CN104451445B - High-strength non-hardened and non-tempered steel for welded structures and production technology thereof - Google Patents
High-strength non-hardened and non-tempered steel for welded structures and production technology thereof Download PDFInfo
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Abstract
The invention discloses the high-strength non-hardened and non-tempered steel for welded structures of a kind of yield tensile ratio≤0.80, in terms of mass fraction, it comprises following chemical composition: 0.02～0.06%C, 0.10～0.28%Si, 2.50～3.50%Mn, P≤0.005%, S≤0.002%, 0.05～0.30%Mo, 0.05～0.25%Cr, 0.05～0.25%Cu, 0.10～0.40%Ni, 0.030～0.080%Nb, 0.030～0.10%V, 0.005～0.020%Ti, 0.010～0.050%Als, 0.0005～0.0060%Ca, 0.0005～0.0060%Mg, 10～50 × 10～4% [N], 10～20 × 10‑4% [O], surplus is Fe and inevitable impurity；Wherein, 6C+Mn=2.8～3.7；Mo+2Cr+2Cu=0.65～0.80%；(Ca+Mg)/[O]=2.5～6.5；Pcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B≤0.25%.Present invention also offers the production technology of the high-strength non-hardened and non-tempered steel for welded structures of a kind of yield tensile ratio≤0.80.Utilize the steel excellent combination property that present invention process produces, it is not necessary to carry out the Tempering and Quenching operation of complexity, overcome the shortcomings such as high, the welding performance difference of hardened and tempered steel plate yield tensile ratio, have with low cost, the advantages such as manufacturing process is simple, with short production cycle.
Description
Technical field
The present invention relates to low-alloy high-strength steel making field, particularly refer to a kind of Micro Alloying
High-strength welding structure steel and production technology thereof.
Background technology
Tradition high-strength steel is usually taken hardening and tempering process and produces, higher yield tensile ratio and poor
Welding performance is a major defect of this type of steel.Yield tensile ratio is resistant to from surrender to plasticity
A kind of ability of unstable deformation, from safety considerations, low yield strength ratio is steel construction
One key character.But the high-strength steel using hardening and tempering process to produce is guaranteeing that steel are high-strength
While degree, yield tensile ratio is also improving constantly, especially when tensile strength reach 600MPa with
Time upper, its yield tensile ratio has reached more than 0.90, plasticity index also drop to 20% with
Under even lower, consideration based on secure context, higher yield tensile ratio and poor welding
Performance limits the popularization and application at engineering field of this type of high-strength steel.Along with metallurgical science and technology
Continuous progressive, the technology of high-strength steel is required more and more higher by heavy construction, except
Outside the traditional index such as intensity, toughness, plasticity improve requirement, the also shock resistance to steel
Energy (low yield strength ratio) and welding performance are had higher requirement, and require that steel have simultaneously
Having relatively low manufacturing cost, excellent comprehensive mechanical performance and application performance, to reduce steel
Material consumption, saves construction cost and alleviates component own wt, and ensureing stablizing of component
Property and safety.Obviously, the tradition higher yield tensile ratio of high-strength steel and relatively low elongation percentage with
And poor welding performance can not meet the demand of heavy construction.And in recent years, Zeng You
The steel plate that document report uses two-phase section quenching+tempering mode to produce meets such engineering
Technology requirement, its organization type is ferrite+martensite, utilizes soft phase ferritic structure
Rational proportion reach the purpose of low yield strength ratio, but this kind of process of thermal treatment window is relatively
Narrow, wayward in actual production, even need to carry out repeatedly heat treatment process, greatly
Extend greatly the technological process of production, add production cost, be unfavorable for popularization and application.
The Chinese invention patent of Patent No. " 200910061106.1 " discloses a kind of high
Intensity low yield ratio welding structure steel and production method thereof, this invention steel must be containing higher
The expensive alloying elements such as Cu, Cr, Ni, and need to carry out stress relief tempering process, right
The elongation percentage of steel plate does not the most do requirement.Separately have Patent No. " 201110003640.4 " and
The Chinese invention patent of " 201110003621.1 " discloses a kind of high heat-input welding and uses
Structural steel and manufacture method thereof and a kind of high heat-input structural steel for welding and manufacturer thereof
Method, these two invention hardness of steel ranks are the most relatively low, and yield tensile ratio is not done requirement.Also have
The Chinese invention patent of Patent No. " 201010599469.3 " discloses a kind of 800MPa
Level low yield strength ratio structural steel and iron and production method thereof, this steel must be containing more Cu, Ni
Element, cost of alloy is high, and interpolation B element causes elongation percentage relatively low, steel plate after tempering
Yield strength is relatively low.The patent of invention of Patent No. " EP20010930007 " discloses
“THICK STEEL PLATE BEING EXCELLENT IN CTOD
CHARACTERISTIC IN WELDING HEAT AFFECTED ZONE AND
HAVING YIELD STRENGTH OF 460MPa OR MORE ", this invention steel
Use direct quenching+tempering or TMCP process route to produce, but its invention steel grade is strong
Spend the most relatively low, and the oxide particle number of Mg and Al of unit are limited,
Control difficulty relatively big, be unfavorable for promoting at each metallurgy industry producing.Patent No.
The patent of invention of " 201310649811.X " discloses the low-carbon (LC) shellfish of a kind of yield tensile ratio ＜ 0.8
Family name's body construction(al)steel and production method thereof, this invention uses TMCP technique to produce, follow-up
Without carrying out any heat treatment, but this invention add more Cu, Cr, Ni, Mo,
The precious alloys such as W, and require that in structure of steel, ferrite area percentage is 12～25%,
Extremely difficult control in big production, is unfavorable for popularization and application.Separately there is Patent No.
The patent of invention of " 201310498628.4 " disclose a kind of low-cost high-strength steel plate and
Its production method, this invention uses TMCP+ tempering process to produce, but the steel of the present invention
Yield tensile ratio is above 0.80, and anti-seismic performance is poor, and elongation percentage is relatively low, it is impossible to meet
The technology requirement of modern heavy construction.
Summary of the invention
Present invention aim to provide a kind of high-strength non-hardened and non-tempered steel for welded structures
And production technology.
For achieving the above object, the Micro Alloying of yield tensile ratio≤0.80 that the present invention provides is high-strength
Degree steel for welded structures, it is characterised in that: in terms of mass fraction, it comprises following chemistry
Composition:
0.02～0.06%C, 0.10～0.28%Si, 2.50～3.50%Mn, P≤
0.005%, S≤0.002%, 0.05～0.30%Mo, 0.05～0.25%Cr, 0.05～
0.25%Cu, 0.10～0.40%Ni, 0.030～0.080%Nb, 0.030～0.10%V,
0.005～0.020%Ti, 0.010～0.050%Als, 0.0005～0.0060%Ca,
0.0005～0.0060%Mg, 10～50 × 10-4% [N], 10～20 × 10-4% [O],
Surplus is Fe and inevitable impurity；
Wherein, 6C+Mn=2.8～3.7；Mo+2Cr+2Cu=0.65～0.80%；
(Ca+Mg)/[O]=2.5～6.5；Pcm=C+Si/30+ (Mn+Cu+Cr)
/ 20+Ni/60+Mo/15+V/10+5B≤0.25%.
Present invention also offers the high-strength non-hardened and non-tempered Welding Structure of a kind of yield tensile ratio≤0.80
By the production technology of steel, it comprises the steps:
(1) deep desulfurization is carried out: supplied materials molten iron temperature controls at 1280～1320 DEG C, S
≤ 0.020%, desulfurization terminal S≤0.0008%；
(2) converter smelting is carried out: control, into converter molten iron temperature 1230～1260 DEG C, to protect
Card hot metal composition P≤0.10%, S≤0.0010%, control converter smelting midpoint and blow number of times not
More than 2 times, tapping temperature controls at 1660～1700 DEG C；
(3) LF refine is carried out: ensure that refining time was at 45～55 minutes；Carry out subsequently
RH application of vacuum, the time that processes was at 12～25 minutes；
(4) by heating steel billet to 1230～1280 DEG C, the rate of heat addition controls at 7～11 DEG C
/ s, is incubated 30～50min at a temperature of 1120～1160 DEG C；
(5) I stages roughing start rolling temperature is 1080～1130 DEG C, and single pass reduction ratio is
15～45%, roughing end temp is 1020～1050 DEG C；
(6) II stages finish rolling start rolling temperature is 880～980 DEG C, total reduction 50～70%,
Finish rolling end temp 760～840 DEG C；
(7) quickly cooling down steel plate, it starts temperature is 720～800 DEG C, the coldest
Temperature is 200～500 DEG C, and rate of cooling is 15～25 DEG C/s, and air cooling is to room temperature subsequently；
(8) steel plate is carried out off-line temper, temperature 200～500 DEG C, insulation
Time [thickness of slab (mm)+50～70] min.
Preferably, in described step (1), supplied materials molten iron temperature is 1320 DEG C；
In described step (2), entering converter molten iron temperature is 1260 DEG C, and converter smelting midpoint is blown
Number of times is 2 times, and tapping temperature is 1700 DEG C；In described step (3), refining time
Being 55 minutes, carrying out the RH vacuum treated time is 25 minutes；Described step (4)
In, by heating steel billet to 1280 DEG C, the rate of heat addition is 11 DEG C/s, at a temperature of 1160 DEG C
Insulation 50min；In described step (5), I stage roughing start rolling temperature is 1130 DEG C,
Single pass reduction ratio is 45%, and roughing end temp is 1050 DEG C；Described step (6)
In, II stage finish rolling start rolling temperature is 980 DEG C, and total reduction is 70%, and finish rolling terminates
Temperature is 840 DEG C；In described step (7), the beginning temperature that steel plate is quickly cooled down
Degree is 800 DEG C, and final cooling temperature is 500 DEG C, and rate of cooling is 25 DEG C/s；Described step (8)
In, temperature is 500 DEG C, temperature retention time [thickness of slab (mm)+70] min.
The reason of the operation principle of the present invention and wherein chemical composition limited amount is as follows:
(1) C content of the present invention selects 0.02～0.06%, and C is replaced by gap
Solution strengthening improves the intensity of steel strongly, is to ensure that one of requisite element of hardness of steel,
Improve C content and can also reduce the yield tensile ratio of steel.C belongs to expansion austenite phase field unit
Element, when C content is less than 0.02%, transformation temperature is obviously improved, and is unfavorable for tissue crystal grain
Refinement, causes steel strength not enough and the raising of yield tensile ratio, and causes TMCP process window
Stenostomy, is unfavorable for producing.When C content is higher than 0.06%, the tendency of carbon segregation,
The welding cold crack sensitivity coefficient of Gang Zhong M-A island amount and steel increases, thus deteriorates steel
Plasticity and toughness and welding performance, affect the cold and hot working performance of steel.Therefore C content is defined to
0.02～0.06%.
(2) the Si content of the present invention selects 0.10～0.28%, Si master in steel
Act on is solution strengthening and deoxidation.Owing to steel of the present invention being added with Mg, Ca, Als
Deng having the element of higher adhesion with [O], therefore, Si is the most solid in steel of the present invention
Molten invigoration effect.When Si content is less than 0.10%, its solution strengthening is to steel strength
Contribute limited, when Si content is higher than 0.28%, be unfavorable for steel and welding heat affected zone
Low-temperature impact toughness.Therefore Si content is defined to 0.10～0.28%.
(3) the Mn content of the present invention selects 2.50～3.50%, and Mn is to ensure that steel
The important element of obdurability, when Mn content is less than 2.50%, it is impossible to guarantee that steel are strong
Degree, when Mn content is higher than 3.50%, then can form larger-size MnS complexity sulfur
Compound is mingled with, and is unfavorable for steel mechanics performance and welding performance.Therefore Mn content is defined to
2.50～3.50%.
(4) P≤0.005% of the present invention, S≤0.002%, P, S are being harmful in steel
Impurity element.High P is easily caused segregation, affects the structural homogenity of steel, S Yu Mn, Ca
It is easily formed sulphide inculsion, is all unfavorable for low-temperature flexibility.
(5) the Mo content of the present invention is selected in 0.05～0.30%, main in steel of Mo
Effect is solution strengthening, and a small amount of Mo separates out with carbide form, improves the intensity of steel.Mo
It is stabilization of austenite element, promotes that the bainite of high density dislocation substructure is formed, Mo
Temper brittleness can also be prevented in drawing process.When Mo content is less than 0.05%, above-mentioned
Act on inconspicuous, but when Mo content is more, deteriorate low-temperature flexibility and the welding performance of steel.
(6) Cr, Cu content of the present invention is selected in 0.05～0.25%, identical with Mo,
Cr, Cu are also the elements being effectively improved armor plate strength, and Cu can also separate out in drawing process
ε-Cu phase, plays precipitation strength effect.
(7) the Ni content of the present invention is selected in 0.10～0.40%, in steel of the present invention, Ni with
The solution strengthening element such as Cu, Cr add the fashionable low-temperature flexibility that can be obviously improved steel together,
Ni too high levels, in addition to increasing production cost, surface of steel plate is easily generated the oxidation being difficult to come off
Iron sheet, is unfavorable for the welding performance of steel simultaneously.
(8) the Nb content of the present invention selects 0.030～0.080%, and Nb is a kind of strong
Carbide former, has strong Grain refinement, can significantly improve austenite
Recrystallization temperature, expands rolling mill practice scope, makes invention steel during II stage rolling
Fully thinning microstructure, it is ensured that steel have good obdurability coupling.In the operation of rolling,
The carbonitride particle that Nb is formed in steel can effectively suppress Austenite Grain Growth, improves
Steel strength and toughness.In steel of the present invention, when Nb content is less than 0.030%, cause
Yield strength is not enough, when Nb content is higher than 0.080%, deteriorates welded steel performance.
(9) V of the present invention is selected in 0.03～0.10%, and V is a kind of considerably more intense carbon
Compound forms element, and appropriate V has obvious precipitation hardening effect.Work as Nb
Compound with V add fashionable, can obviously improve the generation of transversal crack phenomenon.But V content mistake
Height, is unfavorable for steel toughness.
(10) Ti of the present invention selects 0.008～0.020%, and Ti is also a kind of strong carbon nitrogen
Compound forms element, separates out tiny TiN, Ti on Mg, Als superfine oxide granule
(CN) or Nb the composite carbon nitride of Ti, stop austenite crystal in heating and welding process
Grain length is big, improves heat affected area low-temperature flexibility.Ti with Nb is simultaneously introduced, and can carry further
High steel austenite recrystallization temperature, expands rolling mill practice scope.But when Ti is more than 0.020%,
The carbonitride particle size of the Ti separated out is relatively big, and the effect of its fining austenite grains subtracts
Weak, it is unfavorable for welding heat influence area toughness, when Ti is less than 0.008%, its above-mentioned effect
Inconspicuous, therefore Ti is defined to 0.008～0.020%.
(11) the Als content of the present invention selects 0.010～0.050%, and Als is in steel
Main deoxidant element, it is possible to be combined formation AlN granule with N, brilliant by thinning microstructure
Grain improves steel strength.When Als content is higher than 0.050%, easily cause the oxidation of Al in steel
Thing field trash increases, and size is relatively big, reduces degree of purity and the plasticity and toughness of steel, is unfavorable for steel
Material toughness.
(12) Ca of the present invention is deoxidant element, is also desulfurization element, its content control
System is 0.0005～0.0060%.Steel adds appropriate Ca by Sulfide inclusion nodularization,
It is beneficial to base material low-temperature flexibility and HAZ toughness.In order to realize above-mentioned effect, Ca content should
It is not less than 0.0010%；When Ca content is more than 0.0060%, then can be formed larger-size
Ca oxide and sulfide mixing are mingled with, and are unfavorable for steel toughness.
(13) Mg of the present invention controls 0.0005～0.0060%.Mg combines with [O]
Forming tiny oxide particle, these tiny oxide particles can nitrogenize as carbon
The forming core core of thing and phase-change organization, promotes that Carbonitride Precipitation and phase-change organization change,
Promote carbonitride uniform tiny precipitation in steel, promote the transformation of phase-change organization, thus
Thinning microstructure, improves steel strength and toughness.When in steel, Mg content is less than 0.0005%
Time, these oxide complex granule lazy weights, it is impossible to play forming core central role.When
When Mg content is 0.0060%, then it is likely to be formed the composite oxides containing Mg and sulfide
Field trash, is unfavorable for steel toughness and welding heat influence area toughness.
(14) N content of the present invention selects 10～50 × 10-4Nb in %, N and steel,
The elements such as Ti, Al, V, C form nitride, carbide or carbonitride, abundant
Precipitated phase granule is to ensure that the key factor of steel strength and toughness.If N content is less than 10
×10-4%, then nitrogen in steel compound and carbonitride particle limited amount, to steel strength and
Toughness contribution is little.When N content is higher than 50 × 10-4During %, it will increase solid solution in steel
The content of N, is unfavorable for steel and HAZ toughness.
(15) O content of the present invention selects 10～20 × 10-4%, generally,
O belongs to harmful gas in steel, for guaranteeing that oxide in purity of steel and steel is mingled with
Total amount, need to strictly be limited in reduced levels by O content.But when O content less than 10 ×
10-4During %, then steel forms MgO oxide particle limited amount, but for avoiding in steel
Too much oxide-based complex inclusion occur, O content should be limited in 20 × 10-4%
Within.
The most above-mentioned chemical composition must also meet formula: 1. 6C+Mn=2.8～3.7,2.
Mo+2Cr+2Cu=0.65～0.80%, 3. (Ca+Mg)/[O]=2.5～6.5,4.
Pcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B≤0.25%.
In the present invention, as 6C+Mn ＜ 2.8, steel strength is not enough, as 6C+Mn ＞
When 3.7, the welding crack sensibility of steel increases, and is unfavorable for the welding performance of steel；When
During Mo+2Cr+2Cu ＜ 0.65%, cause hardness of steel not enough, as Mo+2Cr+2Cu ＞
When 0.80%, steel toughness is had a negative impact, deteriorate the welding performance of steel simultaneously；
As (Ca+Mg)/[O] ＜ 2.5, the oxide particle lazy weight formed in steel, make
Effective forming core core for precipitated phase and phase transformation is limited, is unfavorable for ensureing steel strength and tough
Property, as (Ca+Mg)/[O] ＞ 6.5, steel will be formed large-sized oxide and
Sulfide complex inclusion, is unfavorable for steel and heat affected area toughness；For guaranteeing the weldering of steel
Connecing performance, Pcm value is necessarily less than equal to 0.25%.
Steel of the present invention is in addition to containing above-mentioned chemical composition, and surplus is Fe and inevitably presss from both sides
Miscellaneous.
It is an advantage of the current invention that: the high-strength non-hardened and non-tempered steel for welded structures that the present invention provides
And production technology, it is therefore intended that overcome the deficiency that the art presently, there are, develop
Cost of alloy and manufacturing cost relatively low there is high intensity, high tenacity, low yield strength ratio, good
The steel of the feature such as ductility, welding performance and cold and hot working performance, the steel of the present invention is comprehensive
Excellent performance, it is not necessary to carry out the Tempering and Quenching operation of complexity, overcomes hardened and tempered steel plate and bends strong
The ratio shortcoming such as high, welding performance is poor, has with low cost, and manufacturing process is simple, produces week
The advantages such as the phase is short.
Detailed description of the invention
Below in conjunction with specific embodiment, the present invention is described in further detail.
The production work of the high-strength non-hardened and non-tempered steel for welded structures of yield tensile ratio≤0.80 of the present invention
Skill, specifically comprises the following steps that
(1) deep desulfurization is carried out: supplied materials molten iron temperature controls at 1280～1320 DEG C, S
≤ 0.020%, desulfurization terminal S≤0.0008%；
(2) converter smelting is carried out: control, into converter molten iron temperature 1230～1260 DEG C, to protect
Card hot metal composition P≤0.10%, S≤0.0010%, control converter smelting midpoint and blow number of times not
More than 2 times, tapping temperature controls at 1660～1700 DEG C；
(3) LF refine is carried out: ensure that refining time was at 45～55 minutes；Carry out subsequently
RH application of vacuum, the time that processes was at 12～25 minutes；
(4) by heating steel billet to 1230～1280 DEG C, the rate of heat addition controls at 7～11 DEG C
/ s, is incubated 30～50min at a temperature of 1120～1160 DEG C；
(5) I stages roughing start rolling temperature is 1080～1130 DEG C, and single pass reduction ratio is
15～45%, roughing end temp is 1020～1050 DEG C；
(6) II stages finish rolling start rolling temperature is 880～980 DEG C, total reduction 50～70%,
Finish rolling end temp 760～840 DEG C；
(7) quickly cooling down steel plate, it starts temperature is 720～800 DEG C, the coldest
Temperature is 200～500 DEG C, and rate of cooling is 15～25 DEG C/s, and air cooling is to room temperature subsequently；
(8) steel plate is carried out off-line temper, temperature 200～500 DEG C, insulation
Time [thickness of slab (mm)+50～70] min.
Below: table 1 is various embodiments of the present invention and comparative example chemical composition value list；
Table 2 is various embodiments of the present invention and comparative example main technologic parameters value list；Table 3 is
The mechanical property test result of the embodiment of the present invention.
Table 1 steel of the present invention contrasts (wt, %) (one) with the chemical composition of compared steel
Table 1 steel of the present invention contrasts (wt, %) (two) with the chemical composition of compared steel
Table 2 embodiment of the present invention (1～9) and the main technologic parameters list of comparative example
Table 3 embodiment of the present invention (1～9) and the mechanical property test result of comparative example
According to the embodiment of the present invention (1～9) steel chemical composition and manufacturing technique requirent, smelting
Refine and rolled 9 batches of steel, be respectively steel 1～the steel 9 of invention.In order to preferably reflect
The various feature performance benefits of steel of the present invention, provide 3 groups of compared steel, routinely in the present invention
Quenched (quenching+tempering) production technology produces.
Through steel plate of the present invention being carried out normal tensile property ,-20 DEG C of impact of collision tests, and
Contrast with compared steel, its result: under room temperature, the yield strength of steel of the present invention and compared steel
Being in same level, and tensile strength is apparently higher than compared steel, steel of the present invention has relatively low
Yield tensile ratio (ReL/Rm＜ 0.80) and higher elongation percentage, and compared steel yield tensile ratio is equal
More than 0.87, elongation percentage is below 22%, and this illustrates that steel of the present invention has more excellent resisting
Shock stability and extension property；At steel of the present invention-20 DEG C, ballistic work is all at more than 250J, far
Higher than about the 100J of compared steel, this illustrates that steel of the present invention has the low-temperature flexibility of excellence.
In sum, steel of the present invention has high intensity, high tenacity, low yield strength ratio, good
The feature such as ductility, welding performance and cold and hot working performance, excellent combination property；This
Invention steel without carrying out the Tempering and Quenching operation of complexity, overcome quenched and tempered steel yield tensile ratio high,
The shortcomings such as welding performance difference, have with low cost, and manufacturing process is simple, with short production cycle
Etc. advantage, all can implement at each smelter.
Claims (2)
1. the high-strength non-hardened and non-tempered steel for welded structures of yield tensile ratio≤0.80, it is characterised in that: in terms of mass fraction, it comprises following chemical composition:
0.02～0.06%C, 0.10～0.28%Si, 2.50～3.50%Mn, P≤0.005%, S≤0.002%, 0.05～0.30%Mo, 0.05～0.25%Cr, 0.05～0.25%Cu, 0.10～0.40%Ni, 0.030～0.080%Nb, 0.030～0.10%V, 0.005～0.020%Ti, 0.010～0.050%Als, 0.0005～0.0060%Ca, 0.0005～0.0060%Mg, 10～50 × 10-4% [N], 10～20 × 10-4% [O], surplus is Fe and inevitable impurity；
Wherein, 6C+Mn=2.8～3.7%；Mo+2Cr+2Cu=0.65～0.80%；(Ca+Mg)/[O]=2.5～6.5；Pcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B≤0.25%；
It is to prepare as follows to form:
(1) deep desulfurization is carried out: supplied materials molten iron temperature controls at 1280～1320 DEG C, S≤0.020%, desulfurization terminal S≤0.0008%；
(2) converter smelting is carried out: control into converter molten iron temperature 1230～1260 DEG C, it is ensured that hot metal composition P≤0.10%, S≤0.0010%, control converter smelting midpoint and blow number of times and be not more than 2 times, tapping temperature controls at 1660～1700 DEG C；
(3) LF refine is carried out: ensure that refining time was at 45～55 minutes；Carrying out RH application of vacuum subsequently, the time that processes was at 12～25 minutes；
(4) by heating steel billet to 1230～1280 DEG C, the rate of heat addition controls at 7～11 DEG C/s, is incubated 30～50min at a temperature of 1120～1160 DEG C；
(5) I stages roughing start rolling temperature is 1080～1130 DEG C, and single pass reduction ratio is 15～45%, and roughing end temp is 1020～1050 DEG C；
(6) II stages finish rolling start rolling temperature is 880～980 DEG C, total reduction 50～70%, finish rolling end temp 760～840 DEG C；
(7) quickly cooling down steel plate, it starts temperature is 720～800 DEG C, and final cooling temperature is 200～500 DEG C, and rate of cooling is 15～25 DEG C/s, and air cooling is to room temperature subsequently；
(8) steel plate is carried out off-line temper, temperature 200～500 DEG C, temperature retention time [thickness of slab (mm)+50～70] min.
The high-strength non-hardened and non-tempered steel for welded structures of yield tensile ratio≤0.80 the most according to claim 1, it is characterised in that:
In described step (1), supplied materials molten iron temperature is 1320 DEG C；
In described step (2), entering converter molten iron temperature is 1260 DEG C, and it is 2 times that number of times is blown at converter smelting midpoint, and tapping temperature is 1700 DEG C；
In described step (3), refining time is 55 minutes, and carrying out the RH vacuum treated time is 25 minutes；
In described step (4), by heating steel billet to 1280 DEG C, the rate of heat addition is 11 DEG C/s, is incubated 50min at a temperature of 1160 DEG C；
In described step (5), I stage roughing start rolling temperature is 1130 DEG C, and single pass reduction ratio is 45%, and roughing end temp is 1050 DEG C；
In described step (6), II stage finish rolling start rolling temperature is 980 DEG C, and total reduction is 70%, and finish rolling end temp is 840 DEG C；
In described step (7), the beginning temperature quickly cooled down steel plate is 800 DEG C, and final cooling temperature is 500 DEG C, and rate of cooling is 25 DEG C/s；
In described step (8), temperature is 500 DEG C, temperature retention time [thickness of slab (mm)+70] min.
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| CN201410713631.8A CN104451445B (en) | 2014-11-28 | 2014-11-28 | High-strength non-hardened and non-tempered steel for welded structures and production technology thereof |
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| CN111441005B (en) * | 2020-05-25 | 2021-08-20 | 江苏联峰实业有限公司 | Free-cutting non-quenched and tempered steel and production method thereof |
| CN113621882B (en) * | 2021-08-12 | 2022-07-01 | 宝武杰富意特殊钢有限公司 | Medium-carbon non-quenched and tempered steel and preparation method thereof |
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| CN102162065A (en) * | 2011-03-27 | 2011-08-24 | 莱芜钢铁集团有限公司 | 550Mpa yield-strength low-carbon bainitic steel for engineering machinery and preparation method thereof |
| CN102605287A (en) * | 2012-03-09 | 2012-07-25 | 武汉钢铁(集团)公司 | Steel for high-ductility anti-seismic structure with yield ratio smaller than or equal to 0.70 and production method of steel |
| CN103352167A (en) * | 2013-07-15 | 2013-10-16 | 南京钢铁股份有限公司 | Low-yield ratio and high-strength steel for bridges and manufacturing method thereof |
| CN103422025A (en) * | 2013-09-13 | 2013-12-04 | 武汉钢铁(集团)公司 | Steel for low-yield-ratio structure with yield strength larger than or equal to 690MPa and production method of steel |
| CN103667921A (en) * | 2013-12-18 | 2014-03-26 | 武汉钢铁(集团)公司 | Thick steel plate with high strength and toughness as well as uniform performance in thickness direction and production method of thick steel plate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN102162065A (en) * | 2011-03-27 | 2011-08-24 | 莱芜钢铁集团有限公司 | 550Mpa yield-strength low-carbon bainitic steel for engineering machinery and preparation method thereof |
| CN102605287A (en) * | 2012-03-09 | 2012-07-25 | 武汉钢铁(集团)公司 | Steel for high-ductility anti-seismic structure with yield ratio smaller than or equal to 0.70 and production method of steel |
| CN103352167A (en) * | 2013-07-15 | 2013-10-16 | 南京钢铁股份有限公司 | Low-yield ratio and high-strength steel for bridges and manufacturing method thereof |
| CN103422025A (en) * | 2013-09-13 | 2013-12-04 | 武汉钢铁(集团)公司 | Steel for low-yield-ratio structure with yield strength larger than or equal to 690MPa and production method of steel |
| CN103667921A (en) * | 2013-12-18 | 2014-03-26 | 武汉钢铁(集团)公司 | Thick steel plate with high strength and toughness as well as uniform performance in thickness direction and production method of thick steel plate |
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