annealing
1. Purpose: Heat the wire to an appropriate temperature, keep it for a certain period of time, and then slowly cool it down to adjust the crystalline structure, reduce the hardness, and improve the workability of the wire at the room temperature.
2. Operation process:
Feeding: Put the products to be processed into the furnace, pay attention to the furnace cover should be tightly covered. Generally, one furnace can process 7 rolls (about 1.2 tons/roll) at the same time.
Heating up: Raise the temperature in the furnace slowly (about 3-4 hours) to the specified temperature.
Insulation: 1018 and 1022 wires are kept at 680℃-715℃ for 4-6 hours, and 10B21, 1039, and CH38F wires are kept at 740℃-760℃ for 5.5-7.5 hours.
Cooling down: Slowly (about 3-4 hours) reduce the temperature in the furnace to below 550°C, and then cool to room temperature with the furnace.
3. Quality control:
1. Hardness: the material is 1018, 1022 wire, the hardness is HV120-170 after annealing, and the material is medium carbon wire, and the hardness is HV120-180 after annealing.
2. Appearance: There should be no oxide film and decarburization on the surface.
