Summary of the invention
Technical problem to be solved by this invention is to provide a kind of method of converter low temperature smelting ultra-low phosphoretic steel.
For solving the problems of the technologies described above, the method of the top blown converter low temperature smelting ultra-low phosphoretic steel of the present invention's design, two slag is made by adopting omnidistance low temperature smelting and smelting process, the concentrations by weight of smelting endpoint P is controlled for [P]≤0.004%, tapping then adopts stays the mode of steel thoroughly to stop slag, effectively inhibit tapping rephosphorization, ladle P≤0.0050% after tapping, thus realize the ultralow phosphorus smelting of converter.
The smelting condition of the inventive method is: carry out ultra-low phosphoretic steel smelting at 35t top blown converter, molten iron 32 ~ 33t, steel scrap 2.5 ~ 3t, and oxygen rifle work oxygen flow is 6500 ~ 7800Nm
3/ h, [P] 0.120 ~ 0.150% in molten iron, its concrete operations are:
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): adopt low oxygen supply intensity, oxygen blast flow is 6500 ~ 7000Nm
3/ h; Open and blow in 1min, blowing rifle position 800 ~ 900mm, main task is for heating up and melting steel scrap; In 1 ~ 4min, divide 2 ~ 4 batches to add lime and amount to 1500Kg and iron ore total 500Kg, rifle position is carried to 1100 ~ 1200mm simultaneously; In 4 ~ 7min, rifle position is carried to 1200 ~ 1300mm, and 2 ~ 4 add iron ore total 500Kg in batches; During 7min, the thermometric of falling stove, sampling; At the end of the high efficiency dephosphorating phase, it is 1450 ~ 1480 DEG C that temperature controls, and [C] controls is 1.70 ~ 2.00%, and [P] controls is 0.025 ~ 0.035%;
2) the deslagging grate phase: after removing the 1/3-1/2 of slag total amount, lifting stove to body of heater departs within the scope of petticoat pipe medullary ray ± 30 °, after slow front and back grate 1min, body of heater is shaken and is back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7600 ~ 7800Nm
3/ h, blowing rifle position 700 ~ 900mm, adds lime 600 ~ 800kg, magnesium ball 300kg, iron ore 700kg; Fall stove after blowing 4min, the control of falling furnace temperature is 1530 ~ 1550 DEG C, stove [C] 0.060 ~ 0.090%, stove [P]≤0.008%, taps after point blows 30 ~ 50s, tapping temperature 1550 ~ 1570 DEG C, tapping [C]≤0.040%, tapping [P]≤0.0040%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization, stays steel amount to be 1t, [P]≤0.0050% in ladle after tapping;
[TFe]>=55% of described iron ore, [SiO
2]≤15%, impurity element [P], [S]≤0.10%, described [P], [C], [S], [TFe] and [SiO
2] be respectively P, C, S, TFe and SiO
2weight percent content.
The present invention has following beneficial effect:
1) the present invention completes ultra-low phosphoretic steel in single seat converter and smelts, and contrast that operational path is simple, smelting cycle controls reasonable, workable with double-united gear oil pump ultra-low phosphoretic steel, is easy to control.
2) production cost of the present invention is low, and steel damages little, only relies on low temperature and two slag to complete ultralow phosphorus and smelts.
Embodiment
Below in conjunction with embodiment, the present invention is described in more detail.
The method of converter low temperature smelting ultra-low phosphoretic steel of the present invention, its smelting condition is: carry out ultra-low phosphoretic steel smelting at 35t top blown converter, molten iron 32 ~ 33t, steel scrap 2.5 ~ 3t, and oxygen rifle work oxygen flow is 6500 ~ 7800Nm
3/ h, [P] 0.120 ~ 0.150% in molten iron, concrete operation step is:
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): the high efficiency dephosphorating phase adopts low oxygen supply intensity, and oxygen blast flow is 6500 ~ 7000Nm
3/ h; Open and blow in 1min, blowing rifle position 800 ~ 900mm, main task is for heating up and melting steel scrap; In 1 ~ 4min, divide 2 ~ 4 batches to add lime and amount to 1500Kg and iron ore total 500Kg, rifle position is carried to 1100 ~ 1200mm simultaneously; In 4 ~ 7min, rifle position is carried to 1200 ~ 1300mm, and 2 ~ 4 add iron ore total 500Kg in batches, slow down temperature rise rate and then reduce decarbonization rate; During 7min, the thermometric of falling stove, sampling; At the end of the high efficiency dephosphorating phase, it is 1450 ~ 1480 DEG C that temperature controls, and [C] controls is 1.70 ~ 2.00%, and [P] controls is 0.025 ~ 0.035%;
2) the deslagging grate phase: after removing the 1/3-1/2 of slag total amount, lifting stove to body of heater departs within the scope of petticoat pipe medullary ray ± 30 °, after slow front and back grate 1min, body of heater is shaken and is back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7600 ~ 7800Nm
3/ h, blowing rifle position 700 ~ 900mm, the quantity of slag adds lime 600 ~ 800kg, magnesium ball 300kg, iron ore 700kg; Fall stove after blowing 4min, the control of falling furnace temperature is 1530 ~ 1550 DEG C, stove [C] 0.060 ~ 0.090%, stove [P]≤0.008%, taps after point blows 30 ~ 50s, tapping temperature 1550 ~ 1570 DEG C, tapping [C]≤0.040%, tapping [P]≤0.0040%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization, stays steel amount to be 1t, ladle [P]≤0.0050% after tapping;
[TFe]>=55% of described iron ore, [SiO
2]≤15%, impurity element [P], [S]≤0.10%, described [P], [C], [S], [TFe] and [SiO
2] be respectively P, C, S, TFe and SiO
2weight percent content.
Embodiment 1
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): adopt low oxygen supply intensity, oxygen blast flow 6500Nm
3/ h; Open and blow in 1min, blowing rifle position 800mm, main task is for heating up and melting steel scrap; During blowing 1 ~ 4min, divide 3 batches to add lime and amount to 1500Kg and iron ore total 500Kg, rifle position is carried to 1100mm simultaneously; During 4 ~ 7min, rifle position is carried to 1200mm, and points 3 batches add iron ore and amount to 500Kg and slow down temperature rise rate and then reduce decarbonization rate; The thermometric of falling stove, sampling after 7min, in earlier stage end temp 1450 DEG C.Early stage terminates [C] 2.00%, [P] 0.035%;
2) the deslagging grate phase: after removing 35% slag, lift stove to body of heater and depart within the scope of petticoat pipe medullary ray ± 30 °, after grate 1min, body of heater is shaken slowly and be back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7600Nm
3/ h, blowing rifle position 700mm, adds lime 600kg, magnesium ball 300kg, iron ore 700kg.Blowing 4min falls stove, falls furnace temperature 1530 DEG C, falls stove [C] 0.080%, falls stove [P] 0.009%, taps after point blows 30s, tapping temperature 1550 DEG C, tapping [C] 0.040%, tapping [P] 0.0040%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization (staying steel amount 1t), ladle [P] 0.0050% after tapping.
Embodiment 2
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): adopt low oxygen supply intensity, oxygen blast flow 6600Nm
3/ h; Open and blow in 1min, blowing rifle position 820mm, main task is for heating up and melting steel scrap; 1 ~ 4min divides 3 batches to add lime total 1500Kg and iron ore amounts to 500Kg, carries to 1120mm by rifle position simultaneously; 4 ~ 7min rifle position is carried to 1220mm, and points 3 batches add iron ore and amount to 500Kg and slow down temperature rise rate and then reduce decarbonization rate, the 7min thermometric of falling stove, sampling, early stage end temp 1460 DEG C.Early stage terminates [C] 2.00%, [P] 0.033%;
2) the deslagging grate phase: lift stove to body of heater after removing 40% slag and to depart within the scope of petticoat pipe medullary ray ± 30 ° after grate 1min, body of heater to be shaken slowly and be back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7650Nm
3/ h, blowing rifle position 750mm, adds lime 650kg, magnesium ball 300kg, iron ore 700kg.Blowing 4min falls stove, falls furnace temperature 1535 DEG C, falls stove [C] 0.085%, falls stove [P] 0.0078%, taps after point blows 35s, tapping temperature 1555 DEG C, tapping [C] 0.038%, tapping [P] 0.0038%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization (staying steel amount 1t), ladle [P]≤0.0048% after tapping.
Embodiment 3
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): adopt low oxygen supply intensity, oxygen blast flow 6700Nm
3/ h; Open and blow blowing rifle position 840mm in 1min, main task is for heating up and melting steel scrap; 1 ~ 4min divides 3 batches to add lime total 1500Kg and iron ore amounts to 500Kg, carries to 1140mm by rifle position simultaneously; 4 ~ 7min rifle position is carried to 1240mm, and points 3 batches add iron ore and amount to 500Kg and slow down temperature rise rate and then reduce decarbonization rate, the 7min thermometric of falling stove, sampling, early stage end temp 1465 DEG C.Early stage terminates [C] 1.80%, [P] 0.030%;
2) the deslagging grate phase: lift stove to body of heater after removing 45% slag and to depart within the scope of petticoat pipe medullary ray ± 30 ° after grate 1min, body of heater to be shaken slowly and be back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7700Nm
3/ h, blowing rifle position 800mm, adds lime 700kg, magnesium ball 300kg, iron ore 700kg.Blowing 4min falls stove, falls furnace temperature 1540 DEG C, falls stove [C] 0.080%, falls stove [P]≤0.0075%, taps after point blows 40s, tapping temperature 1560 DEG C, tapping [C] 0.036%, tapping [P] 0.0036%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization (staying steel amount 1t), ladle [P]≤0.0046% after tapping.
Embodiment 4
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): adopt low oxygen supply intensity, oxygen blast flow 6900Nm
3/ h; Open and blow blowing rifle position 860mm in 1min, main task is for heating up and melting steel scrap; 1 ~ 4min divides 3 batches to add lime total 1500Kg and iron ore amounts to 500Kg, carries to 1160mm by rifle position simultaneously; 4 ~ 7min rifle position is carried to 1260mm, and points 3 batches add iron ore and amount to 500Kg and slow down temperature rise rate and then reduce decarbonization rate, the 7min thermometric of falling stove, sampling, early stage end temp 1470 DEG C.Early stage terminates [C] 1.75%, [P] 0.028%;
2) the deslagging grate phase: lift stove to body of heater after removing 40% slag and to depart within the scope of petticoat pipe medullary ray ± 30 ° after grate 1min, body of heater to be shaken slowly and be back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7750Nm
3/ h, blowing rifle position 850mm, adds lime 750kg, magnesium ball 300kg, iron ore 700kg.Blowing 4min falls stove, falls furnace temperature 1545 DEG C, falls stove [C] 0.075%, falls stove [P] 0.075%, taps after point blows 45s, tapping temperature 1565 DEG C, tapping [C] 0.034%, tapping [P]≤0.035%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization (staying steel amount 1t), ladle [P] 0.0045% after tapping.
Embodiment 5
1) the high efficiency dephosphorating phase (low for oxygen quenching decarburization intensification): adopt low oxygen supply intensity, oxygen blast flow 7000Nm
3/ h; Open and blow blowing rifle position 900mm in 1min, main task is for heating up and melting steel scrap; 1 ~ 4min divides 3 batches to add lime total 1500Kg and iron ore amounts to 500Kg, carries to 1200mm by rifle position simultaneously; 4 ~ 7min rifle position is carried to 1300mm, and points 3 batches add iron ore 500Kg and slow down temperature rise rate and then reduce decarbonization rate, the 7min thermometric of falling stove, sampling, early stage end temp 1480 DEG C.Early stage terminates [C] 1.70%, [P] 0.025%;
2) the deslagging grate phase: lift stove to body of heater after removing 40% slag and to depart within the scope of petticoat pipe medullary ray ± 30 ° after grate 1min, body of heater to be shaken slowly and be back to zero-bit, the object of front and back grate for prevent from slag from tying sticking together and under causing secondary rifle misfire;
3) be rapidly heated the phase: open and blow, oxygen flow 7800Nm
3/ h, blowing rifle position 900mm, adds lime 800kg, magnesium ball 300kg, iron ore 700kg.Blowing 4min falls stove, falls furnace temperature 1550 DEG C, falls stove [C] 0.06%, falls stove [P]≤0.008%, taps after point blows 50s, tapping temperature 1570 DEG C, tapping [C] 0.030%, tapping [P]≤0.0030%;
4) tapping steel: wear slag retaining cap tapping, adopts the mode staying steel to tap to prevent tapping process slag rephosphorization (staying steel amount 1t), ladle [P]≤0.0040% after tapping.
Tapping [P], the content of ladle [P] and the low-sulfur steel smelting process analog value of LF stove routine in embodiment 1 ~ 5 are contrasted, the results are shown in Table 1:
Tapping [P], the content of ladle [P] and the Low-phosphorus Steel smelting process analog value of LF stove routine in table 1 embodiment 1 ~ 5
Tupe |
Tapping [P], % |
Ladle [P], % |
Embodiment 1 |
0.0040 |
0.0050 |
Embodiment 2 |
0.0038 |
0.0048 |
Embodiment 3 |
0.0036 |
0.0046 |
Embodiment 4 |
0.0035 |
0.0045 |
Embodiment 5 |
0.0030 |
0.0040 |
Conventional smelting process |
≥0.010 |
≥0.013 |
After interpretation of result to embodiment 1 ~ 5, can find: adopt the present invention converter can be set off [P] control within 0.0050%.And produce not according to present method, adopt conventional smelting process, converter departures [P] >=0.013%.