US2013136945A1PendingUtilityA1

Tailored Properties By Post Hot Forming Processing

38
Individually held — no corporate assignee on recordPriority: Jun 24, 2010Filed: Jun 23, 2011Published: May 30, 2013
Est. expiryJun 24, 2030(~3.9 yrs left)· nominal 20-yr term from priority
Inventors:Pascal P. CharestNicholas D. Adam
C21D 8/00C21D 1/673B29C 2043/522C21D 1/53C21D 1/18C21D 9/0068B21D 53/88C21D 2221/00Y10T428/12458B29C 43/52C21D 2211/008B29C 43/003B21D 31/00B29C 43/00B21D 22/022B29C 71/02
38
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Claims

Abstract

A method of forming a shaped product from an initial blank comprises subjecting the initial blank to a hot forming and press hardening operation to form the shaped product with substantially a uniform first tensile strength. Subsequently, the shaped product is at least partially immersed into a fluidized bed that is maintained within a known range of operating temperatures. While the shaped product is immersed into the fluidized bed, a first region of the shaped product is heated selectively to above a known temperature. The first region is then cooled, such that the first region attains a second tensile strength that is substantially less than the first tensile strength.

Claims

exact text as granted — not AI-modified
1 . A method of forming a shaped product from an initial blank, comprising:
 subjecting the initial blank to a hot forming and press hardening operation to form the shaped product with substantially a uniform first tensile strength; and subsequently,   at least partially immersing the shaped product into a fluidized bed that is maintained within a known range of operating temperatures so as to selectively heat a first region of the shaped product to above a known temperature, while simultaneously maintaining below the known temperature a second region of the shaped product that is adjacent to the first region, and then cooling the first region such that the first region attains a second tensile strength that is substantially less than the first tensile strength.   
     
     
         2 . A method according to  claim 1 , wherein the initial blank is heated to an austenitization temperature during the hot forming and press hardening operation, and wherein the known temperature is substantially lower than the austenitization temperature. 
     
     
         3 . A method according to  claim 1 , wherein the first region is immersed into the fluidized bed, while the second region of the shaped product that is adjacent to the first region is not immersed into the fluidized bed. 
     
     
         4 . A method according to  claim 3 , further comprising protecting the second region from being heated to substantially the known temperature. 
     
     
         5 . A method according to  claim 4 , wherein protecting the second region comprises directing a flow of a cooling fluid toward the second region. 
     
     
         6 . A method according to  claim 1 , wherein the entire shaped product is immersed into the fluidized bed. 
     
     
         7 . A method according to  claim 1 , wherein a collar is provided about the
 second region of the shaped product, the collar for protecting the second region of the shaped product from being heated substantially.   
     
     
         8 . A method according to  claim 7 , wherein the collar gas-cools or liquid-cools the second region of the shaped product. 
     
     
         9 . A method according to  claim 7 , wherein a central portion of the collared second region is prevented from heating above a predetermined temperature, the predetermined temperature being substantially lower than the known temperature. 
     
     
         10 . A method according to  claim 1 , comprising at least partially immersing the shaped product into the fluidized bed a second time, so as to selectively heat a third region of the shaped product to above the known temperature, and then cooling the third region such that the third region attains a third tensile strength that is substantially less than the first tensile strength. 
     
     
         11 . A method according to  claim 7 , wherein the collar has a predetermined shape and is provided about the shaped product so as to define the second region and a plurality of noncontiguous first regions. 
     
     
         12 . A method according to  claim 7 , wherein the collar comprises a plurality of collars defining a plurality of second regions and a plurality of first regions. 
     
     
         13 . A method according to  claim 1 , wherein prior to at least partially immersing the shaped product into the fluidized bed, substantially the entire shaped product has a martensite structure. 
     
     
         14 . A method according to  claim 1 , wherein the known temperature is between approximately 370° C. and approximately 800° C. 
     
     
         15 . A method according to  claim 1 , wherein the known temperature is between approximately 500° C. and approximately 750° C. 
     
     
         16 . A method according to  claim 1 , wherein the initial blank is fabricated from a press hardenable steel alloy material. 
     
     
         17 . A method according to  claim 1 , comprising performing an intermediate processing step subsequent to subjecting the initial blank to the hot forming and press hardening operation and prior to at least partially immersing the shaped product into the fluidized bed. 
     
     
         18 . A method of forming a shaped product from an initial blank, comprising:
 heating the initial blank to an austenitizing temperature;   hot-shaping the initial blank in a cooled pair of dies to form the shaped product;   cooling the shaped product during a first period of time, using a rate of cooling that is sufficiently rapid to support formation of a martensitic structure within substantially the entire shaped product;   at least partially immersing the shaped product into a fluidized bed that is maintained within a known range of operating temperatures, so as to selectively heat a first portion of the shaped product to a known temperature that is less than the austenitizing temperature, while simultaneously maintaining below the known temperature a second portion of the shaped product that is adjacent to the first portion; and,   cooling the shaped product such that martensite within the first portion of the shaped product is tempered while at the same time martensite within the second portion of the shaped product is other than tempered.   
     
     
         19 . (canceled) 
     
     
         20 . (canceled) 
     
     
         21 . (canceled) 
     
     
         22 . (canceled) 
     
     
         23 . (canceled) 
     
     
         24 . (canceled) 
     
     
         25 . (canceled) 
     
     
         26 . (canceled) 
     
     
         27 . (canceled) 
     
     
         28 . (canceled) 
     
     
         29 . A method of forming a shaped product from an initial blank, comprising:
 providing the initial blank;   heating the initial blank to the austenite state;   hot-shaping the initial blank in a cooled pair of dies to form the shaped product;   hardening substantially the entire shaped product while it is still inside the pair of dies by cooling the product using a rate of cooling that is sufficiently fast to form a martensitic structure;   transferring the shaped and hardened product from the pair of dies to a fluidized bed that is maintained within a known range of operating temperatures;   at least partially immersing the shaped and hardened product into the fluidized bed, so as to heat a first portion of the product to at least a predetermined first temperature, while at the same time maintaining a second portion of the product below a predetermined second temperature that is lower than the first temperature;   removing the product from the fluidized bed; and,   cooling the shaped product such that martensite within the first portion of the shaped product is tempered while at the same time martensite within the second portion of the shaped product is other than tempered,   wherein subsequent to cooling, a tensile strength of the first portion of the shaped product is less than a tensile strength of the second portion of the shaped product.   
     
     
         30 . (canceled) 
     
     
         31 . (canceled) 
     
     
         32 . (canceled) 
     
     
         33 . (canceled) 
     
     
         34 . (canceled) 
     
     
         35 . (canceled) 
     
     
         36 . (canceled) 
     
     
         37 . A method of making a B column for an automobile, comprising:
 providing a B column blank;   heating the B column blank to the austenite state;   hot-shaping the B column blank in a cooled pair of dies to form the B column;   hardening the B column while it is still inside the pair of dies, by cooling the B column during a first period of time using a rate of cooling that is sufficiently rapid to support formation of a martensitic structure within substantially the entire B column;   at least partially immersing the B column into a fluidized bed that is maintained within a known range of operating temperatures, so as to selectively heat a first portion of the B column above a known temperature that is less than the austenitizing temperature, while simultaneously maintaining below the known temperature a second portion of the B column that is adjacent to the first portion; and,   cooling the B column such that martensite within the first portion of the B column is tempered while at the same time martensite within the second portion of the B column is other than tempered,   wherein subsequent to cooling, a tensile strength of the first portion of the B column is less than a tensile strength of the second portion of the B column.   
     
     
         38 . (canceled) 
     
     
         39 . (canceled) 
     
     
         40 . (canceled) 
     
     
         41 . (canceled) 
     
     
         42 . (canceled) 
     
     
         43 . (canceled) 
     
     
         44 . (canceled) 
     
     
         45 . (canceled) 
     
     
         46 . (canceled) 
     
     
         47 . (canceled) 
     
     
         48 . A method of forming a shaped product from an initial blank, comprising:
 providing an initial blank fabricated from an Ultra High Strength Steel;   forming the shaped product from the initial blank; and,   at least partially immersing the shaped product into a fluidized bed that is maintained within a known range of operating temperatures so as to selectively heat a first region of the shaped product to above a known temperature, while simultaneously maintaining below the known temperature a second region of the shaped product that is adjacent to the first region, and then cooling the first region such that the first region attains a second tensile strength that is substantially less than the first tensile strength.   
     
     
         49 . (canceled) 
     
     
         50 . (canceled) 
     
     
         51 . (canceled) 
     
     
         52 . (canceled) 
     
     
         53 . (canceled) 
     
     
         54 . (canceled) 
     
     
         55 . (canceled) 
     
     
         56 . (canceled) 
     
     
         57 . A press-hardened sheet-metal product for use as a motor vehicle structural element, comprising:
 a plurality of non-contiguous first regions, each first region containing martensite that has been tempered;   a second region that is substantially free of martensite that has been tempered; and   a transition zone disposed between the second region and each first region of the plurality of first regions,   wherein each first region of the plurality of non-contiguous first regions has a first tensile strength, the second region has a second tensile strength greater than the first tensile strength, and wherein for each transition zone the tensile strength varies between the first tensile strength and the second tensile strength along a direction between a respective first region and the second region.   
     
     
         58 . The press-hardened sheet-metal product according to  claim 57 , wherein the second region has substantially a uniform martensite structure. 
     
     
         59 . (canceled)

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