CN114959163A - Alloying smelting method in converter - Google Patents
Alloying smelting method in converter Download PDFInfo
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- CN114959163A CN114959163A CN202210771759.4A CN202210771759A CN114959163A CN 114959163 A CN114959163 A CN 114959163A CN 202210771759 A CN202210771759 A CN 202210771759A CN 114959163 A CN114959163 A CN 114959163A
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- 238000003723 Smelting Methods 0.000 title claims abstract description 63
- 238000000034 method Methods 0.000 title claims abstract description 48
- 238000005275 alloying Methods 0.000 title claims abstract description 40
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 146
- 239000010959 steel Substances 0.000 claims abstract description 146
- 238000007664 blowing Methods 0.000 claims abstract description 65
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims abstract description 58
- 239000002893 slag Substances 0.000 claims abstract description 57
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 50
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 48
- 239000001301 oxygen Substances 0.000 claims abstract description 48
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 48
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims abstract description 44
- 229910052786 argon Inorganic materials 0.000 claims abstract description 29
- 229910000604 Ferrochrome Inorganic materials 0.000 claims abstract description 26
- 229910052742 iron Inorganic materials 0.000 claims abstract description 22
- 238000010079 rubber tapping Methods 0.000 claims abstract description 11
- 230000000295 complement effect Effects 0.000 claims abstract description 9
- 238000003756 stirring Methods 0.000 claims abstract description 9
- 229910052719 titanium Inorganic materials 0.000 claims description 27
- 229910052698 phosphorus Inorganic materials 0.000 claims description 15
- 229910052710 silicon Inorganic materials 0.000 claims description 9
- 239000013589 supplement Substances 0.000 claims description 4
- 229910052804 chromium Inorganic materials 0.000 abstract description 26
- 239000011651 chromium Substances 0.000 abstract description 26
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 abstract description 14
- 230000000694 effects Effects 0.000 abstract description 14
- 238000009628 steelmaking Methods 0.000 abstract description 5
- 239000010936 titanium Substances 0.000 description 35
- 230000000052 comparative effect Effects 0.000 description 20
- 239000000956 alloy Substances 0.000 description 17
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 15
- 238000010521 absorption reaction Methods 0.000 description 12
- 229910045601 alloy Inorganic materials 0.000 description 8
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000007254 oxidation reaction Methods 0.000 description 5
- 229910004298 SiO 2 Inorganic materials 0.000 description 3
- 229910010413 TiO 2 Inorganic materials 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- UPHIPHFJVNKLMR-UHFFFAOYSA-N chromium iron Chemical compound [Cr].[Fe] UPHIPHFJVNKLMR-UHFFFAOYSA-N 0.000 description 3
- 238000002844 melting Methods 0.000 description 3
- 230000008018 melting Effects 0.000 description 3
- 230000003647 oxidation Effects 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- NRTOMJZYCJJWKI-UHFFFAOYSA-N Titanium nitride Chemical compound [Ti]#N NRTOMJZYCJJWKI-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000011574 phosphorus Substances 0.000 description 2
- 239000000047 product Substances 0.000 description 2
- 230000001737 promoting effect Effects 0.000 description 2
- 229910001021 Ferroalloy Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 1
- 229910001634 calcium fluoride Inorganic materials 0.000 description 1
- BRPQOXSCLDDYGP-UHFFFAOYSA-N calcium oxide Chemical compound [O-2].[Ca+2] BRPQOXSCLDDYGP-UHFFFAOYSA-N 0.000 description 1
- ODINCKMPIJJUCX-UHFFFAOYSA-N calcium oxide Inorganic materials [Ca]=O ODINCKMPIJJUCX-UHFFFAOYSA-N 0.000 description 1
- 239000000292 calcium oxide Substances 0.000 description 1
- XFWJKVMFIVXPKK-UHFFFAOYSA-N calcium;oxido(oxo)alumane Chemical compound [Ca+2].[O-][Al]=O.[O-][Al]=O XFWJKVMFIVXPKK-UHFFFAOYSA-N 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000005070 sampling Methods 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
Images
Classifications
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
-
- 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
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
-
- 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
-
- 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
-
- 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
-
- 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
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Manufacturing & Machinery (AREA)
- Mechanical Engineering (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The invention provides an alloying smelting method in a converter, which comprises the steps of adding molten iron and scrap steel into the converter; oxygen blowing smelting is carried out in the converter, and meanwhile, argon is blown from the bottom of the converter; controlling the total slag amount in the converter to be 20-35 kg/t; after oxygen blowing is stopped, adding high-carbon ferrochrome from a top bin of the converter, increasing argon flow, carrying out bottom blowing stirring, and alloying molten steel in the converter; and detecting molten steel, tapping after the molten steel meets the smelting requirement, and performing complementary blowing if the molten steel does not meet the smelting requirement. According to the invention, the total slag amount in the converter is controlled to be 20-35 kg/t, so that less-slag steelmaking can be realized, the dephosphorization effect of the slag on molten steel is met, and simultaneously, the phenomenon that the excessive slag forms a thicker slag layer on the upper part of the molten steel to influence the high-carbon ferrochrome to penetrate through the slag layer, so that the high-carbon ferrochrome cannot be completely melted into the molten steel to influence the chromium alloying effect is avoided.
Description
Technical Field
The invention relates to the technical field of steel smelting, in particular to an alloying smelting method in a converter.
Background
The high-carbon chromium bearing steel is used for manufacturing bearing parts such as rolling bodies, ferrules and the like in bearings, and the parts have strict requirements on contact fatigue life. The bearing steel has great influence on the fatigue life of non-metallic inclusions, particularly brittle titanium nitride inclusions, and related research results show that the influence of the titanium nitride inclusions with the size of 8um on the fatigue life is equal to the influence of calcium aluminate inclusions with the size of 25 um. Therefore, the high-carbon chromium bearing steel has strict requirements on the titanium content in the steel, the high-quality steel in the new high-carbon chromium bearing steel standard GB/T18254-2016 requires the titanium content (namely the mass percentage) to be less than or equal to 0.0050 percent, the high-grade high-quality steel requires the titanium content to be less than or equal to 0.0030 percent, and the special-grade high-quality steel requires the titanium content to be less than or equal to 0.0015 percent, so the production of the high-carbon chromium bearing steel has strict requirements on molten iron, alloy and the like.
In order to ensure that the titanium content in the high-carbon chromium bearing steel meets the standard requirement, steel enterprises have to adopt low-titanium high-carbon ferrochrome to replace common high-carbon ferrochrome for carrying out chromium alloying operation, thereby greatly increasing the production cost. In order to ensure the requirement of titanium content in the high-carbon chromium bearing steel and reduce the production cost, steel enterprises carry out a great deal of research on new processes.
The patent with publication number CN104212935B discloses a method for producing high-quality GCr15 bearing steel by using high-carbon ferrochrome, which adopts the procedures of LF and RH to carry out slag formation for three times to remove titanium in steel, but the method needs slag removing operation in the LF procedure and slag formation for the second time again, so that slag removing equipment needs to be added in the LF procedure, the cost of slag amount is greatly increased, and the production cost after chromium alloying is increased to a certain extent.
Patent publication No. CN102383055B discloses a method for reducing the titanium content in high-carbon chromium bearing steel, which adopts a mode of mixing high-carbon chromium iron (alloy amount required by 60-75% Cr) and low-titanium high-carbon chromium iron in the steel tapping alloying process, and although the titanium content of finished products and the alloying cost are considered to a certain extent, the titanium content of the finished products is greatly influenced by the titanium content of high-carbon ferrochrome alloy.
Therefore, in the molten steel smelting process of the high-carbon chromium bearing steel, the absorption rate of the molten steel on the high-carbon chromium iron is ensured, the content of various elements in the molten steel meets the smelting requirement, the content of Ti in the molten steel is reduced, and the dephosphorization load in the smelting process is reduced.
In view of the above, there is a need for an alloying smelting method in a converter to solve the problems in the prior art.
Disclosure of Invention
The invention aims to provide an alloying smelting method in a converter, which aims to solve the problem of low absorptivity of an alloy material in the existing alloying smelting process.
In order to realize the aim, the invention provides an alloying smelting method in a converter, which comprises the following steps:
the method comprises the following steps: adding molten iron and scrap steel into a converter;
step two: oxygen blowing smelting is carried out in the converter, and meanwhile, argon is blown from the bottom of the converter; controlling the total slag amount in the converter to be 20-35 kg/t;
step three: after oxygen blowing is stopped, adding high-carbon ferrochrome from a top bin of the converter, increasing argon flow, carrying out bottom blowing stirring, and alloying molten steel in the converter;
step four: and detecting molten steel, and tapping after the molten steel meets the smelting requirement.
Preferably, the step one is to: the mass percent of Si is less than 0.35%, the mass percent of P is less than 0.08%, and the mass percent of Ti is less than 0.06%.
Preferably, in the first step, the mass ratio of the added scrap steel is less than 20%.
Preferably, in the second step, when oxygen blowing smelting is carried out, the oxygen supply intensity is 1.5-3.0 Nm 3 V (t.min), the oxygen pressure is 0.70-0.90 Mpa; when argon is blown from the bottom, the flow rate of the argon is 0.03-0.20 Nm 3 /(t·min)。
Preferably, in the second step, a slag former is added into the converter to form slag in the converter, and the alkalinity of the slag is 3-4.5.
Preferably, in the third step, when the mass percent of C in the molten steel is 0.08-0.20% and the temperature of the molten steel is 1560-1600 ℃, the oxygen blowing is stopped.
Preferably, in the third step, the flow of the argon gas is increased to 0.20-0.35 Nm 3 And (t & min), the bottom blowing stirring time is 30-60 s.
Preferably, in the fourth step, when the mass percentage of P in the molten steel meets the requirement, the mass percentage of C in the molten steel is 0.06-0.20%, and the temperature of the molten steel is 1540-1590 ℃, the molten steel is regarded as meeting the smelting requirement.
Preferably, in the fourth step, if the molten steel does not meet the smelting requirement, the secondary blowing is carried out until the smelting requirement is met.
Preferably, the complementary blowing is specifically oxygen-complementary blowing smelting in the converter and argon-complementary blowing at the bottom of the converter, wherein: the blowing-in oxygen supply intensity is 0.8-1.5 Nm 3 /(t.min), the flow rate of argon supplement blowing is 0.20-0.35 Nm 3 /(t.min), the blowing time is 30s or less.
The technical scheme of the invention has the following beneficial effects:
(1) according to the invention, the total slag amount in the converter is controlled to be 20-35 kg/t, so that less-slag steelmaking can be realized, the dephosphorization effect of the slag on molten steel is met, and meanwhile, the phenomenon that the excessive slag forms a thick slag layer on the upper part of the molten steel to influence the high-carbon ferrochrome to penetrate through the slag layer, so that the high-carbon ferrochrome cannot be completely melted into the molten steel to influence the chromium alloying effect is avoided.
(2) In the invention, the molten iron added into the converter has lower mass percentages of P, Ti and Si, and the formed slag amount is less; the mass percent of P (phosphorus) in the molten iron is below 0.08 percent, so that the dephosphorization load in the converter smelting process can be reduced; the mass percentage of Ti (titanium) is less than 0.06 percent, and because the activity of Ti is higher, almost all Ti is oxidized into TiO in the smelting process 2 And the titanium content standard of the high-carbon chromium bearing steel is favorably met.
(3) In the invention, by adding the scrap steel into the converter, the use of molten iron can be reduced, the steel-making cost is reduced, a cooling effect can be realized in the blowing process, and the disadvantage of dephosphorization caused by overhigh temperature of the molten steel is avoided.
(4) In the invention, oxygen is introduced into the top of the converter for blowing, so that the advantage of high smelting speed is achieved, and inert gas is introduced into the bottom of the converter, so that the purposes of accelerating molten steel melting and promoting a metallurgical reaction process can be achieved.
(5) In the invention, when oxygen blowing smelting is carried out, the oxygen supply intensity is 1.5-3.0 Nm 3 V (t.min), the oxygen pressure is 0.70-0.90 Mpa; when argon is bottom-blown, the flow rate of the argon is 0.03-0.20 Nm 3 And (t.min), the blowing process can be stably controlled and the dephosphorization effect can be ensured.
(6) In the invention, the mass percent of C in molten steel and the temperature of molten steel are controlled before alloying, if the content of C in the molten steel is higher, dephosphorization of the molten steel is not facilitated, if the content of C in the molten steel is lower, the content of O in the molten steel is high, and when the molten steel is alloyed, because the alloy material is more active, the alloy material can firstly carry out oxidation reaction with O in the molten steel and then is alloyed with the molten steel, and the absorption rate of the molten steel on alloy elements can be influenced.
(7) In the invention, the oxygen supply intensity and the complementary blowing time are greatly reduced during complementary blowing, and P element in steel can be further removed or the temperature of molten steel is slightly raised, so that the molten steel meets the tapping condition; the blowing-supplementing time is too long, the oxygen supply intensity is too high, the oxidation amount of chromium in molten steel is increased, the alloy absorption rate is reduced, the blowing-supplementing time and the oxygen supply intensity are reasonably combined, and molten steel in a furnace is further dephosphorized or heated to meet the tapping condition.
In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be described in further detail below with reference to the drawings.
Drawings
The accompanying drawings, which are incorporated in and constitute a part of this application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. In the drawings:
FIG. 1 is a flow chart of an alloying smelting method in a converter according to example 1 of the present application.
Detailed Description
Embodiments of the invention will be described in detail below with reference to the drawings, but the invention can be implemented in many different ways, which are defined and covered by the claims.
Example 1:
referring to fig. 1, the embodiment is applied to smelting of low-titanium high-carbon chromium bearing steel.
An alloying smelting method in a converter comprises the following steps:
the method comprises the following steps: adding molten iron and scrap steel into a converter;
molten iron is added into the converter, the mass percent of P (phosphorus) in the molten iron is below 0.08 percent, the dephosphorization load in the converter smelting process can be reduced, and in the smelting process, P is oxidized to become P 2 O 5 (ii) a The mass percentage of Ti (titanium) in the molten iron is less than 0.06 percent, and because the activity of Ti is higher, almost all Ti is oxidized into TiO in the smelting process 2 The titanium content standard of the high-carbon chromium bearing steel is favorably met; the mass percentage of Si (silicon) in the molten iron is below 0.35 percent, and Si is oxidized into SiO in the smelting process 2 ；P 2 O 5 、TiO 2 And SiO 2 The molten iron finally turns into the slag in the converter, and the mass percentages (content) of P, Ti and Si in the molten iron added into the converter are all low, so that the formed slag amount is small. In this embodiment, in molten iron: the mass percent of P is 0.08 percent and the mass percent of Ti isThe ratio was 0.06% and the mass percentage of Si was 0.35%.
The mass ratio of the scrap steel added into the converter is below 20%, the use of molten iron can be reduced by adding the scrap steel, the steelmaking cost is reduced, a cooling effect can be achieved in the blowing process, and the disadvantage of dephosphorization caused by overhigh temperature of the molten steel is avoided.
Step two: oxygen blowing smelting is carried out in the converter, and meanwhile, argon is blown from the bottom of the converter; controlling the total slag amount in the converter to be 20-35 kg/t and the slag alkalinity to be 3-4.5;
the essence of converter smelting is that oxygen is blown into the converter to oxidize elements such as C, Si, Mn, P and the like in the molten iron, and finally the primary molten steel which meets the conditions such as C content, P content, temperature and the like is obtained.
Introducing oxygen at the top of the converter to oxidize molten iron in the converter, so that P, Ti and Si in the molten iron are respectively oxidized into P 2 O 5 、TiO 2 And SiO 2 The mass percentage of P, Ti in the initial molten steel is reduced and simultaneously slag is formed, so that the molten steel is further dephosphorized by the slag.
The oxygen top-blown converter steelmaking method has the advantages of high smelting speed, more smelted steel types, better quality and the like, and the inert gas is introduced into the bottom of the converter, so that the aims of accelerating melting and promoting the metallurgical reaction process can be achieved.
In this embodiment, the oxygen supply intensity is 1.5 to 3.0Nm when oxygen-blown smelting is performed 3 V (t.min), the oxygen pressure is 0.70-0.90 Mpa; when argon is blown from the bottom, the flow rate of the argon is 0.03-0.20 Nm 3 And (t.min), the blowing process can be stably controlled and the dephosphorization effect can be ensured.
During the blowing process, a slag former, such as calcium fluoride or calcium oxide, is added to the converter for forming slag in the converter. With P formed by the oxidation of P, Ti and Si in molten iron 2 O 5 、TiO 2 And SiO 2 The slag and the molten steel together play a role in dephosphorizing the molten steel.
The total slag amount of the finally formed slag is 20-35 kg/t which is far lower than 50kg/t in the conventional process, and because the slag floats on the upper part of the molten steel, when the alloy material is added, the total amount of the slag is controlled, the thickness of a slag layer is reduced, the resistance of the alloy material penetrating through the slag layer can be reduced, and the absorption rate of the molten steel on the alloy material is further improved; the basicity of the slag is 3-4.5, the proper basicity is a necessary condition for dephosphorization in the blowing process, the basicity is controlled to be 3-4.5, the dephosphorization rate of the converter can be improved to a certain degree, and the implementation of the alloying process in the converter is guaranteed.
In this example, the total amount of slag in the converter was 35kg/t, and the basicity of the slag was 4.5.
Step three: after oxygen blowing is stopped, adding high-carbon ferrochrome from a top bin of the converter, increasing argon flow, carrying out bottom blowing stirring, and alloying molten steel in the converter;
stopping oxygen blowing when the mass percent of C in the molten steel is 0.08-0.20% and the temperature of the molten steel is 1560-1600 ℃; if the content of C in molten steel is high, dephosphorization of molten steel is not facilitated, if the content of C in molten steel is low, the content of O in molten steel is high, and during molten steel alloying, because the chromium which is an alloy material is active, oxidation reaction can be firstly carried out on the chromium and then the chromium and the molten steel are alloyed, so that the absorption rate of molten steel on alloy elements can be influenced. In the embodiment, the mass percent of C in the molten steel is 0.08%, oxygen blowing is stopped when the temperature is 1600 ℃, and temperature measurement and sampling are carried out on the molten steel.
Adding high-carbon ferrochrome into a top bin of the converter, wherein the high-carbon ferrochrome enters molten steel through a slag layer, and performing chromium alloying operation in the converter; after the high-carbon ferrochrome is added into the converter, the flow of the argon is increased to 0.20-0.35 Nm 3 And (t.min), the bottom blowing stirring time is 30-60 s, the melting of the high-carbon ferrochrome in the molten steel is accelerated, and the high-carbon ferrochrome is completely melted into the molten steel. In this example, the bottom-blowing stirring time was 30 seconds.
Step four: and detecting molten steel, and tapping after the molten steel meets the smelting requirement.
And when the P content in the molten steel meets the requirement, the mass percent of C in the molten steel is 0.06-0.20%, and the temperature of the molten steel is 1540-1590 ℃, the molten steel is considered to meet the smelting requirement, and steel can be tapped.
If the molten steel does not meet the smelting requirements (namely the P content exceeds the standard, the molten steel temperature is lower than 1540 ℃, and the like), oxygen and argon are introduced again for blowing supplement, and the oxygen and the argon are used for raising the molten steel temperature or further carrying out dephosphorization treatment on the molten steel.
When the blowing is performed, the oxygen supply intensity is 0.8 to 1.5Nm 3 /(t.min), the flow rate of bottom-blown argon is 0.20-0.35 Nm 3 (t.min), the blowing time is below 30s, the addition and chromium alloying of the high-carbon ferrochrome in the converter are realized, the molten steel contains a certain amount of chromium elements, the alloyed chromium elements and the blown oxygen can react greatly due to the large oxygen supply strength, the absorption rate of the high-carbon ferrochrome is reduced, the production cost is increased, the oxygen supply strength and the blowing time are greatly reduced during blowing supplement, and the main purpose is to further remove the P element in the steel or slightly increase the temperature of the molten steel, so that the molten steel meets the tapping condition; the blowing-supplementing time is too long, the oxygen supply intensity is too high, the oxidation amount of chromium in molten steel is increased, the alloy absorption rate is reduced, the blowing-supplementing time and the oxygen supply intensity are reasonably combined, and molten steel in a furnace is further dephosphorized or heated to meet the tapping condition.
In this example, the oxygen supply intensity during the post-blowing was 0.8Nm 3 /(t.min), the bottom-blowing argon flow rate was 0.20Nm 3 /(t · min), the blowing time was 30 s.
Example 2:
this example differs from example 1 in that the total amount of slag in the converter was 20kg/t and the basicity of the slag was 3.0 in this application.
Example 3:
the difference between this example and example 1 is that the total amount of slag in the converter is 30kg/t and the basicity of the slag is 4.5.
Example 4:
the difference between the embodiment and the embodiment 1 is that in the third step of the embodiment, the mass percent of C in molten steel is 0.20%, the temperature of the molten steel is 1560 ℃, the bottom blowing stirring time of bottom blowing argon is 60s, and no complementary blowing operation is performed after tapping.
Example 5:
the difference between this example and example 1 is that the oxygen supply intensity in the case of the after-blowing in this example was 1.5Nm 3 /(t.min), the bottom-blowing argon flow rate was 0.35Nm 3 /(t·min)。
Example 6:
the difference between this example and example 1 is that in the third step of this example, the mass percentage of C in the molten steel is 0.15%.
Comparative example 1:
the difference between the comparative example and the example 1 is that the alloying operation is carried out in a chromium-free ferroalloy furnace, and high-carbon ferrochrome is added into a ladle after molten steel is subjected to oxygen blowing smelting.
Comparative example 2:
the comparative example is different from the example 1 in that the mass percent of Si in the molten iron of the comparative example is more than 0.35 percent and is 0.40 percent, and the total slag amount in the converter is 50 kg/t.
Comparative example 3:
the difference between the comparative example and the example 1 is that the mass percent of P in the molten iron of the comparative example is more than 0.08 percent and is 0.125 percent, and the total slag amount in the converter is 35 kg/t.
Comparative example 4:
this comparative example is different from example 1 in that the oxygen supply intensity was 2.0Nm when the after-blowing was performed 3 /(t.min), the bottom-blowing argon flow rate was 0.15Nm 3 /(t.min), the blowing time was 120 s.
Comparative example 5:
the main difference between this comparative example and example 1 is that less slag former was added in this comparative example, so that the total amount of slag inside the converter was 15 kg/t.
Comparative example 6:
the main difference between this comparative example and example 1 is that the mass percentage of C in the molten steel in step three is 0.05% in this comparative example.
Comparative example 7:
the comparative example is mainly different from example 1 in that the mass percentage of C in the molten steel in step three is 0.25% in the comparative example.
TABLE 1 Effect of the steps on the smelting results
As can be seen from Table 1, proper complementary blowing can improve dephosphorization effect and simultaneously reduce the mass percentage of Ti in molten steel without alloying through a converter (comparative example 1), and although the absorption rate of the high-carbon ferrochrome is equivalent to that of the method, the mass percentage of Ti in the molten steel is far higher than that of the molten steel alloyed in the converter, and the smelting requirement of the low-titanium high-carbon chromium bearing steel is not met.
TABLE 2 influence of the total slag content in the converter on the smelting result
As can be seen from table 2, when the total amount of slag in the converter is low, the absorption rate of high-carbon ferrochrome is high, but the mass percentage of P in the molten steel is also high; when the total amount of the slag in the converter is high, the high-carbon ferrochrome is influenced to enter the molten steel, so that the high-carbon ferrochrome cannot be completely melted into the molten steel, and the high-carbon ferrochrome absorption rate is low.
TABLE 3 influence of mass percentage of C in molten steel before alloying on smelting effect
As can be seen from table 3, when the mass percentage of C in the molten steel is high before alloying, dephosphorization of the molten steel is not facilitated, and when the content of C in the molten steel is low, the content of O in the molten steel is high, and when alloying is performed on the molten steel, since the alloy material is relatively active, the alloy material is oxidized with O in the molten steel first and then alloyed with the molten steel, and the absorption rate of the alloy element by the molten steel is affected.
TABLE 4 influence of oxygen supply intensity and blowing time on the smelting effect during blowing
As can be seen from table 4, the large oxygen supply strength causes a large amount of reaction between the alloyed chromium element and the blown oxygen, and the high-carbon ferrochrome absorption rate is reduced to increase the production cost, and the oxygen supply strength and the complementary blowing time are greatly reduced during the complementary blowing, so that the P element in the steel can be further removed or the temperature of the molten steel can be slightly raised, and the molten steel can satisfy the tapping conditions.
The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. An alloying smelting method in a converter is characterized by comprising the following steps:
the method comprises the following steps: adding molten iron and scrap steel into a converter;
step two: oxygen blowing smelting is carried out in the converter, and meanwhile, argon is blown from the bottom of the converter; controlling the total slag amount in the converter to be 20-35 kg/t;
step three: after oxygen blowing is stopped, adding high-carbon ferrochrome from a top bin of the converter, increasing argon flow, carrying out bottom blowing stirring, and alloying molten steel in the converter;
step four: and detecting molten steel, and tapping after the molten steel meets the smelting requirement.
2. The alloying smelting method in the converter according to claim 1, wherein the step one is as follows: the mass percent of Si is less than 0.35%, the mass percent of P is less than 0.08%, and the mass percent of Ti is less than 0.06%.
3. The alloying smelting method in the converter according to the claim 1 or 2, characterized in that, in the step one, the mass ratio of the added scrap steel is below 20%.
4. The alloying smelting method in converter according to claim 1, wherein in the second step, oxygen supply strength is 1.5-3.0 Nm when oxygen blowing smelting is performed 3 V (t.min), the oxygen pressure is 0.70-0.90 Mpa; when argon is blown from the bottom, the flow rate of the argon is 0.03-0.20 Nm 3 /(t·min)。
5. The alloying smelting method in the converter according to claim 1 or 4, wherein in the second step, a slag former is added into the converter for forming slag in the converter, and the alkalinity of the slag is 3-4.5.
6. The alloying smelting method in the converter according to claim 1, wherein in the third step, when the mass percent of C in molten steel is 0.08-0.20% and the temperature of the molten steel is 1560-1600 ℃, oxygen blowing is stopped.
7. The alloying smelting method in the converter according to claim 1 or 6, wherein in the third step, the argon flow is increased to 0.20-0.35 Nm 3 And (t & min), the bottom blowing stirring time is 30-60 s.
8. The alloying smelting method in the converter according to claim 1, wherein in the fourth step, when the mass percent of P in the molten steel meets the requirement, the mass percent of C in the molten steel is 0.06-0.20%, and the temperature of the molten steel is 1540-1590 ℃, the smelting requirement is met.
9. The alloying smelting method in the converter according to claim 8, wherein in the fourth step, if the molten steel does not meet the smelting requirement, the complementary blowing is carried out until the smelting requirement is met.
10. The alloying smelting method in the converter according to claim 9, characterized in that the additional blowing is carried out specificallyOxygen-supplementing and smelting are carried out in the converter, and argon is supplemented and blown at the bottom of the converter, wherein: the blowing-in oxygen supply intensity is 0.8-1.5 Nm 3 /(t.min), the flow rate of argon supplement blowing is 0.20-0.35 Nm 3 /(t.min), the blowing time is 30s or less.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE973707C (en) * | 1949-06-05 | 1960-05-12 | Phoenix Rheinrohr Ag Vereinigt | Process for producing alloyed steels |
| CN107034421A (en) * | 2017-04-01 | 2017-08-11 | 江苏省沙钢钢铁研究院有限公司 | High-corrosion-resistance high-strength steel bar and converter manufacturing method thereof |
| CN107130078A (en) * | 2016-02-29 | 2017-09-05 | 鞍钢股份有限公司 | Smelting method for producing low-phosphorus high-alloy steel through alloying in converter |
| CN108660278A (en) * | 2017-03-27 | 2018-10-16 | 宝山钢铁股份有限公司 | A kind of converter smelting method of low-phosphorous low-oxygen steel |
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Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE973707C (en) * | 1949-06-05 | 1960-05-12 | Phoenix Rheinrohr Ag Vereinigt | Process for producing alloyed steels |
| CN107130078A (en) * | 2016-02-29 | 2017-09-05 | 鞍钢股份有限公司 | Smelting method for producing low-phosphorus high-alloy steel through alloying in converter |
| CN108660278A (en) * | 2017-03-27 | 2018-10-16 | 宝山钢铁股份有限公司 | A kind of converter smelting method of low-phosphorous low-oxygen steel |
| CN107034421A (en) * | 2017-04-01 | 2017-08-11 | 江苏省沙钢钢铁研究院有限公司 | High-corrosion-resistance high-strength steel bar and converter manufacturing method thereof |
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