Initially friction stir welding was confined to relatively soft materials such as lead, zinc, magnesium and a range of aluminum alloys. More recently, copper, titanium, low carbon ferritic steel, alloy steels, stainless steels and nickel alloys have been welded. In theory, any material which can be hot worked should be weldable by this process. However, the pin tool material is often the limiting factor, rather than the material being welded. Visit our materials compatibility page to learn which materials can be welded together.