CN102634638A - Calcium treatment process of rod wire alloy steel - Google Patents

Calcium treatment process of rod wire alloy steel Download PDF

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Publication number
CN102634638A
CN102634638A CN2012101102357A CN201210110235A CN102634638A CN 102634638 A CN102634638 A CN 102634638A CN 2012101102357 A CN2012101102357 A CN 2012101102357A CN 201210110235 A CN201210110235 A CN 201210110235A CN 102634638 A CN102634638 A CN 102634638A
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China
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calcium
molten steel
steel
wire
soft blow
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CN2012101102357A
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Inventor
朱苗勇
邓志银
田新中
胡黎宁
祭程
阴峻峰
钟保军
戴永刚
苏庆林
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Northeastern University China
Xingtai Iron and Steel Co Ltd
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Northeastern University China
Xingtai Iron and Steel Co Ltd
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Priority to CN2012101102357A priority Critical patent/CN102634638A/en
Publication of CN102634638A publication Critical patent/CN102634638A/en
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Abstract

The invention belongs to the technical field of metallurgy of iron and steel, and particularly relates to a calcium treatment process of rod wire alloy steel. The invention adopts a converter smelting-LF (ladle furnace) refining-RH refining-square billet continuous casting production technique. The calcium treatment process is implemented in a way that: after the LF refining finishes, feeding an iron calcium wire, silico-calcium wire or solid calcium wire into molten steel at the linear speed of 50-250m/min to control the mass percent of calcium aluminum in the molten steel at 0.08-0.16%; after the soft blow, carrying out RH treatment; after the RH treatment finishes, carrying out calcium carbonate treatment, and feeding the iron calcium wire, silico-calcium wire or solid calcium wire into molten steel at the linear speed of 50-250m/min to control the mass percent of calcium aluminum in the molten steel at 0.04-0.08%; and carrying out soft blow, and casting. When the treatment process is used for producing high-quality steel, the inclusion level can not deteriorate, the castability of the molten steel is good, the number of continuous casting furnaces is increased, the calcium content of the molten steel is low but does not influence the casting performance, and the treatment process plastifies the inclusions and improves the mechanical properties of steel.

Description

A kind of calcium treating method of Bar Wire Product steel alloy
Technical field
The invention belongs to technical field of ferrous metallurgy, more particularly to a kind of calcium treating method of Bar Wire Product steel alloy.
Background technology
With the development of society, the industrial combination property to steel requires increasingly strict, Alloy Constructional Steel proposes an urgent demand of higher intensity, greater security, long-life and low cost.Substantial amounts of research shows that steel inclusion severely impacts the various mechanical properties of steel, therefore, improves the degree of purity of molten steel, and the non-metallic inclusion of control molten steel seems abnormal important.In metallurgical industry, on the one hand by making inclusion content fewer and fewer using various smelting processes, size is less and less;On the other hand it is then, by inclusion conditioning, to make field trash more yielding in hot-working, makes its plastification, such as Calcium treatment technology.
When carrying out aluminium deoxidation to Bar Wire Product steel alloy, it is poor often to have a pourability of molten steel, the problems such as continuous casting sprue bonding and blocking, and 12CaO can be generated by carrying out rational Calcium treatment to it7Al2O3And CaOAl2O3Deng lower melting point inclusion, this type impurity will not be bonded on the mouth of a river, do not result in nozzle blocking, can substantially improve the casting properties of aluminum killed steel.When carrying out Calcium treatment, enough calcium is disposably typically added into molten steel before pouring, molten steel is handled, but the nonmetallic liquid inclusions infiltration angle that the denaturation of this Calcium treatment is obtained is big, it is difficult to float, easily remains in steel and generate a small amount of large-sized CaO-Al2O3It is that inclusion behavior after field trash, therefore Calcium treatment often deteriorates.In addition, if calcium content control is too low, not enough, generation is still high-melting-point field trash to inclusion modification, can not improve the castability of molten steel;If Calcium treatment control is too high, dystectic calcium sulfide field trash can be also generated, this type impurity is not only unfavorable for solving the problems such as pourability of molten steel is poor, can increase the probability that the mouth of a river bonds and blocked on the contrary.Part Bar Wire Product steel alloy, such as welding wire steel, it is desirable to which the calcium content of finished product is as far as possible low, to meet, calcium content is up to standard during production, and usual Calcium treatment is incorrect, causes pourability of molten steel poor, and casting sequence is low, greatly increases production cost.Therefore, rationally control Calcium treatment is particularly important.
The content of the invention
In order to solve the inclusion behavior deterioration problem after Bar Wire Product steel alloy Calcium treatment, the present invention provides a kind of calcium treating method of Bar Wire Product steel alloy, it is therefore an objective to improve the cleanliness factor of molten steel, and improves the castability of molten steel, controls the calcium content of molten steel.
Realize the technical scheme is that:Using " converter smelting → LF(Ladle)Refining → RH(Degassing circulation)Refining → billet continuous casting " production technology, carries out Calcium treatment to molten steel at the end of LF refining, carries out RH processing again after soft blow, RH processing carries out fine particle calcium carbonate processing after terminating, then carries out soft blow again.The purpose of first time Calcium treatment is the field trash in molten steel is just denatured in RH before processings, and can be removed as early as possible by RH circulation collision;The purpose of second of Calcium treatment is that the field trash for reducing and separating out with temperature is denatured, due to precipitation to be mingled with object amount relatively few, therefore handled using fine particle calcium carbonate.Specific operating procedure is as follows:
(1)Use aluminium to carry out deoxidation the molten steel of converter smelting, make oxygen content in molten steel<10×10-4%, it is CaO then to carry out controlling the composition in clinker in LF refining, refining process:47 ~ 65wt%, Al2O3:18 ~ 30wt%, SiO2:3 ~ 25wt%, MgO:5 ~ 10wt%, FeO:<1wt%, 30 ~ 55min of LF refining time;
(2)After LF refining terminates, iron calcium line, silicon-calcium wire or solid calcium line, 50 ~ 250m/min of wire-feeding velocity are fed to molten steel, controls the calcium aluminium mass percent in molten steel to be(0.08~0.16);
(3)After line feeding is finished, soft blow argon gas is carried out to molten steel, the soft blow time is 2 ~ 10min, and soft blow tolerance is controlled in 20 ~ 50NL/min;
(4)RH application of vacuum is carried out to molten steel, vacuum < 267Pa are controlled, 20 ~ 40min of processing time, pure 10 ~ 30min of degassing time, lifting tolerance is 1300 ~ 1600NL/min;
(5)After RH application of vacuum is finished, iron calcium line, silicon-calcium wire or solid calcium line, 50 ~ 250m/min of wire-feeding velocity are fed to molten steel, controls the calcium aluminium mass percent in molten steel to be(0.04~0.08);
(6)After line feeding is finished, soft blow argon gas is carried out to molten steel, 10 ~ 25min of soft blow time, soft blow tolerance controls 20 ~ 50NL/min;
(7)Tundish covering flux is added in most backward molten steel, is poured into a mould using Con casting ladle long nozzle blowing argon, obtains strand.
Wherein, described Bar Wire Product steel alloy be cold-forging steel, prestress steel or pinion steel etc. with the Bar Wire Product steel alloy of aluminium deoxidation, be not limited merely to these three steel grades;
Step(2)Described in feeding calcium line in, a diameter of the 13 of iron calcium line0.6mm, wherein 64 ~ 70wt% of iron content, 30 ~ 36wt% of calcium content, surplus is impurity;A diameter of the 13 of silicon-calcium wire0.6mm, wherein silicone content are 50 ~ 65wt%, and 28 ~ 50wt% of calcium content, surplus is impurity;A diameter of the 9.5 of solid calcium line0.5mm, wherein calcium content >=97%, surplus are impurity;
Step(7)Described in the composition of tundish covering flux be:CaO:45 ~ 55wt%, Al2O3:30 ~ 40wt%, SiO2:≤ 9wt%, MgO:≤6wt%.
The beneficial effects of the invention are as follows:
(1)High-quality steel is produced, after the Calcium treatment scheme using the present invention, inclusion behavior will not deteriorate.Common process is typically disposably to add calcium to carry out Calcium treatment before cast, easily generates larger field trash and is difficult to float, causes field trash exceeded;First time Calcium treatment is placed on after LF processing terminates by the present invention, field trash is changed into the field trash of liquid at this moment, even if the larger field trash of generation, is operated by RH circular treatment and soft blow twice, liquid inclusions floating interval of floating dock 30min at least longer than common process, larger-size field trash(Diameter is more than 10 μm)Also polymerization can be collided completely and is discharged from molten steel, in addition, the present invention has soft blow processing after first time Calcium treatment, calcium that so can uniformly in molten steel, enables field trash to be preferably denatured, can avoid being directly entered the incomplete problem of inclusion modification after RH processing, second segment Calcium treatment is denatured to the field trash of precipitation, this kind of inclusion size is small, and quantity is also few, will not also cause inclusion behavior to deteriorate by soft blow after denaturation.
(2)Pourability of molten steel is good, casting sequence increase, production cost reduction.Field trash in the present invention program after first time Calcium treatment in steel is in a liquid state, second of fine particle calcium carbonate processing makes the field trash of precipitation also can be effectively denatured, therefore the field trash that either field trash of deoxidation process generation or temperature reduction process are separated out is difficult to bond at the mouth of a river, nozzle blocking can not be caused, the castability of molten steel is substantially improved.So casting sequence can be greatly increased, and made the production cost of ton steel and reduced.
(3)The calcium content of molten steel is relatively low without influenceing casting performance.Under vacuum, dissolving calcium in steel easily generates calcium steam and escaped from steel, therefore in RH processing procedures, the dissolving calcium content in steel can be fewer and fewer, second of fine particle calcium carbonate processing is more much lower than conventional Calcium treatment technique calcium content, generally calcium content can be controlled into 20 × 10-4It is even lower within %, therefore on the premise of casting performance is not influenceed, calcium content in molten steel can be efficiently controlled, this controls strict steel grade to be extremely advantageous calcium content.
(4)Make field trash plastification, improve the mechanical property of steel.Because inclusion melting point is low, liquid is presented in steel spherical.In hot rolling, low-melting field trash can occur slightly to deform, and due to the globular inclusion compared with low melting point and the reduction of steel matrix interfacial stress intensity, this is also beneficial to improve the mechanical property of steel.
Table 1 is that original Calcium treatment technique is graded with the field trash obtained by the present invention.Ranking method, as it can be seen from table 1 the present invention is substantially reduced compared to protocalcium handling process D type impurity ranks, can meet the requirement of D type impurity≤1 grade with reference to GB/T 10561-2005.
The original Calcium treatment technique of table 1 is graded with the field trash obtained by the present invention
Embodiment
Embodiment 1
The present embodiment is illustrated with producing Bar Wire Product cold-forging steel ML40Cr.
(1)The molten steel of converter smelting carries out deoxidation using aluminium, makes oxygen content in molten steel<10×10-4After %, it is CaO controlled in LF refining, refining process the composition in clinker:65wt%, Al2O3:26wt%, SiO2:3wt%, MgO:5wt%, FeO:0.3wt%, surplus is impurity, LF refining time 30min;
(2)At the end of LF refining, to a diameter of 12.4mm iron calcium line of molten steel feeding, wherein iron content 64wt%, calcium content 30wt%, surplus is impurity;Wire-feeding velocity 200m/min, it is 0.16 to control the calcium aluminium mass percent in molten steel: 
(3)After line feeding is finished, soft blow argon gas is carried out to molten steel, the soft blow time is 10min, and soft blow tolerance is controlled in 50NL/min;
(4)RH application of vacuum is carried out to molten steel, control vacuum is less than 267Pa, and processing time 20min, pure degassing time 10min, lifting tolerance is 1300NL/min;
(5)After RH application of vacuum is finished, to a diameter of 12.4mm iron calcium line of molten steel feeding, wire-feeding velocity 200m/min, it is 0.08 to control the calcium aluminium mass percent in molten steel.
(6)After line feeding is finished, soft blow argon gas, soft blow time 10min, soft blow tolerance control 50NL/min are carried out to molten steel.
(7)Add tundish covering flux, wherein CaO:45wt%, Al2O3:40wt%, SiO2:9wt%, MgO:6wt%, is poured into a mould using Con casting ladle long nozzle blowing argon, obtains strand.
The each component content of final products ML40Cr steel grade Bar Wire Product steel alloys is:C:0.40wt%、Si:0.22wt%、Mn :0.76wt%、P:0.015 wt%、S:0.008wt%、Cr:0.97 wt%、Al:0.04wt%, surplus is iron.The total oxygen content of steel is 7.1 × 10-4Calcium content is 30 × 10 in %, molten steel-4%, D type impurity are rated 1.0 grades, and field trash is most for calcium-aluminate in spherical.
Embodiment 2
The present embodiment is illustrated with producing Bar Wire Product prestress steel 30MnSi.
(1)The molten steel of converter smelting carries out deoxidation using aluminium, makes oxygen content in molten steel<10×10-4After %, it is CaO controlled in LF refining, refining process the composition in clinker:50wt%, Al2O3:18wt%, SiO2:25wt%, MgO:6wt%, FeO:0.9wt%, surplus is impurity, LF refining time 55min;
(2)At the end of LF refining, a diameter of 13.6mm silicon-calcium wires are fed to molten steel, wherein silicone content is 65wt%, and calcium content is 28wt%, and surplus is impurity;Wire-feeding velocity 250m/min, it is 0.1 to control the calcium aluminium mass percent in molten steel; 
(3)After line feeding is finished, soft blow argon gas is carried out to molten steel, the soft blow time is 10min, and soft blow tolerance is controlled in 20NL/min;
(4)RH application of vacuum is carried out to molten steel, control vacuum is less than 267Pa, and processing time 40min, pure degassing time 30min, lifting tolerance is 1600NL/min;
(5)After RH application of vacuum is finished, to a diameter of 13.6mm silicon-calcium wires of molten steel feeding feeding, wire-feeding velocity 250m/min, it is 0.065 to control the calcium aluminium mass percent in molten steel.
(6)After line feeding is finished, soft blow argon gas, soft blow time 10min, soft blow tolerance control 50NL/min are carried out to molten steel.
(7)Add tundish covering flux, wherein CaO:55wt%, Al2O3:32wt%, SiO2:8wt%, MgO:5wt%, is poured into a mould using Con casting ladle long nozzle blowing argon, obtains strand.
The each component content of final products SWRH82B steel grade Bar Wire Product steel alloys is: C:0.31wt%、Si:0.86wt%、Mn:1.25 wt%、P:0.016 wt%、S:0.007 wt%、Al:0.02wt%, surplus is iron.The total oxygen content of steel is 7.1 × 10-4Calcium content is 13 × 10 in %, molten steel-4%, D type impurity are rated 1.0 grades, and field trash is most for calcium-aluminate in spherical.
Embodiment 3
The present embodiment is illustrated with producing Bar Wire Product pinion steel 20CrMoH.
(1)The molten steel of converter smelting carries out deoxidation using aluminium, makes oxygen content in molten steel<10×10-4After %, it is CaO controlled in LF refining, refining process the composition in clinker:47wt%, Al2O3:30wt%, SiO2:12wt%, MgO:9.9wt%, FeO:0.5wt%, surplus is impurity, LF refining time 40min;
(2)At the end of LF refining, a diameter of solid calcium lines of 10mm, wherein calcium content 97% are fed to molten steel, surplus is impurity;Wire-feeding velocity 50m/min, it is 0.08 to control the calcium aluminium mass percent in molten steel;
(3)After line feeding is finished, soft blow argon gas is carried out to molten steel, the soft blow time is 6min, and soft blow tolerance is controlled in 30NL/min;
(4)RH application of vacuum is carried out to molten steel, control vacuum is less than 267Pa, and processing time 30min, pure degassing time 20min, lifting tolerance is 1400NL/min;
(5)After RH application of vacuum is finished, to a diameter of solid calcium lines of 10mm of molten steel feeding feeding, wire-feeding velocity 50m/min, it is 0.04 to control the calcium aluminium mass percent in molten steel.
(6)After line feeding is finished, soft blow argon gas, soft blow time 15min, soft blow tolerance control 20NL/min are carried out to molten steel.
(7)Add tundish covering flux, wherein CaO:50wt%, Al2O3:35wt%, SiO2:9wt%, MgO:6wt%, is poured into a mould using Con casting ladle long nozzle blowing argon, obtains strand.
The each component content of final products 20CrMoH steel grade Bar Wire Product steel alloys is C:0.2wt%、Si:0.3wt%、Mn:0.55 wt%、P:0.015 wt%、S:0.008 wt%、Cr:0.9wt%、Al :0.03wt%, surplus is iron.The total oxygen content of steel is 7.0 × 10-4Calcium content is 12 × 10 in %, molten steel-4%, D type impurity are rated 1.0 grades, and field trash is most for calcium-aluminate in spherical.

Claims (4)

1. a kind of calcium treating method of Bar Wire Product steel alloy, it is characterised in that follow the steps below:(1)Use aluminium to carry out deoxidation the molten steel of converter smelting, make oxygen content in molten steel<10×10-4%, it is CaO then to carry out controlling the composition in clinker in LF refining, refining process:47 ~ 65wt%, Al2O3:18 ~ 30wt%, SiO2:3 ~ 25wt%, MgO:5 ~ 10wt%, FeO:<1wt%, 30 ~ 55min of LF refining time;
(2)After LF refining terminates, iron calcium line, silicon-calcium wire or solid calcium line, 50 ~ 250m/min of wire-feeding velocity are fed to molten steel, controls the calcium aluminium mass percent in molten steel to be(0.08~0.16);
(3)After line feeding is finished, soft blow argon gas is carried out to molten steel, the soft blow time is 2 ~ 10min, and soft blow tolerance is controlled in 20 ~ 50NL/min;
(4)RH application of vacuum is carried out to molten steel, vacuum < 267Pa are controlled, 20 ~ 40min of processing time, pure 10 ~ 30min of degassing time, lifting tolerance is 1300 ~ 1600NL/min;
(5)After RH application of vacuum is finished, iron calcium line, silicon-calcium wire or solid calcium line, 50 ~ 250m/min of wire-feeding velocity are fed to molten steel, controls the calcium aluminium mass percent in molten steel to be(0.04~0.08);
(6)After line feeding is finished, soft blow argon gas is carried out to molten steel, 10 ~ 25min of soft blow time, soft blow tolerance controls 20 ~ 50NL/min;
(7)Tundish covering flux is added in most backward molten steel, is poured into a mould using Con casting ladle long nozzle blowing argon, obtains strand.
2. the calcium treating method of a kind of Bar Wire Product steel alloy according to claim 1, it is characterised in that described Bar Wire Product steel alloy is the Bar Wire Product steel alloy with aluminium deoxidation, is cold-forging steel, prestress steel or pinion steel.
3. a kind of calcium treating method of Bar Wire Product steel alloy according to claim 1, it is characterised in that step(2)Described in feeding calcium line in, a diameter of the 13 of iron calcium line0.6mm, wherein 64 ~ 70wt% of iron content, 30 ~ 36wt% of calcium content, surplus is impurity;A diameter of the 13 of silicon-calcium wire0.6mm, wherein silicone content are 50 ~ 65wt%, and 28 ~ 50wt% of calcium content, surplus is impurity;A diameter of the 9.5 of solid calcium line0.5mm, wherein calcium content >=97%, surplus are impurity.
4. a kind of calcium treating method of Bar Wire Product steel alloy according to claim 1, it is characterised in that step(7)Described in the composition of tundish covering flux be:CaO:45 ~ 55wt%, Al2O3:30 ~ 40wt%, SiO2:≤ 9wt%, MgO:≤6wt%.
CN2012101102357A 2012-04-16 2012-04-16 Calcium treatment process of rod wire alloy steel Pending CN102634638A (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102876851A (en) * 2012-10-08 2013-01-16 武汉钢铁(集团)公司 Method for improving calcium yield of RH vacuum furnace
CN103849711A (en) * 2014-03-19 2014-06-11 武汉钢铁(集团)公司 Production method of aluminium deoxidation 20 Cr steel
CN104212934A (en) * 2014-09-10 2014-12-17 广东韶钢松山股份有限公司 Control method for titanium nitride inclusion of gear steel bar material
CN104212942A (en) * 2014-08-07 2014-12-17 北京科技大学设计研究院有限公司 Technology method for improving sulfide form in sulfur bearing steel
CN108866276A (en) * 2018-07-26 2018-11-23 攀钢集团攀枝花钢铁研究院有限公司 Improve the smelting process of heavy rail steel cleanness
CN110257589A (en) * 2019-06-03 2019-09-20 邢台钢铁有限责任公司 Reduce the production method of calcium-aluminate field trash in aluminum killed steel

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CN101962702A (en) * 2010-10-22 2011-02-02 首钢总公司 Method for controlling non-metallic inclusions in steel
CN102268512A (en) * 2011-07-08 2011-12-07 攀钢集团有限公司 Control method for inclusion in steel
CN102399938A (en) * 2011-11-29 2012-04-04 东北大学 Inclusion control method for rod and wire alloy steel

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JPH083620A (en) * 1994-06-14 1996-01-09 Kawasaki Steel Corp Method for melting calcium-added steel
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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102876851A (en) * 2012-10-08 2013-01-16 武汉钢铁(集团)公司 Method for improving calcium yield of RH vacuum furnace
CN102876851B (en) * 2012-10-08 2014-10-15 武汉钢铁(集团)公司 Method for improving calcium yield of RH vacuum furnace
CN103849711A (en) * 2014-03-19 2014-06-11 武汉钢铁(集团)公司 Production method of aluminium deoxidation 20 Cr steel
CN103849711B (en) * 2014-03-19 2015-07-01 武汉钢铁(集团)公司 Production method of aluminium deoxidation 20 Cr steel
CN104212942A (en) * 2014-08-07 2014-12-17 北京科技大学设计研究院有限公司 Technology method for improving sulfide form in sulfur bearing steel
CN104212942B (en) * 2014-08-07 2016-02-17 北京科技大学设计研究院有限公司 A kind of processing method improving Sulfur Bearing Steel medium sulphide content form
CN104212934A (en) * 2014-09-10 2014-12-17 广东韶钢松山股份有限公司 Control method for titanium nitride inclusion of gear steel bar material
CN108866276A (en) * 2018-07-26 2018-11-23 攀钢集团攀枝花钢铁研究院有限公司 Improve the smelting process of heavy rail steel cleanness
CN110257589A (en) * 2019-06-03 2019-09-20 邢台钢铁有限责任公司 Reduce the production method of calcium-aluminate field trash in aluminum killed steel

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Application publication date: 20120815