A kind of steel, its heat treatment steel formed and manufacture method thereof
Technical field
The present invention relates to a kind of steel, the heat treatment steel particularly relate to a kind of steel, being formed by it and
Its manufacture method.
Background technology
Steel are the requisite valuable cargos of nation-building, and it is widely used, various in style.According to state
Border standard, steel can be divided into non-alloyed steel and the big class of steel alloy two, and with the total amount containing alloying element
Steel alloy can be divided into again low-alloy steel, medium alloy steel and high-alloy steel by size.Low-alloy steel is (the lowest
Alloy high strength steel) because having higher yield strength, preferable cold and hot working mouldability, weldability and
Corrosion resistance and relatively low cold short tendency, breach and aging sensitivity and become in steel and iron industry and develop
Rapid and the most dynamic steel grade.
Domestic Hi-Stren steel subject matter in the presence of development includes that intensity is low, quality relatively
Difference, product composition and unreasonable structure etc., the most mainly rely on the total amount of C element and alloying element
Improve the intensity of steel.Since the seventies, worldwide Hi-Stren steel enters one
Brand-new developing period, the proposition of chemical composition-technique-tissue-performance quaternity relation, make steel
Tissue and microstructure occupy leading position.
At present, the method for the intensity improving Hi-Stren steel mainly includes solution strengthening, diffusion-precipitation
Strengthening, refined crystalline strengthening etc..Solution strengthening is to cause distortion of lattice by the solute atoms incorporating in solid solution,
Thus increase the resistance of dislocation motion, and make sliding be difficult to, the intensity of Alloy solid solution is able to hardness
Increasing, conventional alloying element includes Mn, Si, Al, Cr, Ni, Mo, Cu etc.;Refined crystalline strengthening is
Make metal material mechanics performance improve by crystal grain thinning, conventional alloying element include Al, Nb, V,
Ti, N etc.;And the hard particles that diffusion-precipitation strengthening is by the distribution of diffusion-precipitation in the material, utilize more
The ultrafine dust dissipated hinders dislocation motion, thus improves the strength of materials, conventional alloying element include Nb,
V, Ti etc..
20SiMn2MoV is a kind of widely used structural alloy steel, and its main chemical compositions is (matter
Amount percentage composition): C:0.17~0.23%;Si:0.9~1.2%;Mn:2.2~2.6%;Mo:0.3~
0.4%;V:0.05~0.12%;P :≤0.025%;S :≤0.025%;Cu :≤0.25%;Cr :≤0.
3%;Ni :≤0.3%;Surplus is Fe and inevitable element.20SiMn2MoV is carried out heat treatment
Method usually: first after 900 DEG C of quenchings, oil is cold, then air cooling, heat treatment after 200 DEG C of tempering
Rear obtained it is organized as tempered martensite, its tensile strength Rm >=1380Mpa, elongation after fracture
A >=10%, shrinkage factor Z >=40% of having no progeny, impact absorbing energy Aku2 >=55J, though the intensity of this tissue and hardness
So increasing, but combination property is not good enough, particularly impact flexibility is relatively low.
Summary of the invention
The present invention provides a kind of steel, be used for solving Hi-Stren steel of the prior art second-rate,
The technological deficiency such as the Nomenclature Composition and Structure of Complexes of product is unreasonable.
The present invention also provides for a kind of heat treatment steel formed by these steel and manufacture method thereof, is used for solving
The technological deficiency such as the impact flexibility of heat treatment steel of the prior art is relatively low.
The present invention provides a kind of steel, contain by mass percentage following component raw material: C:0.16~
0.21%;Si:0.6~1.2%;Mn:1.9~2.3%;Mo:0.3~0.4%;Nb:0.03~0.12%;
Al:0.015~0.035%;Ti :≤0.13%;P :≤0.012%;S :≤0.01%;Surplus be Fe and
Inevitably element.
Further, described steel contain following raw material components: C:0.17~0.21% by mass percentage;
Si:0.8~1.2%;Mn:1.9~2.3%;Mo:0.3~0.4%;Nb:0.03~0.06%;Al:
0.015~0.035%;Ti :≤0.13%;P :≤0.012%;S :≤0.01%;Surplus is Fe and can not
The element avoided.
Further, described steel contain following raw material components: C:0.19% by mass percentage;Si:
1.0%;Mn:2.1%;Mo:0.35%;Nb:0.05%;Al:0.025%;Ti :≤0.08%;P:
≤ 0.008%;S :≤0.005%;Surplus is Fe and inevitable element.
The present invention also provides for the manufacture method of a kind of heat treatment steel, carries out any of the above-described described steel
Heat treatment.
Further, described heat treatment includes normalized treatment, Quenching Treatment and the temper carried out successively.
Further, described normalized treatment specifically includes: by any of the above-described described heat steel to 920~
940 DEG C and cool down after being incubated 2~3 hours;Described Quenching Treatment specifically includes: will be through described normalized treatment
Heat steel to 900~920 DEG C and be incubated 2~3.5 hours (such as 2~3 hours) cool down afterwards;Institute
State temper to specifically include: to 520~580 DEG C and be incubated by the heat steel through described Quenching Treatment
Within 3.5~7.5 hours, (such as 3.5~4.5 hours) cool down afterwards.
Further, the programming rate of described normalized treatment is 80~120 DEG C/h, be further 90~
110 DEG C/h, such as 100 DEG C/h;The programming rate of described Quenching Treatment is 80~120 DEG C/h,
It is 90~110 DEG C/h further, such as 100 DEG C/h;The programming rate of described temper be 40~
60 DEG C/h, it is 50 DEG C/h further.
Further, the cooling medium of described normalized treatment and described temper is air, described quenching
The cooling medium processed is water.Further, described normalized treatment is cooled to room temperature, and described Quenching Treatment cools down
To Ms (martensite start) point (Ms) left and right or more than, described temper is cooled to room temperature.
The present invention also provides for a kind of heat treatment steel, prepares according to any of the above-described described manufacture method.
The steel that the present invention provides, product the Nomenclature Composition and Structure of Complexes is reasonable, its by the dislocation strengthening of alloying element,
The precipitation strength of fine grain strengthening and microalloy significantly improves intensity and the toughness of steel;Additionally, this
Bright by optimizing the Technology for Heating Processing to steel, while ensureing steel strength, also significantly improve its punching
Hitting toughness, the heat treatment steel formed have good combination property.
Detailed description of the invention
For making the object, technical solutions and advantages of the present invention clearer, below in conjunction with the reality of the present invention
Execute example, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described
Embodiment be a part of embodiment of the present invention rather than whole embodiments.Based on the reality in the present invention
Executing example, it is every other that those of ordinary skill in the art are obtained under not making creative work premise
Embodiment, broadly falls into the scope of protection of the invention.
The steel of the present invention, contain following component raw material: C:0.16~0.21% by mass percentage;
Si:0.6~1.2%;Mn:1.9~2.3%;Mo:0.3~0.4%;Nb:0.03~0.12%;Al:
0.015~0.035%;Ti :≤0.13%;P :≤0.012%;S :≤0.01%;Surplus is Fe and can not
The element avoided.
Hereinafter, the component raw material of the steel to the present invention is described in detail, if no special instructions, " % "
Represent mass percent.
C:0.16~0.21%
When the content of carbon (C) is less than 0.21%, steel are through influence of high austenizing temp and thermal deformation
After cooling procedure in, no longer occur the austenite two phase decompositions to ferrite Yu cementite, supercool Austria
Family name's body translates directly into the ferrite of various form and leaves the retained austenite of a small amount of rich carbon, so that
Steel have good plasticity and toughness;And the carbon content of necessity (more than 0.16%) can be with the trace added
Alloying element (such as Nb, Ti) effect separates out microalloy carbide, and it suppresses recrystallization at hot stage
And cold stage plays precipitation strength effect.C can be 0.17~0.20%, such as 0.19% further.
Si:0.6~1.2%
The element silicon (Si) of more than 0.6% is conducive to improving the impact wear resistance of steel, strengthening ferrum element
Body (Si of every 1% can make ferrite yield strength improve 85MPa), the stabilisation of promotion retained austenite;
Element silicon can also play solution strengthening effect to improve the anti-temper brittleness of low temperature of steel the precipitation to carbide
Playing inhibition, it can also reduce the transition temperature of bainite and improve the toughness of steel;But steel
The toughness of material (> 1.2%) can decrease when Si too high levels.Si can be 0.85~1.15% further,
Such as 1%.
Mn:1.9~2.3%
Manganese element (Mn) is the alloying element strongly postponing perlitic transformation, certain content (1.9% with
On) be conducive to improving the quenching degree of steel and being improved the intensity of steel by solution strengthening effect, it is permissible
Substitute For Partial metal Mo;But Mn too high levels (> 2.3%) can make steel crystal grain have the tendency of roughening.
Mn can be 2.0~2.2%, such as 2.1% further.
Mo:0.3~0.4%
The molybdenum element (Mo) of more than 0.3% can postpone perlitic transformation, but pushes away bainite transformation
Effect is less late, and the addition of Mo can meet steel requirement in high intensity and high tenacity, its addition phase
Low for traditional nickel element (Ni), and effect is more preferable;Addition can the property taken into account below 0.4%
Energy and cost.Mo can be 0.32~0.38%, such as 0.35% further.
Nb:0.03~0.12%
Niobium element (Nb) can separate out the carbide of extremely small and dispersed in steel, plays anchoring crystal boundary
Effect, thus crystal grain thinning, raising toughness, particularly at the temperature transition microstructure ultra-fining treatment of new development
Controlling in technical process, trace Nb is to be formed and strengthen the polygon born of the same parents' shape substructure having certain misorientation
Essential condition, the most oarse-grained Nb precipitate is conducive to being formed before bainitic transformation intracrystalline needle-like ferrum
Ferritic or granular bainite.The Nb of more than 0.03% can improve the impact flexibility of steel, reduce steel
Brittle transition temperature, and improving welding property, when containing Nb and Mn, the effect of crystal grain thinning is more simultaneously
Substantially;The too high levels of Nb then may cause the reduction of hardenability of steel.Nb can be further
0.04~0.06%, such as 0.05%.
Al:0.015~0.035%
Aluminium element (Al) determines nitrogen agent as deoxidation during steel-making, can refine when content is more than 0.015%
Crystal grain, improves the steel toughness when low temperature and reduces the brittle transition temperature of steel;But it is too high
Al content (> 0.035%) can reduce steel intensity at high temperature and toughness.Al can be further
0.02~0.03%, such as 0.025%.
Ti :≤0.13%
Titanium elements (Ti) is that disperse phase forms element, and appropriate interpolation can improve the uniformity of steel;So
And the second phase of disperse can be caused too much during addition too much (> 0.13%), thus cause the disconnected of steel
Rear percentage elongation declines.
P :≤0.012%
P elements (P) is inevitable impurity element, its plasticity that can make steel and toughness substantially under
Fall, even more serious (cold brittleness), therefore its content strictly should be controlled,
To reaching extremely low content, admissible scope is≤0.012%, further≤0.01%, more enters
One step ground≤0.008%.
S :≤0.01%
Element sulphur (S) is inevitable impurity element, and it can make steel produce red brittleness, thus reduces
The ductility of steel and toughness, its content should strictly control, and the content range allowed is≤0.01%, enters
One step ground≤0.008%, further≤0.005%.
In the steel of the present invention, also include other inevitable impurity element, such as N, O, H,
Its content should control in ppm level, such as N≤60ppm, O≤10ppm, H≤1.3ppm.
The steel of the present invention can use conventional method to manufacture, such as: electric furnace steel making (tapping temperature
>=1580 DEG C)+LF stove refine+VD stove vacuum outgas → pouring molten steel becomes steel ingot → ingot annealing → steel ingot
Heating (1200~1220 DEG C are incubated about 6 hours, programming rate≤80 DEG C/h) → Rolling from Ingot is made
Material → steel slow cooling → steel cleaning → steel inspection/inspection → packaging steel.Wherein it is possible to use routine
Method adjusts each chemical composition in the refining procedure of steel, so that each element in the steel prepared reaches
To above-mentioned content range.
The steel of the present invention breach the composition mentality of designing of tradition high-strength low alloy steel, rely on the most merely
The total amount of C and alloying element improves intensity and the performance of steel, but by optimizing the Nomenclature Composition and Structure of Complexes of product
(bainite structure), makes steel have good mechanical property and physicochemical property, it may be possible to alloying element
The precipitation strength of dislocation strengthening, fine grain strengthening and microalloy improves intensity and the toughness of steel.
It is possible to further above-mentioned steel to be carried out heat treatment, thus form heat treatment steel.Described heat
Process selected from normalizing, anneal, quench, be tempered, solid solution, timeliness, quenched in one or more, its
Technique generally comprises heating and cooling, the most also includes insulation, and those skilled in the art can be according to reality
Border needs to carry out conventional selection.This heat treatment can change the microscopic structure within steel, thus gives steel
The serviceability that material is good.
Particularly, the present invention proposes the manufacture method of a kind of heat treatment steel, and it carries out heat to above-mentioned steel
Process.Further, described heat treatment includes at the normalized treatment, Quenching Treatment and the tempering that carry out successively
Reason.
Described normalized treatment specifically includes: to 920~940 DEG C and protected by any of the above-described described heat steel
Temperature cooled down after 2~3 hours, specifically can be cooled to room temperature after being incubated 2 hours at 930 DEG C;Described quenching
Process specifically includes: by through the heat steel of described normalized treatment, to 900~920 DEG C and to be incubated 2~3.5 little
Cool down time after, specifically can be cooled to Ms (martensite start) point (Ms) after being incubated 2 hours at 910 DEG C
Left and right or more than;Described temper specifically includes: by the heat steel through described Quenching Treatment to 520~
580 DEG C and cool down after being incubated 3.5~7.5 hours, specifically can be cooled to after 3.5 hours 550 DEG C of insulations
Room temperature.
Further, the programming rate controlling described normalized treatment is 80~120 DEG C/h, described quenching
The programming rate processed is 80~120 DEG C/h, the programming rate of described temper is 40~60 DEG C/
Hour.
Through the heat treatment steel of above-mentioned heat treatment, in microexamination tissue, there is bainite structure, its
Having a combination property of excellence, particularly its tensile strength, impact of collision toughness, low-temperature impact toughness is equal
Increase.
Embodiment 1
According to the above-mentioned common manufacturing method preparation steel containing following raw material components (by mass percentage
Meter): C:0.19%;Si:1.0%;Mn:2.1%;Mo:0.35%;Nb:0.05%;Al:0.025%;
Ti:0.07%;P:0.006%;S:0.005%;Surplus is Fe and inevitable element.
Using dilatometry to detect the transformation temperature of these steel, wherein Ac1 is 737 DEG C, and Ac3 is 877 DEG C,
Ms is 388 DEG C, measures transformation temperature and is conducive to the parameter of Technology for Heating Processing is selected and optimized.
Above-mentioned steel are carried out heat treatment, specifically include the step that order below is carried out:
Normalized treatment: with programming rate be about 100 DEG C/h by above-mentioned heat steel to about 930 DEG C,
After at a temperature of this, (about 930 DEG C) are incubated about 2 hours, air cooling is to room temperature;
Quenching Treatment: with programming rate be about 100 DEG C/h by the heat steel through above-mentioned normalized treatment
To about 910 DEG C, after at a temperature of this, (about 910 DEG C) are incubated about 2 hours, water-cooled is to about 500 DEG C;
Temper: with programming rate be about 50 DEG C/h by the heat steel through above-mentioned Quenching Treatment extremely
About 550 DEG C, after at a temperature of this, (about 550 DEG C) are incubated about 3.5 hours, air cooling is to room temperature, is i.e. formed
Heat treatment steel.
In microexamination, the tissue of these heat treatment steel, there is bainite structure;Additionally, employing ability
Territory conventional method detects above-mentioned heat treatment steel and the combination property of 20SiMn2MoV, the results are shown in Table 1.
Embodiment 2
According to the above-mentioned common manufacturing method preparation steel containing following raw material components (by mass percentage
Meter): C:0.21%;Si:0.8%;Mn:1.9%;Mo:0.4%;Nb:0.06%;Al:0.015%;
Ti:0.08%;P:0.008%;S:0.005%;Surplus is Fe and inevitable element.
Above-mentioned steel are carried out heat treatment, specifically include the step that order below is carried out:
Normalized treatment: with programming rate be about 90 DEG C/h by above-mentioned heat steel to about 920 DEG C, in
After being incubated about 3 hours at a temperature of Gai, air cooling is to room temperature;
Quenching Treatment: with programming rate be about 90 DEG C/h by the heat steel through above-mentioned normalized treatment extremely
About 900 DEG C, after being incubated about 3 hours at a temperature of this, water-cooled is to about 450 DEG C;
Temper: with programming rate be about 60 DEG C/h by the heat steel through above-mentioned Quenching Treatment extremely
About 580 DEG C, after being incubated about 5 hours at a temperature of this, air cooling is to room temperature, i.e. forms heat treatment steel,
Having bainite structure in its tissue, mechanics properties testing the results are shown in Table 1.
Embodiment 3
According to the above-mentioned common manufacturing method preparation steel containing following raw material components (by mass percentage
Meter): C:0.17%;Si:1.2%;Mn:2.3%;Mo:0.3%;Nb:0.03%;Al:0.035%;
Ti:0.1%;P:0.01%;S:0.006%;Surplus is Fe and inevitable element.
Above-mentioned steel are carried out heat treatment, specifically include the step that order below is carried out:
Normalized treatment: with programming rate be about 110 DEG C/h by above-mentioned heat steel to about 940 DEG C,
After being incubated about 2.5 hours at a temperature of this, air cooling is to room temperature;
Quenching Treatment: with programming rate be about 100 DEG C/h by the heat steel through above-mentioned normalized treatment
To about 920 DEG C, after being incubated about 2.5 hours at a temperature of this, water-cooled is to about 400 DEG C;
Temper: with programming rate be about 40 DEG C/h by the heat steel through above-mentioned Quenching Treatment extremely
About 520 DEG C, after being incubated about 4.5 hours at a temperature of this, air cooling is to room temperature, i.e. forms heat treatment steel,
Having bainite structure in its tissue, mechanics properties testing the results are shown in Table 1.
Embodiment 4
According to the above-mentioned common manufacturing method preparation steel containing following raw material components (by mass percentage
Meter): C:0.21%;Si:1.0%;Mn:2.1%;Mo:0.35%;Nb:0.12%;Al:0.025%;
Ti:0.13%;P:0.012%;S:0.01%;Surplus is Fe and inevitable element.
Above-mentioned steel are carried out heat treatment, specifically include the step that order below is carried out:
Normalized treatment: with programming rate be about 80 DEG C/h by above-mentioned heat steel to about 930 DEG C, in
After being incubated about 2.5 hours at a temperature of Gai, air cooling is to room temperature;
Quenching Treatment: with programming rate be about 110 DEG C/h by the heat steel through above-mentioned normalized treatment
To about 910 DEG C, after being incubated about 2 hours at a temperature of this, water-cooled is to about 500 DEG C;
Temper: with programming rate be about 50 DEG C/h by the heat steel through above-mentioned Quenching Treatment extremely
About 550 DEG C, after being incubated about 7.5 hours at a temperature of this, air cooling is to room temperature, i.e. forms heat treatment steel,
Having bainite structure in its tissue, mechanics properties testing the results are shown in Table 1.
The mechanics properties testing result of table 1 heat treatment steel
As seen from the results in Table 1:
Tensile strength >=1450Mpa, the impact of collision toughness >=62J of the heat treatment steel that the present invention manufactures is low
Temperature impact flexibility >=40J;Relative to traditional 20SiMn2MoV, its tensile strength improves 64Mpa
Above, impact of collision toughness improves more than 7J, and low-temperature impact toughness improves more than 13J, this heat
Process the excellent combination property of steel, can be widely applied to the field such as offshore oil, traffic.
Last it is noted that various embodiments above is only in order to illustrate technical scheme, rather than right
It limits;Although the present invention being described in detail with reference to foregoing embodiments, this area common
Skilled artisans appreciate that the technical scheme described in foregoing embodiments still can be modified by it,
Or the most some or all of technical characteristic is carried out equivalent;And these amendments or replacement, and
The essence not making appropriate technical solution departs from the scope of various embodiments of the present invention technical scheme.