CN108642389A - A kind of Welding seam inclusion it is few exempt from application weathering steel and preparation method thereof - Google Patents
A kind of Welding seam inclusion it is few exempt from application weathering steel and preparation method thereof Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- 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
- C21C7/076—Use of slags or fluxes as treating agents
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- 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
- C21C7/10—Handling in a vacuum
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- 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
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Abstract
The present invention provide a kind of Welding seam inclusion it is few exempt from application weathering steel and preparation method thereof, belong to weathering steel technical field, the technical solution adopted is that being matched by the content optimized between chemical composition, optimizing Si, Mn, Ni, Cr, Cu, Mo, Ca content in weathering steel and the proportioning between each element being made to meet：1.7 >=J >=1.2, wherein J is the ratio between (Si+Mn+50Ca) and (Cr+Ni+Cu+Mo).Advantageous effect is：In welding, the amount of inclusions of all kinds of weld seams significantly reduces weathering steel provided by the invention, size is obviously reduced, and bead crack tendency is significantly reduced caused by Large Inclusions, and Welding Metallurgy quality greatly improves, and flaw detection qualification rate improves；The weathering steel is not only more resistant to atmospheric corrosion, but also keeps excellent mechanical property, is also adapted to plank, the proximate matter production of general industry flow, and relative inexpensiveness.
Description
Technical field
The invention belongs to weathering steel technical fields, and in particular to a kind of Welding seam inclusion it is few exempt from application weathering steel and its system
Preparation Method is particularly suitable for welding structure with exempting from application weathering steel.
Background technology
With the development of Bridges in Our Country industry Approach To Steel Bridge Designing manufacturing technology, the requirement to special bridge steel material comprehensive performance
It is higher and higher.Weathering steel is gradually widely used in exempting from the weather-proof steel bridge of application due to its good weather resistance and mechanical property
Construction.Exempt from the novel steel bridge that the weather-proof steel bridge of application manufactures new technology as a kind of green high-efficient, there is overall life cycle cost
It reduces, manufacturing schedule shortens, endangers the advantages such as organic matter release is reduced, tan appearance is mutually coordinated with natural environment.It is existing weather-proof
Steel mainly uses Cr-Ni-Cu-Mo-Si alloy series components, such as patent " 500MPa grades of Weather-resistance bridges of rolled yield strength
Steel and its manufacturing method "（ CN101892431A）, " a kind of weather resistant thick steel plate and its manufacturing method "（ CN102021494A）、
" a kind of high-performance bridge weathering steel and preparation method thereof containing Mo "（CN102534417B）, " a kind of bridge disclosed in 2015 years
With the welding method of Q345qENH ~ Q420qENH grades of high-performance weather-proof steel "（CN105252122A）, disclosed in 2016 years
" 485MPa grades of TMCP+ tempering Weather-resistance bridge steel plates and production method "（ CN105779883A）, it is " a kind of resistance to disclosed in 2016 years
Wait structural steel and iron and its production method "（CN106191669A）, " a kind of Steel Bridge exempts from application with Q420qENH disclosed in 2017 years
The welding method of weathering steel "（CN106956064A）, the chemical composition of above-mentioned weathering steel is as shown in table 1,
The chemical composition of 1 prior art weathering steel of table（wt. %）
。
But a large amount of type approval tests are found with practical engineering application, add the weathering steel of Cr, Ni, Cu, Mo at present in reality
In border welding, particularly consumable electrode carbon dioxide gas arc welding termination process, because of these weather-proof alloying elements fusings, it is transitioned into weldering
In seam, molten bath viscosity is set to improve, and the elemental oxygen in molten bath and ferrous oxide（FeO）Make Cr and Mo oxidization burning loss and is easy to be formed
Larger-size field trash further declines molten bath mobility, and more field trash and gas are accordingly difficult to float, be trapped in
In weld seam, -40 DEG C of low-temperature flexibilities of weld seam are damaged, bead crack is even resulted in when serious, to be degrading welding performance and weldering
The weather resistance of seam.This weld seam be harmful to field trash largely exists on weathering steel weld seam section, average-size reach 3 μm and
More than, in every square millimeter of region, par reaches 400 or more, how to reduce field trash in weld seam, resistance to improving
The weather resistance of the welding performance and weld seam of waiting steel is extremely important, but currently, there is no effective solution measure.
Invention content
Weathering steel Welding seam inclusion is more, technical problem of low-temperature flexibility difference to solve, a kind of slag in weld of present invention offer
Object it is few exempt from application weathering steel and preparation method thereof, by optimize chemical composition between content match, optimize Si, Ca, make it
It is transitioned into weld seam, preferably to control molten bath metallurgy reaction, realizes and exempts from substantially reducing for application weathering steel Welding seam inclusion.
The technical solution adopted by the present invention is：
A kind of Welding seam inclusion it is few exempt from application weathering steel, the mass percent of chemical composition is in the weathering steel：C：0.03~
0.07, Si：0.35 ~ 0.80, Mn：0.90 ~ 1.40, P：0.005 ~ 0.0015, S≤0.005, Cr：0.25 ~ 0.55, Ni：0.25~
0.60, Cu：0.25 ~ 0.50, Mo：0.03 ~ 0.25, Nb：0.010 ~ 0.045, Ti：0.005 ~ 0.015, V≤0.040, Al：
0.020 ~ 0.045, Ca：0.003 ~ 0.015, surplus Fe, in the weathering steel between Si, Mn, Ni, Cr, Cu, Mo, Ca content
Proportioning meet：1.7 >=J >=1.2, wherein J is the ratio between (Si+Mn+50Ca) and (Cr+Ni+Cu+Mo).
Preferably, the mass percent of the weathering steel Si contents is 0.50 ~ 0.65.
Preferably, the mass percent of the weathering steel Cr contents is 0.35 ~ 0.50.
Preferably, the mass percent of the weathering steel Ni contents is 0.30 ~ 0.45.
Preferably, the mass percent of the weathering steel Cu contents is 0.28 ~ 0.38.
Preferably, the mass percent of the weathering steel Mo contents is 0.05 ~ 0.15.
Preferably, atmospheric corrosion resistance index I >=6.5 that the weathering steel is calculated according to chemical composition, wherein：
I=26.01(%Cu)+3.88(%Ni)+1.20(%Cr)+1.49(%Si)+17.28(%P)-7.29(%Cu)(%Ni)-9.10
(%Ni)(%P) -33.39(%Cu)2。
Preferably, the weld seam of the weathering steel is gas shield welding line, and protective gas is pure carbon dioxide gas.Using
Wlding be to comply with standard TB 2374-2008T《Rail truck weather resisting steel and stainless steel welding material》Wlding.
The present invention also provides a kind of few preparation method for exempting from application weather-resistant steel plate of Welding seam inclusion, the preparation method packets
Include following steps：
（1）Smelting molten steel：After desulfurizing agent, desiliconization agent, Dephosphorising agent pretreatment molten steel, with electric arc furnaces or converter control 1500 ~
1650 DEG C are smelted, and molten steel is obtained；
（2）LF stoves refine：Molten steel goes to LF stoves, using CaO-Al2O3-SiO2Ternary slag system is sprinkled into aluminum shot to the top of the slag and makes reduction
Slag reduces rapidly in slag MnO+FeO contents to 0.5wt.% or less；Ensure micro-positive pressure in stove, control argon blowing rate 350-650NL/
Min, refines 40 ~ 50min, and the mass percent for adjusting chemical composition is：C：0.03 ~ 0.07, Si：0.35 ~ 0.80, Mn：0.90~
1.40 P：0.005 ~ 0.0015, S≤0.005, Cr：0.25 ~ 0.55, Ni：0.25 ~ 0.60, Cu：0.25 ~ 0.50, Mo：0.03~
0.25, Nb：0.010 ~ 0.045, Ti：0.005 ~ 0.015, V≤0.040, Al：0.020 ~ 0.045, Ca：0.003 ~ 0.015, it is remaining
It is Fe to measure, and the proportioning in the weathering steel between Si, Mn, Ni, Cr, Cu, Mo, Ca content meets：1.7 >=J >=1.2, wherein J
It is the ratio between (Si+Mn+50Ca) and (Cr+Ni+Cu+Mo), it is quiet to stir 20 ~ 30 minutes；
（3）VD stoves are vacuum-treated：Vacuum degree≤1 millibar is 20 ~ 25 minutes vacuum retention times, quiet after vacuum breaker to stir 12 ~ 18 points
Clock feeds Al lines and Si-Ca lines, terminal [O], [N] is made to be controlled respectively in [O]≤0.0025%, [N]≤0.0045%；
（4）Protect continuous casting：Using whole process protection pouring type, slab is obtained；
（5）Thermo-mechanical rolling：By heating of plate blank to 1200 ± 20 DEG C, 3 ~ 7 passage of temperature >=1000 DEG C roughing is controlled, is obtained intermediate
Base, then 4 ~ 7 passage finish rolling are carried out to intermediate base with 800 ~ 920 DEG C, it is then so cooling that exempt from application weather-resistant steel plate, wherein when cooling
5~15 DEG C 760 ~ 800 DEG C of cold temperature, 500 ~ 700 DEG C of red temperature, cooling rate/s are opened in control.
Further, the preparation method further includes step（6）Temper：500 ~ 600 DEG C of temperature, soaking time
For " plate thickness+(10 ~ 50) min ".
In above-mentioned technical proposal, the chemical constituent of the alloying element of weathering steel is defined, main cause is as follows：
Cr：Quenching degree can be increased, to improve intensity, and fine and close oxidation film can be formed on the surface of steel, generate passivation effect
Fruit, to improve atmospheric corrosion resistance.But Cr too high levels can improve the brittle transition temperature of steel, weld dimensions,
And have the tendency that forming large-size trapped oxide and increasing brittleness and crackle during weld seam melt tank reaction, therefore, Cr
Content is limited to 0.25 ~ 0.55wt.%.
Ni：The compactness that the interior rusty scale of steel can be dramatically increased, makes the corrosion potential of steel shuffle, significantly improves atmospheric corrosion resistance
Performance；Be effectively improved fracture toughness, also significantly reduce the brittle transition temperature of steel, weld dimensions, be it is most effective really
Protect the alloying element of low-temperature flexibility.The content of Ni is limited to 0.30 ~ 0.60 wt.%, can be due to base material local melting if excessively high
It is transitioned into weld seam, increases molten bath viscosity and reduces mobility, Welding seam inclusion quantity is caused to be easy to increase, on the other hand, Ni contains
If measuring noble element, too high amount will increase considerably cost, more preferable 0.30 ~ 0.45 wt.% of content.
Cu：Steel surface is easily enriched with Cu and forms form compact and stable rusty scale and prevent to corrode, and during the corrosion reaction of steel, Cu
Promote steel that passivation occurs as anode and slows down corrosion；When Cu contents are less than 0.28 wt.%, corrosion resistance is difficult to show；But
When higher than 0.38 wt.%, surface of steel plate is easily caused hot tearing occur, atmospheric corrosion resistance effect saturation trend is larger, especially because of mother
Material local melting and be transitioned into weld seam, molten bath viscosity improve and mobility reduce, Welding seam inclusion quantity is easy to increase, or even makes
Weld seam generates hot tearing.Therefore, the content of Cu is limited to 0.25 ~ 0.50 wt.% in the present invention, more preferable 0.28 ~ 0.38
wt.%。
Mo：Can significantly improve reduces austenite to ferritic transition temperature, promotes middle temperature transformation, fining ferrite grains
And improve obdurability；Refinement corrosion product particle and significantly improve the compactness of rusty scale, to enhance weatherability；It can also be in steel table
Face reacts to form molybdate, has corrosion inhibition.Content is too low, it is difficult to play the effect；Too high levels, then because base material is locally molten
Change is transitioned into weld seam, and melt tank reaction is easily mingled with larger-size oxide and increases brittleness and crackle tendency, and Mo is valuable member
Element, too high levels can cause cost to increase considerably, and content is limited to 0.03 ~ 0.25 wt.% in the present invention.
Mn：In steel-making and weld seam melt tank reaction, with desulfurization, deoxidation, steel plate is prevented and weld seam is hot-short and the property of hot tearing
Energy.In addition, also having stronger solution strengthening and Grain refinement, the obdurability of steel plate and weld seam can be improved.But it is excessively high
Mn contents easily cause to be segregated, or even reduce corrosion resistance.Therefore, Mn contents are limited to 0.90 ~ 1.50 wt.%.
Si：Higher Si forms nano silicone oxide in base material and weld seam, promotes alpha-feooh transformation, promotes interior rust
Layer densification, can also be by refining corrosion product particle, promoting ferriferous oxide Fe2SiO4It crystallizes and enhances the stability of rusty scale, richness
Collection helps to repair rusty scale defect in rusty scale cracks, to significantly improve weather resistance.It is alternatively arranged as alloying constituent, is significantly strengthened
Ferrite significantly improves the intensity of base material and weld seam；Particularly, Si is transitioned into weldering because of base material local melting in the welding process
Seam participates in melt tank reaction, can effectively mitigate the oxidation of Cr, Mo, improves molten bath mobility and substantially reduces Welding seam inclusion.Work as Si
Content be less than 0.30 wt.% when, above-mentioned effect is not notable；But when higher than 0.80 wt.%, steel, weld seam and heat affecting can be made
The black brittleness in area increases, while deteriorating the cold-forming property of steel.Therefore, the content of Si is limited to 0.35 ~ 0.80 wt.%'s
Range, more preferable range are 0.50 ~ 0.65 wt.%.
Ca：Enter weld seam in the welding process, in the melt tank reaction stage, calciate is formed with refractory metal, is reduced molten
Pond viscosity improves molten bath mobility.In addition, Ca can achieve the effect that deoxidation, desulfurization, dephosphorization and removal trace harmful elements,
Not only weld seam impact toughness can be improved, but also oxide morphology in steel can be improved, prevent face of weld rust liquid from flying to hang phenomenon.It is micro
Ca can play above-mentioned effect.Therefore, the content of Ca is limited to the range of 0.005 ~ 0.015 wt.%.
The present invention controls 1.7 >=J >=1.2, wherein and J is the ratio between (Si+Mn+50Ca) and (Cr+Ni+Cu+Mo),
By strictly controlling the content of each chemical alloying element, make by the coordinated between Si, Mn, Ni, Cr, Cu, Mo, Ca element
With realizing weather-proof hardness of steel and greatly improve, weather resistance is excellent, and so that field trash greatly reduces in weld seam.With base material
Fusing participates in melt tank reaction in the element transitions to weld seam such as Si, Mn, Ca, common to participate in deoxidation dedoping step, Si can reduce Cr and
The oxidization burning loss of Mo；Elemental oxygen in Si, Ca, Mn and molten bath and ferrous oxide（FeO）It has an effect, generates SiO respectively2、
CaO, MnO, the combined deoxidation product of Si, Mn（MnO•SiO2）, easily float and be excluded as Silicate inclusion；Ca is in addition to de-
Other than oxygen, product CaO also participate in desulfurization, dephosphorization and reduce sulfide and phosphide inclusion, CaO respectively with oxide
（SiO2）, sulfide（FeS）, phosphide（P2O5）It reacts and further removes corresponding field trash；Due to generally containing in weathering steel
There is a fairly large number of Mn, in order to reduce Welding seam inclusion, then needs containing sufficient amount of Si and Ca.When in weathering steel weld seam
When the content of Cr, Ni, Cu, Mo are higher, molten bath viscosity accordingly improves, mobility accordingly reduces, and the overall content of Si, Ca and Mn are not
When sufficient, the removal effect of field trash is not notable, should accordingly increase；But when the overall content of Si, Ca and Mn are excessive, instead
Welding performance and/or corrosive nature can be deteriorated, for example, excessive Si contents can reduce the toughness of base material and weld seam, excessive Mn contents
Segregation can be increased, even reduce weather resistance, excessive Ca contents can cause a fairly large number of calcium-aluminate class to be mingled with instead；It is another
Aspect, Si, Ca and Mn have part similar effect, wherein a certain member procatarxis content is relatively low and when acting on insufficient, or can be by other
The effect of one or two kinds of elements and replace, for example, Mn contents on the low side or it can be made up by the Si contents properly increased
Effect.The present invention combines verification experimental verification to summarize by theoretical research, controls 1.7 >=J >=1.2, J be (Si+Mn+50Ca) with
(Cr+Ni+Cu+Mo) ratio between can substantially reduce weather-proof steel inclusion, while greatly improve the intensity of weathering steel and tough
Property.
The beneficial effects of the invention are as follows：（1）When weathering steel provided by the invention carries out welding for steel structure manufacture, all kinds of weld seams
（Especially gas metal-arc welding weld seam）The amount of inclusions significantly reduce, size is obviously reduced, due to Large Inclusions
Caused bead crack tendency is significantly reduced, and Welding Metallurgy quality greatly improves, and flaw detection qualification rate improves；（2）It is described weather-proof
Steel is not only more resistant to atmospheric corrosion, but also keeps excellent mechanical property, is also adapted to plank, the proximate matter production of general industry flow, and
Relative inexpensiveness.
Description of the drawings
Fig. 1 is that 1 welding point section welding bead of embodiment is distributed photomacrograph；
Fig. 2 is that 2 welding point section welding bead of embodiment is distributed photomacrograph；
Fig. 3 is that 3 welding point section welding bead of embodiment is distributed photomacrograph；
Fig. 4 is that 4 welding point section welding bead of embodiment is distributed photomacrograph；
Fig. 5 is that 1 welding point section welding bead of comparative example is distributed photomacrograph；
Fig. 6 is that 2 welding point section welding bead of comparative example is distributed photomacrograph；
Fig. 7 is that 3 welding point section welding bead of comparative example is distributed photomacrograph；
Fig. 8 is 1 Welding seam inclusion metallograph of embodiment；
Fig. 9 is 2 Welding seam inclusion metallograph of embodiment；
Figure 10 is 3 Welding seam inclusion metallograph of embodiment；
Figure 11 is 4 Welding seam inclusion metallograph of embodiment；
Figure 12 is 1 Welding seam inclusion metallograph of comparative example；
Figure 13 is 2 Welding seam inclusion metallograph of comparative example；
Figure 14 is 3 Welding seam inclusion metallograph of comparative example.
Specific implementation mode
Below in conjunction with the specific embodiment Welding seam inclusion that the present invention will be described in detail is provided it is few exempt from application weathering steel and
Preparation method, but the protection domain that the invention is not limited in any way, one of ordinary skill in the art are according to technical solution institute
The improvement of progress is changed or similar replacement, should all be included in the protection scope of the present invention.In embodiment, such as without special theory
Bright, the method is conventional method, and reagent is conventional reagent, and another wt.% indicates mass percentage.
It is smelted in the vaccum sensitive stove of 50kg and exempts from application weather-resistant steel plate, wherein 4 stoves are that provided by the invention to exempt from application resistance to
Hou Gang（Number embodiment 1-4）, 3 stoves are compared steel（Number comparative example 1-3）, the chemical composition of each steel plate setting is shown in Table 2 respectively,
（Table 2-1 and 2-2 is continuous form, because length is excessive shown separately）.Wherein, Si contents contain less than Si of the present invention in comparative example 1
Lower limiting value is measured, the Si contents of comparative example 2 are higher than Si upper content limits value of the present invention.In comparative example 3 Si contents within the scope of the present invention,
But Ca contents are only 0.001, suitable with content in the prior art.
Table 2-1 embodiment and comparative example chemical compositions（wt.%）
Table 2-2 embodiment and comparative example chemical compositions（wt.%）
。
The present invention is the resistance to rural area for ensuring provided weathering steel, industrial atmospheric performance, is further limited described resistance to
Atmospheric corrosion resistance index I >=6.5 that steel is calculated according to chemical composition are waited, wherein：I=26.01(%Cu)+3.88(%Ni)+1.20(%
Cr)+1.49(%Si)+17.28(%P)-7.29(%Cu)(%Ni)-9.10(%Ni)(%P) -33.39(%Cu)2。
U.S. material corrosion science man Larrabee and Coburn disclose 270 kinds of low-alloy steel in industrial atmospheric environment
After exposure corrosion data in 15.5, these data were carried out statistical regression analysis by Legault and Leckie again, foundation
Fitting formula reflects these low-alloy steel through between average corrosion Reducing thickness CR in 15.5 and chemical composition mass percent
Relationship, i.e. the Legault-Leckie formula of ASTMG101 standards：
CR（mils）=10.00-26.01Cu+3.88Ni+1.20Cr+1.49Si+17.28P-7.29Cu×Ni-9.10Ni×P-
33.39Cu2=10.00-I（Formula 1）
In formula, 1mil=0.001inch=25.4 μm.The scope of application（wt.%）It is：Ni：0.05 ~ 1.10, Cr：0.10 ~ 1.30, Cu：
0.012 ~ 0.51, Si：0.10 ~ 0.64, P：0.010~0.12.
According to the formula, by the weather-proof steel making exempt from application Weather-resistance bridge steel construction for, if Steel Structural Design is to this
The technology that weathering steel is proposed requires：Caused section is thinned by atmospheric corrosion in weathering steel in 100 years life cycles
The fall of thickness must not exceed the 5% of former weathering steel, then the atmospheric corrosion resistance index of the steel should meet wanting for I >=6.5
It asks.
The preparation method of steel plate is as described below, successively through smelting, refining, continuous casting, thermo-mechanical rolling and temper, specifically
, preparation method includes the following steps：
（1）Smelting molten steel：The melted molten steel of blast furnace flow by skimming tool be divided into desulfurization pretreatment section, desiliconization pretreatment section and
The pretreatment reaction slot of dephosphorizing pretreatment section is blown into corresponding desulfurizing agent, desiliconization agent, dephosphorization respectively in three pretreatment sections
Agent, and stir, it is pre-processed, is then smelted with 1500 ~ 1650 DEG C of electric arc furnaces or converter control, obtain molten steel.Wherein, turn
Stove carries out dephosphorization using double slag patterns, and the 55%-65wt.% of slag charge is added in early period, and oxygen rifle carries rifle when blowing the period to 20%-30%
Pause blowing, deslagging；Continuing lower rifle blowing, remaining slag charge is added, suitably adds and returns mine in converting process, control basicity >=
3.5, maintain best 1280 DEG C ~ 1360 DEG C of dephosphorization temperature, blowing in stove carbon to be determined, according to survey to TSC thermometrics are carried out when 85%-95%
Amount result progress finally re-blows catch carbon temperature raising degree to 1600 ~ 1680 DEG C.
（2）LF stoves refine：The step is used for deep desulfurization, heating and chemical composition fine tuning.The molten steel of smelting is gone into LF stoves,
Using CaO-Al2O3-SiO2Ternary slag system is sprinkled into aluminum shot to the top of the slag and makes reducing slag, reduces rapidly MnO+FeO contents in slag and arrives
0.5wt.% or less；Ensure micro-positive pressure in stove, control ladle bottom argon blowing rate 500NL/min, refines 45min, it is few by being added
The operation of amount alloy adjusts separately the mass percent in the chemical composition to table 2 of each embodiment and comparative example, quiet to stir 20 ~ 30 points
Clock；
（3）VD stoves are vacuum-treated：VD stoves are gone to, vacuum degree≤1 millibar is controlled, it is 20 minutes vacuum retention times, quiet after vacuum breaker
Stir 15 minutes, feed 100-200 meters of AL lines, 200-300 meters of Si-Ca lines, make terminal [O], [N] control respectively [O]≤
0.0025%、[N]≤0.0045%；When the vacuum degree degree of VD stoves is less than 20 minutes or quiet higher than 1 millibar or vacuum retention time
When stirring the time less than 12 minutes, [O], [N] content in molten steel are susceptible to higher than 0.0040%, 0.0060%, then easily lead to steel
In Ca contents be less than 0.005 wt.%, into weld seam participate in melt tank reaction Ca it is accordingly on the low side, cause reduce slag in weld
The effect of object is insufficient.
（4）Protect continuous casting：Whole process protection cast is implemented, slab is made.Whole process protection pours into a mould the secondary oxygen that can prevent molten steel
Change, the field trash for fusing into weld metal is reduced by reducing the field trash of weathering steel base material.In casting process, using in alkalinity
Covering agent and alkaline crystallization device covering slag promote the absorption to deoxidation products；Barricade is arranged in tundish, to promote on field trash
Floating removal.Tundish uses the resistance to materials of high-quality MgCa, is mingled with caused by capable of effectively mitigating erosion；It is automatically controlled using mould liquid level
Technology reduces the regeneration quantity of field trash；The rational allocation degree of superheat, intensity of secondary cooling-pulling rate, electromagnetic agitation, make field trash it is easy on
Floating removal.
（5）Thermo-mechanical rolling：By heating of plate blank to 1200 ± 20 DEG C, 1180 DEG C of 3 ~ 7 passages of roughing of temperature are controlled, are obtained intermediate
Base, then 4 ~ 7 passage finish rolling are carried out to intermediate base with 850 DEG C, it is then so cooling that exempt from application weather-resistant steel plate, wherein to be controlled when cooling
It is 10 DEG C/s of control temperature fall off rate to open 780 DEG C of cold temperature, 530 DEG C of red temperature, cooling rate speed.
（6）Temper：To eliminate stress, tempered 550 DEG C of the temperature of all steel plates, soaking time 50min.
Mechanical property contrast test：
Steel plate sampling to each embodiment and comparative example of above-mentioned preparation, according to 13239 standard testing lengthwise extensibilities of GB/T
Can, sampling point is at the 1/2 of plate thickness, and test result takes the average value of 2 samples.According to -40 DEG C of 229 standard testings of GB/T
Charpy impact work(, sampling point are at the 1/2 of plate thickness, and test result takes the average value of 3 samples.Mechanical experimental results are shown in
Table 3.
3 embodiment of the present invention of table and comparative example mechanical property
3 data of table can be seen that be required according to the scope of the invention, and the embodiment 1-4 of preparation is compared with comparative example 1-3, and surrender is strong
Degree reaches Q420 grade of steels, and -40 DEG C of charpy impact work(are in 120J or more, and yield tensile ratio is below 0.85；As Si contents carry
Up to 0.65% or more, yield strength significantly improves, and -40 DEG C of charpy impact work(are decreased obviously.The yield strength of 2 steel plate of comparative example
Although also reaching Q420 grade of steels, -40 DEG C of charpy impact work(only 78J, the technology requirement less than >=120J.
Weld seam contrast test：
The steel plate of each embodiment and comparative example of above-mentioned preparation is processed as 24 × width of thickness, 150 × length 400（mm）, groove
The docking test specimen that form is V-type, bevel angle is 45 °；Weldering before using conventional method clear up, removal surface film oxide, greasy dirt and
Water；Welding method is consumable electrode carbon dioxide gas arc welding, and welding wire is weather-proof gas shielded solid welding wire, ingredient and performance
Comply with standard TB 2374-2008T《Rail truck weather resisting steel and stainless steel welding material》, gage of wire is
1.2mm, protective gas are pure carbon dioxide, and flow is 16 ~ 20L/min；Specifically welding condition is：Welding current 260~
280A, 28~32V of weldingvoltage, speed of welding are 16~20m/h, 50~70 DEG C of weld preheating temperature, road（Layer）Temperature 100~
150℃。
After welding 24 hours, ultrasonic examination inspection is carried out to all test specimen weld seam overall lengths, internal soundness reaches Q/
CR 9211-2015《Railway steel bridge manufacturing standard》Requirement to I grade and II grades weld seam.
Further cut section from each weld seam sample, and each test specimen takes at least five section sample, the low power of representative section
Observation is shown in that Fig. 1-7, the welding bead of each embodiment and comparative example are arranged well, without macroscopic defect.Further in optics
Microscopically observation and the quantity for counting field trash in weld seam, the results are shown in Table 4.
The field trash par of unit area in 4 weld seam cross section of table（It is a）
。
After 4 data of table and attached drawing 8-14 are as it can be seen that carry out consumable electrode carbon dioxide gas arc welding welding, comparative example 1
The amount of inclusions in the unit visual field of weld seam cross section reaches 25, i.e., the par in every square millimeter zone reaches 440
A or so, quantity is more, and weldquality is poor.
The amount of inclusions in 1 weld seam cross section unit visual field of the embodiment of the present invention is reduced to 16, is equivalent to every square
Par in millimeter region is 280 or so, compares comparative example 1, and rate of descent is up to 36%, and weldquality is obviously improved.
The amount of inclusions in 2 weld seam unit visual field of embodiment continues to be reduced to 10, is equivalent to every square millimeter zone
In par be 170 or so, compare comparative example 1, rate of descent 60%, weldquality continues to improve.
The amount of inclusions in 3 weld seam unit visual field of embodiment is further reduced to 7, is equivalent to every square millimeter zone
In par be 120 or so, rate of descent 72%, weldquality significantly improves.
The amount of inclusions in 4 weld seam unit visual field of embodiment is still further reduced to 6, is equivalent to every square millimeter of area
Par in domain is 100 or so, and rate of descent 76%, weldquality still has improvement, but function and effect have hastened towards saturation.
The Si contents of comparative example 2 are higher than Si upper content limits value of the present invention, but the amount of inclusions in weld seam unit visual field is still
It is 5, the par being equivalent in every square millimeter zone is 100 or so, compared with comparative example 1, rate of descent 76%, but
Function and effect have been substantially saturated（Compared with Si contents in embodiment 4, field trash reduction has been substantially saturated）.
The amount of inclusions in 3 weld seam unit visual field of comparative example is 12, is equivalent to being averaged in every square millimeter zone
Quantity is 210 or so, 1 rate of descent 52% of comparative example is compared, while compared with Example 2, although the content phase of other elements
When, but the lower limit requirement due to Ca contents far below steel of the present invention, function and effect are substantially reduced.
In conclusion the content of common weathering steel Si and Ca are generally respectively in 0.35 wt% and 0.001 wt% hereinafter, this hair
Bright weathering steel is coordinated to control multiple element content simultaneously, and cooperation realizes Si, Ca etc. in the welding process and is transitioned into weld seam
Control melt tank reaction is participated in, the oxidization burning loss of Cr, Mo are mitigated, improves molten bath mobility, hence it is evident that reduces Welding seam inclusion, significantly carries
High weldquality reduces weld preheating temperature；Higher Si forms nano silicone oxide in base material and weld seam, promotes α-
FeOOH changes, and interior rusty scale is promoted to be densified；By reinforced ferrite, the intensity of base material and weld seam is significantly improved.Production technology letter
It is single convenient, it is of low cost.
Claims (9)
1. a kind of Welding seam inclusion it is few exempt from application weathering steel, which is characterized in that the quality hundred of chemical composition in the weathering steel
Point ratio is：C：0.03 ~ 0.07, Si：0.35 ~ 0.80, Mn：0.90 ~ 1.40, P：0.005 ~ 0.0015, S≤0.005, Cr：0.25~
0.55, Ni：0.25 ~ 0.60, Cu：0.25 ~ 0.50, Mo：0.03 ~ 0.25, Nb：0.010 ~ 0.045, Ti：0.005 ~ 0.015, V
≤ 0.040, Al：0.020 ~ 0.045, Ca：0.003 ~ 0.015, surplus Fe, Si, Mn in the weathering steel, Ni, Cr, Cu, Mo,
Proportioning between Ca contents meets：1.7 >=J >=1.2, wherein J is the ratio between (Si+Mn+50Ca) and (Cr+Ni+Cu+Mo)
Value.
2. according to claim 1 exempt from application weathering steel, which is characterized in that the mass percent of the weathering steel Si contents
It is 0.50 ~ 0.65.
3. according to claim 1 exempt from application weathering steel, which is characterized in that the mass percent of the weathering steel Cr contents
It is 0.35 ~ 0.50.
4. according to claim 1 exempt from application weathering steel, which is characterized in that the mass percent of the weathering steel Ni contents
It is 0.30 ~ 0.45.
5. according to claim 1 exempt from application weathering steel, which is characterized in that the mass percent of the weathering steel Cu contents
It is 0.28 ~ 0.38.
6. according to claim 1 exempt from application weathering steel, which is characterized in that the mass percent of the weathering steel Mo contents
It is 0.05 ~ 0.15.
7. according to claim 1 exempt from application weathering steel, which is characterized in that the weathering steel is calculated according to chemical composition
Atmospheric corrosion resistance index I >=6.5, wherein：
I=26.01(%Cu)+3.88(%Ni)+1.20(%Cr)+1.49(%Si)+17.28(%P)-7.29(%Cu)(%Ni)-9.10
(%Ni)(%P) -33.39(%Cu)2。
8. a kind of few preparation method for exempting from application weather-resistant steel plate of Welding seam inclusion, which is characterized in that the preparation method includes
Following steps：
（1）Smelting molten steel：After desulfurizing agent, desiliconization agent, Dephosphorising agent pretreatment molten steel, with electric arc furnaces or converter control 1500 ~
1650 DEG C are smelted, and molten steel is obtained；
（2）LF stoves refine：Molten steel goes to LF stoves, using CaO-Al2O3-SiO2Ternary slag system is sprinkled into aluminum shot to the top of the slag and makes reduction
Slag reduces rapidly in slag MnO+FeO contents to 0.5wt.% or less；Ensure micro-positive pressure in stove, controls ladle bottom argon blowing rate
350-650NL/min, refines 40 ~ 50min, and the mass percent for adjusting chemical composition is：C：0.03 ~ 0.07, Si：0.35~
0.80, Mn：0.90 ~ 1.40, P：0.005 ~ 0.0015, S≤0.005, Cr：0.25 ~ 0.55, Ni：0.25 ~ 0.60, Cu：0.25~
0.50, Mo：0.03 ~ 0.25, Nb：0.010 ~ 0.045, Ti：0.005 ~ 0.015, V≤0.040, Al：0.020 ~ 0.045, Ca：
0.003 ~ 0.015, surplus Fe, the proportioning in the weathering steel between Si, Mn, Ni, Cr, Cu, Mo, Ca content meet：1.7≥
J >=1.2, wherein J is the ratio between (Si+Mn+50Ca) and (Cr+Ni+Cu+Mo), quiet to stir 20 ~ 30 minutes；
（3）VD stoves are vacuum-treated：Vacuum degree≤1 millibar is 20 ~ 25 minutes vacuum retention times, quiet after vacuum breaker to stir 12 ~ 18 points
Clock feeds Al lines and Si-Ca lines, terminal [O], [N] is made to be controlled respectively in [O]≤0.0025%, [N]≤0.0045%；
（4）Protect continuous casting：Using whole process protection pouring type, slab is obtained；
（5）Thermo-mechanical rolling：By heating of plate blank to 1200 ± 20 DEG C, 3 ~ 7 passage of temperature >=1000 DEG C roughing is controlled, is obtained intermediate
Base, then 4 ~ 7 passage finish rolling are carried out to intermediate base with 800 ~ 920 DEG C, it is then so cooling that exempt from application weather-resistant steel plate, wherein when cooling
5~15 DEG C 760 ~ 800 DEG C of cold temperature, 500 ~ 700 DEG C of red temperature, cooling rate/s are opened in control.
9. preparation method according to claim 8, which is characterized in that the preparation method further includes step（6）At tempering
Reason：500 ~ 600 DEG C of temperature, soaking time are " plate thickness+(10 ~ 50) min ".
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