CN109778055A - A kind of smelting process of nitrogenous low-temperature steel P460NL2 - Google Patents
A kind of smelting process of nitrogenous low-temperature steel P460NL2 Download PDFInfo
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- CN109778055A CN109778055A CN201910035192.2A CN201910035192A CN109778055A CN 109778055 A CN109778055 A CN 109778055A CN 201910035192 A CN201910035192 A CN 201910035192A CN 109778055 A CN109778055 A CN 109778055A
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Abstract
The invention discloses the smelting process of nitrogenous low-temperature steel P460NL2 a kind of, the smelting process is the following steps are included: (1) smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into the refining of LF furnace, bull ladle VD furnace is vacuum-treated after refining；(2) it casts: after vacuum breaking, casting；(3) steel billet stacking slow cooling: after steel billet casting, by company's steel billet of well cutting, stacking slow cooling, steel billet are cooled to room temperature immediately.The present invention does not have to the raw materials of compound containing N that higher cost is added, and economic benefit is good；It is easy to operate, it does not need using special nitrogen pick-up equipment；All the components can satisfy inner quality standard, especially N content, and steel is excellent, and steel billet sufur printing reaches 1.0 or more C class, and steel billet flaw detection can close III grade of Sel072-97 or more, and steel plate inspection is minimum to close II grade of JB/T4730.3-2005 or more；P460NL2 steel tensile strength >=630MPa.
Description
Technical field
The invention belongs to metallurgical technology fields, and in particular to a kind of smelting process of nitrogenous low-temperature steel P460NL2.
Background technique
At present at home, tank car tank body material almost all uses the lower 16MnR steel of intensity rank, leads to tank body wall thickness
Thicker, ratio of light weight to loading capacity is big, and the volume to weight ratio of tank car is small and delivers low efficiency.And external tank car tank body generally uses tensile strength with steel
For 550~600MPa grades of normalizing type low-alloy steel, such steel intensity with higher and excellent toughness can reduce self weight,
Volume to weight ratio is improved, to improve delivery efficiency.
Tank car tank body material steel is very high to internal quality requirement, mainly passes through the VN that V, N are combined into product design
Compound thinning microstructure, improves the intensity and toughness of steel plate, and blows the core that N technique is smelting molten steel, Control of Nitrogen Content
The bad grasp of accuracy, and tank car tank body material with steel to steel water degree of purity require it is stringenter.
P460NL2 is a kind of economical low temperature spherical tank steel, and existing P460NL2 is that Nb-V is compound, tensile strength
540MPa or more improves the intensity and toughness of steel plate to meet the market demand, and 10~25mm of exploitation is thick, 630MPa or more is high-strength
It is very necessary to spend the compound nitrogenous low-temperature steel P460NL2 smelting process of VN.
Summary of the invention
The technical problem to be solved in the present invention is to provide the smelting processes of nitrogenous low-temperature steel P460NL2 a kind of.
In order to solve the above technical problems, the technical solution adopted by the present invention is that: a kind of smelting of nitrogenous low-temperature steel P460NL2
Method, the smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, then slag is re-fed into LF furnace refining desulfuration, when LF refining, when
When molten steel S content≤0.005%, bottom blown gas is changed into nitrogen by argon gas, it is online when replacing nitrogen, first pressure is turned up
To 0.09-0.11kg/L, quick-replaceable connector after ladle is removed, the control of nitrogen flushing time exists in 20~30min, nitrogen flow control
60~100L/min；Bull ladle VD furnace is vacuum-treated after LF refining, and before VD furnace Fruit storage, CaSi block, dosage is added
>=60kg/t steel；
(2) it casts: starting to cast after vacuum breaking, casting degree of superheat control is at 15~45 DEG C, pulling rate are as follows: 0.5~0.75m/s；
Cooling water is opened, inner arc hydraulic pressure control is in 100~150MPa, and outer arc hydraulic pressure control is in 120~150MPa；
(3) steel billet stacking slow cooling: after steel billet casting, by the steel billet of well cutting, stacking slow cooling, temperature are 700~800 DEG C immediately, are delayed
Cool time is 24~48h, and 150~170 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
After step (1) VD furnace of the present invention releases vacuum, sampling carries out N analysis, if nitrogen content in liquid steel >=130ppm
When, N is blown in stopping；If when nitrogen content in liquid steel≤130ppm, the VD Fruit storage later period in normal atmosphere (An), weak nitrogen blowing
>=15min, nitrogen flow control are added in≤60L/min or when ensuring that V or Al is no more than the requirement of standard EN10028
VN, ALN particle 20~50kg/t steel, and sufficiently bottom blowing nitrogen gas stirring, nitrogen flow are controlled in 60~100L/min.
When step (1) VD furnace of the present invention is vacuum-treated, vacuum degree≤66Pa, the vacuum retention time >=20min is used
Nitrogen bottom blowing stirring controls nitrogen flow in 80~100L/min.
When the degree of superheat of casting is less than 35 DEG C, pulling rate is controlled step (2) of the present invention by step (2)；When casting overheats
Degree is 35~45 DEG C, and pulling rate reduces 0.05m/s on the original basis, and when pouring the steel degree of superheat greater than 45 DEG C, molten steel does not allow to pour
Casting.
LF furnace refining desulfuration control technique is as follows in the step (1) of the present invention: feeding Al line >=300m/t steel, white slag is kept
Time >=50min, lime consumption >=16kg/t steel and are skimmed [Al] at process: 0.010~0.020%.
Step (2) of the present invention uses sunken bottom type submersed nozzle, and control mouth of a river insertion depth is whole in 100~120mm
Time slag line additional amount control is poured in 95~105mm.
Nitrogenous low-temperature steel P460NL2 tensile strength >=630MPa of smelting process production of the present invention.
The nitrogenous low-temperature steel P460NL2 nitrogen content of smelting process production of the present invention is 0.012~0.020%.
The nitrogenous low-temperature steel P460NL2 thickness specification of smelting process production of the present invention is 10~24mm.
The steel billet sufur printing of smelting process production of the present invention reaches C class 1.0 hereinafter, steel billet flaw detection can close Sel072-97
III grade or more, steel plate inspection is minimum to close II grade of JB/T4730.3-2005 or more.
Design principle of the present invention:
Smelting process of the invention can make nitrogen by LF refining early period into, argon bottom-blowing to be changed to the mode of nitrogen online
Gas is dissolved into molten steel supersaturatedly；The raw material containing calcium substance is added technique early period by VD, so that being mingled with nodularization, solidifies
When can adhere to more nitrogen compounds；Use VD later period weak nitrogen flushing technique, it is ensured that N content reaches requirement, reduces nitrogen from molten steel
In separation rate；Accelerate cooling and the means such as continuous casting water cooling amount optimization distribution and reasonable pulling rate with continuous casting and solidifying end,
Improve continuous casting billet quality well, improves segregation phenomena.
The nitrogenous low-temperature steel P460NL2 product inspection method of the present invention refers to EN10028；The reference of steel billet non-destructive testing standard
Sel072-97；Steel plate inspection canonical reference JB/T4730.3-2005.
The beneficial effects of adopting the technical scheme are that the 1, present invention contains N without addition higher cost
Raw materials of compound, economic benefit is good.2, operation of the present invention is simple, does not need using special nitrogen pick-up equipment.3, institute of the present invention
There is ingredient to can satisfy inner quality standard, especially N content, and steel is excellent, steel billet sufur printing reaches 1.0 or more C class, and steel billet is visited
Wound can close III grade of Sel072-97 or more, and steel plate inspection is minimum to close II grade of JB/T4730.3-2005 or more.4, the present invention contains
Nitrogen low-temperature steel P460NL2 tensile strength >=630MPa, nitrogen content are 0.012~0.020%.
Detailed description of the invention
Fig. 1 is the nitrogenous low-temperature steel P460NL2 sufur printing figure of embodiment 1；
Fig. 2 is the nitrogenous low-temperature steel P460NL2 sufur printing figure of embodiment 2；
Fig. 3 is the nitrogenous low-temperature steel P460NL2 sufur printing figure of embodiment 3；
Fig. 4 is the nitrogenous low-temperature steel P460NL2 sufur printing figure of embodiment 4；
Fig. 5 is the nitrogenous low-temperature steel P460NL2 sufur printing figure of embodiment 5；
Fig. 6 is the nitrogenous low-temperature steel P460NL2 sufur printing figure of embodiment 6.
Specific embodiment
Present invention will be explained in further detail in the following with reference to the drawings and specific embodiments.
Billet size are as follows: 300mm(thickness) * 2000mm(width), just refining is carried out using converter.
Embodiment 1
The nitrogenous low-temperature steel P460NL2 of the present embodiment with a thickness of 10mm, smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into LF furnace refining desulfuration, feeds Al line 350m/
T steel, white slag retention time 55min, lime consumption 16kg/t steel and are skimmed [Al] at process: 0.010%；When LF refining, work as molten steel
When melting S content is 0.003%, bottom blown gas is changed into nitrogen by argon gas, when replacing nitrogen online, first arrived pressure height-regulating
0.1kg/L removes quick-replaceable connector after ladle, nitrogen flushing time 26min, nitrogen flow 80L/min；
Bull ladle VD furnace is vacuum-treated after refining, and before VD furnace Fruit storage, CaSi block 65kg/t steel is added；Vacuum degree
66Pa, vacuum retention time 210min control nitrogen flow 100L/min using nitrogen bottom blowing stirring；After VD furnace releases vacuum,
Sampling carries out N analysis, nitrogen content in liquid steel 130ppm, and N is blown in stopping；
(2) it casts: before steel billet casting, opening all cooling waters, reinforce the inspection power to nozzle without water spray, drainage
Degree finds the nozzle on-call maintenance replacement of blocking；Ensure offline 0 section, in fan-shaped section roller levelness, between fan-shaped section to arc
Trueness error is 5mm；Using sunken bottom type submersed nozzle, control mouth of a river insertion depth is 120mm, whole to pour time slag line additional amount
98mm；
26 DEG C of the degree of superheat of casting, pulling rate 0.60m/s；Cooling water is opened, by increasing inner arc, outer arc hydraulic pressure, inner arc hydraulic pressure
100MPa, outer arc hydraulic pressure 120MPa increase nozzle atomization effect；
(3) steel billet stacking slow cooling: after steel billet casting, by the steel billet of well cutting stacking slow cooling immediately, temperature is 700 DEG C, when slow cooling
Between for for 24 hours, 170 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
The nitrogenous low-temperature steel P460NL2 tensile strength 650MPa of the present embodiment, nitrogen content 0.0126%, sufur printing figure are shown in Fig. 1,
Steel plate sufur printing result are as follows: C class 0.5, steel billet flaw detection close III grade of Sel072, and steel plate inspection closes JB/T4730.3-2005 I grades, table
Face does not have apparent defect.
Embodiment 2
The nitrogenous low-temperature steel P460NL2 of the present embodiment with a thickness of 13mm, smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into LF furnace refining desulfuration, feeds Al line 400m/
T steel, white slag retention time 50min, lime consumption 18kg/t steel and are skimmed [Al] at process: 0.012%；When LF refining, work as molten steel
When melting S content is 0.005%, bottom blown gas is changed into nitrogen by argon gas, when replacing nitrogen online, first arrived pressure height-regulating
0.1kg/L removes quick-replaceable connector after ladle, nitrogen flushing time 20min, nitrogen flow 90L/min；
Bull ladle VD furnace is vacuum-treated after refining, and before VD furnace Fruit storage, CaSi block 70kg/t steel is added；Vacuum degree
60Pa, vacuum retention time 20min control nitrogen flow 100L/min using nitrogen bottom blowing stirring；After VD furnace releases vacuum,
Sampling carries out N analysis, nitrogen content in liquid steel 200ppm, and N is blown in stopping；
(2) it casts: before steel billet casting, opening all cooling waters, reinforce the inspection power to nozzle without water spray, drainage
Degree finds the nozzle on-call maintenance replacement of blocking；Ensure offline 0 section, in fan-shaped section roller levelness, between fan-shaped section to arc
Trueness error is 10mm；Using sunken bottom type submersed nozzle, control mouth of a river insertion depth is 100mm, whole to pour time slag line additional amount
96mm；
40 DEG C of the degree of superheat of casting, pulling rate 0.65m/s；Cooling water is opened, by increasing inner arc, outer arc hydraulic pressure, inner arc hydraulic pressure
110MPa, outer arc hydraulic pressure 130MPa increase nozzle atomization effect；
(3) steel billet stacking slow cooling: after steel billet casting, by the steel billet of well cutting stacking slow cooling immediately, temperature is 800 DEG C, when slow cooling
Between be 30h, 150 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
The nitrogenous low-temperature steel P460NL2 tensile strength 680MPa of the present embodiment, nitrogen content 0.0138%, sufur printing figure are shown in Fig. 2,
Steel plate sufur printing result are as follows: C class 0.5, steel billet flaw detection close III grade of Sel072, and steel plate inspection closes JB/T4730.3-2005 I grades, table
Face does not have apparent defect.
Embodiment 3
The nitrogenous low-temperature steel P460NL2 of the present embodiment with a thickness of 16mm, smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into LF furnace refining desulfuration, feeds Al line 400m/
T steel, white slag retention time 60min, lime consumption 20kg/t steel and are skimmed [Al] at process: 0.015%；When LF refining, work as molten steel
When melting S content is 0.004%, bottom blown gas is changed into nitrogen by argon gas, when replacing nitrogen online, first arrived pressure height-regulating
0.1kg/L removes quick-replaceable connector after ladle, nitrogen flushing time 30min, nitrogen flow 90L/min；
Bull ladle VD furnace is vacuum-treated after refining, and before VD furnace Fruit storage, CaSi block 80kg/t steel is added；Vacuum degree
55Pa, vacuum retention time 25min control nitrogen flow 90L/min using nitrogen bottom blowing stirring；After VD furnace releases vacuum, take
Sample carries out N analysis, nitrogen content in liquid steel 270ppm, and N is blown in stopping；
(2) it casts: before steel billet casting, opening all cooling waters, reinforce the inspection power to nozzle without water spray, drainage
Degree finds the nozzle on-call maintenance replacement of blocking；Ensure offline 0 section, in fan-shaped section roller levelness, between fan-shaped section to arc
Trueness error is 5mm；Using sunken bottom type submersed nozzle, control mouth of a river insertion depth is 110mm, whole to pour time slag line additional amount
100mm；
15 DEG C of the degree of superheat of casting, pulling rate 0.70m/s；Cooling water is opened, by increasing inner arc, outer arc hydraulic pressure, inner arc hydraulic pressure
120MPa, outer arc hydraulic pressure 130MPa increase nozzle atomization effect；
(3) steel billet stacking slow cooling: after steel billet casting, by the steel billet of well cutting stacking slow cooling immediately, temperature is 750 DEG C, when slow cooling
Between be 36h, 160 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
The nitrogenous low-temperature steel P460NL2 tensile strength 645MPa of the present embodiment, nitrogen content 0.015%, sufur printing figure are shown in Fig. 3, steel
Plate sufur printing result are as follows: 1.0 grades of C class, steel billet flaw detection closes III grade of Sel072, and steel plate inspection closes JB/T4730.3-2005 I grades, table
Face does not have apparent defect.
Embodiment 4
The nitrogenous low-temperature steel P460NL2 of the present embodiment with a thickness of 19mm, smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into LF furnace refining desulfuration, feeds Al line 450m/
T steel, white slag retention time 62min, lime consumption 25kg/t steel and are skimmed [Al] at process: 0.016%；When LF refining, work as molten steel
When melting S content is 0.002%, bottom blown gas is changed into nitrogen by argon gas, when replacing nitrogen online, first arrived pressure height-regulating
0.1kg/L removes quick-replaceable connector after ladle, nitrogen flushing time 25min, nitrogen flow 100L/min；
Bull ladle VD furnace is vacuum-treated after refining, and before VD furnace Fruit storage, CaSi block 80kg/t steel is added；Vacuum degree
62Pa, vacuum retention time 28min control nitrogen flow 100L/min using nitrogen bottom blowing stirring；After VD furnace releases vacuum,
Sampling carry out N analysis, nitrogen content in liquid steel 120ppm, VD the Fruit storage later period in normal atmosphere (An), weak nitrogen blowing
15min；
(2) it casts: before steel billet casting, opening all cooling waters, reinforce the inspection power to nozzle without water spray, drainage
Degree finds the nozzle on-call maintenance replacement of blocking；Reinforce equipment precision management, it is ensured that offline 0 section, in fan-shaped section roller level
It spends, the arc aligning accuracy error between fan-shaped section is 3mm；Using sunken bottom type submersed nozzle, control mouth of a river insertion depth is 115mm,
It is whole to pour time slag line additional amount 100mm；
35 DEG C of the degree of superheat of casting, pulling rate 0.50m/s；Cooling water is opened, by increasing inner arc, outer arc hydraulic pressure, inner arc hydraulic pressure
120MPa, outer arc hydraulic pressure 150MPa increase nozzle atomization effect；
(3) steel billet stacking slow cooling: after steel billet casting, by company's steel billet of well cutting, stacking slow cooling, temperature are 720 DEG C immediately, slow cooling
Time is 48h, and 165 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
The nitrogenous low-temperature steel P460NL2 tensile strength 698MPa of the present embodiment, nitrogen content 0.0175%, sufur printing figure are shown in Fig. 4,
Steel plate sufur printing result are as follows: 0.5 grade of C class, steel billet flaw detection closes III grade of Sel072, and steel plate inspection closes JB/T4730.3-2005 I grades,
Surface does not have apparent defect.
Embodiment 5
The nitrogenous low-temperature steel P460NL2 of the present embodiment with a thickness of 22mm, smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into LF furnace refining desulfuration, feeds Al line 450m/
T steel, white slag retention time 58min, lime consumption 19kg/t steel and are skimmed [Al] at process: 0.018%；When LF refining, work as molten steel
When melting S content is 0.003%, bottom blown gas is changed into nitrogen by argon gas, when replacing nitrogen online, first arrived pressure height-regulating
0.09kg/L removes quick-replaceable connector after ladle, nitrogen flushing time 22min, nitrogen flow 60L/min；
Bull ladle VD furnace is vacuum-treated after refining, and before VD furnace Fruit storage, CaSi block 60kg/t steel is added；Vacuum degree
58Pa, vacuum retention time 27min control nitrogen flow 80L/min using nitrogen bottom blowing stirring；After VD furnace releases vacuum, take
Sample carries out N analysis, and nitrogen content in liquid steel 90ppm, VD the Fruit storage later period in normal atmosphere (An), is ensuring that V is no more than
When EN10028 standard requirements, VN, ALN particle 20kg/t steel, and sufficiently bottom blowing nitrogen gas stirring, nitrogen flow 100L/min is added；
(2) it casts: before steel billet casting, opening all cooling waters, reinforce the inspection power to nozzle without water spray, drainage
Degree finds the nozzle on-call maintenance replacement of blocking；Reinforce equipment precision management, it is ensured that offline 0 section, in fan-shaped section roller level
It spends, the arc aligning accuracy error between fan-shaped section is 4mm；Using sunken bottom type submersed nozzle, control mouth of a river insertion depth is 105mm,
It is whole to pour time slag line additional amount 95mm；
20 DEG C of the degree of superheat of casting, pulling rate 0.75m/s；Cooling water is opened, by increasing inner arc, outer arc hydraulic pressure, inner arc hydraulic pressure
130MPa, outer arc hydraulic pressure 150MPa increase nozzle atomization effect；
(3) steel billet stacking slow cooling: after steel billet casting, by company's steel billet of well cutting, stacking slow cooling, temperature are 780 DEG C immediately, slow cooling
Time is for 24 hours that 155 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
The nitrogenous low-temperature steel P460NL2 tensile strength 672MPa of the present embodiment, nitrogen content 0.012%, sufur printing figure are shown in Fig. 5, steel
Plate sufur printing result are as follows: 0.5 grade of C class, steel billet flaw detection closes III grade of Sel072, and steel plate inspection closes JB/T4730.3-2005 I grades, table
Face does not have apparent defect.
Embodiment 6
The nitrogenous low-temperature steel P460NL2 of the present embodiment with a thickness of 24mm, smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, slag, is then re-fed into LF furnace refining desulfuration, feeds Al line 300m/
T steel, white slag retention time 55min, lime consumption 20kg/t steel and are skimmed [Al] at process: 0.020%；When LF refining, work as molten steel
When melting S content is 0.005%, bottom blown gas is changed into nitrogen by argon gas, when replacing nitrogen online, first arrived pressure height-regulating
0.11kg/L removes quick-replaceable connector after ladle, nitrogen flushing time 24min, nitrogen flow 90L/min；
Bull ladle VD furnace is vacuum-treated after refining, and before VD furnace Fruit storage, CaSi block 80kg/t steel is added；Vacuum degree
58Pa, vacuum retention time 27min control nitrogen flow 100L/min using nitrogen bottom blowing stirring；After VD furnace releases vacuum,
Sampling carries out N analysis, and nitrogen content in liquid steel 80ppm, VD the Fruit storage later period in normal atmosphere (An), is ensuring that Al is no more than
When EN10028 standard requirements, VN, ALN particle 50kg/t steel, and sufficiently bottom blowing nitrogen gas stirring, nitrogen flow 60L/min is added；
(2) it casts: before steel billet casting, opening all cooling waters, reinforce the inspection power to nozzle without water spray, drainage
Degree finds the nozzle on-call maintenance replacement of blocking；Reinforce equipment precision management, it is ensured that offline 0 section, in fan-shaped section roller level
It spends, the arc aligning accuracy error between fan-shaped section is 1mm；Using sunken bottom type submersed nozzle, control mouth of a river insertion depth is 110mm,
It is whole to pour time slag line additional amount 105mm；
45 DEG C of the degree of superheat of casting, pulling rate 0.70m/s；Cooling water is opened, by increasing inner arc, outer arc hydraulic pressure, inner arc hydraulic pressure
150MPa, outer arc hydraulic pressure 150MPa increase nozzle atomization effect；
(3) steel billet stacking slow cooling: after steel billet casting, by company's steel billet of well cutting, stacking slow cooling, temperature are 760 DEG C immediately, slow cooling
Time is 48h, and 160 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
The nitrogenous low-temperature steel P460NL2 tensile strength 702MPa of the present embodiment, nitrogen content 0.020%, sufur printing figure are shown in Fig. 6, steel
Plate sufur printing result are as follows: 0.5 grade of C class, steel billet flaw detection closes III grade of Sel072, and steel plate inspection closes JB/T4730.3-2005 I grades, table
Face does not have apparent defect.
The above embodiments are only used to illustrate and not limit the technical solutions of the present invention, although referring to above-described embodiment to this hair
It is bright to be described in detail, those skilled in the art should understand that: still the present invention can be modified or be waited
With replacement, without departing from the spirit or scope of the invention, or any substitutions, should all cover in power of the invention
In sharp claimed range.
Claims (10)
1. a kind of smelting process of nitrogenous low-temperature steel P460NL2, which is characterized in that the smelting process the following steps are included:
(1) it smelts: after molten steel just refines, being sent into the pre- dephosphorization of LF furnace, then slag is re-fed into LF furnace refining desulfuration, when LF refining, when
When molten steel S content≤0.005%, bottom blown gas is changed into nitrogen by argon gas, it is online when replacing nitrogen, first pressure is turned up
To 0.09-0.11kg/L, quick-replaceable connector after ladle is removed, the control of nitrogen flushing time exists in 20~30min, nitrogen flow control
60~100L/min；Bull ladle VD furnace is vacuum-treated after LF refining, and before VD furnace Fruit storage, CaSi block, dosage is added
>=60kg/t steel；
(2) it casts: starting to cast after vacuum breaking, casting degree of superheat control is at 15~45 DEG C, pulling rate are as follows: 0.5~0.75m/s；
Cooling water is opened, inner arc hydraulic pressure control is in 100~150MPa, and outer arc hydraulic pressure control is in 120~150MPa；
(3) steel billet stacking slow cooling: after steel billet casting, by the steel billet of well cutting, stacking slow cooling, temperature are 700~800 DEG C immediately, are delayed
Cool time is 24~48h, and 150~170 DEG C of de-stacking temperature, steel billet is cooled to room temperature.
2. the smelting process of nitrogenous low-temperature steel P460NL2 according to claim 1 a kind of, which is characterized in that the step
(1) after VD furnace releases vacuum, sampling carries out N analysis, if when nitrogen content in liquid steel >=130ppm, N is blown in stopping；If molten steel nitrogen contains
When amount≤130ppm, the VD Fruit storage later period, weak nitrogen blowing >=15min, nitrogen flow control existed in normal atmosphere (An)
≤ 60L/min or ensure V or Al be no more than standard EN10028 requirement when, be added VN, ALN particle 20~50kg/t steel,
And sufficiently bottom blowing nitrogen gas stirring, nitrogen flow are controlled in 60~100L/min.
3. the smelting process of nitrogenous low-temperature steel P460NL2 according to claim 1 a kind of, which is characterized in that the step
(1) when VD furnace is vacuum-treated, vacuum degree≤66Pa, the vacuum retention time >=20min controls nitrogen using nitrogen bottom blowing stirring
Flow is in 80~100L/min.
4. the smelting process of nitrogenous low-temperature steel P460NL2 according to claim 1 a kind of, which is characterized in that the step
(2) when the degree of superheat of casting is less than 35 DEG C, pulling rate is controlled by step (2)；When the casting degree of superheat is 35~45 DEG C, pulling rate is original
On the basis of reduce 0.05m/s, when pouring the steel degree of superheat greater than 45 DEG C, molten steel does not allow to cast.
5. the smelting process of nitrogenous low-temperature steel P460NL2 according to any one of claims 1-4 a kind of, feature exist
In LF furnace refining desulfuration control technique is as follows in the step (1): hello Al line >=300m/t steel, the white slag retention time >=
50min, lime consumption >=16kg/t steel and are skimmed [Al] at process: 0.010~0.020%.
6. the smelting process of nitrogenous low-temperature steel P460NL2 according to any one of claims 1-4 a kind of, feature exist
In the step (2) uses sunken bottom type submersed nozzle, and control mouth of a river insertion depth adds in 100~120mm, the whole time slag line that pours
Enter amount control in 95~105mm.
7. the smelting process of nitrogenous low-temperature steel P460NL2 according to any one of claims 1-4 a kind of, feature exist
In nitrogenous low-temperature steel P460NL2 tensile strength >=630MPa of the smelting process production.
8. the smelting process of nitrogenous low-temperature steel P460NL2 according to any one of claims 1-4 a kind of, feature exist
In the nitrogenous low-temperature steel P460NL2 nitrogen content of the smelting process production is 0.012~0.020%.
9. the smelting process of nitrogenous low-temperature steel P460NL2 according to any one of claims 1-4 a kind of, feature exist
In the nitrogenous low-temperature steel P460NL2 thickness specification of the smelting process production is 10~24mm.
10. the smelting process of nitrogenous low-temperature steel P460NL2 according to any one of claims 1-4 a kind of, feature exist
In the steel billet sufur printing of smelting process production reaches C class 1.0 hereinafter, steel billet flaw detection can close III grade of Sel072-97 or more, steel
Plate flaw detection is minimum to close II grade of JB/T4730.3-2005 or more.
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| CN112548056A (en) * | 2019-09-25 | 2021-03-26 | 上海梅山钢铁股份有限公司 | Method for controlling hydrogen in low-carbon boron-containing steel continuous casting billet |
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