Upset forging is a plastic deformation process that compresses the end of a bar or wire axially, increasing the cross-sectional area of that section. It is primarily carried out hot, using dedicated upset forging machines and dies, and because it forms the material while maintaining continuous grain flow, it can produce parts with excellent strength and toughness. Compared to machining, material yield is very good, contributing to cost reduction. Typical applications include bolt and rivet heads, shaft flanges, gear blanks, valve stems, and connecting rods, and it is widely applied in the mass production of automotive and aerospace parts that require increased thickness in specific areas.