Innovative phs technology: A comparison of the two lines

6. September 2017

Volkmar Held

As a freelance writer, Volkmar Held reports for voestalpine on topics that move people. The content of his stories ranges from archaeometallurgy to future technologies.

voestalpine is the only company to have mastered direct and indirect forming of galvanized, press-hardened components. This know-how also helps the company keep a firm grasp on its position as technology leader among worldwide suppliers to the automotive industry.

With phs-ultraform® and phs-directform®, voestalpine offers the automotive industry ultra high-strength galvanized components from two different process lines. The decision regarding which of the two technologies will be used depends on the form, intended use and production volume. Both lines offer excellent protection from corrosion, exceptional formability, unsurpassed strength and outstanding crash performance (ductility).

phs-ultraform® – the original

phs-ultraform® is the oldest member of the phs family. It demonstrates its capabilities where larger dimensions or complex shapes are required, and in large quantities. The starting material is cold formed in a first process step and then trimmed to the target format. After being subsequently heated, it is press-hardened in a further process step. Here, in a second tool, it is simultaneously shaped into its final form and cooled.

phs-directform® – the Pioneer

phs-directform® is the newest addition to the phs family. Its strengths are especially useful for simple component series with low quantities. Existing hot forming lines can be retrofitted with this technology. Without prior cold forming, blanks are heated using simple furnace technology and, after being pre-cooled, are hot-formed and then press-hardened.

Unlike its sibling technology phs-ultraform®, the direct forming method enables hot forming and hardening of simple components in a single process step – requiring only one forming tool and simple furnace technology.

Below is a comparison of the phs lines of voestalpine:

phs-ultraform®	phs-directform®
Boron steel (22MnB5) with a coating of FVZ/Zn	Conversion-delayed boron steel (20MnB8) with a galvannealed coating
Multiphase process with cold forming	Simpler process compared to phs-ultraform®, without prior cold forming
In an indirect hot-forming process, steel blanks made from phs-ultraform® are formed into final geometry with traditional cold forming and then undergo a final trimming. The cold-formed components are then heated to approx. 900 °C. Inserting the hot component into a cooled tool results in hardening and finalizes the component geometry (form hardening).	In a direct hot-forming process, steel blanks are heated to around 900 °C and then pre-cooled to 550 °C in a contactless process using air, which prevents the formation of microcracks in the subsequent forming process. The blanks are then formed to their final geometry, hardened and then undergo a final trimming.
Optional surface conditioning and transport corrosion protection	Optional surface conditioning and transport corrosion protection
Separate cold and hot forming – with two tools	Combined forming and hardening process in a single tool
Extremely large components, high-volume production and highly complex geometries achievable	Especially economical for smaller quantities and simpler geometries
Tensile strength 1300–2000 MPa	Tensile strength 1300–2000 MPa
Material and thickness combinations can be manufactured without impacting cycle times by using laser-welded blanks as well as partially hardened components	Material and thickness combinations can be manufactured without impacting cycle times by using laser-welded blanks as well as partially hardened components (medium term)
	Process can be implemented in existing direct hot-forming lines with little modification

Focus mobility: http://www.voestalpine.com/mobility

Website thinkzinc: http://www.voestalpine.com/thinkzinc/

Volkmar Held

About the author

As a freelance writer, Volkmar Held reports for voestalpine on topics that move people. The content of his stories ranges from archaeometallurgy to future technologies.

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