US20210237138A1 - Conduction pre-heating of sheet for hot forming - Google Patents
Conduction pre-heating of sheet for hot forming Download PDFInfo
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- US20210237138A1 US20210237138A1 US17/054,320 US201917054320A US2021237138A1 US 20210237138 A1 US20210237138 A1 US 20210237138A1 US 201917054320 A US201917054320 A US 201917054320A US 2021237138 A1 US2021237138 A1 US 2021237138A1
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- blank
- heat
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- temperature
- heated
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- 238000000034 method Methods 0.000 claims description 27
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- 229910000734 martensite Inorganic materials 0.000 description 2
- 238000012544 monitoring process Methods 0.000 description 2
- 238000010791 quenching Methods 0.000 description 2
- 229910018125 Al-Si Inorganic materials 0.000 description 1
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Images
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D22/00—Shaping without cutting, by stamping, spinning, or deep-drawing
- B21D22/20—Deep-drawing
- B21D22/208—Deep-drawing by heating the blank or deep-drawing associated with heat treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J1/00—Preparing metal stock or similar ancillary operations prior, during or post forging, e.g. heating or cooling
- B21J1/06—Heating or cooling methods or arrangements specially adapted for performing forging or pressing operations
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D37/00—Tools as parts of machines covered by this subclass
- B21D37/16—Heating or cooling
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D—WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS OR PROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21D53/00—Making other particular articles
- B21D53/88—Making other particular articles other parts for vehicles, e.g. cowlings, mudguards
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J17/00—Forge furnaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21J—FORGING; HAMMERING; PRESSING METAL; RIVETING; FORGE FURNACES
- B21J17/00—Forge furnaces
- B21J17/02—Forge furnaces electrically heated
-
- 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
- C21D1/34—Methods of heating
-
- 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
- C21D1/62—Quenching devices
- C21D1/673—Quenching devices for die quenching
-
- 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
- C21D9/0068—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for particular articles not mentioned below
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/001—Austenite
-
- 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
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/008—Martensite
-
- 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
- C21D2221/00—Treating localised areas of an article
Definitions
- the present patent application relates to a system for producing components by hot forming.
- Hot forming generally comprises heating a blank in a furnace, followed by stamping the heated blank between a pair of dies to form a shaped part, and quenching the shaped part between the dies.
- the blank is generally heated in the furnace to achieve an austenitic microstructure, and then quenched in the dies to transform the austenitic microstructure to a martensitic microstructure.
- steel continues to be the material of choice when it comes to modern and cost-effective vehicle bodies.
- new steels that combine high strength with good formability have been developed in response to the demands of the automotive industry for light weight construction materials.
- the multiphase steels are used extensively in hot stamping or forming in which a steel blank is heated into the zone of full austenitization (typically 920° C.). The heated steel blank is subsequently inserted into the forming tool or press while still hot, and is rapidly cooled during the pressing operation.
- the press hardening method include the low forming resistance and the better formability of steel at this temperature, as well as the high strength and good dimensional stability of the obtained component.
- the use of hot stamping methods and new steel materials results in high-strength but low-weight vehicle bodies.
- the press-hardening machinery is becoming faster. Machines that achieve five strokes per minute have been in use for some time already, and newer machines that achieve seven strokes per minute are known. As a result of the reduced cycle length, the efficiency of the hot stamping method is increased.
- the heating of the supplied blanks via heating furnaces has hitherto been the limiting factor. Since the blanks have to be heated to a processing temperature of over 900° C., heating furnaces which are configured as continuous furnaces are used. Over a 30 m length of such a continuous furnace, the blank is heated by 30° C. per meter. Accordingly, the pass-through speed of the blanks and the length of the heating furnaces limits the cycle length of the hot stamping system.
- the present patent application provides improvements to hot forming/stamping systems and operations.
- the system includes a pre-heat station, a furnace, and a press.
- the pre-heat station is configured to receive a blank; and to pre-heat at least a portion of the blank to a pre-heat temperature by thermal conduction.
- the furnace is constructed and arranged to receive the pre-heated blank from the pre-heat station and to heat the entire blank to a deformation temperature. The deformation temperature is higher than the pre-heat temperature.
- the press is constructed and arranged to receive the heated blank from the furnace and to form the heated blank into the shape of the component.
- FIG. 1 shows a system for producing components by hot stamping procedure or hot forming procedure in accordance with an embodiment of the present patent application
- FIG. 2 shows an exploded view of a pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application, wherein FIG. 2 also shows a blank member being received and heated by the pre-heat station;
- FIG. 2A shows the blank member being received and heated by the pre-heat station in accordance with an embodiment of the present patent application
- FIG. 3 shows a side view of the pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application;
- FIG. 4 shows a top perspective view of the pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application;
- FIG. 5 shows another top perspective view of the pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application;
- FIG. 6 shows a table that provides a comparison of various residence times for the system of the present patent application and for the prior art system
- FIG. 7 shows a graphical representation of various temperature profiles of the blank member heated in the prior art system
- FIG. 8 shows a graphical representation of various temperature profiles of the blank member heated in the system of the present patent application.
- FIGS. 9 and 10 show exemplary pre-heat station in accordance with an embodiment of the present patent application.
- a system 100 for producing components by hot forming or hot stamping includes a pre-heat station 102 , a furnace 104 , and a press 106 .
- the pre-heat station 102 is configured to receive a blank 108 .
- the blank 108 includes a patched region 112 and a non-patched region 116 .
- the pre-heat station 102 is configured to pre-heat at least a portion (e.g., the patched region 112 ) of the blank 108 to a pre-heat temperature PH T by thermal conduction.
- the furnace 104 is constructed and arranged to receive the pre-heated blank 108 from the pre-heat station 102 and to heat the entire blank 108 to a deformation temperature D T .
- the deformation temperature D T is higher than the pre-heat temperature PH T .
- the press 106 is constructed and arranged to receive the heated blank 108 from the furnace 104 and to form the heated blank 108 into the shape of the component.
- thermal conduction pre-heat is a method of transferring energy/heat into the blanks 108 using conduction as the mode of heat transfer.
- thermal conduction pre-heat includes contact heating of the blank.
- conduction is the most efficient form of heat transfer and provides the least heating time.
- the blank 108 used to manufacture the shaped parts or components are typically formed of metal, but can be formed of other materials.
- the blank 108 is formed of steel material, such pure steel or a steel alloy.
- At least the portion of the blank 108 includes the entire blank. In one embodiment, at least the portion of the blank 108 includes a patched region (of the blank 108 , where the blank 108 includes both the patched region and a non-patched region). In one embodiment, at least the portion of the blank 108 includes a patched blank (of the blank 108 , wherein the blank includes a base blank and the patch blank attached to the base blank).
- the blank 108 is a tailor welded blank.
- the tailor welded blank is formed by a tailor welded blank procedure.
- the tailor welded blank includes blank members that are welded together during the tailor welded blank procedure.
- the blank members being welded together during the tailor welded blank procedure may have different strengths and/or different thicknesses.
- at least the portion of the tailor welded blank is pre-heated to the pre-heat temperature PH T by thermal conduction in the pre-heat station.
- the blank 108 is a monolithic blank. In one embodiment, at least the portion of the monolithic blank is pre-heated to the pre-heat temperature PH T by thermal conduction in the pre-heat station. In one embodiment, the at least the portion of the monolithic blank includes the entire blank.
- the blank 108 is a tailor rolled blank.
- the tailor rolled blank is formed by a tailor rolled blank procedure.
- the tailor rolled blank includes variable thickness portions.
- at least the portion of the tailor rolled blank is pre-heated to the pre-heat temperature PH T by thermal conduction in the pre-heat station.
- the blank 108 includes a base blank 110 and a patch blank 112 attached to the base blank 110 .
- the base blank 110 and the patch blank 112 are integrally formed.
- the patched region 112 includes the patch blank 112 and a portion 114 of the base blank 110 that is attached to the patch blank 112 .
- the non-patched region 116 includes portions 116 of the base blank 110 that are surrounding the patch blank 112 .
- portions 116 of the base blank 100 that are surrounding the patch blank 112 are not pre-heated to the pre-heat temperature in the pre-heat station 102 .
- the non-patched region 116 includes portions 116 of the base blank 110 that are surrounding at least two sides of the patch blank 112 .
- the non-patched region 116 includes portions 116 of the base blank 110 that are surrounding at least three sides of the patch blank 112 .
- the non-patched region 116 includes portions 116 of the base blank 110 that are surrounding the entire (e.g., all four sides) patch blank 112 . In one embodiment, the non-patched region 116 includes portions 116 of the base blank 110 that are adjacent the patch blank 112 . In one embodiment, the non-patched region 116 does not include the patch blank 112 .
- the base blank 110 may also be referred to as a parent blank.
- the base blank 110 and the patch blank 112 have the same thickness.
- the base blank 110 and the patch blank 112 have different thicknesses.
- the base blank 110 and the patch blank 112 are made of the same material.
- the base blank 110 and the patch blank 112 are made of different materials.
- the base blank 110 and the patch blank 112 are made of the same material grade. In another embodiment, the base blank 110 and the patch blank 112 are made of different material grades.
- the non-patched region 116 includes portions 116 of the blank 108 that are surrounding the patch region 112 . In one embodiment, the non-patched region 116 includes portions 116 of the blank 108 that are adjacent the patch region 112 . In one embodiment, the patched region 112 and the non-patched region 116 have different thicknesses. In one embodiment, the patched region 112 has a thickness greater than the non-patched region 116 . In one embodiment, the patched region 112 and the non-patched region 116 are made of the same material. In another embodiment, the patched region 112 and the non-patched region 116 are made of different materials. In one embodiment, the patched region 112 and the non-patched region 116 are made of the same material grade. In another embodiment, the patched region 112 and the non-patched region 116 are made of different material grades.
- the patch blank 112 has an area smaller than the area of the blank 108 .
- the patch blank 112 is surrounded by portions (e.g., unpatched or remaining portions 116 ) of the base blank 110 .
- the portions of the base blank 110 surrounding the patch blank 112 are referred to as non-patched/unpatched portions or the remaining portions of the blank 108 .
- the patch blank 112 is configured to overlap at least a portion (i.e., portion 114 ) of the base blank 110 .
- the patch blank 112 is attached to the base blank 110 by welding, adhesive or mechanical joining operation/procedure.
- edge or internal portion of the patch blank 112 is joined to the base blank using resistance spot welding (RSW), metal inert gas welding (MIG), laser welding, friction stir welding, self-piercing rivet (SPR) or flow drill screw (FDS) procedures.
- RSW resistance spot welding
- MIG metal inert gas welding
- SPR friction stir welding
- FDS flow drill screw
- the patch blank 112 may be used to provide local reinforcements (i.e., with improved load transfer and/or distribution of stresses) to the blank 108 .
- the patch blank 112 is provided where greater strength, stiffness and Noise, vibration and harshness (“NVH”) performance are desired.
- the system 100 includes one or more robots 500 , 502 , 504 , 506 that are operatively connected to a controller C.
- the number of robots may vary.
- the robot 502 is constructed and arranged to de-stack (i.e., for removing) the topmost (i.e., single) blank 108 from a stack of sheet metal blanks 510 and to automatically dispose the blank 108 in the pre-heat station 102 .
- the system 100 is constructed and arranged to stamp date and/or bench mark indicia on the blank 108 after the de-stacking the blank 108 and before positioning the blank 108 in the pre-heat station 102 .
- the controller C includes a computer and is configured to control the operations of various components (robots, furnace, pre-heat station, press, etc.) of the system 100 .
- the controller C is configured to verify that each component of the system 100 is operating correctly in order to maximize the efficiency.
- each of the components are controlled independently by their own controllers, but the controller C is configured to share signals between the controllers of the robots, furnace, pre-heat station, press, etc.
- thermal conduction pre-heat of patched blank 108 provides a heating solution to reduce overall oven residence time of the blank in the furnace 104 .
- the pre-heat station 102 includes an induction contact oven. In one embodiment, the pre-heat station 102 includes upper and lower contact platens 118 and 120 . In one embodiment, the upper and lower platens 118 and 120 are configured to only heat up the patch area/blank 112 of the blank 108 to an intermediate temperature or the pre-heat temperature PH T .
- the intermediate temperature or pre-heat temperature PH T is below the Al—Si coating eutectic temperature for the coated steel. In another embodiment, the intermediate temperature or pre-heat temperature PH T is lower than 700° C. In yet another embodiment, the intermediate temperature or pre-heat temperature PH T is in the range of 200° C. and 700° C.
- At least one of the upper and lower platens 118 and 120 is a moveable platen.
- the pre-heat station 102 is operatively connected to the controller C.
- the controller C is configured to actuate the upper and/or lower platens 118 and 120 (after the blank 108 is properly placed between the upper and lower platens 118 and 120 (e.g., by the robot 500 )) such that the upper platen 118 and the lower platen 120 are brought into contact with each other.
- each of the lower platen 120 and the upper platen 118 includes a plurality of induction coils 516 therein.
- the induction coils 516 are made of copper material.
- the induction coils 516 are configured to heat the respective lower and upper platens 120 and 118 .
- the induction coils 516 are connected to an external power source 522 .
- the induction coils 516 may have offset inductions leads 518 .
- the offset induction leads 518 are configured to prevent electrical coupling.
- the induction coils 516 are connected to a source of coolant (e.g., via connectors 520 ) located at the ends of the inductive coils 516 .
- the induction coils 516 are cooled by water.
- the induction coils 516 are used to provide energy into the platens 118 and 120 to heat the respective platens 118 and 120 and keep them at the desired temperature (i.e., equal to or higher than pre-heat temperature PH T ).
- any source of heating may be used to heat and keep the platens 118 and 120 at the desired temperature (i.e., equal to or higher than pre-heat temperature PH T ) as long as it provides energy to the platens 118 and 120 .
- the sources of heating such as cartridge, open flame etc. may be used to provide energy/heat to the platens 118 and 120 and maintain the platens 118 and 120 at the desired temperature (i.e., equal to or higher than pre-heat temperature PH T ).
- the blank 108 is the work piece of which the patch area/blank 112 is configured to receive the heat energy from the platens 118 and 120 .
- the heated platens 118 and 120 are used to pre-heat sheets for the purpose of hot stamping.
- only patch areas/blank 112 of sheets or blanks 108 are pre-heated in the pre-heat station 102 through thermal conduction procedure.
- the upper platen 118 is constructed and arranged to provide pressure to the patch blank 112 .
- the upper platen 118 is heated to a desired platen temperature (i.e., equal to or higher than pre-heat temperature PH T ) and then moved into contact with the patch area 112 of the blank 108 .
- the lower platen 120 is constructed and arranged to be used as a base for the blank 108 to be placed on.
- the lower platen 120 is also heated to a desired platen temperature (i.e., equal to or higher than pre-heat temperature PH T ).
- either the upper platen 118 or the lower platen 120 is configured to apply contact pressure on the at least portion of the blank 108 received in the pre-heat station 102 .
- either the upper platen or the lower platen is configured to apply contact pressure on the patched region of the blank received in the pre-heat station.
- each of the upper and lower platens are heated by at least one process selected from conduction, convection, resistance, induction, heat radiation and gas that are configured to provide energy to heat and maintain the respective upper and lower platens at a desired platen temperature.
- the desired platen temperature is higher than the pre-heat temperature. In another embodiment, the desired platen temperature is equal to the pre-heat temperature.
- each of the lower platen 120 and the upper platen 118 includes one or more thermocouples 514 therein.
- the thermocouples 514 are configured to control and/or monitor the surface temperature of the respective lower and upper platens 120 and 118 .
- the controller C is configured to determine whether the patch blank 112 of the blank 108 , in the pre-heat station 102 , has reached the pre-heat temperature PH T . In one embodiment, this may be determined either with sensors or the thermocouples 514 associated with the pre-heat station 102 or by monitoring the amount of time that each blank 108 remains in the pre-heat station 102 . In one embodiment, the controller C is also configured to adjust the amount of time that the blank 108 is in the pre-heat station 102 .
- the controller C is also configured to adjust the surface temperatures of the lower and upper platens 120 and 118 based on the monitored surface temperature data of the lower and upper platens 120 and 118 obtained from the respective thermocouples 514 . In one embodiment, the controller C is also configured to adjust the amount of time that the blank 108 is heated between the upper and lower platens 118 and 120 . In one embodiment, surface temperatures of the lower and upper platens 120 and 118 can also be adjusted by controllers associated with the pre-heat station 102 .
- the system 100 includes the robot 502 that is constructed and arranged to lift the blank 108 from the pre-heat station 102 and place the blank 108 on a blank loader 506 of the furnace 104 .
- the system 100 includes a blank feeder that is disposed between the pre-heat station 102 and the furnace 104 and is operatively connected to both the pre-heat station 102 and the furnace 104 .
- the blank feeder is constructed and arranged to convey the blank 108 from the pre-heat station 102 to the furnace 104 . That is, the blank feeder is constructed and arranged to extend continuously from the pre-heat station 102 to the furnace 104 .
- the blank feeder is an indexing blank feeder and includes a plurality of driven rollers.
- the indexing feature of the blank feeder comprises a plurality of indexing fingers for aligning the blank 108 in a predetermined position prior to entering the furnace 104 .
- the blank feeder is insulated from the surrounding environment, or includes a heater (not shown) so that the temperature of the patch blank 112 of the heated blank 108 is maintained at the desired, pre-heat temperature PH T when the blank 108 enters the furnace 104 .
- FIGS. 9 and 10 show exemplary pre-heat station in accordance with an embodiment of the present patent application.
- the blank 108 is then transferred from the pre-heat station 102 into the roller hearth furnace 104 where the temperature of remaining areas/portions (i.e., without pre-heat) 116 are heated to the deformation temperature D T , as well as that in the pre-heated patch area/blank 112 .
- the final/deformation temperatures between unpatched and patched areas can be different.
- the non-patched region 116 of the blank 108 is first heated in the roller hearth furnace 104 to the pre-heat temperature and the non-patched region 116 of the blank 108 is then further heated to the deformation temperature.
- the patched region 112 of the blank 108 is already at the pre-heat temperature, when received by the roller hearth furnace 104 , the patched region 112 of the blank 108 is heated in the roller hearth furnace 104 to the deformation temperature.
- the furnace 104 includes a housing 124 and a heating system 126 (e.g., direct or indirect).
- the furnace 104 may include a plurality of driven rollers.
- the furnace 104 may include a flat surface 122 to support the pre-heated blank 108 during the furnace heating.
- the furnace 104 is a continuous furnace.
- the furnace 104 is a roller hearth furnace.
- the heating in the furnace 104 is not only limited to roller hearth radiant heating, but can include other heating methods, e.g., induction, conduction, electrical resistance, flame impingement, etc.
- the pre-heated blank 108 received from the pre-heat station 102 , is transported through the furnace 104 using the driven rollers. That is, in one embodiment, the plurality of driven rollers are configured to convey the blank through the furnace 104 .
- the driven rollers comprises mechanically driven (e.g., ceramic material) rollers or rollers of the type used in the hearth type furnaces.
- the driven rollers of the furnace 104 are constructed and arranged to rotate continuously, remain stationary for periods of time, or oscillate forward and backward, depending on the amount of heating desired.
- the heating system 126 includes a gas burner, an electric heater, or another type of heater. In one embodiment, the heating system 126 comprises a single heating element or a plurality of heating elements. For example, the heating system 126 includes a plurality of tubes containing burning gas, or a plurality of heated coils.
- the furnace 104 is operatively connected to the controller C.
- the controller C is configured to determine whether the blank 108 , in the furnace 104 , has first reached the pre-heat temperature PH T and then has reached the deformation temperature D T . In one embodiment, this may be determined either with sensors associated with the furnace 104 or by monitoring the amount of time that each blank 108 remains in the furnace 104 . In one embodiment, the controller C is also configured to adjust the amount of time that the blank 108 is in the furnace 104 .
- the deformation temperature D T is higher than 700° C. In another embodiment, the deformation temperature D T is in the range of 700° C. and 1000° C.
- the system 100 includes the robot 503 that is constructed and arranged to lift the blank 108 from a blank loader 508 of the furnace 104 and place the blank 108 in position in the press 106 .
- the system 100 includes a blank feeder that is disposed between the furnace 104 and the press 106 and is operatively connected to both the furnace 104 and the press 106 .
- the blank feeder is constructed and arranged to convey the blank 108 from the furnace 104 to the press 106 . That is, the blank feeder is constructed and arranged to extend continuously from the furnace 104 to the press 106 .
- the blank feeder is an indexing blank feeder and includes a plurality of driven rollers.
- the indexing feature of the blank feeder comprises a plurality of indexing fingers for aligning the blank 108 in a predetermined position prior to entering the press 106 .
- the blank feeder is insulated from the surrounding environment, or includes a heater (not shown) so that temperature decrease from deformation temperature D T of the heated blank 108 can be minimized, when the blank 108 enters the press 106 .
- the press 106 includes a pair of dies 128 and 130 .
- the press 106 is constructed and arranged to stamp the heated blank 108 between the pair of dies 128 and 130 to form the shaped part or component. That is, the heated blank 108 (i.e., heated to the deformation temperature, D T in the furnace 104 ) is stamped between the pair of dies 128 and 130 to form the shaped part or component.
- the press 106 is operatively connected to the controller C.
- the controller C is configured to actuate the dies 128 and 130 (after the heated blank 108 from the furnace 104 is properly placed between the dies 128 and 130 (e.g., by the robot 503 )) such that the dies 128 and 130 are brought into contact with each other to form the shaped part or component therebetween.
- the shaped parts or components may include parts or components for use as chassis or body components of an automobile. In one embodiment, shaped parts or components alternatively may be used in other applications.
- the press 106 is also constructed and arranged to quench the shaped part between the dies 128 and 130 .
- the controller C is also configured to adjust the amount of time that the parts are quenched between the dies 128 and 130 .
- the blank 108 is typically heated in the furnace 104 to achieve an austenitic microstructure, and then quenched in the dies 128 and 130 to transform the austenitic microstructure to a martensitic and/or mixed microstructure.
- the hot forming procedures i.e., pre-heat in the pre-heat station 102 , heating in the furnace 104 , and shaping in the press 106 ) run continuously to produce a plurality of the shaped parts at a high rate and low cost.
- the system 100 includes the robot 504 that is constructed and arranged to lift the shaped components or parts from the press 106 and place the shaped components or parts in position on cooling racks 512 .
- the table shown in FIG. 6 provides a comparison of various residence times between the system of the present patent application and the prior art system.
- the residence time in the furnace 104 for the center of the patch blank 112 is reduced from 361 seconds when using the prior art system to 273 seconds when using the system 100 of the present patent application.
- the residence time in the furnace 104 for the edge(s) of the patch blank 112 is reduced from 300 seconds when using the prior art system to 249 seconds when using the system 100 of the present patent application.
- the residence time for the patched area/blank 112 of the blank 108 was reduced by 24% in the present patent application compared to the residence time for the blank 108 the prior art system.
- the residence time for the unpatched portions 116 (i.e., portions surrounding the patch blank 112 ) of the blank 108 remained about the same using the prior art system and using the system 100 of the present patent application.
- FIGS. 7 and 8 show graphical representations of the various temperature profiles of the blank heated using the prior art system and using the system of the present patent application, respectively.
- the temperatures (i.e., measured in ° C.) of the various portions of the blank are shown on the left hand side Y-axis of the graphs in FIGS. 7 and 8 and the residence times of the various portions of the blank (i.e., measured in seconds) are on the X-axis of the graphs FIGS. 7 and 8 .
- the temperature profiles of the patch center (PC), the patch edge (PE) and the unpatched portion (UP) show gradual increase in their corresponding temperatures (till they reach the deformation temperature D T ) because of the furnace heating.
- the temperature profiles clearly show that the temperatures of the patch area/blank do not reach the deformation temperature D T till the residence time of 361 seconds in the furnace.
- the patch area/blank of the blank is pre-heated in the pre-heat station 102 by contact, thermal conduction heating.
- the temperature profiles of the patch center (PC) and the patch edge (PE) show that temperatures of the patch center (PC) and the patch edge (PE) reach an intermediate/pre-heat temperature PH T when the patch blank/area is being pre-heated in the pre-heat station 102 , while the temperature profile of the unpatched portion (UP) shows a very slight or no increase in the temperature of the unpatched portion when the patch blank/area is being pre-heated in the pre-heat station 102 .
- the temperature profile of the unpatched portion (UP) shows that the temperature of the unpatched portion when the blank is being heated in the furnace 104 first catches up to the intermediate/pre-heat temperature PH T of the patch center (PC) and the patch edge (PE) and from thereon reaches the deformation temperature D T .
- the temperature profiles of the patch center (PC) and the patch edge (PE) shows that the temperatures of the patch center (PC) and the patch edge (PE) when the blank is being heated in the furnace 104 reaches the deformation temperature D T at about the residence time of 273 seconds and 249 seconds, respectively.
- the timings i.e., furnace residence timing for the patch center, the patch edge, and the unpatched regions with preheat
- the timings may vary and depend on various factors, such as, thickness of the blank, geometry of the blank, pre-heat temperature, contact pressure, etc. and any combination thereof.
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Abstract
Description
- This application claims priority to U.S. provisional patent application No. 62/670,103, filed May 11, 2018, which is hereby expressly incorporated by reference in its entirety.
- The present patent application relates to a system for producing components by hot forming.
- Hot forming generally comprises heating a blank in a furnace, followed by stamping the heated blank between a pair of dies to form a shaped part, and quenching the shaped part between the dies. The blank is generally heated in the furnace to achieve an austenitic microstructure, and then quenched in the dies to transform the austenitic microstructure to a martensitic microstructure.
- Also, steel continues to be the material of choice when it comes to modern and cost-effective vehicle bodies. In terms of material, new steels that combine high strength with good formability have been developed in response to the demands of the automotive industry for light weight construction materials. In particular, the multiphase steels are used extensively in hot stamping or forming in which a steel blank is heated into the zone of full austenitization (typically 920° C.). The heated steel blank is subsequently inserted into the forming tool or press while still hot, and is rapidly cooled during the pressing operation.
- Advantages of the press hardening method include the low forming resistance and the better formability of steel at this temperature, as well as the high strength and good dimensional stability of the obtained component. In general, the use of hot stamping methods and new steel materials results in high-strength but low-weight vehicle bodies.
- Due to the increasing use of hot stamping technology in the automotive industry, the press-hardening machinery is becoming faster. Machines that achieve five strokes per minute have been in use for some time already, and newer machines that achieve seven strokes per minute are known. As a result of the reduced cycle length, the efficiency of the hot stamping method is increased. However, the heating of the supplied blanks via heating furnaces has hitherto been the limiting factor. Since the blanks have to be heated to a processing temperature of over 900° C., heating furnaces which are configured as continuous furnaces are used. Over a 30 m length of such a continuous furnace, the blank is heated by 30° C. per meter. Accordingly, the pass-through speed of the blanks and the length of the heating furnaces limits the cycle length of the hot stamping system.
- Further, hot stamping ovens are often bottlenecked by patched blanks causing a decrease in through-put. Induction and open flame pre-heat methods have been used to pre-heat the blanks. These methods had issues with providing uniform heat to the sheet which can cause significant distortion (bowing) to the blanks.
- The present patent application provides improvements to hot forming/stamping systems and operations.
- One aspect of the present patent application provides a system for producing components by hot forming. The system includes a pre-heat station, a furnace, and a press. The pre-heat station is configured to receive a blank; and to pre-heat at least a portion of the blank to a pre-heat temperature by thermal conduction. The furnace is constructed and arranged to receive the pre-heated blank from the pre-heat station and to heat the entire blank to a deformation temperature. The deformation temperature is higher than the pre-heat temperature. The press is constructed and arranged to receive the heated blank from the furnace and to form the heated blank into the shape of the component.
- These and other aspects of the present patent application, as well as the methods of operation and functions of the related elements of structure and the combination of parts and economies of manufacture, will become more apparent upon consideration of the following description and the appended claims with reference to the accompanying drawings, all of which form a part of this specification, wherein like reference numerals designate corresponding parts in the various figures. In one embodiment of the present patent application, the structural components illustrated herein are drawn to scale. It is to be expressly understood, however, that the drawings are for the purpose of illustration and description only and are not intended as a definition of the limits of the present patent application. It shall also be appreciated that the features of one embodiment disclosed herein can be used in other embodiments disclosed herein. As used in the specification and in the claims, the singular form of “a”, “an”, and “the” include plural referents unless the context clearly dictates otherwise.
-
FIG. 1 shows a system for producing components by hot stamping procedure or hot forming procedure in accordance with an embodiment of the present patent application; -
FIG. 2 shows an exploded view of a pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application, whereinFIG. 2 also shows a blank member being received and heated by the pre-heat station; -
FIG. 2A shows the blank member being received and heated by the pre-heat station in accordance with an embodiment of the present patent application; -
FIG. 3 shows a side view of the pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application; -
FIG. 4 shows a top perspective view of the pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application; -
FIG. 5 shows another top perspective view of the pre-heat station of the system for producing components by the hot stamping/hot forming procedure, wherein some portions of the pre-heat station are not shown for sake of clarity and to better illustrate other portions of the pre-heat station, in accordance with an embodiment of the present patent application; -
FIG. 6 shows a table that provides a comparison of various residence times for the system of the present patent application and for the prior art system; -
FIG. 7 shows a graphical representation of various temperature profiles of the blank member heated in the prior art system; -
FIG. 8 shows a graphical representation of various temperature profiles of the blank member heated in the system of the present patent application; and -
FIGS. 9 and 10 show exemplary pre-heat station in accordance with an embodiment of the present patent application. - Referring to
FIGS. 1, 2 and 2A , in one embodiment, asystem 100 for producing components by hot forming or hot stamping is provided. In one embodiment, thesystem 100 includes apre-heat station 102, afurnace 104, and apress 106. In one embodiment, thepre-heat station 102 is configured to receive a blank 108. In one embodiment, the blank 108 includes a patchedregion 112 and a non-patchedregion 116. In one embodiment, thepre-heat station 102 is configured to pre-heat at least a portion (e.g., the patched region 112) of the blank 108 to a pre-heat temperature PHT by thermal conduction. In one embodiment, thefurnace 104 is constructed and arranged to receive the pre-heated blank 108 from thepre-heat station 102 and to heat the entire blank 108 to a deformation temperature DT. In one embodiment, the deformation temperature DT is higher than the pre-heat temperature PHT. In one embodiment, thepress 106 is constructed and arranged to receive the heated blank 108 from thefurnace 104 and to form the heated blank 108 into the shape of the component. - In one embodiment, thermal conduction pre-heat is a method of transferring energy/heat into the
blanks 108 using conduction as the mode of heat transfer. In one embodiment, thermal conduction pre-heat includes contact heating of the blank. In one embodiment, conduction is the most efficient form of heat transfer and provides the least heating time. - In one embodiment, the blank 108 used to manufacture the shaped parts or components are typically formed of metal, but can be formed of other materials. In one embodiment, the blank 108 is formed of steel material, such pure steel or a steel alloy.
- In one embodiment, at least the portion of the blank 108 includes the entire blank. In one embodiment, at least the portion of the blank 108 includes a patched region (of the blank 108, where the blank 108 includes both the patched region and a non-patched region). In one embodiment, at least the portion of the blank 108 includes a patched blank (of the blank 108, wherein the blank includes a base blank and the patch blank attached to the base blank).
- In one embodiment, the blank 108 is a tailor welded blank. In one embodiment, the tailor welded blank is formed by a tailor welded blank procedure. In one embodiment, the tailor welded blank includes blank members that are welded together during the tailor welded blank procedure. In one embodiment, the blank members being welded together during the tailor welded blank procedure may have different strengths and/or different thicknesses. In one embodiment, at least the portion of the tailor welded blank is pre-heated to the pre-heat temperature PHT by thermal conduction in the pre-heat station.
- In one embodiment, the blank 108 is a monolithic blank. In one embodiment, at least the portion of the monolithic blank is pre-heated to the pre-heat temperature PHT by thermal conduction in the pre-heat station. In one embodiment, the at least the portion of the monolithic blank includes the entire blank.
- In one embodiment, the blank 108 is a tailor rolled blank. In one embodiment, the tailor rolled blank is formed by a tailor rolled blank procedure. In one embodiment, the tailor rolled blank includes variable thickness portions. In one embodiment, at least the portion of the tailor rolled blank is pre-heated to the pre-heat temperature PHT by thermal conduction in the pre-heat station.
- In one embodiment, referring to
FIGS. 2 and 2A , the blank 108 includes a base blank 110 and a patch blank 112 attached to thebase blank 110. In one embodiment, the base blank 110 and the patch blank 112 are integrally formed. - In one embodiment, the patched
region 112 includes thepatch blank 112 and aportion 114 of the base blank 110 that is attached to thepatch blank 112. In one embodiment, thenon-patched region 116 includesportions 116 of the base blank 110 that are surrounding thepatch blank 112. In one embodiment,portions 116 of the base blank 100 that are surrounding the patch blank 112 are not pre-heated to the pre-heat temperature in thepre-heat station 102. In one embodiment, thenon-patched region 116 includesportions 116 of the base blank 110 that are surrounding at least two sides of thepatch blank 112. In one embodiment, thenon-patched region 116 includesportions 116 of the base blank 110 that are surrounding at least three sides of thepatch blank 112. In one embodiment, thenon-patched region 116 includesportions 116 of the base blank 110 that are surrounding the entire (e.g., all four sides) patch blank 112. In one embodiment, thenon-patched region 116 includesportions 116 of the base blank 110 that are adjacent thepatch blank 112. In one embodiment, thenon-patched region 116 does not include thepatch blank 112. - In one embodiment, the base blank 110 may also be referred to as a parent blank. In one embodiment, the base blank 110 and the patch blank 112 have the same thickness. In another embodiment, the base blank 110 and the patch blank 112 have different thicknesses. In one embodiment, the base blank 110 and the patch blank 112 are made of the same material. In another embodiment, the base blank 110 and the patch blank 112 are made of different materials. In one embodiment, the base blank 110 and the patch blank 112 are made of the same material grade. In another embodiment, the base blank 110 and the patch blank 112 are made of different material grades.
- In one embodiment, the
non-patched region 116 includesportions 116 of the blank 108 that are surrounding thepatch region 112. In one embodiment, thenon-patched region 116 includesportions 116 of the blank 108 that are adjacent thepatch region 112. In one embodiment, the patchedregion 112 and thenon-patched region 116 have different thicknesses. In one embodiment, the patchedregion 112 has a thickness greater than thenon-patched region 116. In one embodiment, the patchedregion 112 and thenon-patched region 116 are made of the same material. In another embodiment, the patchedregion 112 and thenon-patched region 116 are made of different materials. In one embodiment, the patchedregion 112 and thenon-patched region 116 are made of the same material grade. In another embodiment, the patchedregion 112 and thenon-patched region 116 are made of different material grades. - In one embodiment, the patch blank 112 has an area smaller than the area of the blank 108. In one embodiment, the patch blank 112 is surrounded by portions (e.g., unpatched or remaining portions 116) of the base blank 110. In one embodiment, the portions of the base blank 110 surrounding the patch blank 112 are referred to as non-patched/unpatched portions or the remaining portions of the blank 108. In one embodiment, the patch blank 112 is configured to overlap at least a portion (i.e., portion 114) of the base blank 110. In one embodiment, the patch blank 112 is attached to the base blank 110 by welding, adhesive or mechanical joining operation/procedure. In one embodiment, edge or internal portion of the patch blank 112 is joined to the base blank using resistance spot welding (RSW), metal inert gas welding (MIG), laser welding, friction stir welding, self-piercing rivet (SPR) or flow drill screw (FDS) procedures. In one embodiment, the patch blank 112 may be used to provide local reinforcements (i.e., with improved load transfer and/or distribution of stresses) to the blank 108. In another embodiment, the patch blank 112 is provided where greater strength, stiffness and Noise, vibration and harshness (“NVH”) performance are desired.
- In one embodiment, the
system 100 includes one ormore robots - In one embodiment, the
robot 502 is constructed and arranged to de-stack (i.e., for removing) the topmost (i.e., single) blank 108 from a stack ofsheet metal blanks 510 and to automatically dispose the blank 108 in thepre-heat station 102. - In one embodiment, the
system 100 is constructed and arranged to stamp date and/or bench mark indicia on the blank 108 after the de-stacking the blank 108 and before positioning the blank 108 in thepre-heat station 102. - In one embodiment, the controller C includes a computer and is configured to control the operations of various components (robots, furnace, pre-heat station, press, etc.) of the
system 100. In one embodiment, the controller C is configured to verify that each component of thesystem 100 is operating correctly in order to maximize the efficiency. In one embodiment, each of the components (robots, furnace, pre-heat station, press, etc.) are controlled independently by their own controllers, but the controller C is configured to share signals between the controllers of the robots, furnace, pre-heat station, press, etc. - In one embodiment, thermal conduction pre-heat of patched blank 108 provides a heating solution to reduce overall oven residence time of the blank in the
furnace 104. - In one embodiment, as shown in
FIGS. 1 and 2 , thepre-heat station 102 includes an induction contact oven. In one embodiment, thepre-heat station 102 includes upper andlower contact platens lower platens - In one embodiment, the intermediate temperature or pre-heat temperature PHT is below the Al—Si coating eutectic temperature for the coated steel. In another embodiment, the intermediate temperature or pre-heat temperature PHT is lower than 700° C. In yet another embodiment, the intermediate temperature or pre-heat temperature PHT is in the range of 200° C. and 700° C.
- In one embodiment, at least one of the upper and
lower platens pre-heat station 102 is operatively connected to the controller C. In one embodiment, the controller C is configured to actuate the upper and/orlower platens 118 and 120 (after the blank 108 is properly placed between the upper andlower platens 118 and 120 (e.g., by the robot 500)) such that theupper platen 118 and thelower platen 120 are brought into contact with each other. - In one embodiment, as shown in
FIGS. 2-4 , each of thelower platen 120 and theupper platen 118 includes a plurality ofinduction coils 516 therein. In one embodiment, the induction coils 516 are made of copper material. In one embodiment, the induction coils 516 are configured to heat the respective lower andupper platens external power source 522. For example, as shown inFIG. 3 , the induction coils 516 may have offset inductions leads 518. In one embodiment, the offset induction leads 518 are configured to prevent electrical coupling. In one embodiment, as shown inFIG. 4 , the induction coils 516 are connected to a source of coolant (e.g., via connectors 520) located at the ends of theinductive coils 516. In one embodiment, the induction coils 516 are cooled by water. - In one embodiment, the induction coils 516 are used to provide energy into the
platens respective platens platens platens platens platens - In one embodiment, the blank 108 is the work piece of which the patch area/blank 112 is configured to receive the heat energy from the
platens heated platens blanks 108 are pre-heated in thepre-heat station 102 through thermal conduction procedure. - In one embodiment, the
upper platen 118 is constructed and arranged to provide pressure to thepatch blank 112. In one embodiment, theupper platen 118 is heated to a desired platen temperature (i.e., equal to or higher than pre-heat temperature PHT) and then moved into contact with thepatch area 112 of the blank 108. In one embodiment, thelower platen 120 is constructed and arranged to be used as a base for the blank 108 to be placed on. In one embodiment, thelower platen 120 is also heated to a desired platen temperature (i.e., equal to or higher than pre-heat temperature PHT). In one embodiment, either theupper platen 118 or thelower platen 120 is configured to apply contact pressure on the at least portion of the blank 108 received in thepre-heat station 102. - In one embodiment, either the upper platen or the lower platen is configured to apply contact pressure on the patched region of the blank received in the pre-heat station. In one embodiment, each of the upper and lower platens are heated by at least one process selected from conduction, convection, resistance, induction, heat radiation and gas that are configured to provide energy to heat and maintain the respective upper and lower platens at a desired platen temperature. In one embodiment, the desired platen temperature is higher than the pre-heat temperature. In another embodiment, the desired platen temperature is equal to the pre-heat temperature.
- In one embodiment, as shown in
FIG. 5 , each of thelower platen 120 and theupper platen 118 includes one ormore thermocouples 514 therein. In one embodiment, thethermocouples 514 are configured to control and/or monitor the surface temperature of the respective lower andupper platens - In one embodiment, the controller C is configured to determine whether the
patch blank 112 of the blank 108, in thepre-heat station 102, has reached the pre-heat temperature PHT. In one embodiment, this may be determined either with sensors or thethermocouples 514 associated with thepre-heat station 102 or by monitoring the amount of time that each blank 108 remains in thepre-heat station 102. In one embodiment, the controller C is also configured to adjust the amount of time that the blank 108 is in thepre-heat station 102. - In one embodiment, the controller C is also configured to adjust the surface temperatures of the lower and
upper platens upper platens respective thermocouples 514. In one embodiment, the controller C is also configured to adjust the amount of time that the blank 108 is heated between the upper andlower platens upper platens pre-heat station 102. - In one embodiment, the
system 100 includes therobot 502 that is constructed and arranged to lift the blank 108 from thepre-heat station 102 and place the blank 108 on ablank loader 506 of thefurnace 104. In another embodiment, thesystem 100 includes a blank feeder that is disposed between thepre-heat station 102 and thefurnace 104 and is operatively connected to both thepre-heat station 102 and thefurnace 104. In one embodiment, the blank feeder is constructed and arranged to convey the blank 108 from thepre-heat station 102 to thefurnace 104. That is, the blank feeder is constructed and arranged to extend continuously from thepre-heat station 102 to thefurnace 104. In one embodiment, the blank feeder is an indexing blank feeder and includes a plurality of driven rollers. In one embodiment, the indexing feature of the blank feeder comprises a plurality of indexing fingers for aligning the blank 108 in a predetermined position prior to entering thefurnace 104. In one embodiment, the blank feeder is insulated from the surrounding environment, or includes a heater (not shown) so that the temperature of thepatch blank 112 of the heated blank 108 is maintained at the desired, pre-heat temperature PHT when the blank 108 enters thefurnace 104. -
FIGS. 9 and 10 show exemplary pre-heat station in accordance with an embodiment of the present patent application. - In one embodiment, the blank 108 is then transferred from the
pre-heat station 102 into theroller hearth furnace 104 where the temperature of remaining areas/portions (i.e., without pre-heat) 116 are heated to the deformation temperature DT, as well as that in the pre-heated patch area/blank 112. In one embodiment, the final/deformation temperatures between unpatched and patched areas can be different. - In one embodiment, the
non-patched region 116 of the blank 108 is first heated in theroller hearth furnace 104 to the pre-heat temperature and thenon-patched region 116 of the blank 108 is then further heated to the deformation temperature. In one embodiment, as the patchedregion 112 of the blank 108 is already at the pre-heat temperature, when received by theroller hearth furnace 104, the patchedregion 112 of the blank 108 is heated in theroller hearth furnace 104 to the deformation temperature. - In one embodiment, the
furnace 104 includes ahousing 124 and a heating system 126 (e.g., direct or indirect). In one embodiment, thefurnace 104 may include a plurality of driven rollers. In one embodiment, thefurnace 104 may include aflat surface 122 to support the pre-heated blank 108 during the furnace heating. In one embodiment, thefurnace 104 is a continuous furnace. In one embodiment, thefurnace 104 is a roller hearth furnace. In one embodiment, the heating in thefurnace 104 is not only limited to roller hearth radiant heating, but can include other heating methods, e.g., induction, conduction, electrical resistance, flame impingement, etc. - In one embodiment, the pre-heated blank 108, received from the
pre-heat station 102, is transported through thefurnace 104 using the driven rollers. That is, in one embodiment, the plurality of driven rollers are configured to convey the blank through thefurnace 104. In one embodiment, the driven rollers comprises mechanically driven (e.g., ceramic material) rollers or rollers of the type used in the hearth type furnaces. In one embodiment, the driven rollers of thefurnace 104 are constructed and arranged to rotate continuously, remain stationary for periods of time, or oscillate forward and backward, depending on the amount of heating desired. - In one embodiment, the
heating system 126 includes a gas burner, an electric heater, or another type of heater. In one embodiment, theheating system 126 comprises a single heating element or a plurality of heating elements. For example, theheating system 126 includes a plurality of tubes containing burning gas, or a plurality of heated coils. - In one embodiment, the
furnace 104 is operatively connected to the controller C. In one embodiment, the controller C is configured to determine whether the blank 108, in thefurnace 104, has first reached the pre-heat temperature PHT and then has reached the deformation temperature DT. In one embodiment, this may be determined either with sensors associated with thefurnace 104 or by monitoring the amount of time that each blank 108 remains in thefurnace 104. In one embodiment, the controller C is also configured to adjust the amount of time that the blank 108 is in thefurnace 104. In one embodiment, the deformation temperature DT is higher than 700° C. In another embodiment, the deformation temperature DT is in the range of 700° C. and 1000° C. - In one embodiment, the
system 100 includes therobot 503 that is constructed and arranged to lift the blank 108 from ablank loader 508 of thefurnace 104 and place the blank 108 in position in thepress 106. In another embodiment, thesystem 100 includes a blank feeder that is disposed between thefurnace 104 and thepress 106 and is operatively connected to both thefurnace 104 and thepress 106. In one embodiment, the blank feeder is constructed and arranged to convey the blank 108 from thefurnace 104 to thepress 106. That is, the blank feeder is constructed and arranged to extend continuously from thefurnace 104 to thepress 106. In one embodiment, the blank feeder is an indexing blank feeder and includes a plurality of driven rollers. In one embodiment, the indexing feature of the blank feeder comprises a plurality of indexing fingers for aligning the blank 108 in a predetermined position prior to entering thepress 106. In one embodiment, the blank feeder is insulated from the surrounding environment, or includes a heater (not shown) so that temperature decrease from deformation temperature DT of the heated blank 108 can be minimized, when the blank 108 enters thepress 106. - In one embodiment, the
press 106 includes a pair of dies 128 and 130. In one embodiment, thepress 106 is constructed and arranged to stamp the heated blank 108 between the pair of dies 128 and 130 to form the shaped part or component. That is, the heated blank 108 (i.e., heated to the deformation temperature, DT in the furnace 104) is stamped between the pair of dies 128 and 130 to form the shaped part or component. - In one embodiment, at least one of the dies 128 and 130 is moveable. In one embodiment, the
press 106 is operatively connected to the controller C. In one embodiment, the controller C is configured to actuate the dies 128 and 130 (after the heated blank 108 from thefurnace 104 is properly placed between the dies 128 and 130 (e.g., by the robot 503)) such that the dies 128 and 130 are brought into contact with each other to form the shaped part or component therebetween. For example, in one embodiment, the shaped parts or components may include parts or components for use as chassis or body components of an automobile. In one embodiment, shaped parts or components alternatively may be used in other applications. - In one embodiment, the
press 106 is also constructed and arranged to quench the shaped part between the dies 128 and 130. In one embodiment, the controller C is also configured to adjust the amount of time that the parts are quenched between the dies 128 and 130. In one embodiment, the blank 108 is typically heated in thefurnace 104 to achieve an austenitic microstructure, and then quenched in the dies 128 and 130 to transform the austenitic microstructure to a martensitic and/or mixed microstructure. In one embodiment, the hot forming procedures (i.e., pre-heat in thepre-heat station 102, heating in thefurnace 104, and shaping in the press 106) run continuously to produce a plurality of the shaped parts at a high rate and low cost. - In one embodiment, the
system 100 includes therobot 504 that is constructed and arranged to lift the shaped components or parts from thepress 106 and place the shaped components or parts in position on coolingracks 512. - The table shown in
FIG. 6 provides a comparison of various residence times between the system of the present patent application and the prior art system. For example, in one embodiment, the residence time in thefurnace 104 for the center of the patch blank 112 is reduced from 361 seconds when using the prior art system to 273 seconds when using thesystem 100 of the present patent application. In one embodiment, the residence time in thefurnace 104 for the edge(s) of the patch blank 112 is reduced from 300 seconds when using the prior art system to 249 seconds when using thesystem 100 of the present patent application. In one embodiment, the residence time for the patched area/blank 112 of the blank 108 was reduced by 24% in the present patent application compared to the residence time for the blank 108 the prior art system. In one embodiment, the residence time for the unpatched portions 116 (i.e., portions surrounding the patch blank 112) of the blank 108 remained about the same using the prior art system and using thesystem 100 of the present patent application. -
FIGS. 7 and 8 show graphical representations of the various temperature profiles of the blank heated using the prior art system and using the system of the present patent application, respectively. The temperatures (i.e., measured in ° C.) of the various portions of the blank are shown on the left hand side Y-axis of the graphs inFIGS. 7 and 8 and the residence times of the various portions of the blank (i.e., measured in seconds) are on the X-axis of the graphsFIGS. 7 and 8 . - As can be seen from the graph of
FIG. 7 , in the prior art system, all the heating of the blank is done in the furnace and there is no pre-heat of the blank in the prior art system. Referring toFIG. 7 , the temperature profiles of the patch center (PC), the patch edge (PE) and the unpatched portion (UP) show gradual increase in their corresponding temperatures (till they reach the deformation temperature DT) because of the furnace heating. The temperature profiles clearly show that the temperatures of the patch area/blank do not reach the deformation temperature DT till the residence time of 361 seconds in the furnace. - Referring to the graph of
FIG. 8 , in the system of the present patent application, the patch area/blank of the blank is pre-heated in thepre-heat station 102 by contact, thermal conduction heating. The temperature profiles of the patch center (PC) and the patch edge (PE) show that temperatures of the patch center (PC) and the patch edge (PE) reach an intermediate/pre-heat temperature PHT when the patch blank/area is being pre-heated in thepre-heat station 102, while the temperature profile of the unpatched portion (UP) shows a very slight or no increase in the temperature of the unpatched portion when the patch blank/area is being pre-heated in thepre-heat station 102. The temperature profile of the unpatched portion (UP) shows that the temperature of the unpatched portion when the blank is being heated in thefurnace 104 first catches up to the intermediate/pre-heat temperature PHT of the patch center (PC) and the patch edge (PE) and from thereon reaches the deformation temperature DT. The temperature profiles of the patch center (PC) and the patch edge (PE) shows that the temperatures of the patch center (PC) and the patch edge (PE) when the blank is being heated in thefurnace 104 reaches the deformation temperature DT at about the residence time of 273 seconds and 249 seconds, respectively. - In one embodiment, the timings (i.e., furnace residence timing for the patch center, the patch edge, and the unpatched regions with preheat) of the present patent application shown in
FIGS. 6 and 8 are exemplary and are not construed to be limiting in anyway. In one embodiment, the timings (i.e., furnace resistance timing for the patch center, patch edge, and unpatched regions with preheat) may vary and depend on various factors, such as, thickness of the blank, geometry of the blank, pre-heat temperature, contact pressure, etc. and any combination thereof. - Although the present patent application has been described in detail for the purpose of illustration, it is to be understood that such detail is solely for that purpose and that the present patent application is not limited to the disclosed embodiments, but, on the contrary, is intended to cover modifications and equivalent arrangements that are within the spirit and scope of the appended claims. In addition, it is to be understood that the present patent application contemplates that, to the extent possible, one or more features of any embodiment can be combined with one or more features of any other embodiment.
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US201862670103P | 2018-05-11 | 2018-05-11 | |
US17/054,320 US20210237138A1 (en) | 2018-05-11 | 2019-05-10 | Conduction pre-heating of sheet for hot forming |
PCT/CA2019/050627 WO2019213774A1 (en) | 2018-05-11 | 2019-05-10 | Conduction pre-heating of sheet for hot forming |
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EP (1) | EP3790687A4 (en) |
CN (2) | CN117943496A (en) |
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WO2020225749A1 (en) * | 2019-05-06 | 2020-11-12 | Magna International Inc. | Conductive post-furnace heating of sheet for hot forming |
DE102022108513A1 (en) * | 2021-04-16 | 2022-10-20 | Aerospace Transmission Technologies GmbH | Control device and method for controlling a system and a process for the heat treatment of metal workpieces |
WO2022218831A1 (en) * | 2021-04-16 | 2022-10-20 | Aerospace Transmission Technologies GmbH | Method for the heat treatment of metal workpieces |
EP4074846A1 (en) * | 2021-04-16 | 2022-10-19 | Aerospace Transmission Technologies GmbH | Control device and method of controlling a press hardening system |
DE102022108514A1 (en) * | 2021-04-16 | 2022-10-20 | Aerospace Transmission Technologies GmbH | Control device and method for controlling a press hardening plant |
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- 2019-05-10 WO PCT/CA2019/050627 patent/WO2019213774A1/en active Application Filing
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CN112118922B (en) | 2024-02-02 |
MX2020011426A (en) | 2020-11-24 |
CN112118922A (en) | 2020-12-22 |
EP3790687A4 (en) | 2022-01-26 |
CN117943496A (en) | 2024-04-30 |
WO2019213774A1 (en) | 2019-11-14 |
EP3790687A1 (en) | 2021-03-17 |
CA3096907A1 (en) | 2019-11-14 |
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