 Bars or rods that are drawn cannot be coiled therefore straight-pull draw benches are used. Chain drives are used to draw workpieces up to 70 mm. Hydraulic cylinders are used for shorter length workpieces .The reduction in area is usually restricted to 20 to 50%, because greater reductions would exceed the tensile strength of the material, depending on its ductility. To achieve a certain size or shape material passes through progressively smaller dies or intermediate anneals may be required. |
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