The present invention relates to a method of hot-shaping from a sheetmetal blank and hardening a sheetmetal object in a cooled tool, at which there is double sheetmetal in part of the blank and the whole blank is shaped in a single forming operation. The invention also relates to a B-pillar for a vehicle.
Shaping a sheetmetal blank together with a reinforcing patch in order to create a product is known from EP 1195208 B1 and DE 4307563 A1.
An object of the invention is to provide greater possibilities for choosing freely different characteristics in different portions of a shaped product and to make it easy to achieve different degrees of hardness in different portions of a product formed from a planar sheet steel blank.
This is achieved by making the blank by placing together two blank elements with an overlap and welding them together before the shaping operation so that during that operation the portions with overlapping sheetmetal are shaped and hardened at the same time as the portions of the two blank elements which do not overlap. The invention is defined by the claims.
The welded-together blank 20,21 is heated in a furnace to austenitising temperature and is hot-shaped in a cooled tool pair, after which it is left with the tools serving as cooling fixtures. This combined shaping and hardening operation is a known process called press-hardening. It is possible to adopt for the upper blank element such a steel grade that the upper portion of the pillar fully hardens and to adopt for the lower blank element a steel grade which is only partly or not at all hardenable. The result is a pillar comprising three portions with different strengths, with a middle portion, the overlap portion, having the greatest strength and a lower portion the least strength. The portion between the hinge fastenings thus becomes the strongest portion. Only the lower portion of the pillar will be subject to corrosion, and the lower blank element 21 may be provided with corrosion protection, whereas the upper portion 20 may be without corrosion protection. Compared with cutting an integral blank, the amount of sheetmetal used is smaller, since the upper blank element 20 is narrower than the lower element and does not need such a broad sheet. The overall result is a B-pillar with desired impact characteristics which costs less than previously and is lighter in weight.
As well as adopting similar or different steel grades, it is also possible to adopt similar or different sheet thicknesses in the two blank elements 20,21.
The cover 12 is welded firmly to the hat beam's side flanges 18,19.
As illustrated in
Welding the two blank elements together to form a Taylor blank may with advantage be effected by remote laser welding both for the overlap edges and for the stitching across the overlap surface.
Although the making of a B-pillar is referred to by way of example, the invention is not limited to that product.
Number | Date | Country | Kind |
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0601735 | Aug 2006 | SE | national |
The present application is a divisional of application Ser. No. 12/310,271, filed Feb. 17, 2009 (currently pending), which is a 371 of PCT/SE2007/000732, filed Aug. 17, 2007, which claims priority from Swedish Patent Application 06017354-4, filed Aug. 25, 2006. The present application claims the benefit of the aforementioned prior applications pursuant to 35 U.S.C 121, 35 U.S.C. 371, and 35 U.S.C. 119 (a).
Number | Name | Date | Kind |
---|---|---|---|
3703093 | Komatsu | Nov 1972 | A |
6350533 | Goto | Feb 2002 | B1 |
6524404 | Gehringhoff | Feb 2003 | B2 |
7310878 | Chernoff | Dec 2007 | B2 |
7857377 | Chen | Dec 2010 | B2 |
9085323 | Busch | Jul 2015 | B2 |
20020104591 | Gehringhoff | Aug 2002 | A1 |
20100084892 | Yoshida | Apr 2010 | A1 |
20120186705 | Sikora | Jul 2012 | A1 |
20120304448 | Hartmann | Dec 2012 | A1 |
Number | Date | Country | |
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20170066481 A1 | Mar 2017 | US |
Number | Date | Country | |
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Parent | 12310271 | US | |
Child | 15299543 | US |