Cold heading in fastener production is a high-speed, cold-forging process that forms bolts, screws, and similar parts by forcing wire into a die. This process subjects tooling to extreme pressure, friction, and repeated stress, so die life becomes a critical factor for productivity and cost. Maximizing die life requires a holistic approach: choosing the right die material and heat treatment, applying effective lubricants, using high-quality wire stock, and employing advanced surface treatments or coatings. This whitepaper examines how each factor influences die performance and outlines best practices for fastener manufacturing [...]

Distortion Mechanisms in Bolt Quenching Quenching of high-strength alloy bolts generates large internal stresses that can exceed the material’s yield strength, causing plastic deformation (warping, bending or twisting). Three primary stress sources contribute: residual stresses (from forging, forming, cold work or machining), thermal stresses (from steep temperature gradients during rapid cooling), and transformation stresses (from martensitic phase change). For example, as steel cools, outer layers solidify and shrink while the still-hot core expands or transforms to martensite with an ~2–4% volume increase. This mismatch creates bending moments in slender bolts [...]

Introduction Threads are the critical helical grooves that allow fasteners to be mated together, and the method by which those threads are created can significantly impact a fastener’s performance and manufacturability. In industrial fastener production, there are two primary ways to form threads: cut threading and rolled threading. Cut threads are produced by machining away material, whereas rolled threads are formed by deforming the material without removing it. Each method has distinct advantages and trade-offs, influencing the strength, durability, cost, and suitability of the resulting threaded part. Manufacturing professionals must [...]

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 [...]