Acid pickling and phosphating is an important step in rack pretreatment, which has a great impact on the quality and life of racks.
Pickling and phosphating is a very complicated and laborious process, and the pre-treatment of some large factories is the whole day of pickling and phosphating. At present, because of the cost, because of environmental protection, many factories no longer carry out this step of pickling and phosphating.
The first step is degreasing. Degreasing is done with a high-temperature alkali solution, which is to wash the grease off the surface of the processed steel workpiece. This step is actually divided into a series of small steps, one is pre-degreasing, one is the main degreasing, each degreasing after the need for a wash.
The second step is to rust, rust is to use acid (hydrochloric acid) immersion, that is, to remove rust from the surface of the steel workpiece with acid, generally a new steel plate processing can be, if the production is placed for a period of time, a lot of rust, it needs to rust many times. After the rust is finished, wash it.
The third step is surface adjustment, also known as surface adjustment, is to use weak alkali or weak alkali to neutralize the acid and alkali of the processed parts, because the surface of the steel workpiece acid and alkali are harmful to spraying. So the acid and base must be neutralized, so that the surface of the steel work-piece acid and base neutralization (measuring PH value), this process is sometimes not a one-time can be dealt with, after the completion of the meter wash.
The fourth step is phosphating, phosphating also known as zinc phosphating, the purpose is to appear on the surface of the steel workpiece a layer of phosphating film, this film is very fine, with this film, can prevent steel and air contact, prevent oxidation rust, but also better adherence to the plastic powder spraying production line behind.
The fifth step is passivation. Passivation is the last step in acid pickling and phosphating. The aim is to remove a large number of powders which adhere to the surface of the phosphating film after phosphating.
The sixth step is drying, this is the last step of acid cleaning and phosphatingoperation, is the processing of washed steel workpieces with a dryer to dry, remove the surface of the steel workpiece moisture.
The processing time for each of these steps is 40 minutes, including washing, so if you count all the steps and go through them once, you won't be able to complete them in a day. And the process needs a variety of chemicals input, and the greater investment is the subsequent environmental protection treatment input is very huge.
So, now many manufacturers say that they are pickling phosphating, but the price is very low, that is certainly problematic, not false propaganda did not carry out pickling phosphating at all, or the product undertook jerry-building. It is generally believed that the cost of pickling and phosphating is about 1 yuan per kilogram (liquid medicine, site, labor, environmental protection, etc.).
The difference between pickling phosphating and non-pickling phosphatingracks is that the unprocessed racks may be sprayed out of the factory as they were, but because there is no degreasing, rust removal, phosphating, etc. The surface of the steel workpiece is still sprayed with these things, oh, the surface looks very good (in fact, the surface can be distinguished, there is no pretreatment of the surface is uneven, many bubbles, small dots, etc.), can be used for a period of time will be a problem, if the environment is relatively humid, the paint may start to crack for half a year, rust, More than a year, the racks were completely rusted. Even if the environment is dry, the service life will be less than half of the rack life. I have seen a rack we produced 12 years ago, customer cold storage environment, unexpectedly no obvious rust marks, this is the credit of pretreatment, if not pretreated, rack life up to one and a half years.
Welfor is specialized in producing various pallet rack, cantilever rack, medium duty rack, mezzanine and platform, slotted angle shelving, push back rack, longspan rack, rivet rack, drive in rack, carton flow rack, stacking rack and other related storage equipment.
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