Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P6/00—Restoring or reconditioning objects
  • B23P6/02—Pistons or cylinders
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K5/00—Gas flame welding
  • B23K5/18—Gas flame welding for purposes other than joining parts, e.g. built-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K9/00—Arc welding or cutting
  • B23K9/04—Welding for other purposes than joining, e.g. built-up welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
  • B23P6/00—Restoring or reconditioning objects
  • B23P6/04—Repairing fractures or cracked metal parts or products, e.g. castings
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
  • Y10T29/49721—Repairing with disassembling
  • Y10T29/49723—Repairing with disassembling including reconditioning of part
  • Y10T29/49725—Repairing with disassembling including reconditioning of part by shaping
  • Y10T29/49726—Removing material
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
  • Y10T29/49721—Repairing with disassembling
  • Y10T29/49723—Repairing with disassembling including reconditioning of part
  • Y10T29/49725—Repairing with disassembling including reconditioning of part by shaping
  • Y10T29/49726—Removing material
  • Y10T29/49728—Removing material and by a metallurgical operation, e.g., welding, diffusion bonding, casting
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
  • Y10T29/49732—Repairing by attaching repair preform, e.g., remaking, restoring, or patching
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
  • Y10T29/49732—Repairing by attaching repair preform, e.g., remaking, restoring, or patching
  • Y10T29/49734—Repairing by attaching repair preform, e.g., remaking, restoring, or patching and removing damaged material
  • Y10T29/49737—Metallurgically attaching preform
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
  • Y10T29/49732—Repairing by attaching repair preform, e.g., remaking, restoring, or patching
  • Y10T29/49742—Metallurgically attaching preform
• • 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
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49718—Repairing
  • Y10T29/49746—Repairing by applying fluent material, e.g., coating, casting

Definitions

• This invention relates generally to repairing castings, and more specifically to a process for repairing damaged material by pouring melted filler material to the solidified original casting.
• Cast components often require repair during their life. Because of the physical characteristics of cast materials, it is difficult and time consuming to repair cast components. Typically repairs to castings involve removing damaged portions of the casting through machining, and subsequently rebuilding the damaged area by welding.
• a component that is susceptible to damage is the cylinder head of an internal combustion engine. Because of repeated heating and cooling of the engine, the cylinder heads often develop cracks near openings, such as valve seats, fuel injector bores, and exhaust ports. Another problem associated with cylinder heads is warping. When warped, the bottom surface of the head becomes uneven and does not seal properly. Some warped cylinder heads can be milled until the fireside surface is again flat. However, milling the surface reduces the thickness of the head, making the head more susceptible to future operating damage. Heads that can't be milled flat are typically scrapped. Current processes are unable to repair warped heads by building up the surface thickness. One example of repairing a casting is discussed in U.S. Patent
• the present disclosure is directed to overcoming one more of the problems set forth above.
• the present invention provides a method of repairing a cast component.
• a cast component is prepared and preheated to a first predetermined temperature and a quantity of melted filler material is poured onto the cast component.
• Figure 1 is an illustration of a cast component adapted to repair using the present disclosure.
• Figure 2 is a flowchart describing the method of the claimed invention.
• Figure 3 is a sectional elevational view of the cast component of
• Figure 3 a is an enlarged sectional view of a portion of the cast component of Figure 3 taken along line 3 a.
• Figure 4 is an enlarged sectional of the cast component of Figure 1 taken along line 4 - 4.
• a flowchart showing an embodiment of the method of repairing a cast component is generally illustrated.
• the component is cleaned and inspected for damaged portions. Grinding or machining then removes damaged portions of the component.
• the component is preheated to a predetermined temperature.
• the preheat temperature will vary depending on the type and thickness of material being repaired. It is desirable to preheat the component as much as possible without damaging the component. Depending on the component, types of damage include, stress relieving and warping caused by overheating. On the other hand, failure to preheat the component to high enough of a temperature may cause cracking of the parent material when the melted filler material is poured.
• the preheat temperature for a cast iron cylinder head may be in the range of 950°F to 2000°F. For a certain cylinder head, a preheat temperature of 1100°F has been found to reduce stress and warping while reducing the risk of cracking.
• a quantity of filler material is melted and poured into the damaged portion of the cast component.
• the cylinder head includes a bottom, or fireside surface 12, a plurality of side surfaces 14 and a top surface (not shown).
• the bottom surface 12 of cylinder head is adapted to be fastened to a cylinder block (not shown) of an internal combustion engine, in a typical manner.
• the bottom surface 12 of the cylinder head 10 includes a fuel injector opening 16 and two or more valve openings 18.
• the valve openings 18 include a pair of exhaust valve openings 22 and a pair of intake valve openings 24.
• the valve openings 18 may be evenly spaced about the fuel injector opening 16.
• Each valve opening 18 includes a valve seat 26 and a valve guide 28.
• a passage (not shown) is defined in the cylinder head 10 extending from each valve opening 18 to a respective one of an exhaust port 32 and an intake port 34.
• the intake and exhaust ports 32, 34 are typically defined in one of the side surfaces 14 of the cylinder head 10.
• the cylinder head 10 also includes a plurality of bores 36 adapted to receive bolts (not shown) for attaching the cylinder head 10 to the engine block.
• the cylinder head includes a plurality of fluid passages (not shown).
• the fluid passages include a coolant jacket and lubrication passages. The coolant jacket and lubrication passages function in a conventional fashion and will not be discussed in further detail.
• the cylinder head 10 Configured for operation with an internal combustion engine (not shown), the cylinder head 10 is assembled having a pair of exhaust valves (not shown) and a pair of intake valves (not shown) movably positioned in the valve openings 10.
• a rocker arm assembly (not shown) is additionally assembled on the cylinder head 10. To facilitate inspection and repair of the cylinder head 10, the intake valves, exhaust valves, rocker arm assembly and all other removable components are disassembled from the cylinder head 10.
• the casting for example a cylinder head 10
• the casting is inspected for damage. Cracked, or otherwise damaged portions of the cylinder head 10 are machined away to define cavities 38 in the bottom surface 12.
• plugs 40 (shown in Figure 3 a) may be inserted into the respective valve opening 18.
• the plugs 40 prevent the molten filler material from entering original features of the cylinder head 10.
• the plugs may be manufactured from a heat resistant material, such as machinable graphite. In one embodiment the plugs are capable of withstanding extreme temperatures without deforming and are thermally conductive.
• the plugs 40 may be of a variety of shapes and sizes to fill specific features. For example, a plug 40 to fill and protect a valve opening 18 is machined to a size and shape substantially equal to that of its respective valve.
• a cavity 38 is defined between the fuel injector opening 16 and a valve opening 18.
• a plug 40 may be provided sized to fit the fuel injector opening 16. The plug 40 is pushed into the opening 16, preventing filler material from running through or otherwise filling the fuel injector opening 16.
• a dam 42 may be positioned around the fuel injector opening 16 on the bottom surface 12. The dam 42 may be positioned on the bottom surface 12 in a manner where pouring the molten material into the cavity 38 provides a riser 46 of filler material.
• the dam 42 may be made of machinable graphite similar to the plug 40.
• the riser 46 provides a surplus of filler material to allow for shrinkage during cooling.
• the graphite dam 42 may be manufactured by cutting a piece of machinable graphite stock to a desired thickness and boring or machining an opening 48 in the stock, thus defining an outer boundary 52.
• the cylinder head 10 is preheated in an oven to a first temperature.
• the first temperature range is in the range of 950°F to 2000°F, more preferably 1050°F to 1150°F.
• the heated box 54 may include a plurality of wheels adapted to permit moving the box 54 about a shop.
• the box 54 further defines opening 56, a bottom 58 and a plurality of side surfaces 60.
• the opening 56 includes a plurality of removable covers (not shown) adapted to close and maintain the temperature inside the box 54.
• the temperature inside the heated box 54 may be maintained at a temperature of in the first temperature range until filler material is added.
• a quantity of filler material such as cast iron, is prepared by melting.
• the filler material is melted in a crucible and held in a furnace at a temperature sufficient to bond with the parent material. In the case of a cylinder head, the temperature may be approximately 2725°F.
• the filler material may be of a chemical composition similar to that of the cylinder head 10 or component to be repaired. In one embodiment, a torch having a rosebud tip is used to locally heat the area to be repaired to a second predetermined temperature.
• the second predetermined temperature may also vary depending upon the type, mass and wall thickness of the parent material and the volume of filler material.
• the second predetermined range is hot enough to permit bonding of the parent and filler materials, but cool enough to prevent the filler material from melting through the parent material.
• the lower limit of the range may be determined through simulation and/or experimentation and may account for factors such as material shrinkage, bonding strength, microstructure, and stress associated the parent and/or filler material. Factors that impact bonding point may include type and volume of the parent material, the type and volume of the filler material, the chemistry of the parent component.
• the second preheat temperature prevents rapid cooling of the filler material, in turn maintaining desired mechanical properties.
• a quantity of welding flux (not shown) is applied to the surface to be repaired.
• the flux acts to remove oxidation and other contaminants from the filler material and cast component after the filler material is poured.
• a typical flux is manufactured from a borax-based material. With the temperature of the cavity 38 within the temperature range, melted filler material is removed from the furnace. Slag that may be floating on the surface of the molten filler material may be skimmed from the melted filler material. With the filler material substantially free of slag, it is poured into, and fills the cavity 38. In one embodiment, filler material may be permitted to overflow from the damaged area and rise above the bottom 12 surface.
• the temperature of the filler material in the cavity may be maintained at the second temperature for a time period by moving the torch about the filler material. For example the time period may be in the range of thirty seconds to two minutes. Moving the torch about the filler material allows trapped gas vapor and contaminants to be released and improves bonding of the filler material to the original cast component.
• the cast component may then be allowed to cool.
• the cast component, or a portion thereof may be partially cooled using compressed air.
• a wand (not shown) having a diffuser attached thereto and being attached to a compressed air source is moved about, over the filler material.
• a cooling rate sufficient enough, depending on chemistry, to cool the entire volume of repaired area to achieve desired microstructure, or transformation products, of the matrix structure. For example using cast iron and dependent on the volume of material affected, it may be desired to bring the temperature of the repaired area down to a range of
• the cylinder head 10 is slowly cooled, preferably, at a rate slow enough to avoid distortion or cracking of the component. The cylinder head 10 may then be machined to original specifications and reassembled for use.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Cylinder Crankcases Of Internal Combustion Engines (AREA)
• Molds, Cores, And Manufacturing Methods Thereof (AREA)
• Heat Treatment Of Articles (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

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Citations (5)

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• 2003
  • 2003-05-02 US US10/428,871 patent/US7047612B2/en not_active Expired - Fee Related
• 2004
  • 2004-03-16 JP JP2006507243A patent/JP2006525128A/ja active Pending
  • 2004-03-16 CN CN200480011744.8A patent/CN100509263C/zh not_active Expired - Lifetime
  • 2004-03-16 GB GB0519689A patent/GB2414695B/en not_active Expired - Fee Related
  • 2004-03-16 WO PCT/US2004/008040 patent/WO2004098827A1/en not_active Ceased

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