Cold-drawn (CD) or cold-finished bars are produced by drawing hot-rolled and descaled (pickled) bars through a die at room temperature. This process changes the specifications significantly:
Standards: Covered under "cold-finished" sections of standards like ASTM A29 or specific cold-drawn standards.
Surface: A smooth, bright, or shiny surface with a much better finish (lower roughness Ra). Minimal to no decarburization if processed correctly.
Dimensional Tolerances: Very tight, as per h9/h11 ISO tolerances or similar. Diameter control is excellent (e.g., ±0.05mm for smaller sizes).
Straightness: Much straighter than HR bars.
Mechanical Properties: The cold-working induces strain hardening, increasing yield and tensile strength but reducing ductility. The bar is often supplied in a soft-annealed state before drawing (for easier drawing) or a hard-drawn state (for higher strength without heat treatment). A final stress-relief anneal may be applied.
Applications: Used for precision components requiring minimal final machining, excellent surface finish, and close dimensional accuracy, such as pins, shafts, and hydraulic cylinder rods.