Processes & Products
The Major Processes:
- Cold Drawing: Descale, pull through tungsten carbide or high speed steel die, straighten & cut-to-length. Improves dimensional tolerance and shape, straightness, surface finish, strength and machinability.
- Turning and Polishing: Remove bar surface with revolving cutting tool, rotate bar through rolls to straighten and polish, then cut-to-length. Improved dimensional tolerances and removes surface defects and decarburization.
- Grinding: Abrasive wheel grinds off surface metal. Improves surface finish and achieves very close dimensional tolerances.
- Stress Relieve Anneal: Sub-critical thermal treatment applied after cold drawing. Removes residual stresses in the bar and may also increase yield strength.
- Straightening: Bending applied to bar through a set of rolls. Improves straightness.
- Cutting: Separates into desired lengths by cold shearing or sawing. Improved length tolerance, end distortion and perpendicularity.
Other Common Processes:
- Cold Rolling: Descale, pass through series of rolling stands, strengthening and cut-to-length. Improves dimensional tolerance and shape, surface finish and strength.
- Chamfering: Cutting a taper and end-facing the bar. Eliminates end distortion and improves bar feeding.
- Annealing: Heating above the critical temperature and slow coating the bar. Controls microstructure and softens the bar.
- Normalizing: Heating above the critical temperature and air cooling the bar. Improves uniformity of microstructure.
- Quenching and Tempering: Heating above the critical temperature and quenching the bar in oil or water followed by a tempering operation increased strength, hardness and toughness.
A vast range of process combinations are available to meet different quality characteristics. Some of the most common process classifications are:
- Cold Drawn (CD)
- Cold Drawn, Stress Relieved (CD, SR)
- Turned & Polished (T&P)
- Ground & Polished (G&P)
- Turned, Ground & Polished (TG&P)
- Cold Drawn, Turned & Polished (CD, T&P)
- Cold Drawn, Ground & Polished (CD, G&P)
- Cold Drawn, Turned, Ground & Polished (CD, TG&P)
- Cold Drawn, Stress Relieved, Turned, Ground & Polished (CD, SR, TG&P)