CN1571862A - Duplex steel alloy - Google Patents

Duplex steel alloy Download PDF

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CN1571862A
CN1571862A CNA028206177A CN02820617A CN1571862A CN 1571862 A CN1571862 A CN 1571862A CN A028206177 A CNA028206177 A CN A028206177A CN 02820617 A CN02820617 A CN 02820617A CN 1571862 A CN1571862 A CN 1571862A
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CN100465325C (en
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安·森德斯特龙
安娜-莱娜·奈斯特龙
帕西·坎加斯
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Sandvik Intellectual Property AB
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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
    • 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
    • C22C38/005—Ferrous alloys, e.g. steel alloys containing rare earths, i.e. Sc, Y, Lanthanides
    • 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
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • 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
    • C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
    • 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
    • C22C38/52—Ferrous alloys, e.g. steel alloys containing chromium with nickel with cobalt
    • 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
    • C22C38/54—Ferrous alloys, e.g. steel alloys containing chromium with nickel with boron
    • 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
    • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese

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Abstract

The present invention relates to a stainless steel alloy, closer determined a duplex stainless steel alloy with ferritic-austenitic matrix and with high resistance to corrosion in combination with good structural stability and hotworkability, in paricular a duplex stainless steel with a content of ferrite of 40-65% and a well balanced compositon that imparts material corrosion properties, which makes it is more suitable for use in chloride-containing environments than earlier been considered being possible. The total PRE- or PREW-number exceeds 44 a PRE-number on at least between 46 and 50 in both the austenite phase and the ferrite phase, whereby PRE = %Cr + 3,3%Mo + 16N and PREW = %Cr + 3,3(%Mo + 0,5%W) + 16N, wherein % considers weight-% and ratio between PRE(W)-value for the austenite phase and PRE(W)-value for the ferrite phase lies between 0,90 and 1,15. These purposes are fulfilled according to the present invention with duplex stainless steel alloys which contain (in weight-%) up to 0,03% C, up to 0,5% Si, 24,0-30,0% Cr, 4,9-10,0% Ni, 3,0-5,0% Mo, 0,28-0,5% N, 0-3,0% Mn, 0-0,0030% B, up to 0,010%, 0-0,03% Al, 0-0,010% Ca, 0-3,0% W, 0-2,0% Cu, 0-3,5% Co, 0-0,3% Ru, balance Fe and inevitable impurities.

Description

Duplex steel alloys
Technical field
The present invention relates to a kind of Stainless Steel Alloy, relate to or rather and a kind ofly contain the ferritic-austenitic matrix and have high corrosion resistance, good structural stability and the duplex stainless steel of hot workability, especially relate to that a kind of to have volume percent content be the duplex stainless steel that the ferrite and being used for of 40-65% is given the equilibrium composition of this material erosion resistance, compare with the advised material that may use in the past, described composition makes this stainless steel be more suitable for using in the environment of chloride composition.
Background technology
In recent years, used the environment of erosion resistance metallic substance to become and had corrodibility more, the requirement of the mechanical property of materials and corrosion resistance was all being improved.Be established as the two-phase alloys steel that uses the surrogate of steel grade to present, for example high alloy austenitic steel, nickel-base alloy steel or other high quality steel are indispensable in Future Development.
Known erosion resistance method in the chloride environment is a so-called anti-tubercular corrosion method of equal value (being called for short PRE), is defined as:
PRE＝％Cr+3.3％Mo+16％N
Wherein the per-cent of every kind of element refers to weight percent.
The high more expression of numerical value especially has better erosion resistance aspect the anti-tubercular corrosion.According to top formula, Cr, Mo, N are the basic alloy elements that influences this characteristic.An example of this steel grade is open in EP0220141, and the document is cited as a reference in this manual.The contained main alloying constituent of this steel grade with symbol SAF2507 (UNS S32750) expression is high-load Cr, Mo and N.Thereby at this research that in chloride environment, has good corrosion just in evolution.
Recently, shown that for corrosion resistance element Cu and the W of further optimization steel in chloride environment be that effective alloy adds element.So adopted the alternative of element W as a part of Mo, for example in industrial alloy DP3W (UNS S39274) or Zeron100, these alloys comprise 2.0% and 0.7% W respectively, and the latter also comprises 0.7% Cu to be used for improving the corrosion resistance at the sour environment interalloy.
Alloy adds elemental tungsten and has caused further developing of erosion resistance method, and makes the PRE formula develop into the PREW formula thus, and this makes Mo and the relation of W between the influence on the alloy erosion resistance clearer:
PREW＝％Cr+3.3(％Mo+0.5％W)+16％N
For example the same described in EP0545753.The document relates to the duplex stainless steel that a kind of its corrosion resistance is improved substantially.Above-mentioned steel grade have one with method of calculation irrelevant greater than 40 PRE value.
Have in chloride environment in the alloy of good corrosion energy, it might also be mentioned SAF2906, its moiety is open in EP0708845.It is characterized in that, its Cr and the higher this alloy of N content have demonstrated to be particularly suitable for being used in and have paid attention in anti intercrystalline corrosion and the ammonium carbamate corrosive environment for SAF2507 for example, but it also has very high erosion resistance in the environment of chloride.
US-A-4985091 has disclosed a kind of be used for mainly the occurring hydrochloric acid of intergranular corrosion and the alloy of thiosulfonic acid environment.This alloy mainly is intended as the surrogate of the austenitic steel of present use.
US-A-6048413 has also disclosed a kind of duplex stainless steel of the surrogate as austenitic steel, and its plans to be used in the environment of chloride.
Above-mentioned alloy shortcoming with higher PRE value is, especially for example can occur hard frangible intermetallic precipitate by welding after heat-treating under aftertreatment in steel, for example the σ phase.This shortcoming has caused producing the poorer and therefore harder material of corrosion resistance variation of processibility.
In order further to improve the especially pitting resistance of duplex stainless steel, need to improve, and can not damage the structural stability or the workability of material for this reason in ferritic phase and austenite PRE value mutually.If composition is unbalanced aspect effective alloying constituent in this two-phase, a phase will become responsive more to spot corrosion and crevice corrosion so.Therefore, to responsive more this of corrosion mutually its corrosion resistance reduce, simultaneously structural stability since high alloy phase reduce.
Summary of the invention
Therefore, an object of the present invention is to provide a kind of double phase stainless steel alloy, this alloy demonstrates its mechanical property of high corrosion resistance while and also improves, and this alloy optimum is used in and need has in the environment of high resistibility for general corrosion and local corrosion, for example the environment of chloride.
Another object of the present invention provides a kind of double phase stainless steel alloy, its ferrite volume percent content be 40-65% and its austenite mutually and the PRE value in the ferritic phase at least between 46-50, and the best proportion between austenite PRE and ferrite PRE is 0.90-1.15, is preferably 0.9-1.05.
Another object of the present invention provides a kind of double phase stainless steel alloy, and its critical pitting temperature value (hereinafter to be referred as CPT) is higher than 90 ℃, preferably is higher than 95 ℃, and at 6%FeCl 3In critical crevice corrosion temperature value (C T) minimum be 50 ℃, preferably at 6%FeCl 3In be at least 60 ℃
Another object of the present invention provides a kind of shock strength at room temperature and is at least unit elongation after 100J and the drawn test at room temperature and is at least 25% alloy.
Because its high alloy content, material according to the invention has significantly good workability, particularly good hot workability should be highly suitable for producing for example for example pump, valve, flange, junctor one class of welded tube and seamless tube, sheet material, band, wire rod, welding rod and structural parts of for example bar, tubing thus.
Double phase stainless steel alloy according to the present invention is realized these purposes, and this alloy comprises (weight percent) C of 0.03% at the most, 0.5% Si at the most, the Cr of 24.0-30.0%, the Ni of 4.9-10.0%, the Mo of 3.0-5.0%, the N of 0.28-0.5%, 0-3.0%Mn, the B of 0-0.0030%, 0.010% S at the most, the Al of 0-0.03%, the Ca of 0-0.010%, the W of 0-3.0%, the Cu of 0-2.0%, the Co of 0-3.5%, the Ru of 0-0.3%, the Fe content and the unavoidable impurities of equal amount.
Brief description of drawings
Fig. 1 demonstrates with dual phase steel SAF2507, SAF2906 and high alloy austenitic steel 654SMO and compares, the CPT value that obtains through in the ASTM G48C experiment of revising test sample being tested of carrying out in " Green Death " solution.
Fig. 2 demonstrates with dual phase steel SAF2507 and austenitic steel 654SMO and compares, by test sample being passed through the CPT value of the ASTM G48C experiment acquisition of revising in " Green Death " solution.
Fig. 3 demonstrates the average etching extent mm/ in 2%HCl under 75 ℃ environment.
Fig. 4 demonstrates and most of sample is carried out high-temperature ductility tests resulting result.
Detailed description of preferred embodiments
Systematic study work shows: people can realize the optimum allocation of these elements in austenite and ferrite by well balanced composite component Cr, Mo, Ni, N, Mn and Co, this just can realize a kind of very corrosion-resistant material, and only has it measure negligible σ phase in this material.Described material has also obtained good workability, and this makes it possible to extrusion molding is weldless steel tube.This work also shows, in order to obtain the combination of high corrosion resistance and satisfactory texture stability, need carry out narrower combination to alloying element in this material in the present invention.Alloy according to the present invention includes (wt%):
C at the most 0.03%
Si at the most 0.5%
Mn?????????????????0-3.0％
Cr?????????????????24.0-30.0％
Ni?????????????????4.9-10.0％
Mo?????????????????3.0-5.0％
N??????????????????0.28-0.5％
B??????????????????0-0.0030％
S at the most 0.010%
Co?????????????????0-3.5％
W??????????????????0-3.0％
Cu?????????????????0-2.0％
Ru?????????????????0-0.3％
Al?????????????????0-0.03％
Ca?????????????????0-0.010％
Equal amount Fe and normal impurity and the additive that occurs, wherein ferritic volumn concentration is 40-65%.
Carbon (C) solubleness in ferrite and austenite is limited.Limited solubleness means the danger that has chromium carbide to separate out, so the content of carbon can not surpass 0.03wt%, preferably is no more than 0.02wt%.
Silicon (Si) is used as reductive agent in steel production, it has improved flowability in production and welding process simultaneously.But the intermetallic phase that the Si too high levels can cause not expecting to have is separated out, so the content of Si 0.5wt% at the most, preferably is no more than 0.3wt%.
Manganese (Mn) adds the solubleness that is used for improving N in the material, and still verified, Mn is limited to the influence of N solubleness in the alloy of described type.On the contrary, found other element higher to the influence of this solubleness.In addition, Mn combines meeting with high-load S and causes forming manganese sulfide, and this is as the starting point of tubercular corrosion, so the content of Mn should be limited in being preferably 0.5-1.2wt% between the 0-3.0wt%.
Chromium (Cr) is a kind of quite useful element, can improve the resistibility to most of form of corrosion.In addition, high-load chromium means can obtain extraordinary N solubleness in material.Therefore require to make Cr content to keep high as far as possible so that improve corrosion resistance.The chromium content that corrosion resistance is good should reach 24.0wt% at least, is preferably 27.0-29.0wt%.But high-load chromium can increase the danger of intermetallic precipitate, the content of chromium must be limited in the 30wt% for this reason.
Nickel (Ni) is used as the austenite stable element, adds the ferrite that an amount of nickel can also obtain desired content.For in volume percent being obtains desired austenite mutually and the ratio between the ferritic phase in the ferrite of 40-65%, need to add 4.9-10.0wt%, be preferably the nickel of 4.9-8.0wt%.
Aluminium (Mo) is a kind of useful element, and it can improve the corrosion resistance in chloride environment and reductive acid environment.Too high-load Mo can combine with high-load Cr, this means that the danger that produces the intermetallic precipitate increases, and Mo content in the present invention should be preferably 3.6-4.7wt% in the scope of 3.0-5.0wt%, especially be 4.0-4.3wt%.
Nitrogen (N) is very useful element, and it can improve erosion resistance, structural stability and the intensity of material.In addition, high-load N can improve the austenitic recovery in welding back, and this has given good performance in solder joint.More obvious for the effect that makes N, should add 0.28% N at least.Under N content condition with higher, especially when the content while of chromium was also very high, the danger that produces the chromium nitride precipitate increased, in addition, because N excessive dissolution in melting, so high N content means that porous danger occurring increases.Therefore, N content should be restricted to 0.5wt% at the most, the preferred N that adds greater than 0.35-0.45wt%.
Boron (B) is to add the hot workability that is used for improving material.Under the too high situation of B content, erosion resistance and weldability meeting variation, therefore, B content should be restricted to 0.0030wt%.
Sulphur (S) has a negative impact to erosion resistance by forming soluble sulfide, and in addition, therefore the hot workability variation is restricted to S content and is no more than 0.010wt%.
Cobalt (Co) adding is used at first improving erosion resistance and structural stability.Co is a kind of austenite stable element.In order to produce useful effect, the content of Co should be at least 0.5wt%, preferably is at least 1.5wt%.Because Co is relatively costly element, therefore the addition with cobalt is restricted to 3.5wt% at the most.
TungstenCan improve anti-spot corrosion and crevice corrosion performance, but the Cr of the tungsten that adds too high amount and high level and Mo combine and mean the danger increase that the intermetallic precipitate occurs.W content in the present invention should be preferably between the 0.5-1.8wt% in the 0-3.0wt% scope.
CopperAdd and to be used for improving at the sour environment general corrosion resistance in the sulfuric acid for example.Cu can influence stability of structure simultaneously.But high-load Cu means will surpass solid solubility, and therefore, Cu content should be restricted to 2.0wt% at the most, is preferably at 0.5-1.5wt%.
Ruthenium (Ru) adds and to be used for improving erosion resistance, because ruthenium is very expensive element, so content should be limited in 0.3wt% at the most, is preferably 0-0.1wt%.
Aluminium (Al) and calcium (Ca) are used as reductor in product made from steel, the content of Al should be limited in 0.03wt% scope at the most the formation with the restriction nitride.Ca can produce useful effect to hot ductility, and still, the content of Ca should be restricted to 0.010wt% to avoid occurring undesirable slag inclusion.
In order to obtain favorable mechanical performance, corrosion resistance and good weldability energy, ferritic content is extremely important.Consider that from the angle of erosion resistance and weldability the ferrite content of 40-65% is an ideal for obtaining superperformance.In addition, high-load ferrite means shock strength and the brittle resistibility deterioration to being caused by hydrogen at low temperatures, and therefore, ferritic volume percent content is 40-65%, is preferably 42-60%, especially is 45-55%.
In the following embodiments, provided the component of many test samples, these embodiment have illustrated the effect of different-alloy element on performance.Sample 605182 is represented one with reference to component, is not the part in field of the present invention therefore.Remaining sample should not thought to limit the invention, also should only not only limit to the embodiment of these samples, these embodiment have set forth the present invention who limits according to claim.
Although there be not clear and definite mentioning, always specific PRE number or value are considered to calculate according to the PREW formula.
Embodiment 1
The test sample of this embodiment is produced by following steps: cast out the steel ingot that weight is 170kg in the laboratory, subsequently its forge hot is become round steel.They are hot extruded into bar (band steel and round steel), wherein from these round steel, choose test materials.In addition, band steel is annealed before cold rolling carrying out, obtain other experiment material subsequently.Consider that from the material engineering angle described process can be taken as the representative of more scale operation, for example produces stainless steel tube by extrusion method, carries out cold rolling afterwards.Table 1 demonstrates the component of first experimental sample.
The composition of table 1 experimental sample, wt%
Sample ????Mn ?????Cr ????Ni ????Mo ????W ????Co ????V ????La ????Ti ????N
???605193 ???1.03 ????27.90 ???8.80 ???4.00 ???0.01 ???0.02 ???0.04 ???0.01 ???0.01 ???0.36
???605195 ???0.97 ????27.90 ???9.80 ???4.00 ???0.01 ???0.97 ???0.55 ???0.01 ???0.35 ???0.48
???605197 ???1.07 ????28.40 ???8.00 ???4.00 ???1.00 ???1.01 ???0.04 ???0.01 ???0.01 ???0.44
???605178 ???0.91 ????27.94 ???7.26 ???4.01 ???0.99 ???0.10 ???0.07 ???0.01 ???0.03 ???0.44
???605183 ???1.02 ????28.71 ???6.49 ???4.03 ???0.01 ???0.03 ???0.54 ???0.01 ???0.01 ???0.28
???605184 ???0.99 ????28.09 ???7.83 ???4.01 ???0.01 ???0.03 ???0.54 ???0.01 ???0.01 ???0.44
???605187 ???2.94 ????27.74 ???4.93 ???3.98 ???0.01 ???0.98 ???0.06 ???0.01 ???0.01 ???0.44
???605153 ???2.78 ????27.85 ???6.93 ???4.03 ???1.01 ???0.02 ???0.06 ???0.02 ???0.01 ???0.34
???605182 ???0.17 ????23.48 ???7.88 ???5.75 ???0.01 ???0.05 ???0.04 ???0.01 ???0.10 ???0.26
In order to study the structural stability of sample, the described sample of choosing from each sample is annealed for going forward one by one with 50 ℃ under 900-1150 ℃ respectively, subsequently respectively at air or quenching-in water.Under a minimum temperature, form intermetallic phase.By in opticmicroscope, studying to determine the intermetallic phase negligible minimum temperature that becomes.Afterwards under described temperature to from the fresh sample of respective samples annealing constant temperature 5 minutes, with 140 ℃/minute constant speed of cooling these samples are cooled to room temperature afterwards, form the area part that the digital scanning picture is determined σ phase in these materials with back scattered electron subsequently under scanning electronic microscope, the result is as shown in table 2.
T Maxσ is calculated by Thermo-Calc (the TC type N thermodynamic data storehouse of TCFE99 steel) according to the eigenwert of all element-specific in different variablees.T Maxσ is the solvent temperature of σ phase, and high solvent temperature is represented lower structural stability.
Table 2
Sample Thermal treatment σ content (Vol%) ???T maxσ
???605193 1100 ℃, 5 minutes ?????7.5％ ????1016
???605195 1150 ℃, 5 minutes ?????32％ ????1047
???605197 1100 ℃, 5 minutes ?????18％ ????1061
???605178 1100 ℃, 5 minutes ?????14％ ????1038
???605183 1050 ℃, 5 minutes ?????0.4％ ?????997
???605184 1100 ℃, 5 minutes ?????0.4％ ?????999
???605187 1050 ℃, 5 minutes ?????0.3％ ?????962
???605153 1100 ℃, 5 minutes ?????3.5％ ????1032
???605182 1100 ℃, 5 minutes ?????2.0％ ????1028
The purpose of this research is can be according to structural stability with the material classification, and promptly this is not the σ real content mutually in the sample of Overheating Treatment and quenching before corrosion test for example.The T that calculates by Thermo-Calc as can be seen Maxσ does not have directly consistent with the σ phasor that measures, but obviously has the minimum T that calculates MaxThe experimental sample of σ includes the σ phase of the minimum quantity in this experimentation.
Carry out the classification experiment of spot corrosion performance in so-called " Green Death " solution, described solution comprises 1% FeCl 3, 1% CuCl 2, 11% H 2SO 4With 1.2% HCl.Experimental procedure is with identical according to the spot corrosion of ASTM G48C experiment, but it finishes in more acrid " Green Death ", and in addition, some samples are according to ASTM G48C experimentize (each sample carries out 2 experiments).Also in containing 3%NaCl, carry out electrochemistry experiment (each sample carries out 6 experiments).The result of critical pitting temperature (CPT) form that draws from all experiments is as shown in table 3, for example for whole compositions and austenite, ferritic PREW value (Cr+3.3 (Mo+0.5W)+16N) in the alloy.Symbol is represented ferrite, and γ represents austenite.
Table 3
Sample ???PRE α ???PRE γ ????PRE γ??????/PRE α ???PRE The ASTM G48C Green death of CPT ℃ of correction ?????CPT℃ ????????ASTM?G48C ????6％FeCl 3 ???CPT℃ ????????3％ ????NaCl
??605193 ???51.3 ???49.0 ???0.9552 ??46.9 ???????90/90 ????64
??605195 ???51.5 ???48.9 ???0.9495 ??48.7 ???????90/90 ????95
??605197 ???53.3 ???53.7 ???1.0075 ??50.3 ???????90/90 ??????＞95 ???＞95
??605178 ???50.7 ???52.5 ???1.0355 ??49.8 ???????75/80 ????94
??905183 ???48.9 ???48.9 ???1.0000 ??46.5 ???????85/85 ???????90 ????93
??605184 ???48.9 ???51.7 ???1.0573 ??48.3 ???????80/80 ????72
??605187 ???48.0 ???54.4 ???1.1333 ??48.0 ???????70/75 ????77
??605182 ???54.4 ???46.2 ???0.8493 ??46.6 ???????75/70 ???????85 ????62
??654SMO ???????90/85
??SAF2507 ???????70/70
??SAF2609 ???????60/50
People determine to have linear scaling between minimum PRE value in duplex stainless steel austenite or the ferrite and the CPT value, can not be used for explaining the CPT value separately but the result in the table 3 shows the PRE value.Fig. 1 shows the CPT value that is obtained through the ASTM G48C experiment of revising in the mode of chart.Comprise dual phase steel SAF2507, SAF2906 and high alloy austenitic steel 654SMO as a reference.Can know from these results and see that all experiment materials demonstrate than SAF2507 and the better CPT value of SAF2906 in through the ASTM G48C experiment of revising.In addition, some experiment materials demonstrate with 654SMO in through the ASTM G48C experiment of revising and are equal to or better CPT result.Although utilize the cobalt-base alloy change experimental sample 605183 it include High Content Chromium and molybdenum, under controlled rate of cooling (140 ℃/minute), demonstrate good structural stability, and demonstrate the result who is better than SAF2507 and SAF2906.Studies show that a higher PRE value can not be used for explaining separately the CPT value, under the situation that should not concern, PRE Austenite/ PRE FerritePerformance for more heavy alloyed duplex stainless steel is vital, need between alloying element, carry out tight and accurately balanced so that obtain the optimization ratio, described ratio should be preferably 0.9-1.05 between 0.9-1.15, also be convenient to obtain to be higher than 46 PRE value simultaneously.In table 3, provided at the PRE that concerns through the CPT value of the sample in the ASTM G48C experiment of revising Austenite/ PRE Ferrite
Determine intensity and the shock strength under room temperature (RT) of all samples under room temperature (RT), 100 ℃ and 200 ℃, and represent with the mean value of 3 experiments.
Produce stretching experiment sample (DR-5C50) by φ 20mm extrusion bar, under according to the temperature of table 2, these samples are carried out thermal treatment in 20 minutes, cooling (specimen coding is respectively 605195,605197,605184) in air or water subsequently.Experimental result is shown in table 4 and table 5.The result of these stretching experiments shows that chromium, nitrogen and tungsten are very big to the shock strength influence of material.Except that 605153, it is 25% requirement that all samples have all satisfied under room temperature (RT) under tension test unit elongation.
Table 4 shock strength
Sample Temperature ??R p0.2 ?????R p1.0 ?????R m ????A5 ????Z
??(MPa) ?????(MPa) ????(MPa) ???(％) ???(％)
???605193 ????RT ???652 ??????791 ?????916 ???29.7 ????38
???100℃ ???513 ??????646 ?????818 ???30.4 ????36
???200℃ ???511 ??????583 ?????756 ???29.8 ????36
???605195 ????RT ???671 ??????773 ?????910 ???38.0 ????66
???100℃ ???563 ??????637 ?????825 ???39.3 ????68
???200℃ ???504 ??????563 ?????769 ???38.1 ????64
???605197 ????RT ???701 ??????799 ?????939 ???38.4 ????66
???100℃ ???564 ??????652 ?????844 ???40.7 ????69
???200℃ ???502 ??????577 ?????802 ???35.0 ????65
???605178 ????RT ???712 ??????828 ?????925 ???27.0 ????37
???100℃ ???596 ??????677 ?????829 ???31.9 ????45
???200℃ ???535 ??????608 ?????763 ???27.1 ????36
???605183 ????RT ???677 ??????775 ?????882 ???32.4 ????67
???100℃ ???560 ??????642 ?????788 ???33.0 ????59
???200℃ ???499 ??????578 ?????737 ???29.9 ????52
???605184 ????RT ???702 ??????793 ?????915 ???32.5 ????60
???100℃ ???569 ??????657 ?????821 ???34.5 ????61
???200℃ ???526 ??????581 ?????774 ???31.6 ????56
???605187 ????RT ???679 ??????777 ?????893 ???35.7 ????61
???100℃ ???513 ??????628 ?????799 ???38.9 ????64
???200℃ ???505 ??????558 ?????743 ???35.8 ????58
???605153 ????RT ???715 ??????845 ?????917 ???20.7 ????24
???100℃ ???572 ??????692 ?????817 ???29.3 ????27
???200℃ ???532 ??????611 ?????749 ???23.7 ????31
???605182 ????RT ???627 ??????754 ?????903 ???28.4 ????43
???100℃ ???493 ??????621 ?????802 ???31.8 ????42
Table 5 shock strength
Sample Annealing [℃/minute] Cooling Shock strength [J] Annealing [℃/minute] Cooling Shock strength [J]
??605193 ????1100/20 Air ????35 ????1100/20 Water ????242
??605195 ????1150/20 Water ????223
??605197 ????1100/20 Water ????254 ????1130/20 Water ????259
??605178 ????1100/20 Air ????62 ????1100/20 Water ????234
??905183 ????1050/20 Air ????79 ????1050/20 Water ????244
??605184 ????1100/20 Water ????81 ????1100/20 Air ????78
??605187 ????1050/20 Air ????51 ????1100/20 Water ????95
??605153 ????1100/20 Air ????50 ????1100/20 Water ????246
??605182 ????1100/20 Air ????22 ????1100/20 Water ????324
This research shows that most clearly shrend is absolutely necessary for obtaining best structure and therefore obtaining good shock strength numerical value.Except that 605184 and 605187, all samples have at room temperature all passed through the intensity of essential 100J, and the former is also very near required value certainly.
Fig. 6 demonstrates from the result that tungsten-rare gas element remelting experiment (hereinafter to be referred as TIG) draws, and wherein (Heat AffectedZone is hereinafter to be referred as HAZ) demonstrates good structure to sample 605193,605183,605184 and 605253 in the heat affected zone.The sample that contains Ti demonstrates in HAZ has TiN.Too high chromium and nitrogen content cause Cr 2N separates out, because this can make the degradation of this material, thereby should avoid occurring this situation.
Table 6
Sample Precipitate protection gas Ar (99.99%)
???605193 HAZ: good
???605195 HAZ: a large amount of TiN and σ are mutually
???605197 HAZ: contain a spot of Cr in the δ crystal grain 2N, few
???605178 HAZ: the Cr that contains in the δ crystal grain 2N, other are good
???605183 HAZ: good
???605184 HAZ: good
???605187 ?HAZ：Cr 2N approaches the melted join thing, and further precipitation does not produce
???605153 HAZ: good
???605182 HAZ:TiN and crystal boundary δ/δ with decorative pattern
Embodiment 2
In the following embodiments, provided the component of other test sample of producing in order to find optimal component.From the result shown in the embodiment 1, from the performance of sample, begin these samples are changed with satisfactory texture stability and high corrosion resistance.All samples in the table 7 have comprised component of the present invention, and the sample that wherein is numbered 1-8 number includes only the statistical test pattern, and are numbered the alloy that has added in e-n number the sample in the scope of the present invention.
Described sample becomes round steel to obtain by the steel ingot of 270kg by casting, forge hot.With these round steel extrusion moldings is bar, thereby chooses test sample.Before cold rolling one-tenth band steel, bar is annealed afterwards, choose further test material afterwards.Table 7 demonstrates the component of these test samples.
Table 7
Sample ?????Mn ????Cr ????Ni ?????Mo ????W ????Co ????Cu ????Ru ??????B ?????N
???1 ???605258 ????1.1 ???29.0 ???6.5 ????4.23 ????1.5 ????0.0018 ???0.46
???2 ???605249 ????1.0 ???28.8 ???7.0 ????4.23 ????1.5 ????0.0026 ???0.38
???3 ???605259 ????1.1 ???29.0 ???6.8 ????4.23 ????0.6 ????0.0019 ???0.45
???4 ???605260 ????1.1 ???27.5 ???5.9 ????4.22 ????1.5 ????0.0020 ???0.44
???5 ???605250 ????1.1 ???28.8 ???7.6 ????4.24 ????0.6 ????0.0019 ???0.40
???6 ???605251 ????1.0 ???28.1 ???6.5 ????4.24 ????1.5 ????0.0021 ???0.38
???7 ???605261 ????1.0 ???27.8 ???6.1 ????4.22 ????0.6 ????0.0021 ???0.43
???8 ???605252 ????1.1 ???28.4 ???6.9 ????4.23 ????0.5 ????0.0018 ???0.37
???e ???605254 ????1.1 ???26.9 ???6.5 ????4.8 ????1.0 ????0.0021 ???0.38
???f ???605255 ????1.0 ???28.6 ???6.5 ????4.0 ????3.0 ????0.0020 ???0.31
???g ???605262 ????2.7 ???27.6 ???6.9 ????3.9 ????1.0 ????1.0 ????0.0019 ???0.36
???h ???605263 ????1.0 ???28.7 ???6.6 ????4.0 ????1.0 ????1.0 ????0.0020 ???0.40
???i ???605253 ????1.0 ???28.8 ???7.0 ????4.16 ????1.5 ????0.0019 ???0.37
???j ???605266 ????1.1 ???30.0 ???7.1 ????4.02 ????0.0018 ???0.38
???k ???605269 ????1.0 ???28.5 ???7.0 ????3.97 ????1.0 ????1.0 ????0.0020 ???0.45
???l ???605268 ????1.1 ???28.2 ???6.6 ????4.0 ????1.0 ????1.0 ????1.0 ????0.0021 ???0.43
???m ???605270 ????1.0 ???28.8 ???7.0 ????4.2 ????1.5 ????0.1 ????0.0021 ???0.41
???n ???605267 ????1.1 ???29.3 ???6.5 ????4.23 ????1.5 ????0.0019 ???0.38
Table 8.Thermo-Calc
Variable α formula empirical value ?αT-C Whole PRE ???PRE α ???PRE γ ??T maxσ ?T maxCr 2N
???1 ????46 ???50 ???50.2 ???47.8 ???50.5 ???1006 ???1123
???2 ????52 ???50 ???49.1 ???48.4 ???49.8 ???1019 ???1084
???3 ????45 ???50 ???50.2 ???47.9 ???52.6 ???1007 ???1097
???4 ????46 ???50 ???49.2 ???46.5 ???49.8 ????986 ???1121
???5 ????47 ???50 ???49.1 ???48.5 ???49.7 ???1028 ???1038
???6 ????52 ???50 ???48.1 ???47.1 ???49.2 ????998 ???1086
???7 ????44 ???50 ???49.2 ???46.6 ???52.0 ????985 ???1081
???8 ????46 ???50 ???48.1 ???47.2 ???49.1 ???1008 ???1044
???e ????46 ???53 ???49.3 ???48.4 ???49.5 ???1010 ???1099
???f ????65 ???52 ???46.7 ???47.2 ???46.1 ???1008 ???1090
???g ????48 ???51 ???48.4 ???48.4 ???48.3 ???1039 ????979
???h ????50 ???53 ???50.0 ???48.4 ???51.7 ???1035 ???1087
???i ????52 ???50 ???49.1 ???48.4 ???49.8 ???1019 ???1084
Thermo-Calc value according to table 8 (the TC type N thermodynamic data storehouse of TCFE99 steel) is based on the characteristic quantity of all element-specific in different variablees.Ferrite and austenitic PRE value are based on they balanced components under 1100 ℃.T Maxσ is the solvent temperature of σ phase, and high solvent temperature means lower structural stability.
Utilize microprobe analysis to alloying element the distribution in ferrite and austenite study, the result is as shown in table 9.
Table 9
Sample Crystalline phase ???Cr ???Mn ??Ni ???Mo ?W ???Co ??Cu ???N
?605258 Ferrite ??29.8 ??1.3 ??4.8 ??5.0 ???1.4 ??0.11
Austenite ??28.3 ??1.4 ??7.3 ??3.4 ???1.5 ??0.60
?605249 Ferrite ??29.8 ??1.1 ??5.4 ??5.1 ???1.3 ??0.10
Austenite ???27.3 ????1.2 ???7.9 ????3.3 ????1.6 ???0.53
??605259 Ferrite ???29.7 ????1.3 ???5.3 ????5.3 ????0.5 ???0.10
Austenite ???28.1 ????1.4 ???7.8 ????3.3 ???0.58 ???0.59
??605260 Ferrite ???28.4 ????1.3 ???4.4 ????5.0 ????1.4 ???0.08
Austenite ???26.5 ????1.4 ???6.3 ????3.6 ????1.5 ???0.54
??605250 Ferrite ???30.1 ????1.3 ???5.6 ????5.1 ???0.46 ???0.07
Austenite ???27.3 ????1.4 ???8.8 ????3.4 ???0.53 ???0.52
??605251 Ferrite ???29.6 ????1.2 ???5.0 ????5.2 ????1.3 ???0.08
Austenite ???26.9 ????1.3 ???7.6 ????3.5 ????1.5 ???0.53
??605261 Ferrite ???28.0 ????1.2 ???4.5 ????4.9 ???0.45 ???0.07
Austenite ???26.5 ????1.4 ???6.9 ????3.3 ???0.56 ???0.56
??605252 Ferrite ???29.6 ????1.3 ???5.3 ????5.2 ???0.42 ???0.09
Austenite ???27.1 ????1.4 ???8.2 ????3.3 ???0.51 ???0.48
??605254 Ferrite ???28.1 ????1.3 ???4.9 ????5.8 ???0.89 ???0.08
Austenite ???26.0 ????1.4 ???7.6 ????3.8 ????1.0 ???0.48
??605255 Ferrite ???30.1 ????1.3 ???5.0 ????4.7 ????2.7 ???0.08
Austenite ???27.0 ????1.3 ???7.7 ????3.0 ????3.3 ???0.45
??605262 Ferrite ???28.8 ????3.0 ???5.3 ????4.8 ????1.4 ????0.9 ???0.08
Austenite ???26.3 ????3.2 ???8.1 ????3.0 ???0.85 ????1.1 ???0.46
??605263 Ferrite ???29.7 ????1.3 ???5.1 ????5.1 ????1.3 ???0.91 ???0.07
Austenite ???27.8 ????1.4 ???7.7 ????3.2 ???0.79 ????1.1 ???0.51
??605253 Ferrite ???30.2 ????1.3 ???5.4 ????5.0 ????1.3 ???0.09
Austenite ???27.5 ????1.4 ???8.4 ????3.1 ????1.5 ???0.48
??605266 Ferrite ???31.0 ????1.4 ???5.7 ????4.8 ???0.09
Austenite ???29.0 ????1.5 ???8.4 ????3.1 ???0.52
??605269 Ferrite ???28.7 ????1.3 ???5.2 ????5.1 ????1.4 ????0.9 ???0.11
Austenite ???26.6 ????1.4 ???7.8 ????3.2 ???0.87 ????1.1 ???0.52
??605268 Ferrite ???29.1 ????1.3 ???5.0 ????4.7 ????1.3 ???0.91 ????0.84 ???0.12
Austenite ???26.7 ????1.4 ???7.5 ????3.2 ???0.97 ????1.0 ????1.2 ???0.51
??605270 Ferrite ???30.2 ????1.2 ???5.3 ????5.0 ????1.3 ???0.11
Austenite ???27.7 ????1.3 ???8.0 ????3.2 ????1.4 ???0.47
??605267 Ferrite ???30.1 ????1.3 ???5.1 ????4.9 ????1.3 ???0.08
Austenite ???27.8 ????1.4 ???7.6 ????3.1 ????1.8 ???0.46
The spot corrosion characteristic of all samples all (contains 1% FeCl at " Green Death " solution 3, 1% CuCl 2, 11% H 2SO 4With 1.2% HCl) in test grading.Experimental procedure is with identical according to the spot corrosion of ASTM G48C experiment, but this experiment is than 6%FeCl 3More acrid solution carries out in promptly so-called " Green Death " solution.And before carrying out the dew point experiment, in 2%HCl, carry out general corrosion test (each sample experiment 2 times) so that carry out classification.From table 10, Fig. 2 and Fig. 3, can see the result who obtains by all tests.The performance of all experimental samples in " Green Death " solution all is better than SAF2507, the PRE of all samples Austenite/ PRE FerriteProportional limit is preferably 0.9-1.05 in the 0.9-1.5 scope, simultaneously austenite and ferritic PRE value be all above 44, most of sample even substantially exceed 44, some samples even the value of reaching capacity 50.Although it should be noted that the chromium content in the sample 605251 is lower, the performance of sample 605251 in " Green Death " solution that contains the 1.5wt% cobalt almost is equal to the sample 605250 that cobalt contents is 0.6wt%.Especially amazing and interestedly be that because ca. (calculatings) the PRE value of sample 605251 is up to 48, this has surpassed some present commercial super duplex alloys, its T of while MaxThe σ value is lower than 1010 ℃, this means on the basis based on table 2 train value in the example 1 to have good structural stability.
In table 10, listed the whole compositions of measuring with microprobe of this alloy mean P REW value (%Cr+3.3% (Mo+0.5%W)+16%N) and austenite and in ferrite based on the PRE value (rounding up) of the component of these phases.Carry out after under 1100 ℃, heat-treating measuring ferritic content after the Water Quenching.
Table 10
Sample α-stagnation point (halt) Whole PREW ???PRE α ???PRE γ ??PRE α/PRE γ ????CPT℃ ?Green?death
??605258 ????48.2 ???50.3 ???48.1 ????49.1 ????1.021
??605249 ????59.8 ???48.9 ???48.3 ????46.6 ????0.967 ????75/80
??605259 ????49.2 ???50.2 ???48.8 ????48.4 ????0.991
??605260 ????53.4 ???48.5 ???46.1 ????47.0 ????1.019
??605250 ????53.6 ???49.2 ???48.1 ????46.8 ????0.974 ????95/80
??605251 ????54.2 ???48.2 ???48.1 ????46.9 ????0.976 ????90/80
??605261 ???50.8 ???48.6 ???45.2 ???46.3 ????1.024
??605252 ???56.6 ???48.2 ???48.2 ???45.6 ????0.946 ????80/75
??605254 ???53.2 ???48.8 ???48.5 ???46.2 ????0.953 ????90/75
??605255 ???57.4 ???46.9 ???46.9 ???44.1 ????0.940 ????90/80
??605262 ???57.2 ???47.9 ???48.3 ???45.0 ????0.931
??605263 ???53.6 ???49.7 ???49.8 ???47.8 ????0.959
??605253 ???52.6 ???48.4 ???48.2 ???45.4 ????0.942 ????85/75
??605266 ???62.6 ???49.4 ???48.3 ???47.6 ????0.986
??605269 ???52.8 ???50.5 ???49.6 ???46.9 ????0.945
??605268 ???52.0 ???49.9 ???48.7 ???47.0 ????0.965
??605270 ???57.0 ???49.2 ???48.5 ???45.7 ????0.944
??605267 ???59.8 ???49.3 ???47.6 ???45.4 ????0.953
In order to study structural stability in great detail, under 1080 ℃, 1100 ℃ and 1150 ℃, these samples are carried out annealing in 20 minutes, then at quenching-in water.By in opticmicroscope, studying to determine the intermetallic phase negligible temperature that becomes.To comparing, show which sample more may comprise the σ phase that does not expect to have through the sample structure that carries out after 1080 ℃ of annealing after the Water Quenching.In Figure 11, demonstrate these results.Structure controlled demonstrate, sample 605249,605251,605252,605253,605254,605255,605259,605260,605266 and 605267 σ that do not expect to have are mutually.In addition, the sample 605249 that contains cobalt 1.5wt% does not contain the σ phase, and 605250 on the sample that contains cobalt 0.6wt% contains the σ phase of very few number.These samples contain High Content Chromium that is about 29.0wt% and the molybdenum that is approximately 4.25wt%.If at the σ phase content component in sample 605249,605250,605251 and 605252 is compared, very obviously the structural stability aspect is very narrow for the compositional range of most optimum materials in this case.It also demonstrates, and 605268 on sample comprises the σ phase that is equivalent to sample 605263, and sample 605263 comprises a lot of σ phases.The key distinction between these samples is, is added with copper in the sample 605268.Although sample 605266 and 605267 contains in high-load chromium and the latter's alloy and also contains copper, but they do not contain the σ phase, in addition, the sample 605262 and 605263 that is added with 1.0wt% demonstrates has many σ structure mutually, it should be noted that simultaneously and also contain 1.0% tungsten but demonstrate its σ phase content obviously still less with respect to sample 605262 and the higher sample 605269 of 605263 its nitrogen contents.Therefore, need for example carry out the balance of well-tuned between chromium and the molybdenum at the different-alloy element that is in these high alloy content, so that obtain good structure properties.
Table 11 demonstrates from the result who carries out after 20 minutes through 1080 ℃ of annealing obtaining the shrend optical observation afterwards.The σ phasor is represented that by 1-5 wherein 1 representative is not found the σ phase in detecting, and 5 expressions are found high-load σ phase in detecting.
Table 11
Sample The σ phase ????Cr ????Mo ????W ????Co ???Cu ?????N ????Ru
?605249 ???1 ???28.8 ???4.23 ????1.5 ????0.38
?605250 ???2 ???28.8 ???4.24 ????0.6 ????0.40
?605251 ???1 ???28.1 ???4.24 ????1.5 ????0.38
?605252 ???1 ???28.4 ???4.23 ????0.5 ????0.37
?605253 ???1 ???28.8 ???4.16 ????1.5 ????0.37
?605254 ???1 ???26.9 ???4.80 ????1.0 ????0.38
?605255 ???1 ???28.6 ???4.04 ????3.0 ????0.31
?605258 ???2 ???29.0 ???4.23 ????1.5 ????0.46
?605259 ???1 ???29.0 ???4.23 ????0.6 ????0.45
?605260 ???1 ???27.5 ???4.22 ????1.5 ????0.44
?605261 ???2 ???27.8 ???4.22 ????0.6 ????0.43
?605262 ???4 ???27.6 ???3.93 ????1.0 ????1.0 ????0.36
?605263 ???5 ???28.7 ???3.96 ????1.0 ????1.0 ????0.40
?605266 ???1 ???30.0 ???4.02 ????0.38
?605267 ???1 ???29.3 ???4.23 ???1.5 ????0.38
?605268 ???2 ???28.2 ???3.98 ????1.0 ????1.0 ???1.0 ????0.43
?605269 ???3 ???28.5 ???3.97 ????1.0 ????1.0 ????0.45
?605270 ???3 ???28.8 ???4.19 ????1.5 ????0.41 ????0.1
Be displayed in Table 12 out from some samples are carried out shock strength and test resulting result.These results are very high, and this shows after carrying out shrend then through 1100 ℃ of annealing to have good structure properties, and all test samples can satisfy the requirement of 100J with big surplus.
Table 12
Sample Annealing [℃/minute] Quench Shock strength [J] Shock strength [J] Shock strength [J]
??605249 ???1100/20 Water ????＞300 ????＞300 ?????＞300
??605250 ???1100/20 Water ????＞300 ????＞300 ?????＞300
??605251 ???1100/20 Water ????＞300 ????＞300 ?????＞300
??605252 ???1100/20 Water ????＞300 ????＞300 ?????＞300
??605253 ???1100/20 Water ?????258 ?????267 ??????257
??605254 ???1100/20 Water ????＞300 ????＞300 ?????＞300
??605255 ???1100/20 Water ????＞300 ????＞300 ?????＞300
Fig. 4 demonstrates from most of samples being carried out the result that the high-temperature ductility experiment is drawn.Good workability is for material being made bar, tubing for example welded tube and seamless tube, sheet material, band, wire rod, welding rod and vital such as yes for the structural parts of pump, valve, flange, junctor one class.The sample 605249,605250,605251,605252,605255,605266 and 605267 that major part contains the nitrogen of about 0.38wt% can improve high-temperature ductility numerical value to a certain extent.
Experimental result is summed up
Have good structural stability, hot workability and weldability simultaneously in order to make material obtain good erosion resistance, this material should be according to following described being optimized:
● the PRE value in the ferrite should preferably be at least 47 greater than 45.
● the PRE value in the austenite should preferably be at least 47 greater than 45.
● the PRE value of whole alloy should preferably be at least 46.
● PRE Austenite/ PRE FerriteRatio should be between 0.9-1.15, preferably in the 0.9-1.05 scope.
● ferritic volume percent content is preferably in the 45-55% scope.
● T Maxσ should be above 1010 ℃.
● nitrogen content should in the scope of 0.35-0.48wt%, more preferably be 0.38-0.40wt% preferably in the 0.28-0.5wt% scope.
● cobalt contents should be preferably 1.0-2.0wt%, more preferably 1.3-1.7wt% in the 0-3.5wt% scope.
● in order to ensure the high-dissolvability of nitrogen, that is, be under the situation of 0.38-0.40wt% at nitrogen content, need add the Cr of 29wt% and the Mo of 3.0wt% at least, the total content of element Cr, Mo and N satisfies the requirement to described PRE value like this.

Claims (16)

1. a ferritic-austenitic double phase stainless steel alloy is characterized in that it comprises following ingredients, by weight percentage:
C at the most 0.03%
Si at the most 0.5%
Mn????????????????0-3.0％
Cr????????????????24.0-30.0％
Ni????????????????4.9-10.0％
Mo????????????????3.0-5.0％
N?????????????????0.28-0.5％
B?????????????????0-0.0030％
S at the most 0.010%
Co????????????????0-3.5％
W?????????????????0-3.0％
Cu????????????????0-2.0％
Ru????????????????0-0.3％
Al????????????????0-0.03％
Ca????????????????0-0.010％
The Fe of equal amount and normal impurity and the additive that occurs, wherein ferritic volume percent content is 40-65%.
2. alloy as claimed in claim 1, the content that it is characterized in that manganese is 0.5-1.2wt%.
3. alloy as claimed in claim 1 or 2 is characterized in that, the content of chromium is 27.0-29.0wt%.
4. as each described alloy among the claim 1-3, the content that it is characterized in that nickel is 5.0-8.0wt%.
5. as each described alloy among the claim 1-4, the content that it is characterized in that molybdenum is 3.6-4.7wt%.
6. as the described alloy of arbitrary claim among the claim 1-5, the content that it is characterized in that nitrogen is 0.35-0.45wt%.
7. as each described alloy among the claim 1-5, it is characterized in that the content of ruthenium is 0-0.3wt%, be preferably and be higher than 0 and up to 0.1%.
8. as each described alloy in the claim of front, it is characterized in that the content of cobalt is 0.5-3.5wt%, be preferably 1.5-3.5wt%.
9. as each described alloy in the claim of front, it is characterized in that the content of copper is 0.5-2.0wt%, be preferably 1.0-1.5wt%.
10. as each described alloy in the claim of front, it is characterized in that ferritic volume percent content is 42-60%, is preferably 45-55%.
11. as each described alloy in the claim of front, it is characterized in that total PRE value of this alloy or PREW value all above 44, PRE=%Cr+3.3%Mo+16N wherein, PREW=%Cr+3.3 (%Mo+0.5%W)+16N, wherein % represents wt%.
12. as each described alloy in the above-mentioned arbitrary claim in front, it is characterized in that ferritic phase and austenite mutually the PRE value or the PREW value all greater than 45, and the PRE value of alloy all components or PREW value are greater than 46.
13., it is characterized in that the PRE value of ferritic phase and austenite phase or PREW value are between 47 and 49 as claim 11 or 12 described alloys.
14., it is characterized in that ratio between PRE (W) value of PRE (W) value of austenite phase and ferritic phase is between 0.90-1.15, preferably between 0.9-1.05 as claim 11 or 12 or 13 described alloys.
15., be used for the environment of chloride as each described alloy in the claim of front.
16. as each described alloy that is used for the environment of chloride in the claim of front, it for example adopts for example welded tube and seamless tube, sheet material, band, wire rod, welding rod and the structural parts product form of pump, valve, flange, junctor for example of bar, tubing.
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CN107937825A (en) * 2017-11-15 2018-04-20 江阴方圆环锻法兰有限公司 Oil gas dual phase steel valve forging and its forging method
CN112342473A (en) * 2020-09-17 2021-02-09 江苏华久辐条制造有限公司 Cold-rolled strip steel surface corrosion-resistant treatment method

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CN103975088A (en) * 2011-11-04 2014-08-06 奥托库姆普联合股份公司 Duplex stainless steel
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CN107937825A (en) * 2017-11-15 2018-04-20 江阴方圆环锻法兰有限公司 Oil gas dual phase steel valve forging and its forging method
CN112342473A (en) * 2020-09-17 2021-02-09 江苏华久辐条制造有限公司 Cold-rolled strip steel surface corrosion-resistant treatment method

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