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Whether thru-feed or infeed, Keystone Threaded Products can form threads on your components at a pace unparalleled by conventionally machined cut threads.
Our thread rolling machines use a constant hydraulic force at high pressures to ensure the form of any thread we make is fully realized. This cold-working process not only saves cost by eliminating the scrappage of material as compared to cut threads, but also imparts a smooth, work-hardened exterior which makes them stronger and longer-lasting.
Much like forging, cold-working a steel alloy will change its physical characteristics. The material is strengthened by using large forces to compress the steel into itself, forming a layer on the exterior far tougher than that of its core. This differing of physical characteristics is called anisotropy, and it directly influences the mechanical properties of the workpiece that has been cold-worked.
Mechanical properties of a material are highly dependent on its crystalline structure. Metallic bonds group crystallites to form a grain. Grains of differing size, shape, and direction of flow known as polycrystalline structures are propagated during the cooling process of a steel after smelting.
These polycrystalline structures permeate the entire body of the material before being cold-worked. Forming the metal, as in the case of thread rolling, causes its grain flow to align with the direction of the force cold-working it. The crest and root radius of a rolled thread is made to be denser and stronger as a result of this action.
Converse to machined threads, which may fail given adequate side load, rolled threads are able to withstand far greater trans axial forces which is why they are optimal in applications such as screw jacks and lead screws.
Additionally, rolled threads tend to have far superior surface finishes than those which have been turned or milled. Smoother operation and better aesthetic quality are excellent advantages of this feature in rolled threads, but there is added strength due to it as well.
The phenomenon of fatigue in steel is thwarted by the compressive residual stresses imparted to the exterior of a rolled thread. Fatigue is the propagation of microscopic cracks within the metallic structure which grow in size after repeated cycles of load application.
These microscopic fissures, which may have existed in the material previous to the rolling process, are essentially smoothed out across the surface of the thread profile after rolling it. Plastic deformation of the material, the permanent alteration of its form, greatly diminishes its elasticity and ductility which is necessary to propagate fatigue.
Hence, rolled threads are akin to a burnished surface and are far less susceptible to fatigue. Keystone Threaded Products is a leader in the production of rolled threads, specializing in Acme, Trapezoidal, as well as any number of Unified form threads.
We have the experience and capability necessary to produce long-lasting components integral to your design. With added strength, the cost savings of efficiency and material maximization inherent to the process by which they are made, rolled threads are the clear choice in myriad applications.
The diameter of the blank is between the major and minor diameters of the threads and varies with the material, type of thread, and thread specifications.
Rolled threads maintain grain structure in continuous, unbroken lines following contours, increasing tensile and shear strength.
The smooth flanks of rolled threads provide better surface contact with mating threads so burnished roots and flanks are free from chatter, tearing, and cutter marks.
Thread rolling is unique in its ability to maintain accuracy of the original set up during long runs of high-speed production.
