EP4282989A2 - Hochfestes kraftstoffleitungsmaterial für die wasserstoffmobilität - Google Patents
Hochfestes kraftstoffleitungsmaterial für die wasserstoffmobilität Download PDFInfo
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- EP4282989A2 EP4282989A2 EP23175028.2A EP23175028A EP4282989A2 EP 4282989 A2 EP4282989 A2 EP 4282989A2 EP 23175028 A EP23175028 A EP 23175028A EP 4282989 A2 EP4282989 A2 EP 4282989A2
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- Prior art keywords
- pipe
- area
- heat treatment
- hydrogen
- strength
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- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 89
- 239000001257 hydrogen Substances 0.000 title claims abstract description 89
- 239000000446 fuel Substances 0.000 title claims abstract description 24
- 239000000463 material Substances 0.000 title claims description 49
- 238000010438 heat treatment Methods 0.000 claims abstract description 69
- 239000000956 alloy Substances 0.000 claims abstract description 54
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 51
- 239000000203 mixture Substances 0.000 claims abstract description 22
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 21
- 229910052750 molybdenum Inorganic materials 0.000 claims abstract description 18
- 229910052799 carbon Inorganic materials 0.000 claims abstract description 17
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 17
- 238000005482 strain hardening Methods 0.000 claims abstract description 17
- 229910052748 manganese Inorganic materials 0.000 claims abstract description 16
- 229910052717 sulfur Inorganic materials 0.000 claims abstract description 16
- 229910052698 phosphorus Inorganic materials 0.000 claims abstract description 11
- 238000011084 recovery Methods 0.000 claims description 32
- 238000000034 method Methods 0.000 claims description 30
- 230000008569 process Effects 0.000 claims description 26
- 238000005096 rolling process Methods 0.000 claims description 20
- 229910001220 stainless steel Inorganic materials 0.000 claims description 20
- 229910000734 martensite Inorganic materials 0.000 claims description 19
- 239000010935 stainless steel Substances 0.000 claims description 18
- 238000010622 cold drawing Methods 0.000 claims description 17
- 238000004519 manufacturing process Methods 0.000 claims description 15
- 229910052751 metal Inorganic materials 0.000 claims description 14
- 239000002184 metal Substances 0.000 claims description 14
- 238000013461 design Methods 0.000 claims description 12
- 238000000137 annealing Methods 0.000 claims description 11
- 230000009467 reduction Effects 0.000 claims description 11
- 239000006104 solid solution Substances 0.000 claims description 9
- 230000005389 magnetism Effects 0.000 claims description 4
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 abstract description 105
- 230000001965 increasing effect Effects 0.000 abstract description 25
- 229910045601 alloy Inorganic materials 0.000 abstract description 24
- 238000005516 engineering process Methods 0.000 abstract description 10
- 239000011651 chromium Substances 0.000 description 20
- 229910001566 austenite Inorganic materials 0.000 description 17
- 229910000831 Steel Inorganic materials 0.000 description 16
- 239000011572 manganese Substances 0.000 description 16
- 239000010959 steel Substances 0.000 description 16
- 230000000087 stabilizing effect Effects 0.000 description 12
- 238000004364 calculation method Methods 0.000 description 10
- 229910000859 α-Fe Inorganic materials 0.000 description 10
- 238000005452 bending Methods 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 238000007670 refining Methods 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 229910052802 copper Inorganic materials 0.000 description 5
- 239000010949 copper Substances 0.000 description 5
- 238000005260 corrosion Methods 0.000 description 5
- 230000007797 corrosion Effects 0.000 description 5
- 230000007423 decrease Effects 0.000 description 5
- 230000003247 decreasing effect Effects 0.000 description 5
- 238000012805 post-processing Methods 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 4
- 238000011160 research Methods 0.000 description 4
- 239000011593 sulfur Substances 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 3
- BHEPBYXIRTUNPN-UHFFFAOYSA-N hydridophosphorus(.) (triplet) Chemical compound [PH] BHEPBYXIRTUNPN-UHFFFAOYSA-N 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 3
- 238000003754 machining Methods 0.000 description 3
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 2
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 229910000423 chromium oxide Inorganic materials 0.000 description 2
- 238000012937 correction Methods 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000011733 molybdenum Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000005728 strengthening Methods 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 229910000851 Alloy steel Inorganic materials 0.000 description 1
- 229910000975 Carbon steel Inorganic materials 0.000 description 1
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 1
- 238000007545 Vickers hardness test Methods 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 239000010962 carbon steel Substances 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000000460 chlorine Substances 0.000 description 1
- 229910052801 chlorine Inorganic materials 0.000 description 1
- QKCQJEFEQXXXTO-UHFFFAOYSA-N chromium;methane Chemical compound C.C.[Cr].[Cr].[Cr] QKCQJEFEQXXXTO-UHFFFAOYSA-N 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- RKTYLMNFRDHKIL-UHFFFAOYSA-N copper;5,10,15,20-tetraphenylporphyrin-22,24-diide Chemical compound [Cu+2].C1=CC(C(=C2C=CC([N-]2)=C(C=2C=CC=CC=2)C=2C=CC(N=2)=C(C=2C=CC=CC=2)C2=CC=C3[N-]2)C=2C=CC=CC=2)=NC1=C3C1=CC=CC=C1 RKTYLMNFRDHKIL-UHFFFAOYSA-N 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005262 decarbonization Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- 230000007717 exclusion Effects 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 230000001939 inductive effect Effects 0.000 description 1
- 239000013067 intermediate product Substances 0.000 description 1
- 229910000765 intermetallic Inorganic materials 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 238000003672 processing method Methods 0.000 description 1
- 238000012827 research and development Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 230000006641 stabilisation Effects 0.000 description 1
- 238000011105 stabilization Methods 0.000 description 1
- 229910001256 stainless steel alloy Inorganic materials 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Images
Classifications
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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
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/08—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes
- C21D9/14—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for tubular bodies or pipes wear-resistant or pressure-resistant pipes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C1/00—Manufacture of metal sheets, metal wire, metal rods, metal tubes by drawing
- B21C1/16—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes
- B21C1/22—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes specially adapted for making tubular articles
- B21C1/24—Metal drawing by machines or apparatus in which the drawing action is effected by other means than drums, e.g. by a longitudinally-moved carriage pulling or pushing the work or stock for making metal sheets, bars, or tubes specially adapted for making tubular articles by means of mandrels
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C35/00—Removing work or waste from extruding presses; Drawing-off extruded work; Cleaning dies, ducts, containers, or mandrels
- B21C35/02—Removing or drawing-off work
- B21C35/023—Work treatment directly following extrusion, e.g. further deformation or surface treatment
-
- 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
-
- 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
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/004—Heat treatment of ferrous alloys containing Cr and Ni
-
- 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
- C21D7/00—Modifying the physical properties of iron or steel by deformation
- C21D7/02—Modifying the physical properties of iron or steel by deformation by cold working
- C21D7/10—Modifying the physical properties of iron or steel by deformation by cold working of the whole cross-section, e.g. of concrete reinforcing bars
-
- 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
- C21D8/10—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies
- C21D8/105—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of tubular bodies of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21B—ROLLING OF METAL
- B21B21/00—Pilgrim-step tube-rolling, i.e. pilger mills
Definitions
- the present disclosure relates to a hydrogen fuel tube (piping material) technology for a hydrogen mobility such as a hydrogen vehicle, the technology being able to prevent hydrogen embrittlement and reduce weight by increasing strength.
- a hydrogen vehicle that is an eco-friendly vehicle has been popularized.
- a hydrogen fuel cell system has a problem that when hydrogen is contained in the metal of a hydrogen fuel pipe, toughness decreases, so the pipe easily breaks. This phenomenon accelerates at a low temperature and is generated in a strain-induced martensite structure in the case of stainless steel.
- it may be considered to suppress a bet structure that is strain-induced martensite of stainless steel by increasing the content of fcc stabilizing nickel.
- Korean Patent Application Publication No. 10-2022-0010184 is based on a composition that can improve hydrogen embrittlement resistance by having a nickel equivalent over 28.5% in austenite-based stainless steel 316, but is not satisfactory when taking aim at reducing the weight of austenite-based stainless steel.
- Japanese Re-publication Patent No. WO2015/098981 increases hydrogen embrittlement resistance of a surface by forming a plurality of aluminum-based special coatings having a thickness of 3 ⁇ 35 ⁇ m on a mother material, but does not increase hydrogen embrittlement resistance of alloy steel itself.
- Patent Application Publication No. 2011-026650 (2011.02.10 .) is focused on increasing insufficient toughness and ductility at high strength under 1% (preferably, prescribed at 0.9%) by prescribing a nickel value under 12% (preferably, prescribed at 10.6%) as a steel wire that is used for high-strength shaft, pin, spring, rope, etc. having high hydrogen embrittlement resistance and by putting in a large amount of copper over an impurity level, and on minimizing strain-induced martensite by minimizing internal stress (0 ⁇ 400MPa).
- a strain-induced martensite structure that is generated in austenite-based stainless steel is removed when heat treatment over 400°C is performed.
- An objective of the present disclosure is to provide a high strength and lightweight fuel pipe for a mobility by increasing a nickel equivalent, configuring an alloy composition having price competitiveness, and designing optimized pipe dimensions to a pipe for carrying hydrogen formed in the alloy composition under applicable pressure.
- the present disclosure provides an alloy material having a Ni equivalent (Ni eq ) over 28.5 % by controlling the composition of C, Si, Mn, P, S, Ni, Cr, and Mo, a pipe is machined using the alloy material, and a high-strength pipe of about 1/8 hard is provided by applying a strength increasing technology using work hardening and heat treatment. It is included in an alloy corresponding to 316 and 316-class alloys.
- the structure of 1/8 hard in the above description means a recovery heat treatment structure after drawing.
- the high-strength pipe can be thinned by applying a technology of increasing strength, the pipe can be designed to have a smaller thickness than the related art for an operating pressure reference by reversely calculating a pipe thickness from the allowable pressure and the allowable stress of a pipe for delivering hydrogen fuel of a hydrogen mobility such as a hydrogen vehicle, thereby providing a lightweighted and thinned pipe.
- the present disclosure provides a hydrogen fuel pipe for a hydrogen mobility
- the thickness pipe is calculated by the following equation, and
- a pipe using the alloy material undergoes work hardening that includes pilger rolling and drawing processes and increases strength of a pipe, and then undergoes heat treatment.
- the pipe is a metal structure pipe composed of a recovery structure.
- a member for a hydrogen mobility to which the hydrogen fuel pipe for a hydrogen mobility is applied is provided.
- the present disclosure provides a hydrogen fuel pipe for a hydrogen mobility, wherein
- a pipe for a hydrogen commercial vehicle that is manufactured by providing an alloy material having a Ni equivalent (Ni eq ) over 28.5 wt% and applying a technology of increasing strength through work hardening and heat treatment on the alloy material has a high-strength characteristic, so even though the inner diameters are the same and lightweighting of 50% is achieved, allowable pressure increases to 1114bar that is remarkably higher than 713bar of existing piping materials. Accordingly, it is possible to provide a pipe having a thickness that is smaller about a half than existing pipe thicknesses, whereby it is possible to achieve lightweighting over almost 50% in comparison to existing pipes.
- the weight of the piping material can be reduced about 31%, and it is also possible to provide a pipe thinner than existing pipes, so the inner diameter increases and the flow rate of hydrogen can be increased. Allowable pressure also increases to 994bar higher than 752bar in the related art, so when the allowable pressure is adjusted to 700bar, lightweighting over 31% can be achieved.
- the allow of the present disclosure has a high nickel equivalent, but the composition of Mn and Cr of the composition of the alloy material is increased higher than existing alloy materials, so the alloy material can have price competitiveness and the weight thereof is reduced, whereby the price per weight is further decreased and the price competitiveness is further increased.
- fcc structure stability is increased by increasing a Ni eq. (nickel equivalent, wt%) in a stainless steel alloy, thereby suppressing strain-induced martensite bet of stainless steel.
- a nickel equivalent means the ratio of an element acting like nickel in an alloy (an alloy technology of a Ni eq. over 28.5% in an alloy within a 316L class has been know in relation to container boss part application 316L of compressed hydrogen gas high court KGS AC118.
- the present disclosure designs a piping material for a hydrogen vehicle that has a high nickel equivalent exceeding 28.5% for stainless steel and increases allowable pressure of a pipe by performing work hardening and heat treatment to provide a high-strength property to the piping material, thereby achieving both lightweighting and price competitiveness by decreasing the thickness of the pipe.
- FIG. 1 is a table comparing the composition of an alloy material of the present disclosure with an existing one.
- a nickel equivalent of 316L is 22.36-+31.5% and a corresponding composition of C, Si, Mn, P, S, Ni, Cr, and Mo has been exemplified. Minimum values and maximum values are proposed for the components Ni, Cr, and Mo. Further, the current nickel equivalent of domestic mother pipes is 25.99% and a corresponding alloy composition has also been proposed.
- FIG. 1 shows an example.
- an alloy material containing C of 0.005-0.015, Si of 0.35-0.45, Mn of 1.55-1.65, P of 0.027-0.035, S of 0.0075-0.0085, Ni of 13.15-13.25, Cr of 17.45-17.55, Mo of 2.55-2.65 wt%, and the balance of Fe, etc.
- a piping material for a hydrogen vehicle in which a Ni equivalent (Ni eq ) is 29.07 wt% is provided by containing C of 0.010, Si of 0.40, Mn of 1.6, P 0.03, S of 0.008, Ni of 13.2, Cr of 17.5, Mo of 2.6 wt%.
- Ni and Mo which are relatively expensive, less within a composition range within a standard, it is possible to manufacture an economically cheap alloy.
- Such a high-nickel equivalent piping material is machined into a pipe shape through pilger rolling and drawing in the process in which it is manufactured into a pipe, and the pilger rolling and drawing themselves act as work hardening processes that increase the strength of the pipe. Further, strength is increased and resistance against hydrogen embrittlement is increased through heat treatment.
- a pipe that has a high nickel equivalent and has undergone work hardening and heat treatment has high strength, so it can be thinned. That is, the maximum allowable pressure for a pipe for delivering hydrogen fuel of a hydrogen vehicle is increased due to high strength, the thickness of the pipe can be correspondingly decreased. This results in reduction of weight and material costs.
- FIG. 2 shows thinning and lightweighting of a pipe that can be achieved when an alloy material according to the present disclosure is applied.
- the piping material of the present disclosure has yield strength and tensile strength over 75ksi and over 105ksi, respectively, so they are considerably increased in comparison to existing products and the elongation is over 25%.
- [Table 1] Example of lightweighting and flow rate increase by thickness calculation predetermined use pressure Dimensions (outer diamter ⁇ innner diameter ⁇ thickness) Weight lightweighting ratio Specifications (9 p perfomance factors) Allowable pressure Yield strength (ksi) Tensile strength (ksi) Elongation ASME B31.3 Process Piping, Chapter IX High Pressure Piping.
- the lightweighting ratio is 76%.
- the lightweighting ratio is 49% and the flow rate increases 2.4 times.
- the pipe thickness calculated using an operating pressure of 700bar for the piping material according to the present disclosure is 1.75mm for passenger vehicles, as in FIG. 2 , which is considerably smaller than 3mm in the related art, and the weight per 1m is 340g whereas it is 677g in the related art, so the weight is reduced almost about 50%.
- the thickness may include an allowable tolerance of ⁇ 10%.
- the thickness is 1.65mm in the related art, but, in the present disclosure, the thickness of the piping material is 1.0mm and the weight per 1m is 134g whereas it is 194g in the related art, so the weight is reduced almost about 31%. In the above case, the thickness may include an allowable tolerance of ⁇ 10%.
- the allowable pressure according to the thickness of the piping material of the present disclosure increases from 713bar to 1114bar for commercial vehicles and from 752bar to 994bar for passenger vehicles. Accordingly, the flow rate can be increased about two times in comparison to the related art.
- Such thinning and lightweighting provides price competitiveness of a pipe and make it possible to decrease the weight and size of subsidiary materials for the pipe.
- FIG. 3 is a picture exemplifying downsizing and lightweighting of a manifold as a part to which a piping material of the present disclosure can be applied.
- FIG. 4 is a table for describing price competitiveness of a piping material of the present disclosure.
- a lightweight pipe made of the pipe material according to the present disclosure has a reference unit cost of 71,420 Won per 6m under the assumption that it is sold in the unit of weight, which is about 30% cheaper than 101,534 Won. Drawing is added once in the process condition, unlike the related art, so the strength is further increased and the high-strength characteristic can be maintained in a heat treatment process. Accordingly, the manufacturing process cost increases, but the weight of the product decreases, so the price per unit length decreases.
- FIG. 5 is a table showing calculation of the ratio of a channel cross-sectional area (inner cross-sectional area)/channel-included pipe cross-sectional area (outer cross-sectional area) for a piping material of the present disclosure.
- the hydrogen fuel pipe for a hydrogen mobility is made of an alloy material that is based on 316-series stainless steel and has a Ni equivalent (Ni eq ) 28.5% or more by controlling the composition of C, Si, Mn, P, S, Ni, Cr, and Mo and is machined into a pipe using the alloy material, thereby having properties of yield strength 75 ksi or more, tensile strength 105 ksi or more, and elongation 18% or more.
- the hydrogen fuel pipe for a hydrogen mobility is made of an alloy material that is based on 316-series stainless steel and has a Ni equivalent (Ni eq ) 28.5% or more by controlling the composition of C, Si, Mn, P, S, Ni, Cr, and Mo and is machined into a pipe using the alloy material, thereby having properties of yield strength of 55 ksi to less than 75 ksi, tensile strength 100 ksi or more, and elongation 25% or more.
- the machining process includes recovery heat treatment that is a step before drawing for increasing the strength and recrystalization are generated, thereby making the piping material forms a recovery structure.
- recovery structure is a metal engineering terminology for metal structures and is generally used among those skilled in the art.
- the alloy of the present disclosure is formed to suppress production of strain-induced martensite that is generated in plastic working to improve hydrogen embrittlement resistance.
- austenite-based stainless steel having a face centered cubic (FCC) structure has resistance against hydrogen embrittlement, and particularly, the 316L steel grade has high austenite stability, so it has been known as a steel grade having high hydrogen embrittlement resistance.
- BCT body centered tetragonal
- hydrogen embrittlement complexly acts also with low-temperature embrittlement and austenite-based materials have known as materials that do not have low-temperature embrittlement, but low-temperature hydrogen embrittlement is generated by due complex action at a low temperature under a hydrogen atmosphere.
- the present disclosure increases a nickel equivalent that means stabilization contribution of an element that stabilizes austenite (FCC structure), thereby stabilizing hydrogen embrittlement at a low temperature.
- the nickel equivalent should be over 28.5%, and as described above, a 316L steel grade for a hydrogen pipe having a nickel value over 12% is applied.
- the nickel range of 316L is 10-15%.
- the alloy of the present disclosure is an alloy corresponding to stainless steel 316.
- Processes of work hardening and heat treatment for a hydrogen pipe are as follows.
- a pipe formed through refining-casting-extruding is decreased in cross-sectional area by cold working by pilger rolling and drawing and is formed in desired dimensions, whereby a piping material having precise dimensions is manufactured.
- a pilger rolling process and cold working are processes of forming a metal tube or a pipe by applying a plastic working method (see FIG. 6 ).
- a pilger rolling facility includes two circular dies having a U-shaped groove of which the shape gradually changes along a cylinder axis. The circular dies come in contact with a large pipe. The entire pipe is pressed by rolling the dies forward and backward, thereby reducing the diameter of the pipe to a desired level.
- Drawing and heat treatment are repeatedly applied using the pipe, which has undergone recrystalization heat treatment after pilger rolling, as a mother material, thereby manufacturing a pipe having desired dimensions.
- Drawing is one of plastic working that manufacture a thin pipe by reducing the cross-sectional area by pulling and passing a tube material (pipes) through a die (see FIG. 7 ).
- austenite-based steel grades work hardening is generated due to movement and tangle of dislocations in a metal material by cord working, and when nickel and a nickel equivalent is not sufficiently high like the alloy stated in the present disclosure, an austenite structure is not stabilized, so a strain-induced martensite structure is generated in plastic working.
- strain-induced martensite Since strain-induced martensite also has the same magnetism as ferrite, so it can be measured through a ferrite meter.
- ferrite around 10% is measured in maximum machining.
- Ferrite around 3% is measured in a 316 steel grade having nickel of 10%.
- Magnetism is not measured in the alloy in the present disclosure even though plastic working has been applied (very small amount cannot be measured).
- the strengthening characteristic of work hardening is maintained through heat treatment within a temperature range that maintains dislocation tangle of plastic working, removes strain-induced martensite that may be generated in a very small amount, and secure elongation by removing stress for post-processing.
- solid solution heat treatment is performed so that next plastic working can be performed in a completely annealed state, and recovery treatment is performed after plastic working for the product (invention) with desired dimensions.
- a heat treatment process of metal is composed of recovery, recrystalization, and grain growth.
- a temperature range with poor recrystalization in 316 is 850-900°C. At temperatures over the range, recrystalization is generated and grain growth is generated.
- the present disclosure is characterized by performing recovery heat treatment preferably between 850-900°C about 5 minutes for a 316L steel grade.
- a recovery heat treatment structure is as follows.
- a recovery heat-treated structure (see FIG. 9 ) is not recrystalized (see FIG. 10 , so a plastic-worked grain shape (see FIG. 8 ) is intactly shown and a structure (see FIGS. 8 and 9 ) in which line shapes due to unidirectional slip of dislocations are shown in the grains is maintained.
- a high-strength piping material is characterized in that a shape maintaining dislocation slip without recrystalization serves to maintain high strength.
- It is characterized by manufacturing a 316L pipe for high-strength hydrogen of YS 55KSI, TS 100KSI, and E25% ⁇ to YS 75KSI, TS 105KSI, and E25% ⁇ by performing recovery heat treatment within a range in which recrystalization is not generated at a temperature at which plasticity-induced martensite is little produced even in the plastic working and induced martensite that may be generated is sufficiently removed.
- a 316L steel grade that has undergone complete solid solution heat treatment has strength of YS 25KSI, TS 70KSI, and E35% or more.
- a product of the present disclosure is characterized by having twice to triple yield strength in comparison to that described above and having sufficient elongation for post-processing (forming, bending, etc.).
- a pressure resistance characteristic of a piping material is based on a calculation equation based on a limit at which deformation does not occur, so allowable pressure increases in proportion to yield strength at which deformation starts to occur.
- a thicker material should be used as use pressure increases in a high-pressure pipe, but when the high-strength pipe for hydrogen by plastic working and recovery heat treatment proposed in the present disclosure is used, weight can be reduced by about 1/2 ⁇ 1/3. If a material has yield strength and tensile strength of YS 75KSI and TS 105KSI in the state in which recovery heat treatment has not been performed, the elongation is around 15%, which is not suitable for post-processing (bending and forming). It may be described that since recovery heat treatment is performed, slip shapes of dislocations remain, but stress is removed, so the limit for more deformation may increase. This is set as a design value of a company that requires a pipe for hydrogen.
- Recrystalization heat treatment is performed on the obtained pipe, and annealing and solid solution heat treatment is performed at 1000 to 1200°C for 3 to 7 minutes, preferably, at 1080°C for 5 minutes.
- recrystalization heat treatment is performed. That is, annealing and solid solution heat treatment is performed at 1000 to 1200°C for 3 to 7 minutes, preferably, at 1080°C for 5 minutes.
- recrystalization heat treatment is performed. That is, annealing and solid solution heat treatment is performed at 1000 to 1200°C for 3 to 7 minutes, preferably, at 1080°C for 5 minutes.
- recovery heat treatment is performed. It is performed at 850 to 950°C for 3 to 7 minutes, preferably, at 900°C for 5 minutes, thereby recovering and removing magnetism (induced martensite).
- It is characterized by manufacturing a 316L pipe for high-strength hydrogen of YS 55KSI, TS 100KSI, and E25% ⁇ to YS 75KSI, TS 105KSI, and E25% ⁇ by performing recovery heat treatment within a range in which recrystalization is not generated at a temperature at which induced martensite is little produced even in the plastic working and induced martensite that may be generated is sufficiently removed.
- a 316L steel grade that has undergone complete solid solution heat treatment has strength of YS 25KSI, TS 70KSI, and E35%T.
- the invention is characterized by having twice to triple yield strength in comparison to that described above and having sufficient elongation for post-processing (forming, bending, etc.).
- a pressure resistance characteristic of a piping material is based on a calculation equation based on a limit at which deformation does not occur, so allowable pressure increases in proportion to yield strength at which deformation starts to occur.
- a thicker material should be used as use pressure increases in a high-pressure pipe, but when the high-strength pipe for hydrogen by plastic working and recovery heat treatment proposed in the present disclosure is used, 1/2 ⁇ 1/3 of pipe weight due to an existing pipe thickness can be reduced.
- An entire processing method for manufacturing a pipe is as follows.
- the product of the present disclosure is characterized by being able to be immediately applied by manufacturing it by adjusting chemical components within the range of the 316L steel grade which has been verified in dimensions.
- Silicon is a ferrite-based stabilizing element, produces an oxide after being put in as a deoxidizer in a refining process, becomes a slag rising up to the surface by high-temperature floatation and is then removed. Accordingly, when a large amount of silicon remains, it is handled as an impurity. When a large amount of silicon is contained, a large amount of nonmetallic inclusion is contained in a metal structure, thereby causing generation of cracks and deterioration of mechanical characteristics. Accordingly, it is the most preferable to minimize the content of silicon. However, about 0.4% is taken as an aim in common VOD refining process.
- Manganese is austenite-based stabilizing metal at a similar level to nickel and serves to produce MnS, prevent high-temperature cracks, and increase toughness by stably combining with S (sulfur), so it is preferable to put in manganese as much as possible.
- S sulfur
- about 1.6% is taken as an aim for a stable value not exceeding a maximum limit within a range satisfying a 316L standard.
- Phosphorous and sulfur are handled as representative impurities and have a possibility of generating inter-granular cracks b producing an intermetallic compound with iron, so it is preferable to minimize them in a pipe for a hydrogen atmosphere, however, preferably, phosphorous of about 0.03% and sulfur of about 0.008% are taken as aims in a common VOD refining process.
- Nickel is a representative austenite stabilizing element, and when nickel is contained over 10% in the 316L steel grade, it forms an austenite phase of a stable FCC structure in hydrogen and serves to improve machinability and impact toughness, particularly, a low-temperature characteristic. It has been known that strain-induced martensite is little produced in an 316L steel grade containing nickel over 12%, so nickel greatly increases hydrogen embrittlement resistance, so it is preferable to put in nickel as much as possible, but it is expensive as rare metal, so, in accordance with the research results described above, preferably, about 13.2% is taken as an aim.
- Chromium is a ferrite stabilizing element, is an important element that gives a stainless characteristic by producing a chromium oxide when it is contained over 12%, and serves to improve hardness and corrosion resistance.
- an austenite stabilizing element increases, a more stable alloy is formed without unbalance only when a ferrite stabilizing element is also slightly increased. Since chromium is put in as much as possible by a stabilized austenite elements, preferably, about 17.5% is taken as an aim.
- Molybdenum is a ferrite stabilizing element and produces an oxide on a chromium oxide passive coating layer when it is added, thereby greatly improve resistance particularly against pitting corrosion due to chlorine. Similar to chromium, a stabilized alloy is formed only when a ferrite stabilizing alloy is sufficiently put in an alloy containing a large amount of austenite stabilizing element, so preferably, about 2.6% is taken as an aim.
- the present disclosure manufactures a piping material for hydrogen that has precise dimensions and a lustrous surface by performing a pilger rolling process one time and repeatedly performing bright annealing and cold drawing processes on a seamless tube manufactured in accordance with the alloy manufacturing method described above.
- a pilger rolling process acts in accordance with a malleability characteristic of metal, so the process is possible by setting a cross-section reduction ratio maximally at 80% with respect to stainless.
- Pilger has the advantage that it is possible to make a thickness value different to satisfy a process schedule determined in accordance with the dimensions of a final product.
- a material machined by pilger rolling and cold drawing undergoes plastic working by deformation, so heat treatment for recrystalization and solution is performed at a high temperature over 1040°C.
- heat treatment is performed at a setting temperature of 1080°C for about 5 minutes in a continuous heat treatment furnace under a hydrogen atmosphere (99.999%).
- a washing process using and an organic solvent that removes a plastic working lubricant and contamination is performed first before bright annealing, and then a straightening correction process for the next process is performed on an intermediate product that is thermally deformed after bright annealing.
- Cold drawing is a process that acts in accordance with the characteristic of toughness (longitudinal direction) unlike the malleability characteristic of a pilger rolling process, and generally, the toughness characteristic gives low machinability to a metal structure in comparison to the malleability characteristic, so cross-section reduction of maximally about 40% is possible.
- a cold drawing process uses a mold having precise dimensions, it has the advantage that it is possible to more easily follow desired dimension tolerance and the production speed is high over 5 times the pilger rolling process.
- Bright annealing heat treatment, straightening correction, and bending (swaging) are performed before cold drawing, and bending cutting and washing using an organic solvent are performed after cold drawing.
- Recovery heat treatment may be referred to as stress-relieved annealed, and according to heat treatment acting principle of metal, it is composed of three steps of recovery (removing internal stress of a structure strain-hardened through plastic working), recrystalization (generation of new crystal nucleus without internal stress), and growth (granular growth by combination of the new generated crystal nucleus and surrounding metal), and it takes aim at performing even recovery of removing internal stress that makes more movement difficult while maintaining the shape of strain hardening by plastic working.
- the recovery heat treatment of the present disclosure is performed in a temperature range of 850 ⁇ 900°C for about 5 minutes in a continuous heat treatment furnace.
- the invention was made by the following national research and development projects.
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Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110026650A1 (en) | 2009-07-31 | 2011-02-03 | Albert Molina | Rapid Sampling Phase Recovery |
WO2015098981A1 (ja) | 2013-12-27 | 2015-07-02 | 国立大学法人九州大学 | 水素機器用の基材及びその製造方法 |
KR20180111416A (ko) | 2017-03-31 | 2018-10-11 | 엘지전자 주식회사 | 연성 스테인리스 강관 |
KR20220010184A (ko) | 2020-07-17 | 2022-01-25 | 주식회사 포스코 | 내수소취성이 개선된 고질소 오스테나이트계 스테인리스강 |
Family Cites Families (2)
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JP5176561B2 (ja) * | 2007-07-02 | 2013-04-03 | 新日鐵住金株式会社 | 高合金管の製造方法 |
CN113088832A (zh) * | 2021-03-26 | 2021-07-09 | 中国石油天然气集团有限公司 | 一种铁镍基耐蚀合金连续管及其制造方法 |
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20110026650A1 (en) | 2009-07-31 | 2011-02-03 | Albert Molina | Rapid Sampling Phase Recovery |
WO2015098981A1 (ja) | 2013-12-27 | 2015-07-02 | 国立大学法人九州大学 | 水素機器用の基材及びその製造方法 |
KR20180111416A (ko) | 2017-03-31 | 2018-10-11 | 엘지전자 주식회사 | 연성 스테인리스 강관 |
KR20220010184A (ko) | 2020-07-17 | 2022-01-25 | 주식회사 포스코 | 내수소취성이 개선된 고질소 오스테나이트계 스테인리스강 |
Non-Patent Citations (3)
Title |
---|
S. MATSUOKAJ. YAMABEH. MATSUNAGA: "Criteria for determining hydrogen compatibility and the mechanisms for hydrogen-assisted, surface crack growth in austenitic stainless steels", ENG. FRACT. MECH., vol. 153, 2016, pages 103 - 127, XP029417081, DOI: 10.1016/j.engfracmech.2015.12.023 |
T. YAMADAH. KOBAYASHI: "Criteria for Selecting Materials to be Used for Hydrogen Station Equipment", J. HIGH PRESS. GAS SAF. INST. JAPAN, vol. 49, 2013, pages 885 - 893 |
THORSTEN MICHLERJOERG NAUMANNMARTIN HOCKKARL BERRETHMICHAEL P. BALOGHERICH SATTLER: "Microstructural properties controlling hydrogen environment embrittlement of cold worked 316 type austenitic stainless steels", MATERIALS SCIENCE & ENGINEERING A, vol. 628, 2015, pages 252 - 261 |
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