Types of Annealing Furnaces for Hot-Dip Galvanizing Lines and Their Advantages & Disadvantages

A galvanizing line furnace is required to :

1. Heat treat the strip (Specified thermal trajectory) to obtain desired.

2. Clean the strip in the case of DFF(direct fired furnace).

3. Remove oxide by reduction.

4. Adjust strip temperature down to that required for entry into the galvanizing bath.

5. Remove microscopic iron oxide films and produce a clean surface which will react correctly with the galvanizing bath.

Annealing furnace type : Horizontal furnace,Vertical furnace, Horizontal furnace+Vertical furnace combine.

Advantages                                                                                                                                   Disadvantages

Lower initial equipment investment                                                                                Larger floor space occupation in the workshop

Lighter equipment self-weight

Lower civil engineering construction costs                                                                      Larger quantity of small guide rolls

Lower roll procurement costs

Easier to operate and maintain                                                                                Surface scratches and roll sticking issues can be well                                                                                                                                       controlled thanks to rational structural design and                                                                                                                                      operation & maintenance solutions (the top surface of                                                                                                                                      steel strip contacts the sink roll).

No hot buckling risk

                                                                                                                       Wedge-type thermometer cannot be installed after annealing

Optimized looper mechanism design

(especially suitable for heavy-gauge steel strips)                                                  Water-cooled rolls cause heat loss

Convenient for later production line revamping and capacity expansion

Smaller line shutdown scope in case of strip breakage