CN1480549A - Clean steel containing barium and its manufacturing method - Google Patents

Abstract

A Ba contained alloy steel contains C (0.35-0.90 wt.%), Si (0.15-20), Mn (0.25-2.0), Ba (0.0001-0.04), S (0-0.035), P (0-0.035), Cr (0-3.0), Ni (0-3.0), V (0-0.5), Nb (0-0.5), Cu (0-0.5), Mo (0-3.0) and Fe (rest). It is prepared through smelting, refining, adding aluminium or silico-aluminium for predeoxidizing, blowing argon gas for stirring, and adding Ba alloy element chosen from BaSi, BaCaSi and BaSiAl.

Description

A kind of baric Clean Steel and production method thereof

Technical field

The invention belongs to field of alloy steel, particularly the steel alloy of baric and production technique.

Background technology

Along with development of modern industry, composition, form, size and the distribution of performance, cleanliness factor and the steel inclusion of ferrous materials are had higher requirement.For some specific steel grades, as bearing steel, spring steel and pipe line steel, not only require oxygen content in steel low, and Al in the strict control steel ₂O ₃Be mingled with low simultaneously Al ₂O ₃Being mingled with also is the key that realizes the casting of continuous casting low overheat.And deoxidization technique mainly contains aluminium deoxidation and two kinds of methods of non-aluminium deoxidation at present, and wherein the former utilizes aluminium and the strong characteristics of oxygen binding ability, earlier with 90% or more the generation Al of aluminium with entire oxygen content in the steel ₂O ₃Be mingled with, and then adopt methods such as stirring, wash heat Al ₂O ₃Get rid of; The latter is only with thick deoxidations such as silicomanganese, and aluminium and calcium contents in the strict control steel, to separate out composition, form and the distribution of inclusion in the control steel.From these two kinds of methods comparatively speaking, the former can drop to lower level with the oxygen level in the steel in conjunction with measures such as vacuum, wash heat and stirrings, but in the steel remnants to be mingled with mainly be with Al ₂O ₃Be main (accounting for more than 60%), and the latter can be with the Al in remaining being mingled with in the steel ₂O ₃Ratio drops to lower level (accounting for below 40%), but total oxygen content level higher (seeing " special steel " the 22nd the 6th phase of volume, " special steel " the 24th volume first phase and " steel research journal " the 15 volume second phase) in the steel.

The clear 57-23047 of Japan provides a kind of pipe line steel of baric, and this is a kind of senior pipeline steel that prevents to cause the hydrogen crackle of carbon content 0.3%, and this steel is because carbon content is lower, and the degree of steel is relatively poor, makes the obdurability effect of barium fail to give full play to.

Summary of the invention

The objective of the invention is on the basis that overcomes above-mentioned existing in prior technology defective, a kind of decontamination effect improving that can improve steel is provided, can significantly improve the toughness of steel again, and become low baric Clean Steel.

At above-mentioned purpose, the chemical ingredients of baric Clean Steel of the present invention (wt%) is: C 0.35-0.90%, Si 0.15-2.0%, Mn 0.25-2.0% Ba 0.0001-0.04%, S≤0.035%, following composition: Cr≤3.0%, Ni≤3.0%, V≤0.5%, Nb≤0.5%, Cu≤0.5%, Mo≤3.0% are surplusly also contained for Fe. in P≤0.035 in chemical ingredients.

The present invention utilizes barium to have the deoxidizing capacity stronger than aluminium; Than calcium, density that magnesium is big, high boiling point, the characteristics of low vapour pressure add adjustable clamp foreign material density fusing point in steel with it, improve adhesivity wetting property and the metallic contact surface energy of molten steel to inclusion, thereby make inclusion be easy to discharge; Barium is that (interfacial tension between barium and iron liquid is 1626MJ/m to surface active element ², higher about one times than aluminium) gather partially in crystal boundary and phase boundary, can change attribute, pattern, quantity, size and the distribution of carbide and nonmetal inclusion in the steel, strengthen crystal boundary, thereby improve the obdurability of steel.Barium can also with Al ₂O ₃Or SiO ₂Deng being mingled with the characteristics that form duplex impurity, change the attribute of inclusion.

Specifically, adopt barium alloyization can reach following purpose: 1. to change attribute, pattern, quantity, size and the distribution of carbide and non-metallic inclusion in the steel, strengthen crystal boundary or play the microalloying effect, improve the performance of material; 2. reduce the gas in the steel and be mingled with content; 3. make Al ₂O ₃Being mingled with sex change for the brittle oxide of base is tiny, uniform plasticity Spherical Inhomogeneity, makes Al in the oxide inclusion ₂O ₃Ratio less than 40%, the steel inclusion pollution level significantly reduces; 4. make the aluminium of the fatigue life ratio same oxygen content of steel grades such as bearing steel and spring steel handle the steel raising more than 20%; 5. reduce Al in the steel ₂O ₃Be mingled with and the aluminium amount, help eliminating the continous casting sprue dross.

The production method of baric Clean Steel of the present invention:

The production of baric Clean Steel of the present invention is in electric furnace, converter or other non-vacuum melting stove in routine behind the smelting furnace, carries out refining in a refining unit, carry out barium alloyization in the refining later stage.Before adding the barium alloy element, add reductor aluminium or sial, carry out pre-deoxidation, carry out blowing argon gas after the deoxidation and stir, add the barium alloy element then; Alloying element barium adds with any alloy form among BaSi, BaCaSi, the BaSiAl; Its add-on is calculated by the proportioning of the chemical ingredients (wt%) of this baric Clean Steel; The adding mode of barium alloy adds with cored-wire or alloy block.

Consider that the barium oxidisability is strong and the solubleness in molten steel is little, and the aluminium characteristics stronger to oxygen affinity, what add that aluminium can be with the dissolved oxygen in the steel changes Al into more than 99% ₂O ₃, stir by Argon, the coralloid large-scale Al of cohesion ₂O ₃Get rid of from the molten steel come-up; According to generating Al in the molten steel after the pre-deoxidation ₂O ₃And SiO ₂Amount adds different types of barium alloy (comprising silicon barium, silico-calcium barium, sial barium and silico-calcium aluminium barium), impels to form low-melting macrobead baric duplex impurity.It is bigger to utilize such to be mingled with the specific surface tension difference of molten steel, and very easily the characteristics of come-up eliminating are eliminated Al ₂O ₃The harm that is mingled with, and further reduce oxygen level.Simultaneously to being difficult to small-sized Al by the come-up eliminating ₂O ₃Inclusion carries out sex change, assembles and handle, and forms oarse-grained liquid state and the discharge of floating.

Compared with prior art, the present invention has the following advantages:

(1) by the barium microalloying, can crystal grain thinning, strengthen crystal boundary, thereby significantly improve the toughness of steel.

(2) by the degree of depth deoxidation and the inclusion modification of barium, can significantly improve steel cleanness, optimization is mingled with distribution.

(3) on the aluminium deoxidation basis, by the barium alloy processing under antivacuum oxygen content in steel is further reduced, reach the oxygen level effect identical, but compare with the vacuum-treated steel of the same terms with vacuum-treated steel, can save the vacuum-treat expense, promptly reduce cost.

(4) can improve fatigue lifetime of material, be that the same steel grade of only handling through aluminium of fatigue life ratio same oxygen content of the bearing steel of 8ppm improves 63.5% as the oxygen level that adopts the present invention to produce.

Embodiment:

Embodiment

According to baric Clean Steel of the present invention and production method thereof on testing furnace and refining furnace melting 3 stove steel, on electric furnace, carry out earlier refining just, measure its chemical ingredients before the tapping, the tapping back adds conventional refining slag and adds pre-deoxidant aluminium or silumin in ladle, the ladle that will fill molten steel then enters and carries out refining in the refining furnace, adopt cored-wire feeding method or alloy block method to add barium alloy after the chemical ingredients to be adjusted, the suitable tapping again of liquid steel temperature, pour into strand and roll into material, sampling and measuring chemical ingredients then, and after corresponding thermal treatment, measure mechanical property.The chemical ingredients of three stove steel is as shown in table 1, and pre-deoxidant and barium alloy and add-on thereof are as shown in table 2, and refining slag is formed and the barium alloy mode that adds is also listed in the table 2, and table 3 is the mechanical property and the inclusion detected result of steel.

Table 1 barium alloy composition of steel, wt%

Sequence number	Steel grade	??C	??Si	??Mn	??Cr	????P	????S	??Ni	??Cu	??Ba #	??T.[O]	Fe
													1	?60Si2Mn	?0.60	?1.80	?0.80	?0.25	?0.015	?0.010	?0.25	?0.15	?0.010	?0.0009	Surplus
2	?U71Mn	?0.68	?025	?1.30	?/	?0.018	?0.010	?0.15	?0.15	?0.020	?0.0013	Surplus
													3	?SWRH82B	?0.82	?0.20	?0.8	?/	?0.015	?0.010	?0.15	?0.20	?0.015	?0.0012	Surplus

The composition of table 2 embodiment reductor and barium alloy add-on, refining slag

Sequence number	Steel grade	Tapping carbon	Pre-deoxidant and amount	Barium alloy	Add the barium amount	Refining slag is mainly formed	Remarks
								1	?60Si2Mn	?0.40％	????SiAl ????1.2Kg/t ????SiAl ????1.4Kg/t	BaCaSi	?0.10Kg/t	??CaO52％；SiO 217％；Al 2O 37％； ??CaF 28％	The white slag feeding
2	?U71Mn	?0.45％	BaSi	?0.2Kg/t	??CaO54％；SiO 216％；Al 2O 39％； ??CaF 27％	The white slag feeding
							3	?SWRH ?82B	?0.50％	????SiAl ????1.5Kg/t		BaCaSi	?0.15Kg/t	??CaO53％；SiO 219％；Al 2O 3??11％；CaF 26％	The white slag feeding

Table 3 barium alloy mechanical property and inclusion assay

Sequence number	Steel grade	Yield strength Mpa	Tensile strength Mpa	Unit elongation, %	Section shrinks %	Category-B is mingled with	The C class is mingled with	The D class is mingled with
									?1	?60Si2Mn	?1480/1520	1580/1650	?δ 10：8/10	?34/41	/	?/	?/
?2	?U71Mn	?/	1030	?δ 5：13	?/	0.5×4，1.0×2	?0.5×3，1.0×3	?05×6
									?3	?SWRH82B	?/	1180	?δ 5：10	?42	/	?0.5×5，1.0×1	?0.5×6

Claims (6)

1. baric Clean Steel is characterized in that its chemical ingredients (wt%) is: C 0.35-0.90%, and Si 0.15-2.0%, Mn 0.25-2.0% Ba 0.0001-0.04%, S≤0.035%, P≤0.035, surplus is Fe.

2. baric Clean Steel according to claim 1 is characterized in that also containing in the chemical ingredients Cr≤3.0%.

3 according to claim 1,2 described baric Clean Steels, it is characterized in that also containing in the chemical ingredients Ni≤3.0%.

4. according to claim 1,2 described baric Clean Steels, it is characterized in that also containing in the chemical ingredients V≤0.5%, Nb≤0.5%, Cu≤0.5%.

5. according to claim 1,2 described baric Clean Steels, it is characterized in that also containing in the chemical ingredients Mo≤3.0%.

6. the production method of the described baric Clean Steel of claim 1: in electric furnace, converter or other non-vacuum melting stove of routine, behind the smelting furnace, in a refining unit, carry out refining earlier, carry out barium alloyization, it is characterized in that in the refining later stage:

(1) before adding the barium alloy element, add reductor aluminium or sial, carry out pre-deoxidation, carry out blowing argon gas after the deoxidation and stir, add the barium alloy element then;

(2) alloying element barium can add with any alloy form among BaSi, BaCaSi, the BaSiAl;

(3) the adding mode of barium alloy adds with cored-wire or alloy block.