Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F10/00—Additive manufacturing of workpieces or articles from metallic powder
  • B22F10/20—Direct sintering or melting
  • B22F10/22—Direct deposition of molten metal
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B32—LAYERED PRODUCTS
  • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
  • B32B15/00—Layered products comprising a layer of metal
  • B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
  • B32B15/011—Layered products comprising a layer of metal all layers being exclusively metallic all layers being formed of iron alloys or steels
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y80/00—Products made by additive manufacturing
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C33/00—Making ferrous alloys
  • C22C33/02—Making ferrous alloys by powder metallurgy
• • 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
  • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
• • 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
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F22—STEAM GENERATION
  • F22B—METHODS OF STEAM GENERATION; STEAM BOILERS
  • F22B37/00—Component parts or details of steam boilers
  • F22B37/002—Component parts or details of steam boilers specially adapted for nuclear steam generators, e.g. maintenance, repairing or inspecting equipment not otherwise provided for
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21C—NUCLEAR REACTORS
  • G21C5/00—Moderator or core structure; Selection of materials for use as moderator
  • G21C5/02—Details
  • G21C5/10—Means for supporting the complete structure
• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21D—NUCLEAR POWER PLANT
  • G21D1/00—Details of nuclear power plant
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B33—ADDITIVE MANUFACTURING TECHNOLOGY
  • B33Y—ADDITIVE MANUFACTURING, i.e. MANUFACTURING OF THREE-DIMENSIONAL [3D] OBJECTS BY ADDITIVE DEPOSITION, ADDITIVE AGGLOMERATION OR ADDITIVE LAYERING, e.g. BY 3D PRINTING, STEREOLITHOGRAPHY OR SELECTIVE LASER SINTERING
  • B33Y10/00—Processes of additive manufacturing
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
  • Y02E30/00—Energy generation of nuclear origin
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P10/00—Technologies related to metal processing
  • Y02P10/25—Process efficiency

Definitions

• TITLE Solid metal part and its manufacturing process
• the present invention lies in the general field of the manufacture of massive metal parts.
• This invention finds a non-exclusive application for the manufacture of metal parts of large dimensions and of great thickness such as, for example, those found in the lower part of the steam generators of nuclear power stations, called "tube sheets".
• the tube sheet of steam generators in pressurized water power plants is a thick (50 to 60 cm) large diameter forging, pierced with thousands of holes for the passage of exchange tubes. Highly mechanically stressed due to the pressure difference on either side, its rigidity is obtained by its thickness and by the mechanical properties of the material of which it is made, namely a low alloy steel of the carbon manganese category.
• the yield strength, tensile strength and ductile bearing are lowered while the resilience transition temperature is increased by more than 50 ° C.
• C * Carbon equivalent (C *) of the steel, calculated according to EN 10028-2, is approximately 0.52% (typical value) to 0.62% (for steel "18 AAND 5 ", which is optimized for heat treatment), which represents a target value that should not be exceeded too much, otherwise the preheating temperatures of the various welds could be called into question, but above all the risk of cold cracking.
• the state of the art of such fabrications indicates that for the first defect mentioned above (poor homogeneity), the casting of the ingot, the dropping of the segregation zones and the forging of the plate are difficult to achieve and that the risk of scrap exists.
• the object of the present invention is to overcome these drawbacks.
• the invention relates firstly to a massive metal part characterized in that it comprises a core and an outer casing which surrounds said core in all directions, these core and casing being made of steels of different grades, 'steel of said core exhibiting critical martensitic and bainitic quenching rates lower than those of the steel or steels of said envelope.
• the part obtained has particularly homogeneous mechanical characteristics. This is particularly the case with hardness. On the other hand, the resilience and toughness are high.
• said heart is itself surrounded by at least one inner casing, this inner casing being surrounded by said outer shell, the steel having said heart reviews tempering martensitic speeds and bainitic less than those of the steel of said inner shell, these speeds of said inner shell being themselves lower than those of said outer shell.
• the invention also relates to a method of manufacturing such a part.
• This method is remarkable in that it comprises a step consisting in depositing said steels by additive manufacturing or welding, on a base previously manufactured, so as to form at the same time said core and the remainder of said envelope, respectively of said envelopes.
• the steel grade of the rest of said outer shell is different from that of said base, these two grades exhibiting critical martensitic and bainitic quenching rates that are identical or almost identical;
• - Said base is produced by forging or rolling
• - Said base is produced by additive manufacturing or welding.
• FIG. 1 is a schematic view, along a vertical section plane, of a part according to the present invention
• FIG. 2 is a schematic view illustrating a step in the manufacture of the part of FIG. 1;
• FIG. 3 is a schematic view illustrating the manufacturing process of the part, at a more advanced stage than that which appears in FIG. 2;
• FIG. 4 is a diagram showing the variation in the hardness of a part according to the invention, at the center thereof, after quenching and tempering, using the materials indicated in Table I to which reference will be made here- after.
• the present invention is based on a combination of carefully organized materials and a manufacturing process which, after quality treatment, confer high mechanical properties and are homogeneous throughout. thickness of the part thus generated.
• the term "part” is understood to mean both a plate, that is to say an object whose thickness is smaller than its length and width, than any other.
• three-dimensional object for example parallelepiped or cylindrical, the thickness of which would be greater than its other dimensions.
• this thickness is preferably related to the plate 1, after manufacture of the latter.
• the thickness 2 is in contact with the primary water and thus constitutes a corrosion barrier for the rest of the plate 1.
• This plate 1 comprises a heart 5 and an outer casing 3 which surrounds said heart 5 in all directions.
• This heart 5 and this envelope 3 are made of steel of different grades.
• the heart 5 is itself surrounded by an internal envelope 4, this internal envelope 4 being surrounded by said external envelope 3.
• the steel grades of the core 5 and of each casing 3 and 4 are different, and the steel of said core 5 has critical martensitic and bainitic quenching speeds lower than those of the steel of the envelope 4 which surrounds it, and so on for each envelope which surrounds the previous envelope.
• This plate 1 can be manufactured according to the methodology detailed below.
• this sheet 30 can be manufactured according to the same methodology as that which will be described below.
• the rest of the plate 1 is said to be “deposited”, and is obtained by additive manufacturing or welding. This means that the entire thickness of plate 1 is gradually increased.
• This operation is preferably carried out by means of one of the following methods or a combination of these:
• GMAW Metal arc welding
• SAW Submerged Arc Welding
• arc welding under solid flux C'ASF arc welding under solid flux
• the variants considered preferentially are the following metal inputs which have in common high deposition rates (kg / h):
• the filler materials are preferably chosen with an equivalent carbon less than 0.65%, typically 0.62%, and exhibiting very low diffusible hydrogen levels, in order to guard against cold cracking, with preheating temperatures as low as possible.
• the fluxes used in the SAW and ESW processes will preferably be basic fluxes which allow better properties of the molten zones.
• the hardenability gradient thus generated is intended to counterbalance the decrease in the cooling rate during the quenching between the shell and the core.
• the grades will preferably be chosen as follows:
• the grade of the base 30 is ideally "18 MND 5", conforming to the current specification, but in a version optimized for heat treatment. Its typical analysis in mass percentage is C 0.2, Mn 1.3, Mo 0.5, Ni 0.65.
• the perlite ferrite contents remain below 10% in all the deposited metal, which indirectly indicates for these C - Mn - Ni steels that the resilience and toughness will be high.
• a microstructure exhibiting good mechanical properties preferably contains more than 90% bainite + martensite and therefore less than 10% ferrite + perlite.
• VIOFP ferrite + perlite
• V10FP 1900
• V10FP 640.
• the geometry of the plate 1 being circular, the deposits are easily but not necessarily carried out with welding heads movable only radially and welding circumferentially.
• welding heads can usefully be used simultaneously or sequentially, for example to make the exterior and interior passes, or quite simply to reduce manufacturing time.
• Temperature control devices are advantageously used in order to guarantee the preheating (greater than 150 ° C.), inter-pass and post-welding (greater than 250 ° C. for 24 h) temperatures.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Physics & Mathematics (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Manufacturing & Machinery (AREA)
• General Engineering & Computer Science (AREA)
• High Energy & Nuclear Physics (AREA)
• Plasma & Fusion (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Composite Materials (AREA)
• Thermal Sciences (AREA)
• Heat Treatment Of Articles (AREA)
• Powder Metallurgy (AREA)
• Butt Welding And Welding Of Specific Article (AREA)
• Forging (AREA)
• Laminated Bodies (AREA)
• Heat Treatment Of Steel (AREA)

Applications Claiming Priority (2)

Publications (1)

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• 2019
  • 2019-11-22 FR FR1913081A patent/FR3103498B1/fr active Active
• 2020
  • 2020-11-19 KR KR1020227018926A patent/KR20220104183A/ko active Pending
  • 2020-11-19 US US17/778,578 patent/US12103085B2/en active Active
  • 2020-11-19 CN CN202080080939.7A patent/CN114728337B/zh active Active
  • 2020-11-19 WO PCT/FR2020/000263 patent/WO2021099697A1/fr not_active Ceased
  • 2020-11-19 CA CA3162447A patent/CA3162447A1/fr active Pending
  • 2020-11-19 EP EP20824600.9A patent/EP4061565A1/de active Pending
  • 2020-11-19 JP JP2022529469A patent/JP7670414B2/ja active Active

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