WO1995027090A1 - Acier inoxydable a deux phases - Google Patents
Acier inoxydable a deux phases Download PDFInfo
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- WO1995027090A1 WO1995027090A1 PCT/JP1995/000647 JP9500647W WO9527090A1 WO 1995027090 A1 WO1995027090 A1 WO 1995027090A1 JP 9500647 W JP9500647 W JP 9500647W WO 9527090 A1 WO9527090 A1 WO 9527090A1
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- 229910001220 stainless steel Inorganic materials 0.000 title claims abstract description 20
- 239000010935 stainless steel Substances 0.000 title claims abstract description 7
- 239000012535 impurity Substances 0.000 claims abstract description 27
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 16
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 14
- 229910052757 nitrogen Inorganic materials 0.000 claims abstract description 8
- 229910001039 duplex stainless steel Inorganic materials 0.000 claims description 49
- 101100383698 Secale cereale rscc gene Proteins 0.000 claims description 28
- 229910052748 manganese Inorganic materials 0.000 claims description 10
- 229910052698 phosphorus Inorganic materials 0.000 claims description 10
- 229910052721 tungsten Inorganic materials 0.000 claims description 9
- 229910052761 rare earth metal Inorganic materials 0.000 claims description 8
- 229910052717 sulfur Inorganic materials 0.000 claims description 8
- 229910052749 magnesium Inorganic materials 0.000 claims description 4
- 229910052784 alkaline earth metal Inorganic materials 0.000 claims description 2
- 229910052742 iron Inorganic materials 0.000 claims 1
- 230000007797 corrosion Effects 0.000 abstract description 69
- 238000005260 corrosion Methods 0.000 abstract description 69
- 229910000831 Steel Inorganic materials 0.000 abstract description 40
- 238000005336 cracking Methods 0.000 abstract description 40
- 239000010959 steel Substances 0.000 abstract description 40
- 238000003466 welding Methods 0.000 abstract description 33
- 239000000463 material Substances 0.000 abstract description 15
- 239000000126 substance Substances 0.000 abstract description 13
- 229910052750 molybdenum Inorganic materials 0.000 abstract description 10
- 239000013535 sea water Substances 0.000 abstract description 8
- 238000011156 evaluation Methods 0.000 abstract description 4
- 239000003129 oil well Substances 0.000 abstract description 4
- 238000012360 testing method Methods 0.000 description 34
- 229910000859 α-Fe Inorganic materials 0.000 description 25
- 239000012071 phase Substances 0.000 description 23
- 238000010586 diagram Methods 0.000 description 13
- 229910001566 austenite Inorganic materials 0.000 description 12
- 239000000203 mixture Substances 0.000 description 12
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- 239000007791 liquid phase Substances 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000010953 base metal Substances 0.000 description 2
- 229910052791 calcium Inorganic materials 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 229910052802 copper Inorganic materials 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
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- 150000001247 metal acetylides Chemical class 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000009864 tensile test Methods 0.000 description 2
- 238000010998 test method Methods 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 229910052727 yttrium Inorganic materials 0.000 description 2
- 229910052684 Cerium Inorganic materials 0.000 description 1
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 1
- 229910001122 Mischmetal Inorganic materials 0.000 description 1
- 101100465000 Mus musculus Prag1 gene Proteins 0.000 description 1
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000001174 ascending effect Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000003796 beauty Effects 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- -1 chlorine ions Chemical class 0.000 description 1
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- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 1
- 238000007654 immersion Methods 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 229910052746 lanthanum Inorganic materials 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000013001 point bending Methods 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
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- 229910000601 superalloy Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
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Classifications
-
- 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
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
Definitions
- the present invention is directed to a duplex stainless steel made of austenitic and ferrite, particularly a heat exchanger using seawater, chemical equipment and structures requiring seawater resistance, piping for various chemical plants, and line pipe.
- the present invention relates to super duplex stainless steel with excellent weldability, oil corrosion resistance, stress corrosion cracking resistance and toughness of the welded area.
- duplex stainless steels with excellent corrosion resistance and weldability have been used as heat exchangers that use seawater, chemical equipment and structures that require seawater resistance, piping for various chemical plants, line pipes, oil well pipes, etc.
- Demand is growing, especially the requirements for corrosion resistance are becoming more stringent.
- duplex stainless steels There are many duplex stainless steels already in practical use.
- a literature introducing weldable duplex stainless steels Duplex Stainless Steel for Welding and Super Duplex Stainless Steel, edited by The Dutch Welding Society, L. van Nassau, H. Meelker, J. Hilker '91
- the following four types (a) to (d) are disclosed in ascending order of corrosion resistance.
- Super duplex stainless steels have high mechanical properties and good corrosion resistance.All of them are based on 25% Cr steel so that the above-mentioned pitting resistance index (PREN) exceeds 40. It is designed to contain a large amount of N as a basic concept.
- Patent Application Laid-Open No. 62-56556 discloses the above-mentioned corrosion resistance index (PREN).
- Japanese Patent Application Laid-Open No. Hei 5-132741 discloses a pitting corrosion resistance index.
- the inventors of the present invention disclosed in Japanese Patent Application No. Hei 4-293844 that the pitting corrosion index in ferrite and the pitting corrosion index in austenite were not less than 43 and less than 65 in machinability index.
- Duplex stainless steel with a difference of -3.0 to 3.0 which is superior to conventional super-duplex stainless steel in that it is a component system in which intermetallic compounds such as (:) are less likely to be formed. Proposed steel.
- PREN or PREW which is uniquely determined by the initial composition of the alloy, has been used as an index of pitting corrosion resistance.
- PREN and PREW are said to have a good correspondence with the corrosion rate or pitting resistance in the corrosive environment containing chlorine ions, and those with a value exceeding 40 are called super duplex stainless steels. It is positioned as a high-performance alloy system.
- the corrosion resistance of PREN and PREW can be evaluated only when the appropriate solution treatment is performed after hot working and the two-phase structure of austenite and ferrite is obtained.
- Corrosion of the heat affected zone (HAZ) which has become a solidified structure after welding or has received a heat history different from that of the homogenized material.
- Corrosion resistance in the environment especially stress corrosion cracking resistance in a corrosive environment containing hydrogen sulfide, does not always correspond to the performance that can be estimated from the PREN or PREW values obtained from the average composition of the alloy.
- JP-A-62-56556 and JP-A-5-132741 are disclosed.
- the disclosed super duplex stainless steel is given sufficient consideration to weldability (welding workability) and stress corrosion cracking resistance and toughness of the weld as in the conventional duplex stainless steel. Not.
- duplex stainless steel of the invention of Japanese Patent Application No. 4-293844 proposed by the present inventors also limited the pitting resistance index of ferrite and austenite mainly as a means of improving the pitting resistance in HAZ.
- no study has been made from the viewpoint of welding workability.
- Duplex stainless steel is widely used as a material for oil country tubular goods, power plants, chemical plants, etc. In that case, in addition to its corrosion resistance (pitting corrosion resistance, stress corrosion cracking resistance), It is also required that welding work is easy and that defects such as welding cracks are unlikely to occur. Therefore, it is a super duplex stainless steel that has excellent mechanical properties and corrosion resistance, and has excellent weldability, and a super duplex that also has excellent toughness and stress corrosion cracking resistance of the as-welded weld. Development of stainless steel is required. Disclosure of the invention
- the present inventors have studied in detail the correspondence between the weld cracking susceptibility and the chemical composition of the material when super duplex stainless steel is actually welded, and have obtained the following findings.
- the pitting corrosion resistance index (PREW) defined in the invention of the above-mentioned Japanese Patent Application Laid-Open No. 5-132741 that is, an index uniquely determined by the initial composition of the alloy, is a duplex stainless steel.
- PREW pitting corrosion resistance index
- the following findings were newly obtained.
- the present invention has been made based on the above findings, and has as its gist the following duplex stainless steels (1) and (2).
- Si 2.0% or less
- Mn 2.0% or less
- Cr 22.0 to 24.0%
- Ni 4.5 to 6.5%
- C as an impurity is 0.03% or less
- P is 0.05% or less
- S is 0.005% or less
- RVS represented by the following formula is 7
- PREW also represented by the formula (1)
- RVS C ⁇ 1.100X (3 ⁇ 4) Cr / 52.0 ⁇ + ⁇ 9.888X (3 ⁇ 4) Mo / 95.94 ⁇
- Group 1 element Cu 0.01-2.0%
- Group 2 element V 0.01 to 0.50%
- Group 3 element Ca 0.0005-0.010%
- Rare earth element 0.0005 to 0.010%
- RVS C ⁇ 1.100x (3 ⁇ 4) Cr / 52.0 ⁇ + ⁇ 9.888 x O Mo / 95.94 ⁇
- FIGS 1 and 2 are diagrams showing the chemical compositions of the test materials used in Example 1 with the components adjusted so that the pitting corrosion resistance evaluation index PREW exceeds 40.
- FIG. 3 is a diagram illustrating a valley strain test method for evaluating cracking susceptibility during welding.
- Figures 4 and 5 show the test results of Example 1 together with the PREW value, the RVS value, and the RSCC value as a reference value.
- Figure 6 shows the relationship between the weld crack length and the RVS value in the valley train test. It is a figure explaining a relation.
- Fig. 7, Fig. 8 and Fig. 9 are diagrams showing the chemical compositions of the test materials used in Example 2 to evaluate the corrosion resistance and other performances of the welds.
- FIG. 10 is a diagram showing a groove shape of a welded joint portion in a welding test
- FIG. 11 is a diagram showing a position at which a stress corrosion cracking test piece is sampled from the welded joint portion and a shape of the test piece
- FIG. 12 is a diagram showing a position at which a Charpy impact test specimen of a welded joint is sampled and a shape of the specimen.
- - Figures 13, 14, and 15 show the test results of Example 2 along with the ferrite fraction (%), PREW value, RVS value, RSCC value, and ferrite change rate (% change). It is.
- FIGS. 16, 17, and 18 show the results of the tensile test, the Charpy impact test, and the stress corrosion cracking test in Example 2, respectively.
- FIG. 19 shows the ferrite fraction of the duplex stainless steel tested in Example 2.
- FIG. 4 is a diagram showing the relationship between the rate of change of light and the RSCC value.
- FIG. 20 is a diagram showing the relationship between the critical stress for crack initiation ( th ) and the RSCC value in the stress corrosion cracking test of Example 2, and
- FIG. 21 is a graph showing the ⁇ 30 ° of the duplex stainless steel tested in Example 2.
- FIG. 9 is a diagram showing the relationship between the Charpy impact test (vE_3 () ) and the RSCC value in C. BEST MODE FOR CARRYING OUT THE INVENTION
- Si Since Si is effective in deoxidizing steel and increasing corrosion resistance, its addition is essential. This Si does not need to be contained in the steel, and the lower limit of the content may be substantially 0 (zero) or trace. On the other hand, if the Si content exceeds 2.00%, the steel becomes brittle, so the upper limit is set to 2.00%.
- Mn Mn is added for the purpose of deoxidation and desulfurization. However, its content
- the lower limit may be substantially zero or a trace amount as in the case of Si.
- Cr is one of the basic components of duplex stainless steel and is one of the important elements that control corrosion resistance together with Mo. 22.0% or more is required to obtain the high corrosion resistance required in the corrosive environment.
- the steel of the present invention is added with a large amount (4 to 8%) of Mo as compared with the conventional steel in order to increase the pitting resistance, so that the Cr phase containing more than 24% of Cr and : Remarkably promotes precipitation of intermetallic compounds such as phases, etc. Accordingly, the Cr content was set to 22.0 to 24.0%.
- Ni has conventionally been added in view of the Cr, Mo, and W contents, and the N content in order to obtain a two-phase structure. In the steel of the present invention, it is the most important element that controls the improvement of the stress corrosion cracking resistance and toughness of the weld bond and HAZ. In order to achieve the desired high corrosion resistance, the content must be 4.5% or more, but if it exceeds 6.5%, the precipitation amount of the ⁇ phase significantly increases. Therefore, Ni was set to 4.5 to 6.5%.
- Mo is also an element that improves corrosion resistance, and it is necessary to contain 4.0% or more to obtain the desired corrosion resistance in the corrosive environment. However, if the content exceeds 4.8%, and the coarsening of the phase is rapidly promoted, the content is set to 4.0 to 4.8%.
- A1 Indispensable as a deoxidizing element, it is added for the purpose of reducing oxygen to obtain sufficient corrosion resistance.
- the addition amount can be changed in consideration of the addition amount of Si and Mn.However, if the content is less than 0.001%, a sufficient effect cannot be obtained, and if the content exceeds 0.15%, A1N is easily precipitated and toughness is increased. However, in order to deteriorate the corrosion resistance, the content was set to 0.001 to 0.15%.
- N is a super element that contains a large amount of the Cr and Mo, which are the elements that form the fluoride. In a duplex stainless steel, it is an important element that stabilizes the austenite for forming the dual phase structure. It is the most effective element for improving pitting. Content of less than 0.25% is not enough to obtain these effects. On the other hand, if N exceeds 0.35%, many defects (such as pro-holes) occur in large ingots, and the hot workability of the steel decreases significantly. Therefore, N was set to 0.25 to 0.35%.
- duplex stainless steels of the present invention comprises the above alloying elements and the balance of Fe and inevitable impurities. Note that the allowable upper limit of typical impurities will be described later.
- Another one of the duplex stainless steels of the present invention further includes at least one of the first, second and third element groups in addition to the above alloy elements. It contains at least one element selected from one group. Hereinafter, these elements will be described.
- Group 1 elements (Cu and W):
- W has a complementary effect of Mo, it may be contained in an amount of 0.01% or more, but the addition of a large amount exceeding 1.5% causes an increase in production cost.
- Each of these elements stabilizes carbides and enhances corrosion resistance, so one or more of these elements may be contained as necessary. 0.01% or more is required for each of the above effects. However, when their contents exceed 0.50%, the effect saturates.
- Group 3 elements (Ca, Mg, B, Zr, Y and rare earth elements):
- Ca, Mg, Y and rare earth elements all improve the hot workability of steel by forming S-0 compound (composite compound of sulfide and acid) by themselves.
- the content of each must be 0.0005% or more (however, ⁇ is 0.001%), but if it exceeds 0.010% (however, ⁇ is 0.20%), the effect is saturated.
- ⁇ and Zr are deflected to the grain boundaries, lowering the grain boundary energy, and promoting grain boundary facetting.
- the hot workability of the steel is improved to increase the grain boundary strength.
- the effect is remarkable at 0.0005% for B and 0.01% or more for Zr, but when it exceeds 0.010% and 0.50%, the effect saturates. 0.010%, 0.01 ⁇ 0.50% is appropriate
- the rare earth element may be added as a single element such as La and Ce, or may be added as a mixture such as misch metal.
- the main ones are (:, P and S.
- C is an unavoidable element contained in steel, but if its content exceeds 0.03%, carbides precipitate in HAZ and significantly deteriorate its corrosion resistance. The upper limit is 0.03%
- P is also an impurity element inevitably contained in steel and degrades hot workability and corrosion resistance, so it is necessary to reduce P as much as possible.
- the allowable upper limit was set to 0.05% or less in consideration of neighboring costs.
- S is also an unavoidable impurity element contained in steel and is an element that degrades the hot workability of two-phase stainless steel, so it is necessary to reduce it as much as possible. 0.005% is the allowable upper limit. i l. About PREW, RVS and RSCC:
- PREW is defined by the above formula (2), which itself is known from the above-mentioned Japanese Patent Application Laid-Open No. 5-137274. This PREW is also used in the present invention. The value is set to exceed 40 in order to secure excellent pitting corrosion resistance as a basic property of super duplex stainless steel.
- RVS has been newly incorporated as an index for evaluating crack susceptibility during welding.
- RSCC which is an index for evaluating the stress corrosion cracking resistance of welds used when necessary and the toughness of HAZ.
- RVS is obtained by the above equation (1), and is an index of the temperature difference between the liquidus line and the solidus line in the region where the solid phase and the liquid phase coexist at the welding tip during welding. There is a good correspondence between this RVS value and the crack susceptibility during welding.
- FIG. 6 is a diagram showing the relationship between the crack length and the RVS value in a burestrain test when TIG welding was performed on the duplex stainless steel subjected to the test of Example 1 described below.
- RVS value is within the range of 7 or less, the susceptibility to weld cracking decreases, and the crack length during welding is less than 1 band, but when it exceeds 7, the weld crack susceptibility increases and the weld crack length exceeds 1 mm. You can see that The RVS value of 7 or less in the present invention is based on this reason.
- RSCC is defined by the above equation (3).
- the phase at the interface between ferrite and austenite due to a sharp decrease in the ferrite fraction and! It is an index indicating the tendency of heterogeneous precipitation of intermetallic compounds such as phases. Therefore, this RSCC has a good correspondence with the stress corrosion resistance and the toughness of the weld.
- ferrite fraction refers to the amount of ferrite and austenite in a water-cooled specimen after holding the duplex stainless steel at 1100 for 1 hour, for example, by X-ray diffraction. And the value (volume) calculated by the following equation (1).
- Ferrite fraction ⁇ Amount of ferrite / (Amount of ferrite + Austenite) ⁇ X 100
- the rate of change of the filament described below refers to the ferrite fraction determined for a water-cooled test piece after holding the two-phase stainless steel at 1300 ° C for 1 hour. This is the difference from the flat fraction obtained for the test piece which was kept at 110 ° C. for 1 hour and cooled with water as described above.
- Figure 1921 shows the relationship between the fraction of fly, the rate of change of ferrite, the critical stress for stress corrosion cracking initiation and the impact value of the duplex stainless steel subjected to the test of Example 2 described below, and the RSCC.
- FIG. As shown in Fig. 19 (b), when the RSCC value is less than 13, the change rate of the light is large, and as shown in Fig.
- Example 1 The operation and effect of the duplex stainless steel of the present invention will be described based on Example 1 and Example 2.
- the steel with the chemical composition shown in Figs. 1 and 2 whose components were adjusted so that the pitting corrosion resistance evaluation index PREW exceeded 40, was melted using a 150 kg vacuum induction melting furnace, and converted to a 150 IM0 ingot. Built.
- the ingot was turned into a 20-band thick steel by hot forging and hot rolling, and then subjected to a solution treatment in which the ingot was kept at 1100 ° C for 1 hour and then cooled with water. Welded test specimens were taken from the plate.
- the steel of the present invention is a duplex stainless steel corresponding to the example of the present invention
- a comparative steel is a steel used for property comparison
- a conventional steel is an existing duplex stainless steel. Steel equivalent to.
- FIG. 3 is a diagram for explaining a valley strain test method for evaluating the susceptibility to weld cracking during welding.
- a 12-mra-thick, 50-mm-wide, 300-length-long board material is used as a test piece. While the material is melted by TIG welding, a bending strain is given at the same time, and a weld crack is generated in the weld. The length of the crack was actually measured with a microscope in a visual field of 100 magnification, and the total length of the crack was Evaluate weld cracking susceptibility.
- steel having a total crack length of 1 mm or less was defined as steel suitable for the purpose of the present invention.
- test results are shown in Fig. 4 and Fig. 5 together with the PREW value, RVS value and RSCC value as a reference value.
- Figure 6 shows the relationship between weld crack length and RVS value.
- No. 1 to 12 shown as the steel of the present invention in FIG. 4 have a PREW of 40.2 or more and an RVS of 4.78 to 6.68, so that the crack length is as short as 0.2 to 0.8 ⁇ , indicating low crack sensitivity.
- test materials were manufactured in the same manner as in Example 1 using materials having the chemical compositions shown in FIGS. 7, 8, and 9.
- the steels in Fig. 7, Fig. 8 and Fig. 9 were designed so that the PREW value exceeded 40 and the RVS value was 7 or less except for some of the comparative steels.
- Fig. 10 shows a groove processed part for obtaining a test material for a welded joint.
- a 9 mm thick plate was cut out from a 20 mm thick test material prepared in the same manner as in Example 1, and a groove was machined to the dimensions shown in the same figure. .
- Welding is performed by an automatic TIG welding method with a heat input of 15 kJ / cm. At a welding speed of 10 cm / min, the first layer is welded without using filler metal, and 25 Cr—for the second to thirteenth layers is welded. This was performed using a 7% Ni-3! 0 (o-2% W-0.3% N filer metal).
- FIG. 11 and FIG. 12 are views showing positions where various test pieces are collected from the welded joint.
- a test piece for stress corrosion cracking a test piece with a thickness of 2 marauders, a width of 10 and a length of 75 marauders was taken from the position shown in Fig. 11 (b), and the impact test piece was as shown in Fig. 12 (a). From the position shown, a half-size Charpy test specimen shown in FIG.
- the test conditions are as follows.
- Test piece Half size (shape shown in Fig. 5) The test results are shown in Figs. However, in FIG. 13 to FIG. 15, the light fraction is displayed as “%” and the light change rate is displayed as “change”. Nos. 1 to 33 indicated as the steels of the present invention are those whose alloy element content, PREW value, RVS value and RSCC value fall within the ranges specified by the invention. Therefore, the susceptibility to weld cracking is small as clarified in Example 1 described above. As shown in FIGS. 16 and 17, the welded joint had an impact value at ⁇ 30 ° C. of 212 J / cra 2 or more and a stress corrosion cracking initiation critical stress of 52.6 kgf / cm 2 or more. It has excellent toughness and stress corrosion cracking resistance.
- any of Cr, Ni, Mo and N is out of the range defined in the present invention, and No. 39, No. 40 and Except for No. 42, since the RSCC was less than 13, the stress corrosion cracking resistance of the welded joint was inferior and the stress corrosion cracking initiation limit stress was 44.6 kgf / mm 2 or less, as shown in FIG. I have. Some steels also have low impact values.
- each alloying element is within the range specified in the present invention, but the RSCC has a value of less than 13 or a value of more than 18. These materials have low impact values or crack initiation critical stress, and cannot simultaneously satisfy the levels of an impact value of 200 J / cm 2 or more and a crack initiation limit stress of 45.5 kgf / band 2 or more.
- the steels with RSCC of less than 13 or more than 18 are referred to as comparative steels for convenience here. Among them, those whose PREW and RVS are within the range defined by the present invention are in a broad sense. Of the present invention.
- FIG. 19 is a graph in which the fly fraction and the ferrite change rate of the various duplex stainless steels used in Example 2 are arranged in relation to the RSCC value. As shown in (a), the ferrite fraction increases almost monotonically with the increase in RSCC, but as shown in (b), the ferrite change rate stabilizes between 13 and 18 for RSCC. It becomes smaller.
- Figures 20 and 21 show the crack limit stress ( th ) obtained in the stress corrosion test of the duplex stainless steel welds tested in Example 2 and the HAZ of the weld test.
- the toughness (vE- 30 ) is summarized by RSCC. It is clear that both the stress corrosion cracking resistance and the HAZ toughness are very good when the RSCC is in the range of 13 to 18, and the correspondence with FIG. 19 is also clear.
- the duplex stainless steel of the present invention is a super duplex stainless steel having low crack susceptibility during welding and excellent weldability.
- those with an RSCC in the range of 13 to 18 which is an index for improving the stress corrosion cracking resistance of the weld and the toughness of HAZ are in the range of 13 to 18 for the stress corrosion cracking resistance and toughness of the weld. Also exhibit excellent properties. Therefore, the duplex stainless steel of the present invention is extremely suitable as a material for heat exchangers using seawater, equipment and structures requiring seawater resistance, piping for various chemical plants, line pipes, oil well pipes, and the like. It can be used in a wide range of fields such as chemical industry and marine development.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Arc Welding In General (AREA)
- Heat Treatment Of Steel (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69506537T DE69506537T2 (de) | 1994-04-05 | 1995-04-04 | Rostfreier zweiphasiger stahl |
EP95913417A EP0757112B1 (en) | 1994-04-05 | 1995-04-04 | Two-phase stainless steel |
US08/718,574 US5849111A (en) | 1994-04-05 | 1995-04-04 | Duplex stainless steel |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP06747394A JP3446294B2 (ja) | 1994-04-05 | 1994-04-05 | 二相ステンレス鋼 |
JP6/67473 | 1994-04-05 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1995027090A1 true WO1995027090A1 (fr) | 1995-10-12 |
Family
ID=13345975
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP1995/000647 WO1995027090A1 (fr) | 1994-04-05 | 1995-04-04 | Acier inoxydable a deux phases |
Country Status (5)
Country | Link |
---|---|
US (1) | US5849111A (ja) |
EP (1) | EP0757112B1 (ja) |
JP (1) | JP3446294B2 (ja) |
DE (1) | DE69506537T2 (ja) |
WO (1) | WO1995027090A1 (ja) |
Families Citing this family (23)
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JP3161417B2 (ja) * | 1986-04-28 | 2001-04-25 | 日本鋼管株式会社 | 耐孔食性に優れた2相ステンレス鋼 |
US7235212B2 (en) | 2001-02-09 | 2007-06-26 | Ques Tek Innovations, Llc | Nanocarbide precipitation strengthened ultrahigh strength, corrosion resistant, structural steels and method of making said steels |
CN1052036C (zh) * | 1994-05-21 | 2000-05-03 | 朴庸秀 | 有高耐腐蚀性的双相不锈钢 |
JP3370441B2 (ja) * | 1994-07-25 | 2003-01-27 | 日本冶金工業株式会社 | 伸び特性に優れる2相ステンレス鋼板とその製造方法 |
US20050016636A1 (en) * | 2001-11-22 | 2005-01-27 | Yutaka Kobayashi | Stainless steel for use under circumstance where organic acid and saline are present |
KR100460346B1 (ko) * | 2002-03-25 | 2004-12-08 | 이인성 | 금속간상의 형성이 억제된 내식성, 내취화성, 주조성 및열간가공성이 우수한 슈퍼 듀플렉스 스테인리스강 |
BRPI0412092A (pt) * | 2003-06-30 | 2006-09-05 | Sumitomo Metal Ind | aço inoxidável dúplex |
BRPI0406423B1 (pt) * | 2003-08-07 | 2012-12-11 | aço inoxidável duplex e seu método de produção. | |
US7396421B2 (en) | 2003-08-07 | 2008-07-08 | Sumitomo Metal Industries, Ltd. | Duplex stainless steel and manufacturing method thereof |
US8710405B2 (en) * | 2005-04-15 | 2014-04-29 | Nippon Steel & Sumikin Stainless Steel Corporation | Austenitic stainless steel welding wire and welding structure |
JP5072285B2 (ja) | 2006-08-08 | 2012-11-14 | 新日鐵住金ステンレス株式会社 | 二相ステンレス鋼 |
SE530847C2 (sv) * | 2006-12-14 | 2008-09-30 | Sandvik Intellectual Property | Platta till plattvärmeväxlare, plattvärmeväxlare uppbyggd av sådana plattor samt användning av denna plattvärmeväxlare |
JP5096762B2 (ja) * | 2007-02-26 | 2012-12-12 | 株式会社荏原製作所 | 遠心式ポンプ |
UA90217C2 (ru) * | 2007-03-26 | 2010-04-12 | Сумитомо Метал Индастриз, Лтд. | Труба нефтяного сортамента для развальцовывания в скважине и дуплексная нержавеющая сталь для труб нефтяного сортамента, приспособленных для развальцевания |
US8313691B2 (en) | 2007-11-29 | 2012-11-20 | Ati Properties, Inc. | Lean austenitic stainless steel |
EP2229463B1 (en) * | 2007-12-20 | 2017-09-06 | ATI Properties LLC | Corrosion resistant lean austenitic stainless steel |
US8337749B2 (en) | 2007-12-20 | 2012-12-25 | Ati Properties, Inc. | Lean austenitic stainless steel |
DK2245202T3 (da) * | 2007-12-20 | 2011-12-19 | Ati Properties Inc | Austenitisk rustfrit stål med lavt nikkelindhold indeholdende stabiliserende grundstoffer |
JP5675139B2 (ja) * | 2010-03-26 | 2015-02-25 | 新日鐵住金ステンレス株式会社 | 耐食性に優れた二相ステンレス鋼材の製造方法 |
CN103298965B (zh) | 2011-01-27 | 2016-09-28 | 新日铁住金不锈钢株式会社 | 合金元素节减型双相不锈钢热轧钢材、具备双相不锈钢作为夹层材料的包层钢板及它们的制造方法 |
CN103741070B (zh) * | 2014-01-23 | 2015-11-18 | 江苏银环精密钢管有限公司 | 一种环氧乙烷反应器用双相不锈钢无缝钢管 |
CN104195447B (zh) * | 2014-08-19 | 2016-08-24 | 张家港市飞浪泵阀有限公司 | 用在泵阀产品上的超级双相不锈钢及其制备方法 |
RU2693718C2 (ru) * | 2017-06-16 | 2019-07-04 | Акционерное общество "Научно-производственное объединение "Центральный научно-исследовательский институт технологии машиностроения" АО "НПО "ЦНИИТМАШ" | Дуплексная нержавеющая сталь для производства запорной и регулирующей арматуры |
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JPS5713399A (en) * | 1980-06-30 | 1982-01-23 | Hitachi Ltd | Method of storing radioactive waste |
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1994
- 1994-04-05 JP JP06747394A patent/JP3446294B2/ja not_active Expired - Fee Related
-
1995
- 1995-04-04 DE DE69506537T patent/DE69506537T2/de not_active Expired - Lifetime
- 1995-04-04 WO PCT/JP1995/000647 patent/WO1995027090A1/ja active IP Right Grant
- 1995-04-04 US US08/718,574 patent/US5849111A/en not_active Expired - Lifetime
- 1995-04-04 EP EP95913417A patent/EP0757112B1/en not_active Expired - Lifetime
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JPS5713399B2 (ja) * | 1973-02-07 | 1982-03-17 | ||
JPS58224155A (ja) * | 1982-06-19 | 1983-12-26 | Kawasaki Steel Corp | 2相ステンレス継目無鋼管およびその製造方法 |
JPS61113749A (ja) * | 1984-11-09 | 1986-05-31 | Kawasaki Steel Corp | 油井用高耐食性合金 |
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Also Published As
Publication number | Publication date |
---|---|
DE69506537D1 (de) | 1999-01-21 |
DE69506537T2 (de) | 1999-07-08 |
EP0757112B1 (en) | 1998-12-09 |
EP0757112A1 (en) | 1997-02-05 |
EP0757112A4 (en) | 1997-06-18 |
JPH07278755A (ja) | 1995-10-24 |
JP3446294B2 (ja) | 2003-09-16 |
US5849111A (en) | 1998-12-15 |
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