Hot metal gas forming
Materials
Materials
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The HMGF process is compatible with almost any metal. The most significant benefit of HMGF is that cold form resistant materials become viable for complex forming. Often, alloys are enhanced with expensive materials to enable cold forming and increase [machinability](/wiki/Machinability "Machinability"), however with HMFG a less expensive alloy can be used, which reduces piece prices. One example is the use of [ferritic stainless steels](/wiki/Ferritic_stainless_steel "Ferritic stainless steel"), like the 1\.4512 alloy for exhaust components. Typically, the more expensive austenitic [stainless](/wiki/Stainless_steel "Stainless steel") is chosen, like the 1\.4301 alloy, for parts requiring complex forming due to its 40% advantage in ambient formability (38\.5% vs. 27\.4% typical A%).
Hardenable metal alloys (e.g. boron steels) can be used in HMGF. In this case the die can be used not only as a shaping tool, but also as a tempering tool, so that the final hardness of the formed tube after forming and cooling is increased. The process is often called "press hardening" in this case.


How does HMGF affect cold forming materials?