Background technology
It is the low chrome ferritic stainless steel of representative with South Africa 3Cr12, U.S. S41003 and Germany 1.4003 etc., due to havingGood mechanical property, corrosion resisting property and low overall life cycle cost are increasingly becoming engineering structure part carbon steel, weathering steelWith the alternative materials of coating plate etc..This kind of stainless steel Cr equivalents are relatively low, can be formed in ferrite matrix after hot rolling and air coolingA small amount of martensite, therefore there is higher intensity.But the corresponding plasticity of material is poor (elongation percentage is about 10%) at this time, can notDirect engineer application.For this purpose, usually coil of strip will carry out long term annealing processing in 700 DEG C -750 DEG C of bell furnace.
It summarizes
On the one hand, this application involves high-strength low straight-chromiun stainless steel, by weight percentage, it includes 0<C≤0.05%, 0<Si≤ 1.0%, 0<Mn≤2.00%, P≤0.045%, S≤0.03%, 0<N≤0.03%, 10.5%≤Cr≤13.5%, 0<Ni≤ 1.0%, 0<Ti+Nb≤0.5%, surplus are Fe and other inevitable impurity.
On the other hand, this application involves heat treatment methods comprising：A) high-strength low straight-chromiun stainless steel, by weight percentage are providedThan meter, the high-strength low straight-chromiun stainless steel includes 0<C≤0.05%, 0<Si≤1.0%, 0<Mn≤2.00%, P≤0.045%, S≤ 0.03%, 0<N≤0.03%, 10.5%≤Cr≤13.5%, 0<Ni≤1.0%, 0<Ti+Nb≤0.5%, surplus be Fe andOther inevitable impurity；And continuous annealing treatment b) is carried out to the pending stainless steel, wherein the continuous annealingHeat treatment temperature in processing is 800 DEG C -900 DEG C.
In another aspect, this application involves high-strength low straight-chromiun stainless steel, wherein the high-strength low straight-chromiun stainless steel passes through continuous annealingProcessing, by weight percentage, the high-strength low straight-chromiun stainless steel include 0<C≤0.05%, 0<Si≤1.0%, 0<Mn≤2.00%, P≤0.045%, S≤0.03%, 0<N≤0.03%, 10.5%≤Cr≤13.5%, 0<Ni≤1.0%, 0<Ti+Nb≤0.5%, surplus are Fe and other inevitable impurity.
Brief Description Of Drawings
Fig. 1 is the microstructure picture for the high-strength low straight-chromiun stainless steel that embodiment 1 produces.
It is described in detail
In the following description, including certain concrete details to each disclosed embodiment to provide comprehensive reasonSolution.However, those skilled in the relevant art are not, it will be recognized that use one or more of these concrete details, and use otherEmbodiment is still realized in the case of method, component, material etc..
Unless required otherwise in the application, in the whole instruction and appended claims, word " comprising ", " packetContaining ", " containing " and " having " should be interpreted that meaning that is open, including formula, i.e., " include but not limited to ".
" embodiment " mentioned throughout the specification, " embodiment ", " in another embodiment " or " at certainIn a little embodiments " mean an at least embodiment include with described in the embodiment it is relevant with specific reference to element,Structure or feature.Therefore, throughout the specification different location occur phrase " in one embodiment " or " in embodimentIn " or " in another embodiment " or " in certain embodiments " same embodiment need not be all referred to.In addition, specifically wantingElement, structure or feature can combine in one or more embodiments in any suitable manner.
Definition
Herein, " austenite " means the nonmagnetic solid solution that a small amount of carbon is dissolved in γ-Fe, with face-centered cubic knotStructure.Austenite plasticity is preferable, and intensity is relatively low, has certain toughness, does not have ferromagnetism.
Herein, " martensite " means supersaturated solid solution of the carbon in α-Fe, with body-centered structure of the quartet.It is higherIntensity and hardness be martensite in steel one of main feature.
Herein, " ferrite " means interstitial solid solution of the carbon dissolution in α-Fe, with body-centered cubic lattic, oftenIt is indicated with symbol F.Pure ferritic structure has good plasticity and toughness, but intensity and hardness are all relatively low.
Herein, " room temperature " means 25 DEG C ± 5 DEG C.
Herein, " plasticity and toughness " mean the general designation of stainless steel material plasticity and toughness.
Herein, " plasticity " is meant under external force, and permanent deformation can steadily occur for stainless steel material without brokenThe ability of its bad integrality.
Herein, " toughness " means stainless steel material in the ability for being plastically deformed with absorbing energy in fracture process.
Herein, " elongation percentage (δ) " means the total deformation Δ L and original gauge length of gauge length section after stainless steel curved beam tension failureThe percentage of the ratio between length L：δ=Δ L/L × 100%.
Herein, " yield strength " means yield limit when yield phenomenon occurs for stainless steel material, here using ruleDetermine stress value when Non-proportional extension rate is 0.2%.
Herein, " tensile strength " means that stainless steel material bears maximum stress value before breaking.
Herein, " average cooling rate " means (- 300 DEG C of heat treatment temperature)/(stainless steel comes out from continuous annealing furnaceIt is cooled to the time used in 300 DEG C).
Specific embodiment
On the one hand, this application involves high-strength low straight-chromiun stainless steel, by weight percentage, it includes 0<C≤0.05%, 0<Si≤ 1.0%, 0<Mn≤2.00%, P≤0.045%, S≤0.03%, 0<N≤0.03%, 10.5%≤Cr≤13.5%, 0<Ni≤ 1.0%, 0<Ti+Nb≤0.5%, surplus are Fe and other inevitable impurity.
In certain embodiments, C is austenite former, while being also solution strengthening element, however C content is excessively highThe corrosion resistance and plasticity and toughness of steel, therefore, by weight percentage 0 can be reduced<C≤0.05%.
In certain embodiments, deoxidation from Si is in steel-making, while being also ferrite former, suitable siliconIntensity and corrosion resistance can be improved, however the toughness of steel, therefore, by weight percentage 0 can be deteriorated when Si too high levels<Si≤1.0%.
In certain embodiments, Mn and Ni is all austenite former, and Mn, which is added, can make steel form more high temperature AustriaFamily name's body is conducive to improve intensity to obtain more martensites in follow-up cooling procedure；Mn prices are low more than Ni simultaneously, withMn can reduce the cost of steel for Ni.However excessively high Mn contents are unfavorable to the corrosion resistance of steel, and therefore, by weight percentage 0<Mn≤ 2.0%.
In certain embodiments, P, S are the inevitable impurity element of steel-making, while unfavorable to Steel Properties, therefore itsContent should be low as possible, by weight percentage P≤0.045%, S≤0.03%.
In certain embodiments, N is austenite former, and a small amount of nitrogen can play solution strengthening and tissue modulationEffect, however the excessively high toughness that can reduce steel of N content, therefore, by weight percentage 0<N≤0.03%.
In certain embodiments, Cr is main anti-corrosion element, and the content the high more is conducive to improve the corrosion resisting property of steel；Cr is also ferrite former, and too high levels are unfavorable for the formation of martensite and intensity in steel and improve, while excessively high CrContent can also increase the cost of steel, therefore 10.5%≤Cr≤13.5% by weight percentage.
In certain embodiments, Ni is austenite former, the austenite structure ratio of steel when can increase high temperature,It is also beneficial to the toughness of steel simultaneously.However Ni contents, more than after certain value, the increased amplitude of effect becomes smaller.In addition, Ni resources haveLimit, for strategic element, expensive and fluctuation is big, therefore, by weight percentage 0<Ni≤1.0%.
In certain embodiments, Ti, Nb are strong carbonitride-forming elements, and a certain amount of Ti, Nb is added can be preferentialExtra carbon in steel, nitrogen are fixed, the Carbonitride Precipitation of Cr is avoided, improves the corrosion resisting property of steel；Ti, Nb is precipitatedCarbonitride can improve the mechanical property of steel with crystal grain thinning.However excessive Ti, Nb can cause surface defect and be added toThis, therefore Ti, Nb total amount>0 and≤0.5%.
In certain embodiments, in order to ensure the application high-strength low straight-chromiun stainless steel have high intensity and good modelingProperty, it is about 2.1-3.6 that the chemical composition of the stainless steel, which should meet the size of components Factor M, wherein M=[Cr+6Si+5 (Ti+Nb)]/[4Ni+2Mn+40(C+N)].Components Factor M reflects ferrite former and austenite former content is oppositeRatio.Components Factor M values are bigger, illustrate that the ferrite former content of stainless steel is more, and corresponding stainless hardness of steel is low, plasticityIt is good.On the contrary, components Factor M values are smaller, illustrate that the austenite former content of stainless steel is more, can be formed after cooling moreMartensite, corresponding stainless hardness of steel is high, plasticity is poor.
On the other hand, this application involves heat treatment methods comprising：
A) pending stainless steel is provided, by weight percentage, the stainless composition of steel includes 0<C≤0.05%, 0<Si≤ 1.0%, 0<Mn≤2.00%, P≤0.045%, S≤0.03%, 0<N≤0.03%, 10.5%≤Cr≤13.5%, 0<Ni≤ 1.0%, 0<Ti+Nb≤0.5%, surplus are Fe and other inevitable impurity；And
B) continuous annealing treatment is carried out to the pending stainless steel, wherein the heat treatment temperature in the continuous annealing treatmentDegree is 800 DEG C -900 DEG C.
In certain embodiments, it can be used in the illustrative examples packet of the equipment of the carry out continuous annealing treatment of the applicationIt includes but is not limited to continuous annealing furnace.
In certain embodiments, it can be used in the corresponding guarantor of every millimeter of stainless steel thickness in the heat treatment method of the applicationThe warm time is 0.5min-3.0min.
In certain embodiments, it can be used in average cooling rate≤40 DEG C/s in the heat treatment method of the application.
In certain embodiments, the heat treatment postcooling in annealing is to room temperature.
In certain embodiments, after the heating and thermal insulation process of heat treatment, with the average cooling speed of≤40 DEG C/sRate is cooled to room temperature.
In certain embodiments, the stainless steel that can be used in the application heat treatment method is coil of strip.
In certain embodiments, the stainless steel that can be used in the application heat treatment method is rolled.
In certain embodiments, the stainless steel thickness that can be used in the application heat treatment method is about 2.0mm-12.0mm.In certain embodiments, the stainless steel thickness that can be used in the application heat treatment method is about 4.0mm-7.0mm。
In certain embodiments, it can be used in the exemplary reality of the high-strength low straight-chromiun stainless steel of the heat treatment method of the applicationExample includes but not limited to high-strength low straight-chromiun stainless steel coil of strip.
In certain embodiments, the illustrative examples that can be used in the high-strength low straight-chromiun stainless steel coil of strip of the application include butIt is not limited to rolled coil of strip.
In certain embodiments, in order to make stainless steel obtain comparatively fine crystal grain, it can be used in every milli of the applicationThe corresponding soaking time of the low straight-chromiun stainless steel thickness of meter Gao Qiang is about 0.5min-3.0min.In certain embodiments, in order to make notRust steel obtains comparatively fine crystal grain, can be used in the corresponding soaking time of every millimeter of the application high-strength low straight-chromiun stainless steel thicknessAbout 1.5min-3.0min.In certain embodiments, in order to make stainless steel obtain comparatively fine crystal grain, it can be used in thisThe corresponding soaking time of every millimeter of application high-strength low straight-chromiun stainless steel thickness is about 1.5min-2.3min.
In certain embodiments, by the elongation percentage of the heat treatment method of the application treated high-strength low straight-chromiun stainless steelAbout it is more than or equal to 20%.
In certain embodiments, the surrender by the heat treatment method of the application treated high-strength low straight-chromiun stainless steel is strongDegree is about more than or equal to 500MPa.
In certain embodiments, the size that the chemical composition of high-strength low straight-chromiun stainless steel tool should meet components Factor M is about2.1-3.6, wherein M=[Cr+6Si+5 (Ti+Nb)]/[4Ni+2Mn+40 (C+N)].Components Factor M reflects ferrite and is formedElement and austenite former content relative scale.Components Factor M values are bigger, illustrate that the ferrite former of stainless steel containsMeasure more, corresponding stainless hardness of steel is low, plasticity is good.On the contrary, components Factor M values are smaller, illustrate the austenitic formation of stainless steelConstituent content is more, and more martensites can be formed after cooling, and corresponding stainless hardness of steel is high, plasticity is poor.
In certain embodiments, there is Fig. 1 institutes by the high-strength low straight-chromiun stainless steel that the heat treatment method of the application obtainsThe microscopic structure shown.
The heat treatment temperature of continuous annealing in the heat treatment method of the application is higher, can make the abundant austenite of stainless steelChange, more martensites is formed after cooling, to improve intensity.In addition, higher heat treatment temperature can also quickly eliminate changeShape tissue improves the plasticity and toughness of stainless steel.Moderate soaking time can make stainless steel obtain tiny institutional framework, to improveIntensity and plasticity and toughness.Slower cooling rate can make stainless steel that martensite self tempering occur in cooling procedure, can further increaseAdd the plasticity and toughness of steel.
In addition, compared with the cover annealing of this field routine, the annealing cycle of the heat treatment method of the application greatly contractsIt is short.Average steel≤3 ton being heat-treated per hour of the bell furnace of this field routine, and continuously moving back in the heat treatment method of the applicationFire steel >=5 ton heat treatable per hour.
In another aspect, this application involves high-strength low straight-chromiun stainless steel, wherein the high-strength low straight-chromiun stainless steel is by continuously moving backFire processing obtains, and by weight percentage, the high-strength low straight-chromiun stainless steel includes 0<C≤0.05%, 0<Si≤1.0%, 0<Mn≤ 2.00%, P≤0.045%, S≤0.03%, 0<N≤0.03%, 10.5%≤Cr≤13.5%, 0<Ni≤1.0%, 0<Ti+ Nb≤0.5%, surplus are Fe and other inevitable impurity.
In certain embodiments, in order to ensure the application high-strength low straight-chromiun stainless steel have high intensity and good modelingProperty, it is about 2.1-3.6 that the chemical composition of the stainless steel, which should meet the size of components Factor M, wherein M=[Cr+6Si+5 (Ti+Nb)]/[4Ni+2Mn+40(C+N)].Components Factor M reflects ferrite former and austenite former content is oppositeRatio.Components Factor M values are bigger, illustrate that the ferrite former content of stainless steel is more, and corresponding stainless hardness of steel is low, plasticityIt is good.On the contrary, components Factor M values are smaller, illustrate that the austenite former content of stainless steel is more, can be formed after cooling moreMartensite, corresponding stainless hardness of steel is high, plasticity is poor.
Hereinafter, the application will be explained in detail by following examples and attached drawing to more fully understand the applicationVarious aspects and its advantage.It is simply used for illustrating the application it will be appreciated, however, that embodiment below is non-limitingCertain embodiments.