According to the shape of the steel drum and its own production process characteristics, solid pretreatment spray production line is appropriate.
Spraying treatment equipment mainly includes storage tank, sprinkler system, ventilation system and related equipment. Related equipment mainly includes heating system, slag removal system and conveying system.
Pretreatment conditions
Cold-rolled steel plate surface mainly contains oil, no rust, so the pretreatment site mainly to degreasing, phosphate as the center, the overall process is as follows:
Pre-degreasing → degreasing → washing → washing → table tune (can be omitted this site) → phosphating → washing → drying
1, degreasing
High-quality phosphate film only in the oil to the surface of the workpiece to complete the formation, because the oil residue in the workpiece surface will not only seriously hinder the growth of phosphate film, but also affect the coating adhesion, drying performance, decorative properties and resistance Corrosion performance.
Commonly used degreasing agents are: strong alkaline degreasing agent, weak alkaline degreasing agent, organic solvent fat agent; according to the temperature are divided into: high temperature, medium temperature, low temperature degreasing agent.
Strong alkaline degreasing agent contains a large amount of alkali (sodium hydroxide), not easy to clean; In addition, the temperature of degreasing agent can not be too high (usually about 50 ℃) to avoid work in the water before drying, resulting in rust after rust phenomenon.
For the choice of dewaxing solution should take full account of the oil surface of the working conditions, the amount of foam degreasing agent to avoid excessive production of foam caused by difficult or unnecessary consumption.
Using phosphating LT-213 low-temperature weak base degreasing agent, the temperature control between 45-55 ℃, the time is 3-5 minutes, can be completely in addition to oil, easy to clean the workpiece, after cleaning the workpiece water film to completely wet the workpiece surface The
Degreasing workpiece spray pressure should be high, in order to ensure the effect of degreasing, the general pressure of 0.1-0.5MPa. Spray time control in 2 minutes to ensure the full reaction of the degreasing solution with the oil.
Degreasing tank preparation: LT-213 low temperature weak base degreasing agent 5% + water 95%.
2, washed
Water washing station is divided into three, the first two washed in the degreasing, the third water in the phosphating, each wash the PH value should be controlled between 5-7, to maintain water cleanliness. Water spray station pressure is usually controlled at 0.1MPa.
3, table tone (can omit the station)
Table troughs usually control only PH values: generally should be controlled between 8-9.5.
Formulation of liquid preparation: LT301 titanium salt table adjustment 0.1-0.3% water.
4, phosphating
The so-called phosphating, refers to the metal parts through the acid salt containing dihydrogen phosphate treatment of acid solution, a chemical reaction in the surface of a layer of stable insoluble or insoluble phosphate film method, the natural membrane called For the phosphate film. The main role of phosphate film is: to improve the adhesion and increase the corrosion resistance of the coating. Phosphorus on the market varieties of mixed, the effect of treatment can only meet the GB6807-2001Q steel workpiece coating before the technical requirements of the requirements of phosphate treatment, but there are more complex handling, containing a large number of nitrite and other carcinogenic substances, the cost High defects. The use of phosphating LT-101 low temperature zinc film film phosphating solution, not only easy to operate, but also contains no toxic and hazardous substances, low cost, phosphating speed, long life and other advantages, in line with GB6807-2001 and GB / T11376 -1997 metal phosphate conversion film standard. This product through a number of long-term use of enterprises, was well received.
Phosphating station spray pressure is too low, easy to cause phosphate is not complete; pressure is too high, easy to cause a large number of phosphating fluid splash, is not conducive to film. Usually the spray pressure should be controlled at 0.05MPa-0.1MPa, phosphating station spray time should be controlled in 3 minutes to ensure that the phosphating solution and the substrate of the full reaction to give phosphating film growth time to avoid leakage Bottom and yellowing phenomenon.
Phosphating bath preparation: LT101 low temperature zinc film base phosphating solution 5% + water 95%.
5, phosphate film drying
Drying of the phosphate film can play two aspects of the role, on the one hand for the next process to prepare for painting to the surface of the phosphate film to the surface; on the other hand can further improve the resistance of the film after coating Corrosion.
According to the unique characteristics of steel drum and phosphate film type, drying method is best to use drying tunnel drying, drying temperature control at 120 ℃ -150 ℃, drying 5-10 minutes.
New process features and precautions
1, the process characteristics: the main function of the process is: the tank is stable, easy to operate, simple management, the use of long life, less energy consumption, pollution-free, non-toxic harmless, less paint, coating high gloss.
2, Note: water washing station must be washed thoroughly, wash the bath to be frequently replaced.
3, into the bake drying before the steel can not have residual water.
4, strictly control the process parameters, the treatment according to the provisions of the detection and adjustment.
Tel：0576-85221688 13586101975
Fax：0576-85192268
E-mail：hixll868788@163.com
Addr：High-tech Park of Linhai Tangli Economic Development Zone, Zhejiang.
