The process of open coil annealing (OCA) is used to prepare steel sheet for further processing. The OCA process anneals and de-carbonizes the steel in preparation for shaping and finishing by original equipment manufacturers. The steel sheet that undergoes this process is used primarily in the appliance and automotive industries. Because of its use, the steel sheet must be highly formable and have good surface chemical properties. In OCA, a coil of steel is wound with two intertwined 0.035 inch wires between each sheet. The wires are used to space the wraps of the coil, thus creating an open coil . This spacing allows air flow along all of the surfaces of the steel coil. Annealing is done to soften the steel by relaxing the strain hardening caused by cold rolling. The de-carbonization is done simultaneously with the annealing. Lower carbon content allows better adhesion of surface coatings. De-carbonization is accomplished by circulating a specialized gas through the open wraps.After annealing and de-carbonization, gas flow continues to circulate within the furnace to initiate cooling. The coil is then removed from the furnace and placed on a cooling bed.