Galvanizing lines
Continuous hot dip galvanizing line:
Hot-dip galvanizing referred to as hot-dip, is the processing technique to dip the pre-treated carbon steel substrate in the molten zinc solution, to get protective zinc coating; because of its good anti-corrosion performance, galvanized sheet has been widely used in home appliances, decoration, advertising and civil industries, especially in the home appliance industry (air conditioning outdoor unit, refrigerator outside the board, washing machine panels, computer chassis, microwave ovens, etc.) and high color coated substrate demand. According to the processing method, galvanization can be sorted into 2 methods of United States Steel Corp and Sendzimir.
The main machineries process is as the following:
Manual feeding — uncoilerⅠ&Ⅱ —2-roller pinching machineⅠ— shearing machine 1 —2-roller pinching machine Ⅱ— shearing machine 2 — 2-roll pinching machine Ⅲ —welding machine — tensioning machine Ⅰ— stocking looperⅠ— tensioning machine Ⅱ— pre-degreasing — roller brushing machine — electrolyzed degreasing — roller brushing machine — water washingⅠ— roller brushing machine — water washing Ⅱ — water washing Ⅲ— hot air blowing deviceⅠ — tensioning machine Ⅲ measuring tensioning roll—preheating furnace—heating furnace—soaking furnace—furnace throat—cooling furnace—hot tensioning roller—furnace nose- —zinc pot—sink roller—air knife—small zinc spangle device—cooling tower—1st bending roller—horizontal air cooling unit—bending centering machine—vertical air cooling unit—water quenching tank—hot air drying blower—tensioning machine Ⅳ—finishing machine—straightening machine—tensioning machineⅤ—spraying chromising —electrical heating dryer—stocking looperⅡ—tensioning ing machine Ⅵ—spaying oiling machine—shear— 2-rooler pinching machine Ⅳ — recoiler unit — manual coiler unloading .horizontal air cooling unit
Technical parameters
1. Plate material: cold rolling carbon structural steel, high quality carbon structural steel and low alloy steel
2. Strip width: 600～1500 mm
3. Strip thickness: 0.15～3.5mm
4. Coil outer diameter: φ800～2000mm
5. Process speed: 80～200 m/min
6. Energy type: electricity, natural gas, LPG, coal gas, steam, compressed air and etc.
7. Coating type: normal spangle, small spangle, non spangle, skin pass spangle.
8. Coating thickness: 50～300 g/m2(double side).
9. Post coating treatment: skin pass, tensioning level, passivation and oiler.
10. Continuous annealing furnace: horizontal/ vertical/ L type
Equipment Characteristics:
1. Equipped with steel chemical cleaning or high efficiency electrolytic cleaning section, optional cleaning mode combining horizontal spray with vertical immersion spray, and unique electrolytic cleaning and ejecting mixing technology, which achieve higher current efficiency and avoid secondary oil pollution of plate out of slot , liquid surface directive overflow to ensure that the electrolyte surface rarely burst air bubble, and high safety of system service.
2. The combination of non-oxidizing (NOF) and radiant tube heating (RTH) has the advantages of fast heating speed, high thermal efficiency, more finer double cross-limiting air-fuel ratio control method is adopted , special refractory material is selected, which can significantly improve the insulation effect and service life of the high temperature zone.
3. After annealing, the strip cooling adopts protective gas cycling spray cooling way with variable frequency speed control. The use of high-pressure high-speed jet, strip cooling is quick and uniform, which can accurately control the process temperature of strip entering into zinc pot.
4. Straightening machine and finishing machine can effectively improve the finished product surface and shape quality, and improve product coating and cold crushing mechanical properties.
5. Adopt flue gas waste heat recovery technology, recover low temperature flue gas waste heat through the flue gas – water heat exchange or waste heat steam boiler, supply the recovered waste heat to heat liquid cleaning section , thus to improve the utilization of heat and reduce product energy consumption.
6. The use of jet-type ceramic induction heating zinc pot, with fast heating, uniform temperature and alloy composition, long service life and less slag and other advantages. The furnace nose is equipped with wet nitrogen and circulating zinc pump device inside, which can significantly improve the strip surface accuracy, especially suitable for coated substrate quality requirements of home appliances .
7. The coating thickness measuring instrument can be used to monitor the actual thickness of the coating in real time and guide the precise adjustment of the air knife.
8. The use of fingerprint-resistant coating machine with fast switching device can effectively optimize the equipment layout of process section, reduce the investment in plant construction, and obtain accurate organic or composite coating on the strip surface.
9. Control system adopts vector frequency control, CPC and EPC correction, field bus control technologies, with good man-machine interface and stable and reliable equipment service.
| No.1 | |
| Type: | 1450 strip hot dip continuous galvanizing |
| Specifications | Raw material: Cold rolling coiler; Thickness: 0.2~ 1.2mm Width: 700~ 1250mm Coiler weight: 25t Coating thickness: 60~ 280g/m2 |
| Parameters : | Max speed: 180m /min Annual yield: 150,000 tons |
| Features: | 1: so mature technology, and easy control processing; 2: small investment; 3: low temperature requirement of steel strip when passing through zinc pot |
| Remarks: | United States Steel Corp method |
| No.2 | |
| Type: | 1450 strip hot dip continuous aluminum-zinc plating |
| Specifications | Raw material: Cold rolling coiler; Thickness:0 .2~ 1.2mm Width: 700~ 1250mm Coiler weight: 25t Coating thickness: 40~ 200g /m2 |
| Parameters : | Max speed: 180m/min Annual yield: 150,000 tons |
| Features: | 1, strict requirement for substrate surface cleanliness; 2, high temperature of steel strip entering into zinc pot; 3, quick cooling down after galvanizing; 4, large investment, and difficult process control; 5, finishing must be done to finished product; |
| Remarks: | United States Steel Corp method |
| No.3 | |
| Type: | 800 strip hot dip continuous galvanizing |
| Specifications | Raw material: Cold rolling coiler, or hot rolled acid pickling coiler; Thickness: .5~ 3.5mm (or 0.5~ 1.5mm ) Width: 400~ 650mm Coiler weight: 10t Coating thickness: 40~ 200g/m2 |
| Parameters : | Max speed: 55m/min (or 100m /min ) Annual yield: 120,000 tons |
| Features: | 1,small investment, small footprint; 2,easy production management; 3, direct heating and regenerative burning modes adopted, saving energy; 4, no pretreatment, save the investment and maintenance cost; 5, low production cost and stable product quality; |
| Remarks: | Sendzimir method |
| No.4 | |
| Type: | 650 strip hot dip continuous galvanizing |
| Specifications | Raw material: Cold rolling coiler, or hot rolled acid pickling coiler; Thickness: .5~ 3.5mm (or 0.5~ 1.5mm ) Width: 200~ 450mm Coiler weight: 7t Coating thickness: 40~ 200g/m2 |
| Parameters : | Max speed: 60m /min (or 100m /min ) Annual yield: 100,000 tons |
| Features: | 1,small investment, small footprint; 2,easy production management; 3, direct heating and regenerative burning modes adopted, saving energy; 4, no pretreatment, save the investment and maintenance cost; 5, low production cost and stable product quality; |
| Remarks: | Sendzimir method |