Introduction. Threaded fasteners (bolts, screws, nuts, etc.) are commonly produced by cold heading or hot forging, processes that shape a metal blank into its final form. These processes demand tight dimensional accuracy—precise head size, shank diameter, and thread location/concentricity—to meet fastener specifications. Process parameters like forming speed (machine stroke rate or ram speed) and die temperature directly influence material flow, die expansion, and lubrication, all of which affect accuracy. This report examines how these parameters affect thread form precision, concentricity, and tolerance control in cold-headed and hot-forged fasteners of different [...]

Fasteners (such as bolts, screws, and nuts) can be manufactured using cold forging, hot forging, or machining. Each method impacts the fastener’s mechanical properties, dimensional precision, surface finish, and production efficiency in different ways. In this report, we compare cold-forged, hot-forged, and machined fasteners made from carbon steel and stainless steel, outlining the advantages and disadvantages of each process with quantitative data where applicable. Cold Forging (Cold Heading) Cold forging (also known as cold heading) shapes metal at room temperature by high-pressure pressing or striking, typically starting from wire or [...]

Introduction Stainless steel fasteners are made from various classes of stainless alloys, each with distinct microstructures and properties. The major categories are austenitic, ferritic, martensitic, precipitation-hardening (PH), and duplex stainless steels. Heat treatment processes for these fasteners must be tailored to the alloy type. Common heat treatment steps include solution annealing (a high-temperature anneal often followed by rapid cooling), quenching (rapid cooling from high temperature to form hard phases like martensite), tempering (reheating quenched metal to moderate temperatures to adjust hardness and toughness), and aging (holding at an intermediate temperature [...]