Below is a list of Grey Casting manufacturers from New Hampshire. Grey casting is the production of molded products made from any of a particular group of iron alloys with notably high carbon and silicon content.As industries ranging from agriculture, irrigation, ventilation and water treatment to automotive, electronics and aerospace use grey castings for parts such as gears, engine casings, pipes, crankshafts and even decorative embellishments, it is important to consider alloy composition and cooling rates with regard to the intended use of the alloy.