Does GGG40 spark on contact (speaking of a metal to metal contact) and is there any documentation to support this? Any help you can provide would be greatly appreciated.
GGG40 is a flake graphite cast iron. Any excessive friction between 2 parts will result in sparking. However, the presence of graphite flakes affords dry lubrication ,thus reducing sparking tendency when in contact within limits.
Why does sparking matter to you?
Yes this material can spark, but less than steels.
If you are concerned about ignition then non-sparking doesn't really matter. I have watched brass tools used to light solvent fires. It is the heat of the local impact, it is a lot more complex than sparks.
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