One of the challenges with direct hot forming a galvanized PHS is the risk of microcracks in the coating and an associated restricted process window. Steel company voestalpine has with their phs-ultraform® product developed a process that they have termed phs-directform®.  The process steps are similar to conventional direct hot forming with one significant difference – the use of a non-contact “pre-cooler” which cools the heated blanks to around 640°C before press hardening.  Using this approach produces a product that offers cathodic and barrier corrosion protection, rather than just barrier corrosion protect provided by the alternative Al-Si coating.

http://www.voestalpine.com/blog/en/innovation-en/phs-directform-direct-hot-forming-of-hot-dip-galvanized-steel-strip-ready-for-series-production/

Danny Schaeffler
Engineering Quality Solutions, Inc. … http://www.EQSgroup.com
4M Partners, LLC … http://www.Learning4M.com