Cold Heading Wire
Cold heading wire is created through either hot or cold processes as needed to best suit the creation of cold headed parts for which it serves as the body. Cold headed fasteners such as bolts, screws, nails and pins begin as a coil of cold heading wire. This wire must be suited to cold processing as well as the final use for the finished part.
Cold heading wire suppliers must accommodate the vast and variable needs of transport, building, chemical, electronics, aerospace and marine industries among others. For each of these applications, material is one of the most important concerns as the initial properties and integrity of the wire will be reflected in its finished performance. A wide range of materials are commonly available including a number of specialized ferrous, nonferrous, exotic, alloyed and precious metals.
Aluminum, brass, bronze, boron, steel, copper, nickel, silver, stainless steel and carbon steel are all popular options in wire forming as they hold up not only to cold working, but strenuous use as well. Common processes used to form these metals into wire include deep drawing, fine blanking, stamping, extrusion and punch and die processes, all of which may be hot or cold forming. Wire is available in individual packages or continuous coils weighing as much as 4,000lbs. No matter the amount needed, protective sleeves or spooled packaging should be used to ensure quality is maintained throughout the shipping process.
While possibilities abound, wet or dry drawing is the most popular method for wire forming. This process essentially pulls raw or slightly processed materials through a die block which extends length and reduces size considerably. It is important to consider both the inner and out diameters of wire before purchasing. The weight should also be considered as it will reflect the elemental purity of the wire.
Once formed, the wire is coiled, or wound around a spool for easy shipping and handling. Before cold processing may begin, however, a pre-straightening device is used to correct curves and kinks as the material flows directly into subsequent equipment. The wire is cut to the desired length before a cold heading begins.
Also known as a header, the necessary equipment houses a series of punches and dies which allow for the production of collars, necks, lugs, flats or fins on any point along the length of the stock shape or blank. After this process the wire bodies of the newly headed fasteners can be processed for additional finishing or machining needs, such as thread rolling for screws. Along with manufacturing techniques and materials, it is important to consider compositional limits, inclusion rates, impurities, surface defects and even final coatings with regard to the intended use of the part or fastening device.