GGG-Ni35 sits at the high-nickel end of the austenitic ductile iron ("Ni-Resist") family, carrying roughly 34–36% nickel with deliberately minimal chromium. That combination pushes the iron's coefficient of thermal expansion down to a level closer to plain carbon steel than to any other cast iron — a property no ferritic or lower-nickel austenitic grade can match. Where the chromium-bearing Ni-Resist grades trade some of that dimensional stability for extra oxidation resistance, GGG-Ni35 is specifically the grade you reach for when a casting needs to hold its size and shape through repeated thermal cycling, especially in assemblies paired with steel components.

The high nickel content also gives GGG-Ni35 a fully austenitic, non-magnetic matrix with strong low-temperature toughness and solid resistance to seawater, brine, and caustic environments. Of the Ni-Resist family, it's generally regarded as the softest and most machinable, since it carries the least chromium and therefore the fewest hard carbide-forming constituents. Typical uses include precision machine tool components, glass-molding equipment, and marine or process components where dimensional stability under thermal cycling and corrosion resistance both matter.

GGG-Ni35 is generally the most forgiving member of the austenitic Ni-Resist family to machine, precisely because it carries the least chromium of the group — fewer hard carbide-forming constituents mean less abrasive wear on the cutting edge than the chromium-bearing grades. That said, it's still an austenitic, fully non-magnetic matrix, so it retains the characteristic toughness and mild gumminess of that structure and should be treated more like an austenitic stainless steel than like a standard ferritic ductile iron.

Chips tend to be long and ductile rather than short and brittle, so chip control and evacuation deserve attention, particularly in turning and drilling. Work hardening is a real risk if the tool is allowed to rub or dwell rather than maintain a consistent bite, so steady feed rates and adequate depth of cut matter more here than on brittle cast iron. A sharp, positive cutting edge sheared the material cleanly and reduces the heat and force buildup that drives both tool wear and work hardening.

Even with its comparatively good machinability for a Ni-Resist grade, GGG-Ni35 still calls for reduced cutting speeds and more heat-resistant carbide grades than standard ductile iron, along with rigid setups and generous coolant to manage the heat this tougher matrix generates at the edge.