Steel strip annealing is to uniform steel chemical composition and structure, refine grains, adjust hardness, eliminate internal stress and work hardening, and improve the forming properties of steel.
Continuous annealing is a process in which a strip is heated to a suitable temperature under a protective atmosphere for a certain period of time, followed by cooling and overaging. In order to improve the surface quality of the strip, an in-line tempering machine is generally designed.
Main features of the unit:
Material: Strip: Width: 600-1550mm, thickness: 0.2-1.2 （1.5） mm
Material: cold rolled steel coil SPCC, SPCD, SPCE, in line with JISG3141
Product quality: CQ, DQ and DDQ, in line with JISG3141
Unit speed: inlet 0-240mpm, process section, 0-180mpm, exit section 0-240mpm
Annual production: 100,000-300,000tpy
Energy-saving mode: waste heat recovery, SUNNY patent
Continuous annealing furnace: full radiant tube heating （RTF）, vertical
Fuel type: natural gas, liquefied petroleum gas, mixed gas, coke oven gas and electricity
Welding equipment: narrow lap seam welder
Degreased form: chemical degreasing + electrolytic degreasing + tertiary water rinsing, vertical or horizontal
Leveling machine: four-roll wet leveling, maximum rolling force 6,000KN
Straightening machine: two bends and two corrections （Optional）
Oiling method: electrostatic oiling
Electrical control system: SIEMENS or ABB AC variable frequency control system
Automation instrumentation: SIEMENS or ABB automation control system
The main process flow of the unit:
Unwinding → welding → degreasing （alkaline washing + alkali scrubbing + electrolysis + water scrubbing + water washing） → annealing reduction （heating → soaking → rapid cooling → overaging → secondary cooling → water quenching → drying） → leveling → pulling correction → Trimming → inspection → oiling → slitting → coiling.