Annealing Treatment of Cold Heading Wire for Fasteners

Annealing Process Control Points:

(1) Full annealing requires heating to 28 ℃ above Ac3, carbon steel should be 30-50 ℃ above Ac3, and alloy structural steel should be 50-80 ℃ above Ac3.

(2) Spheroidizing annealing: medium carbon steel and low alloy steel are heated to 20-40 ℃ above Ac1 or 13-26 ℃ below Ac1, then slowly cooled to below 550 ℃, air cooled, or cooled after a long isothermal period below Ar1.

(3) Intermediate annealing. Recrystallization annealing is to heat the steel to about 13 ℃ below Ac1, generally 650-700 ℃ for carbon steel; stress relief annealing generally heats the steel to 500-650 ℃ at a rate of 100-150 ℃/h, keeps warm for 2-4 h, and slowly cools to 200-300 ℃ before leaving the furnace.

The spheroidizing annealing process is low-carbon, environmentally friendly and energy-saving, and has a short production cycle. It is the main direction of future fastener production and research.

Motorized Loading Heighten 460mm Rockwell Hardness

Tester 400HRD-150B with Throat 165mm

Technical Specification: