EP1418245A9 - Long-life heat-resisting low alloy steel welded component and method of manufacturing the same - Google Patents
Long-life heat-resisting low alloy steel welded component and method of manufacturing the same Download PDFInfo
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- EP1418245A9 EP1418245A9 EP03025611A EP03025611A EP1418245A9 EP 1418245 A9 EP1418245 A9 EP 1418245A9 EP 03025611 A EP03025611 A EP 03025611A EP 03025611 A EP03025611 A EP 03025611A EP 1418245 A9 EP1418245 A9 EP 1418245A9
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- base metal
- heat
- welding
- hot working
- alloy steel
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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
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/26—Methods of annealing
- C21D1/28—Normalising
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
Definitions
- the present invention relates to a heat-resisting low alloy steel welded component of a structure used under a high-temperature and high-pressure atmosphere such as a thermal power plant or petrochemical plant.
- the invention also relates to a method of manufacturing a welded component of heat-resisting steel used in facilities that use in many occasions a thick structure of a ferritic heat-resisting low alloy steel.
- boilers are employed under a higher temperature and pressure, and their capacities are increasing.
- thermal power plants that can operate under a steam pressure of 316 kg/cm 2 and a steam temperature of 566°C and have a large capacity that is equivalent to a 700,000 to 1,000,000 kW-class plant are constructed at present.
- the steel pipe material used for such a boiler is mainly divided into carbon steel or low-alloy steel, and high alloy steel, a typical example of which is austenitic stainless steel. These materials are carefully selected in accordance with the temperature and pressure of the section where the material is used. For example, for a hot reheat steam pipe or main steam pipe in which the temperature becomes 450°C or higher when in use, Mo steel or Cr-Mo steel, which has an excellent anti-oxidation property and heat resisting property, is used.
- a thick pipe made of Cr-Mo low alloy steel is employed since these pipes have to stand a high internal pressure and temperature.
- ferritic low alloy heat-resisting steel that is defined by JIS G 3458 (1988) is used for the pipes.
- a weld with a high joint efficiency is used.
- various creep damages are created at the weld zone.
- the type 4 damage which is created in a fine grained region of the HAZ, causes to significantly shorten the lifetime of the weld zone of the pipe, and therefore this type of damage is perceived as a problem in many countries.
- the type 4 damage is discussed in, for example, a non-patent document, "Review of Type IV Cracking" written by F.V. Ellis and R. Viswanathan (ASME PVP vol. 380, July 1998).
- a heat-resisting steel pipe is manufactured in a procedure shown in FIG. 8B. That is, a steel lumber is carried out an acceptance test. The tested steel lumber is marked and then cut into steel pieces (S11). Then, steel pieces are bent by hot working (S12). Another marking is carried out on the pieces and then cut (S13). The cut pieces are subjected to a heat treatment (S14). Subsequently, the treated pieces are subjected to a mechanical edge preparation (15). The prepared pieces are aligned edges each other (S16) and then welded together by a submerged arc welding method (S17).
- the present invention has been proposed as a solution to the above-described drawback of the conventional technique, and the object thereof is to provide a long-life heat-resisting low alloy steel welded component that does not easily cause a creep damage in a heat-affected zone and a method of manufacturing the same.
- a method of manufacturing a long-life heat-resisting low alloy steel welded component including the steps of subjecting a base metal containing, at % by weight, C: 0.15% or less, Si: 0.5% or less, Mn: 0.3 to 0.8%, Cr: 1.9 to 2.6%, Mo: 0.87 to 1.20%, and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), the method being characterized by normalizing the base metal once or more times before the welding (S8) in addition to the hot working (S3).
- the method of the present invention can be applied to a base metal containing, at % by weight, Mn: 0.3 to 0.6% and Mo: 0.87 to 1.13%. In this case, it is preferable that the normalizing of the base metal should be carried out at least twice.
- a method of manufacturing a long-life heat-resisting low alloy steel welded component including the steps of subjecting a base metal containing, at % by weight, C: 0.04% to 0.10%, Si: 0.5% or less, Mn: 0.1 to 0.6%, Cr: 1.9 to 2.6%, Mo: 0.05 to 0.3%, V: 0.20 to 0.30%, Nb: 0.02 to 0.08%, W: 1.45 to 1.75%, B: 0.0005 to 0.006% and a balance of iron and unavoidable impurities, to a hot working, to a heat treatment, and then to a welding, the method being characterized by normalizing the base metal once or more times before the welding in addition to the hot working.
- a method of manufacturing a long-life heat-resisting low alloy steel welded component including the steps of subjecting a base metal containing, at % by weight, C: 0.2% or less, Si: 1.0% or less, Mn: 0.3 to 0.9%, Cr: 0.3 to 1.5%, Mo: 0.4 to 0.7%, and a balance of iron and unavoidable impurities, to a hot working, to a heat treatment, and then to a welding, the method being characterized by normalizing the base metal once or more times before the welding in addition to the hot working.
- the method of the present invention can be applied to a base metal containing, at % by weight, Mn: 0.3 to 0.6%, Cr: 0.5 to 1.5% and Mo: 0.40 to 0.65%.
- the method of the present invention can be applied to the base metal further containing, at % by weight, V: 0.22 to 0.50%.
- the method of the present invention can be applied to a base metal that has been subjected to annealing or normalizing and tempering.
- the method of the present invention should be carried out by subjecting the base metal to the normalizing and then to the hot working in a normalizing temperature range.
- the long-life heat-resisting low alloy steel welded component according to the present invention can be manufactured by the above-described methods.
- the welded component of the present invention can be applied to at least one of longitudinal joint and circumferential joint of pipes, vessel, valve casing and branch pipes that are used under a high-temperature and high-pressure steam atmosphere at a temperature of 450°C or higher.
- the form of the base metal may be a plate, pipe, forging and casting.
- the inventors of the present invention carried out intensive studies on creep damages of type 4, and discover the following facts.
- the present invention has been achieved based on these findings.
- FIG. 2 The mechanism of occurrence of creep damages of type 4 is schematically illustrated in FIG. 2. Further, the results of observation of samples extracted from a site where damages of type 4 were created under a transmission electron microscope (TEM) or scanning electron microscope (SEM) are shown in the photographs of FIGS. 3 to 7.
- TEM transmission electron microscope
- SEM scanning electron microscope
- type 4 crack occurs on the base metal side of the HAZ.
- the present invention aims to reduce the amount of coarse carbides, which cause to damages of type 4, remaining in former austenite (y) grain boundaries of a welded component (base metal).
- the creep lifetime of the weld zone of the heat-resisting steel can be significantly improved. More specifically, before the base metal is welded, it is subjected to normalizing once or more times, thereby reducing the amount of coarse carbides.
- a steel lumber 21 is carried out an acceptance test (S1).
- the steel lumber 21 is, as defined, for example, by JIS G 3458, either a material that has been subjected to normalizing and tempering once (NT material) or a material that has been subjected to annealing once (annealed material).
- the steel lumber 21 is marked and then cut into steel pieces 22.
- the steel pieces 22 are subjected normalizing at a predetermined temperature (S2). Subsequently, they are bent by hot working with use of a recess type mold and a projection type mold at a temperature within a range of 900 to 1,000°C into bent steel pieces 22a (S3).
- the hot press bending is not carried out to follow the normalizing, the steel pieces are heated up to a temperature within a range of 900 to 1,000°C, and then subjected to hot press bending.
- bent steel pieces 22a are marked and then cut (S4).
- the cut pieces are subjected to a heat treatment within a predetermined temperature range in a furnace 25 (S5).
- two or more bent steel pieces are placed on an edge rest 26 and then subjected to a mechanical edge preparation with a cutting edge 27.
- the bent steel pieces 22a are aligned their edges each other (S7) and they are welded together by hands from the first to second or third layers. Then, they are subjected to a full-automatic submerged arc welding by 5 to 50 passes, and thus a linear joint steel pipe having a longitudinal joint is prepared (S8).
- high temperature used in this specification indicates mainly a temperature in a range of 450 to 650°C unless the temperature is particularly specified.
- JIS G 4109 SCMV 3 Div 1 ASTM A 387/A 387M Gr.11, Cl.1 K11789 and Gr.11, Cl.2 K11789; JIS G 4109 SCMV 3 Div 2
- JIS G 4109 SCMV 5 Div 1 ASTM A 387/A 387M Gr.21, Cl.1, Gr.21L, Cl.1 and Gr.21, Cl.2 K31545; JIS G 4109 SCMV 5 Div 2
- JIS G 4109 SCMV 6 Div 1 ASTM A 387/A 387M Gr.5, Cl.1 and Gr.5, Cl.2 K41545 S50100 and S50200; JIS G 4109 SCMV 6 Div 2
- KA-SCMV4J1 specified by Code for Thermal Power Generation Facilities (to be abbreviated as "CTPGF” hereinafter) of JSME standard can be also used.
- CPGF Code for Thermal Power Generation Facilities
- JIS G 4110 SCMQ4E, SCMQ4V and SCMQ5V can be employed as well.
- JIS G 3203 SFVA F 11 A ASTM A 182/A 182M F 11, Cl 2 K11572; ASTM A 336/A 336M F11, Cl2 and F11, Cl3 K11572; JIS G 3203 SFVA F 11 B
- JIS G 3203 SFVA F 22 A ASTM A 182/A 182M F 22, Cl 1 K21590; ASTM A 336/A 336M F22, Cl 1 K21590; EN 10222-2 11CrMo9-10 1.7383; ISO 9327-2 13CrMo9-10; ASTM A 182/A 182M F 22, Cl 3 K21590; ASTM A 336/A 336M F22, Cl3 K21590; JIS G 3203 SFVA F 22 B
- JIS G 3203 SFVA F 21 A ASTM A 336/A 336M F21, Cl1 K31545; ASTM A 182/A 182M F 21 K31545; ASTM A 336/A 336M F21, Cl3 K31545; JIS G 3203 SFVA F 21 B
- JIS G 3206 SFVCM F3V JIS G 3206 SFVCM F3V; ASTM A 182/A 182M F 3V K31830; ASTM A 336/A 336M F3V; ASTM A 508/A 508M 3V K31830; ASTM A 541/A 541M 3V K31830
- CTPGF KA-SFVAF22AJ1 of JSME standard can be employed as well. (Extracted from Reference Document 2 ⁇ TABLE II-1-1 Notes> 18.)
- a base metal having the above-specified composition is subjected to hot working and heat treatment, and then it is welded to prepare a component.
- the normalizing process is carried out once or more as a separate step from the hot working.
- Normalizing is carried out for a necessary number of times (once or more) so as to sufficiently,reduce the amount of coarse carbides present in former austenite grain boundaries in steel, that is, to have the carbides solid-dissolved and diffused into the matrix.
- the number of times that the normalizing carried out should preferably be once or twice; however it may be varied widely depending on the thickness and the chemical compositions of the material.
- the normalizing should preferably performed two or three or more times.
- a ferritic heat-resisting low-alloy steel that can be used in the present invention is a normalized and tempered material (NT material), which is, when manufacturing its base metal (for example, a lumber 21 in FIG. 8A), heated up to a complete austenite region and then tempered.
- NT material normalized and tempered material
- heating carried out during the manufacture of the base metal is regarded substantially as normalizing. Therefore, in the case of such a base metal, if the normalizing is carried out at least once before the welding as a separate step from the hot working, it is practically assumed that a total of two or more times of normalizing are carried out. Thereby, the amount of coarse carbides can be reduced.
- the normalizing includes the following procedures. That is, a base metal is heated to an appropriate normalizing temperature of point Ac3 or Ac1 or higher (for example, Ac3 + 50°C), and maintained at the temperature for a certain period of time. Then, the base metal is cooled down in the atmosphere. Alternatively, the base metal is cooled down to a temperature just above the Ar' point and maintained at the temperature until the completion of the isothermal transformation, and then it is air-cooled. In the normalizing, if the maintained temperature is excessively high, it is possible that the ⁇ grains become coarse more than necessary, whereas if the maintained temperature is excessively low, coarse carbides may not be sufficiently solid-dissolved.
- an appropriate normalizing temperature of point Ac3 or Ac1 or higher for example, Ac3 + 50°C
- the maintained time period at the normalizing temperature is excessively long, it is possible that the ⁇ grains become coarse more than necessary, thereby lowering the strength of the base metal.
- the maintained normalizing temperature can be set to 920 to 930°C in the case of, for example, STPA 24.
- the time period maintained at the normalizing temperature can be set to 0.5 to 1 hour in the case of, for example, STPA 24.
- the appropriate maintaining temperature and maintaining time of the normalizing temperature vary depending on the type of steel employed. Therefore, it is preferable that the normalizing process should be carried out in accordance with the specification of the steel type in each case.
- the temperature when carrying out the normalizing, the temperature may be maintained isothermally or the heating carried out within the above temperature range may be maintained within the above time range.
- the normalizing of a base metal may be carried out at any timing if it is before the welding. However, when the normalizing process is carried out after the hot working, some dimensional error may occur due to thermal strain, and therefore it is preferable that the normalizing should be carried out before the hot working.
- the hot working are press forming, rolling and bending.
- the heating temperature, pressure and the like are not particularly limited, but it is preferable that the hot press bending should be carried out at a temperature within a range of 900 to 1,000°C continuously after the normalizing process.
- the material should be heated to a temperature within a range of 900 to 1,000°C, and then the hot press bending should be carried out. It should be noted that if the hot working is carried out continuously after the normalizing process, the step of re-heating the material can be omitted, and therefore it is more efficient and thus more preferable.
- the manufacturing method of the present invention can be applied to a welded steel pipe as well as a seamless steel pipe.
- the hot working includes, for example, a step of hot pressing a hoop iron into a desired shape.
- the material is subjected to normalizing and to hot working (press bending) first, and then the material is marked and cut. After that, the material is tempered to a temperature within a range of 700 to 750°C.
- the material is subjected to normalizing and to hot working (press bending) at a temperature within a range of 850 to 1100°C first, and then the material is marked and cut. After that, the material is annealed by air-cooling, or by a liquid cooling method (such as oil quench hardening) if the material is thick, from a temperature within a range of 950 to 980°C. Subsequently, the material is tempered by maintaining the temperature within a range of 690 to 730°C for 30 minutes.
- a liquid cooling method such as oil quench hardening
- the present invention can be applied not only to longitudinal joint or circumferential joint of a longitudinal joint steel pipe as shown in FIG. 8, but also to circumferential joint of, for example, a spiral joint steel pipe or seamless steel pipe. Further, the present invention is applicable to longitudinal (seam) welding and circumferential welding carried out to prepare a steel pipe, but also to any of a pipe-to-end plate welding and pipe welding for boilers and heat exchanger.
- the present invention can be applied to a heat-resisting low-alloy steel pipe used to make a large-diameter pipe employed in a thermal power plant or petrochemical plant.
- a large-diameter pipe When such a large-diameter pipe is used in a situation where a high-temperature and high-pressure steam flows in the pipe, it may be exposed to an environment of a temperature of 450 to 600°C and a high pressure, in general cases.
- a thermal power plant it may be exposed to an environment of a temperature of 538 to 566°C and a pressure of 169 to 316 kg/cm 2 . Therefore, pipes having a thickness of 25 to 150 mm are used.
- the present invention can be effectively applied because it can reduce the amount of coarse carbides, which are origins of such creep damages, present along former austenite grain boundaries in steel, and thereby suppress the formation of a plate-like agglomeration region.
- ASTM A387 Gr. D (which is equivalent to ASTM A387/A 387M 22) corresponding to STPA 24 defined by JIS was prepared.
- the sample steel was subjected to hot press bending at a temperature of 900 to 930°C, and then marked and cut.
- the cut pieces were subjected to tempering for 4 hours at a temperature of 700 to 730°C.
- the pieces were subjected to mechanical edge preparation, and they were aligned their edges each other.
- the outer side and inner side of the bent site were welded by submerged arc welding. In this manner, a 90° -elbow plate bent longitudinal seam steel pipe having an outer diameter of 508 mm and a thickness of 106 mm was manufactured.
- the obtained steel pipe was used as a main steam pipe of a thermal power plant for about 145,000 hours to have it aged.
- the aging conditions are the maximum pressure of 177.5 kgf/cm 2 and the maximum temperature of 575°C and the average temperature of 566°C.
- the after-use, i.e. damaged, pipe was heated at a temperature of 1,000°C for 0.5 hours and then subjected to hot press to make the material into a plate shape. Then, the material was air-cooled and got a refreshed material (, which is the first substantial normalizing) (S3).
- Two of such plate-like refreshed materials were prepared, and they were normalized at a temperature of 900°C for 2 hours and air-cooled (, which is the second substantial normalizing) (S2). After that, the materials were tempered at a temperature of 750°C for 2 hours and air-cooled (S5). After that, a pair of these plate materials were mechanically beveled to form edges (S6). Then, they were aligned their edges each other (S7), and welded together by submerged arc welding. In this manner, a sample weld having a thickness of 98 mm was manufactured (S8).
- the obtained sample weld was aged by applying a fixed load of 400 kg/mm 2 onto a test piece with use of the method defined by JIS Z 2271 (1993).
- the test piece was obtained from a depth about two fifth of the thickness from the outer surface as it had the HAZ fine grained region in the middle of the gauge.
- the aging conditions are a temperature of 680°C and the test was continued until the piece was ruptured.
- the rupture time of the test piece was about 220 hours. When converted under the actual use conditions, the rupture time is about 240,000 hours.
- a simulation test was carried out until the test piece was ruptured in a similar manner to that of Example 1 except that the aging temperature was set to 670°C.
- the rupture time of the test piece was about 380 hours. When converted under the actual use conditions, the rupture time is about 240,000 hours. Then, the test piece was observed as to whether a type 4 damage has occurred or not. The result was as indicated in TABLE 2.
- Example 2 A simulation test was carried out until the test piece was ruptured in a similar manner to that of Example 1 except that the aging temperature was set to 650°C. The rupture time of the test piece was about 1,100 hours. Then, the test piece was observed as to whether a type 4 damage has occurred or not. The result was as indicated in TABLE 2.
- Example 2 A simulation test was carried out in a similar manner to that of Example 1 except that the aging temperature was set to 566°C. Then, the test piece (, which was not ruptured,) was observed as to whether a type 4 damage has occurred or not. In this reference example, the test was aborted after 10,000 hours.
- FIG. 9 is a TEM photograph showing the carbide structures under a magnification of about 500 times.
- Example 2 In a similar manner to that of Example 1, a test piece (, which was not normalized,) was obtained from the HAZ fine grained region of the inner side of 90° -steel pipe elbow , which was used for about 188,000 hours as a main steam pipe of a thermal power plant. The actual used conditions of this example was substantially similar to the used condition of Example 1. Then, the piece was observed as to whether a type 4 damage has occurred or not. Subsequently, as in a similar manner to that of Example 3, the carbide structures of the sample were observed. The extraction replica (test piece) was taken at a depth about two thirds of the thickness from the outer surface. The results of the observation were as shown in FIG. 3 and TABLE 2.
- the high-density agglomerated carbides can be suppressed as compared to the conventional welded component, thereby making it possible to reduce the type 4 damages.
- Example 3 a type 4 damage was observed; however, the rupture of the test piece was not directly caused by the type 4 damage. It is understood that the type 4 damage can be suppressed significantly in Example 3, thereby the rupture occurred in the portion other than the HAZ fine grained region. This is because, as compared to Comparative Example 1, the amount of high-density agglomerated carbides was remarkably less in Example 3.
- the base metal was normalized once as a separate step from the hot working before the welding as in the present invention.
- the type 4 damage was not observed even though it was aged at substantially an equal temperature and load to the actual use conditions.
- Example 3 indicates a slight reticular carbide agglomeration has been created in a lower right section of the photograph.
- Example 3 a few high-density agglomerated carbides were present as indicated in TABLE 2 but plate-like carbides was not observed.
- another normalizing should be carried out, that is, a total of twice of normalizing should be carried out in addition to the hot working that serves also as refreshing. In this manner, a welded component having better properties with even less high-density agglomerated carbides can be created.
- Comparative Example 1 By contrast, in Comparative Example 1, not only spherical carbides but also plate-like carbide agglomeration regions (dark portion in FIG. 3) were present in a wide range of the sample.
- the identification of precipitates was carried out by an energy dispersion X-ray analysis.
- (Mo, Fe) 6 C, (Cr, Fe) 23 C 6 and the like were defined, which suggested that the plate-like agglomeration of carbides occurs more easily in a steel type containing a great amount of Mo and Cr, as compared to a steel type containing low contents of these.
- the present invention it is possible to provide a low-alloy steel welded component that does not easily have a plate-like agglomeration region of carbides even if it is exposed to multiple thermal cycles by submerged arc weldings, and it is used under conditions where a stress created by high internal pressure is applied thereon at a high temperature. Therefore, a long-life low-alloy steel welded component that does not easily create type 4 creep damages, which are caused by a plate-like carbide agglomeration region, can be obtained.
- the present invention it is possible to provide a long-life low-alloy steel welded component that can be applied to a wide usage in facilities that employs a great number of thick pipes made of ferritic heat-resisting steel. Further, the welded component of the present invention does not easily create creep damages in a heat affected zone even if the submerged arc welding is used.
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Abstract
Description
Claims (19)
- A method of manufacturing a long-life heat-resisting low alloy steel welded component including the steps of subjecting a base metal containing, at % by weight, C: 0.15% or less, Si: 0.5% or less, Mn: 0.3 to 0.8%, Cr: 1.9 to 2.6%, Mo: 0.87 to 1.20%, and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), characterized in that the base metal is normalized (S2) once or more times before the welding (S8) in addition to the hot working (S3).
- The manufacturing method according to claim 1, characterized in that the base metal contains, at % by weight, Mn: 0.3 to 0.6% and Mo: 0.87 to 1.13%.
- The manufacturing method according to claim 2, characterized in that the normalizing (S2) of the base metal is carried out at least twice.
- A method of manufacturing a long-life heat-resisting low alloy steel welded component including the steps of subjecting a base metal containing, at % by weight, C: 0.04% to 0.10%, Si: 0.5% or less, Mn: 0.1 to 0.6%, Cr: 1.9 to 2.6%, Mo: 0.05 to 0.3%, V: 0.20 to 0.30%, Nb: 0.02 to 0.08%, W: 1.45 to 1.75%, B: 0.0005 to 0.006% and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), characterized in that the base metal is normalized (S2) once or more times before the welding (S8) in addition to the hot working (S3).
- A method of manufacturing a long-life heat-resisting low alloy steel welded component including the steps of subjecting a base metal containing, at % by weight, C: 0.2% or less, Si: 1.0% or less, Mn: 0.3 to 0.9%, Cr: 0.3 to 1.5%, Mo: 0.4 to 0.7%, and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), characterized in that the base metal is normalized (S2) once or more times before the welding (S8) in addition to the hot working (S3).
- The manufacturing method according to claim 5, characterized in that the base metal contains, at % by weight, Mn: 0.3 to 0.6%, Cr: 0.5 to 1.5% and Mo: 0.40 to 0.65%.
- The manufacturing method according to claim 5, characterized in that the base metal further contains, at % by weight, V: 0.22 to 0.50%.
- The manufacturing method according to one of claims 1 to 7, characterized in that the base metal has been subjected to annealing or normalizing and tempering.
- The manufacturing method according to one of claims 1 to 8, characterized in that the base metal is subjected to the hot working (S3) in a normalizing temperature range, after the normalizing (S2).
- A long-life heat-resisting low alloy steel welded component manufactured by the steps of subjecting a base metal containing, at % by weight, C: 0.15% or less, Si: 0.5% or less, Mn: 0.3 to 0.8%, Cr: 1.9 to 2.6%, Mo: 0.87 to 1.20%, and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), characterized in that the base metal is normalized (S2) once or more times before the welding (S8) in addition to the hot working (S3) .
- The heat-resisting low alloy steel welded component according to claim 10, characterized in that the base metal contains, at % by weight, Mn: 0.3 to 0.6% and Mo: 0.87 to 1.13%.
- The heat-resisting low alloy steel welded component according to claim 11, characterized in that the normalizing (S2) of the base metal is carried out at least twice.
- A long-life heat-resisting low alloy steel welded component manufactured by the steps of subjecting a base metal containing, at % by weight, C: 0.04% to 0.10%, Si: 0.5% or less, Mn: 0.1 to 0.6%, Cr: 1.9 to 2.6%, Mo: 0.05 to 0.3%, V: 0.20 to 0.30%, Nb: 0.02 to 0.08%, W: 1.45 to 1.75%, B: 0.0005 to 0.006% and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), characterized in that the base metal is normalized (S2) once or more times before the welding (S8) in addition to the hot working (S3).
- A long-life heat-resisting low alloy steel welded component manufactured by the steps of subjecting a base metal containing, at % by weight, C: 0.2% or less, Si: 1.0% or less, Mn: 0.3 to 0.9%, Cr: 0.3 to 1.5%, Mo: 0.4 to 0.7%, and a balance of iron and unavoidable impurities, to a hot working (S3), to a heat treatment (S5), and then to a welding (S8), characterized in that the base metal is normalized (S2) once or more times before the welding (S8) in addition to the hot working (S3).
- The heat-resisting low alloy steel welded component according to claim 14, characterized in that the base metal contains, at % by weight, Mn: 0.3 to 0.6%, Cr: 0.5 to 1.5% and Mo: 0.40 to 0.65%.
- The heat-resisting low alloy steel welded component according to claim 14, characterized in that the base metal further contains, at % by weight, V: 0.22 to 0.50%.
- The heat-resisting low alloy steel welded component according to one of claims 10 to 16, characterized in that the base metal has been subjected to annealing or normalizing and tempering.
- The heat-resisting low alloy steel welded component according to one of claims 10 to 17, characterized in that the base metal is subjected to the hot working (S3) in a normalizing temperature range, after the normalizing (S2).
- The heat-resisting low alloy steel welded component according to one of claims 10 to 18, characterized in that the welded component can be applied to at least one of longitudinal joint and circumferential joint of pipes, vessel, valve casing and branch pipes that are used under a high-temperature and high-pressure steam atmosphere at a temperature of 450°C or higher.
Applications Claiming Priority (4)
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JP2002322969 | 2002-11-06 | ||
JP2002322969 | 2002-11-06 | ||
JP2003357568 | 2003-10-17 | ||
JP2003357568 | 2003-10-17 |
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EP1418245A2 EP1418245A2 (en) | 2004-05-12 |
EP1418245A9 true EP1418245A9 (en) | 2004-08-11 |
EP1418245A3 EP1418245A3 (en) | 2004-10-06 |
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EP20030025611 Withdrawn EP1418245A3 (en) | 2002-11-06 | 2003-11-06 | Long-life heat-resisting low alloy steel welded component and method of manufacturing the same |
Country Status (4)
Country | Link |
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US (1) | US20040089701A1 (en) |
EP (1) | EP1418245A3 (en) |
JP (1) | JP4254483B2 (en) |
CA (1) | CA2448091A1 (en) |
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JP5055736B2 (en) * | 2004-12-02 | 2012-10-24 | Jfeスチール株式会社 | Manufacturing method of high-strength steam piping steel plate with excellent weld heat-affected zone toughness |
WO2008007737A1 (en) * | 2006-07-13 | 2008-01-17 | Sumitomo Metal Industries, Ltd. | Bend pipe and process for producing the same |
JP2008087003A (en) * | 2006-09-29 | 2008-04-17 | Toyota Motor Corp | Friction-welded member |
US20100199678A1 (en) * | 2007-09-13 | 2010-08-12 | Claus Krusch | Corrosion-Resistant Pressure Vessel Steel Product, a Process for Producing It and a Gas Turbine Component |
EP2090825A1 (en) * | 2008-02-14 | 2009-08-19 | Siemens Aktiengesellschaft | Burner element and burner with corrosion-resistant insert |
JP5417017B2 (en) * | 2009-04-01 | 2014-02-12 | 富士重工業株式会社 | Fastening member fixing method |
DE102011055282A1 (en) * | 2011-07-26 | 2013-01-31 | Alstom Technology Ltd. | Method for welding thin-walled pipes by means of peak tempering welding |
DK2764127T3 (en) | 2011-10-07 | 2015-10-19 | Babasaheb Neelkanth Kalyani | A method for improving the fatigue strength of micro-alloy steels, forged parts made by the method and apparatus for carrying out the method |
US20130202908A1 (en) * | 2012-02-08 | 2013-08-08 | Grzegorz Jan Kusinski | Equipment for use in corrosive environments and methods for forming thereof |
US9352369B2 (en) | 2012-02-08 | 2016-05-31 | Chevron U.S.A. Inc. | Equipment for use in corrosive environments and methods for forming thereof |
JP5769204B2 (en) * | 2012-12-28 | 2015-08-26 | 株式会社日本製鋼所 | Fe-Ni base alloy having excellent high temperature characteristics and hydrogen embrittlement resistance and method for producing the same |
JP5475198B1 (en) * | 2013-03-22 | 2014-04-16 | 中国電力株式会社 | Prediction method for creep remaining life of product deteriorated by heating and pressurization, and calibration curve creation method used for this prediction method |
JP5450903B1 (en) * | 2013-03-27 | 2014-03-26 | 中国電力株式会社 | Prediction method for creep remaining life of product deteriorated by heating and pressurization, and calibration curve creation method used for this prediction method |
WO2015059815A1 (en) * | 2013-10-25 | 2015-04-30 | 中国電力株式会社 | Method for predicting creep residual life of product degraded by heat and pressure, and method for creating calibration curve used in the prediction method |
JP6515276B2 (en) * | 2015-01-14 | 2019-05-22 | 日本製鉄株式会社 | High strength ferritic heat resistant steel structure and method of manufacturing the same |
KR102165756B1 (en) * | 2016-09-30 | 2020-10-14 | 닛폰세이테츠 가부시키가이샤 | Ferritic heat-resistant steel welded structure manufacturing method and ferritic heat-resistant steel welded structure |
KR102165755B1 (en) * | 2016-09-30 | 2020-10-14 | 닛폰세이테츠 가부시키가이샤 | Ferritic heat-resistant steel welded structure manufacturing method and ferritic heat-resistant steel welded structure |
CN107633269A (en) * | 2017-09-29 | 2018-01-26 | 黄河勘测规划设计有限公司 | Rock-mass quality nonlinear smearing stage division |
CN113275712A (en) * | 2021-05-14 | 2021-08-20 | 东方电气集团东方锅炉股份有限公司 | Sealing welding process for composite plate tube plate and titanium alloy heat exchange tube |
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-
2003
- 2003-10-29 JP JP2003368915A patent/JP4254483B2/en not_active Expired - Fee Related
- 2003-11-04 CA CA002448091A patent/CA2448091A1/en not_active Abandoned
- 2003-11-04 US US10/699,825 patent/US20040089701A1/en not_active Abandoned
- 2003-11-06 EP EP20030025611 patent/EP1418245A3/en not_active Withdrawn
Also Published As
Publication number | Publication date |
---|---|
JP2005139470A (en) | 2005-06-02 |
EP1418245A3 (en) | 2004-10-06 |
JP4254483B2 (en) | 2009-04-15 |
US20040089701A1 (en) | 2004-05-13 |
CA2448091A1 (en) | 2004-05-06 |
EP1418245A2 (en) | 2004-05-12 |
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