US 12,269,533 B2
Method for producing a welded steel blank and associated welded blank
Cristian Alvarez, Fitz-James (FR); Thierry Lizon, Bury (FR); and Maria Poirier, Villers-Saint-Paul (FR)
Assigned to ArcelorMittal, Luxembourg (LU)
Filed by ArcelorMittal, Luxembourg (LU)
Filed on Aug. 16, 2023, as Appl. No. 18/450,472.
Application 18/450,472 is a continuation of application No. 16/766,725, granted, now 11,945,503, previously published as PCT/IB2018/059288, filed on Nov. 26, 2018.
Claims priority of application No. PCT/IB2017/057386 (WO), filed on Nov. 24, 2017.
Prior Publication US 2023/0399051 A1, Dec. 14, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. B23K 26/60 (2014.01); B21D 22/02 (2006.01); B23K 26/00 (2014.01); B23K 26/24 (2014.01); B23K 33/00 (2006.01); B23K 35/24 (2006.01); B23K 35/38 (2006.01); B62D 21/15 (2006.01); B62D 27/02 (2006.01); C21D 6/00 (2006.01); C21D 9/50 (2006.01); C22C 19/05 (2006.01); C22C 30/02 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/38 (2006.01); B23K 101/00 (2006.01); B23K 101/18 (2006.01)
CPC B62D 21/15 (2013.01) [B21D 22/022 (2013.01); B23K 26/0006 (2013.01); B23K 26/24 (2013.01); B23K 26/60 (2015.10); B23K 33/00 (2013.01); B23K 35/24 (2013.01); B23K 35/383 (2013.01); B62D 27/02 (2013.01); C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 9/505 (2013.01); C22C 19/057 (2013.01); C22C 30/02 (2013.01); C22C 38/002 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/38 (2013.01); B23K 2101/006 (2018.08); B23K 2101/185 (2018.08)] 38 Claims
OG exemplary drawing
 
1. A method for producing a welded steel blank comprising the successive steps of:
providing two precoated sheets, each precoated sheet comprising a steel substrate having a precoating on at least one of its main faces, the precoating comprising an intermetallic alloy layer comprising at least iron and aluminum, the steel substrate being made of a press-hardenable steel, for at least one of the precoated sheets, the steel of the steel substrate comprising, Fe and at least one of C, Mn, Si, Cr, Ti, Al, S, P and B; and
butt welding the precoated sheets using a filler wire so as to form a weld joint at a junction between the precoated sheets, the precoating entirely covering at least one main face of each precoated sheet at a time of butt welding,
the filler wire having a carbon content comprised between 0.01 wt. % and 0.45 wt. %,
a composition of the filler wire and a proportion of filler wire added to a weld pool is chosen in such a manner that the thus obtained weld joint is characterized by:
(a) a quenching factor FTWJ of the weld joint such that FTWJ−0.9FTBM≥0,
where:
FTBM is the quenching factor of a least hardenable steel substrate among the steel substrates of the two precoated sheets, and
the quenching factors FTWJ and FTBM are determined using the following formula: FT=128+1553×C+55×Mn+267×Si+49×Ni+5×Cr−79×Al−2×Ni2−1532×C2−5×Mn2−127×Si2−40×C×Ni−4×Ni×Mn, where Al, Cr, Ni, C, Mn and Si are, respectively, a mean aluminum, chromium, nickel, carbon, manganese and silicon content, expressed in weight percent, of an area whose quenching factor is to be determined, this area being the weld joint in the case of FTWJ and the least hardenable steel substrate in the case of FTBM, and
(b) a carbon content CWJ of the weld joint strictly smaller than 0.15 wt. % or, if the carbon content CWJ of the weld joint is greater than or equal to 0.15 wt. %, a softening factor FAWJ of the weld joint such that FAWJ>5000, where the softening factor FAWJ of the weld joint is calculated as a function of a mean aluminum, chromium, nickel, molybdenum, carbon, manganese and silicon content of the weld joint, expressed in weight percent, using the following formula:
FA=10291+4384.1×Mo+3676.9Si−522.64×Al−2221.2×Cr−118.11×Ni−1565.1×C−246.67×Mn.