; Conical degree of crystallizer is 0.95, and the crystallizer water yield is 1750L/min, and crystallizer adopts induction stirring, and induction stirring electric current is 600A, and frequency is 3Hz, and the basicity of crystallizer protecting residue is 0.80, and fusing point is 1080 ℃; Strand secondary cooling zone adopts four sections of types of cooling, and wherein first and second section is water-cooling pattern, and third and fourth section is the aerosol type of cooling, and secondary cooling water specific water is 0.25L/kg; Strand aligning adopts multi-point straightening mode, and entering straightening section temperature is 980 ℃; After continuously cast bloom after employing flame cutting enters cold bed, hang in rapidly burial pit, it is 8min that strand has cut to hanging in the burial pit time, and strand enters 600 ℃ of burial pit temperature.
Chemical composition and the content thereof of gained continuously cast bloom are as follows: C:0.45%, and Si:0.60%, Mn:1.30%, P:0.050%, S:0.045, N:0.020%, all the other are Fe, trace element and inevitable impurity; The low power of this continuously cast bloom, oxygen, phosphorus, and the control situation of sulphur sees the following form 1.
Embodiment 3:
Produce high-sulfur phosphorus high-strength steel continuously cast bloom for a kind of motor car engine fractured connecting rod, the production method step of this continuously cast bloom is as follows:
1) electrosmelting: adopt molten iron and steel scrap as starting material, the weight ratio of molten iron and steel scrap is 8:1; Be rapidly heated decarburization and flow less slag of initial smelting period, and control oxidation terminal temperature and be: 1630 ℃, endpoint carbon content is 0.40%, and end phosphorus content is 0.042%;
2) heart of the inclined to one side end of electric furnace tapping: tapping adopts and stays steel remaining slag operation, taps and adds quickened lime 3.5kg/t, Iron sulfuret 2.2kg/t at 1/3 o'clock in ladle, aluminium block 1.2kg/t, Si-Ca-Ba 2.2kg/t, controlling and entering oxygen level in follow-up LF refining furnace is 70ppm, sulphur content is 0.055%;
3) LF refining furnace: molten steel adds magnesia 3.2kg/t after entering refining furnace, quartz sand 3.2kg/t makes low basicity refining slag, and refining slag main component is: CaO:38%, SiO
2: 28%, Al
2o
3: 12%, MgO:16%, MnO:3%, CaF
2: 3%, refining slag basicity is 1.4; Power transmission is fed aluminum steel 1.3m/t after 10 minutes, adopt the deoxidation materials such as silicon carbide, carbon dust, ferrosilicon powder and silicon calcium powder to carry out diffusive deoxidation, and deaeration time is 35min, with sulphur line, adjusts sulphur content in steel, and while guaranteeing on bull ladle continuous casting platform, in steel, sulphur content is 0.043%; After composition and temperature adjustment complete, molten steel carries out soft blow, and the soft blow time is 10min;
4) continuous casting: continuous casting of molten steel adopt large bag-long nozzle-tundish-crystallizer-bis-cold-aligning-cutting-retarded cooling process, wherein, long nozzle and tundish adopt argon to seal and protect, argon seal pressure is 0.12MPa; Conical degree of crystallizer is 0.95, and the crystallizer water yield is 1700L/min, and crystallizer adopts induction stirring, and induction stirring electric current is 500A, and frequency is 4Hz, and the basicity of crystallizer protecting residue is 0.80, and fusing point is 1080 ℃; Strand secondary cooling zone adopts four sections of types of cooling, and wherein first and second section is water-cooling pattern, and third and fourth section is the aerosol type of cooling, and secondary cooling water specific water is 0.25L/kg; Strand aligning adopts multi-point straightening mode, and entering straightening section temperature is 1000 ℃; After continuously cast bloom after employing flame cutting enters cold bed, hang in rapidly burial pit, it is 8min that strand has cut to hanging in the burial pit time, and strand enters 650 ℃ of burial pit temperature.
Chemical composition and the content thereof of gained continuously cast bloom are as follows: C:0.50%, and Si:0.75%, Mn:1.10%, P:0.045%, S:0.040%, N:0.0180%, all the other are Fe, trace element and inevitable impurity; The low power of this continuously cast bloom, oxygen, phosphorus, and the control situation of sulphur sees the following form 1.
Embodiment 4:
Produce high-sulfur phosphorus high-strength steel continuously cast bloom for a kind of motor car engine fractured connecting rod, the production method step of this continuously cast bloom is as follows:
1) electrosmelting: adopt molten iron and steel scrap as starting material, the weight ratio of molten iron and steel scrap is 7:1; Be rapidly heated decarburization and flow less slag of initial smelting period, and control oxidation terminal temperature and be: 1635 ℃, endpoint carbon content is 0.38%, and end phosphorus content is 0.037%;
2) heart of the inclined to one side end of electric furnace tapping: tapping adopts and stays steel remaining slag operation, taps and adds quickened lime 3.5kg/t, Iron sulfuret 2.3kg/t at 1/3 o'clock in ladle, aluminium block 1.2kg/t, Si-Ca-Ba 2.2kg/t, controlling and entering oxygen level in follow-up LF refining furnace is 65ppm, sulphur content is 0.055%;
3) LF refining furnace: molten steel adds magnesia 3.3kg/t after entering refining furnace, quartz sand 3.3kg/t makes low basicity refining slag, and refining slag main component is: CaO:40%, SiO
2: 25%, Al
2o
3: 10%, MgO:15%, MnO:5%, CaF
2: 5%, refining slag basicity is 1.6; Power transmission is fed aluminum steel 1.2m/t after 10 minutes, adopt the deoxidation materials such as silicon carbide, carbon dust, ferrosilicon powder and silicon calcium powder to carry out diffusive deoxidation, and deaeration time is 40min, with sulphur line, adjusts sulphur content in steel, and while guaranteeing on bull ladle continuous casting platform, in steel, sulphur content is 0.045%; After composition and temperature adjustment complete, molten steel carries out soft blow, and the soft blow time is 12min;
4) continuous casting: continuous casting of molten steel adopt large bag-long nozzle-tundish-crystallizer-bis-cold-aligning-cutting-retarded cooling process, wherein, long nozzle and tundish adopt argon to seal and protect, argon seal pressure is 0.13MPa; Conical degree of crystallizer is 0.95, and the crystallizer water yield is 1750L/min, and crystallizer adopts induction stirring, and induction stirring electric current is 550A, and frequency is 4Hz, and the basicity of crystallizer protecting residue is 0.80, and fusing point is 1080 ℃; Strand secondary cooling zone adopts four sections of types of cooling, and wherein first and second section is water-cooling pattern, and third and fourth section is the aerosol type of cooling, and secondary cooling water specific water is 0.26L/kg; Strand aligning adopts multi-point straightening mode, and entering straightening section temperature is 980 ℃; After continuously cast bloom after employing flame cutting enters cold bed, hang in rapidly burial pit, it is 8min that strand has cut to hanging in the burial pit time, and strand enters 620 ℃ of burial pit temperature.
Chemical composition and the content thereof of gained continuously cast bloom are as follows: C:0.48%, and Si:0.25%, Mn:1.00%, P:0.040%, S:0.040%, N:0.0210%, all the other are Fe, trace element and inevitable impurity; The low power of this continuously cast bloom, oxygen, phosphorus, and the control situation of sulphur sees the following form 1.
Embodiment 5:
Produce high-sulfur phosphorus high-strength steel continuously cast bloom for a kind of motor car engine fractured connecting rod, the production method step of this continuously cast bloom is as follows:
1) electrosmelting: adopt molten iron and steel scrap as starting material, the weight ratio of molten iron and steel scrap is 8:1; Be rapidly heated decarburization and flow less slag of initial smelting period, and control oxidation terminal temperature and be: 1630 ℃, endpoint carbon content is 0.40%, and end phosphorus content is 0.030%;
2) heart of the inclined to one side end of electric furnace tapping: tapping adopts and stays steel remaining slag operation, taps and adds quickened lime 3.0kg/t, Iron sulfuret 2.5kg/t at 1/3 o'clock in ladle, aluminium block 1.0kg/t, Si-Ca-Ba 2.0kg/t, controlling and entering oxygen level in follow-up LF refining furnace is 75ppm, sulphur content is 0.060%;
3) LF refining furnace: molten steel adds magnesia 3.3kg/t after entering refining furnace, quartz sand 3.3kg/t makes low basicity refining slag, and refining slag main component is: CaO:38%, SiO
2: 28%, Al
2o
3: 12%, MgO:16%, MnO:2%, CaF
2: 4%, refining slag basicity is 1.4; Power transmission is fed aluminum steel 1.0m/t after 10 minutes, adopt the deoxidation materials such as silicon carbide, carbon dust, ferrosilicon powder and silicon calcium powder to carry out diffusive deoxidation, and deaeration time is 35min, with sulphur line, adjusts sulphur content in steel, and while guaranteeing on bull ladle continuous casting platform, in steel, sulphur content is 0.050%; After composition and temperature adjustment complete, molten steel carries out soft blow, and the soft blow time is 10min;
4) continuous casting: continuous casting of molten steel adopt large bag-long nozzle-tundish-crystallizer-bis-cold-aligning-cutting-retarded cooling process, wherein, long nozzle and tundish adopt argon to seal and protect, argon seal pressure is 0.15MPa; Conical degree of crystallizer is 0.95, and the crystallizer water yield is 1700L/min, and crystallizer adopts induction stirring, and induction stirring electric current is 500A, and frequency is 4Hz, and the basicity of crystallizer protecting residue is 0.80, and fusing point is 1080 ℃; Strand secondary cooling zone adopts four sections of types of cooling, and wherein first and second section is water-cooling pattern, and third and fourth section is the aerosol type of cooling, and secondary cooling water specific water is 0.25L/kg; Strand aligning adopts multi-point straightening mode, and entering straightening section temperature is 1000 ℃; After continuously cast bloom after employing flame cutting enters cold bed, hang in rapidly burial pit, it is 8min that strand has cut to hanging in the burial pit time, and strand enters 650 ℃ of burial pit temperature.
Chemical composition and the content thereof of gained continuously cast bloom are as follows: C:0.60%, and Si:0.25%, Mn:1.05%, P:0.035%, S:0.045%, N:0.0170%, all the other are Fe, trace element and inevitable impurity; The low power of this continuously cast bloom, oxygen, phosphorus, and the control situation of sulphur sees the following form 1:
Table 1
As can be seen from Table 1, the continuously cast bloom that embodiment 1~5 produces, phosphorus content is stable to be controlled
0.030~0.050%, sulphur content is stable is controlled at 0.035~0.045%, the low power of strand
Rank≤1.0 grade, oxygen level≤20ppm, cc billet surface quality is good.