A Layer of brittle and hard ferric oxide will on the surface of the steel strip during the hot rolling,and the ferric oxide layer will affect the sueface quality of the strip during cold rolling.Pickling process is ap-plied for removing the ferric oxide.The pickling line is divided into Push-pull Pickling Line(Semi-continuous Pickling Line) and continuous pickling line.Send InquiryChat Now
Introduction of pickling(PPPL)
How to select the anti-corrosion of PPPL project?First, the structure and raw material selection of the fiberglass pipe and storage tank, followed by the floor of the workshop and the basic corrosion protection of the equipment are generally made of resin mortar floor structure.Structural and raw material selection of glass reinforced plastic pipes and tanks.The storage tank and piping system and acid mist recovery system used in the pickling project are now mainly made of fiberglass, and the structure is anti-seepage layer + anti-corrosion layer + structural strength layer.In general, the impermeable layer and anticorrosive layer are at least 6~8 mm thick.The resin is suitable for corrosion resistant epoxy vinyl ester resin. The experts recommend that bisphenol A epoxy vinyl resin should be used when the medium is non-oxidizing acid and the temperature condition is not very high.Phenolic epoxy vinyl resin should be used when the oxidation acid and temperature condition are high.In order to reduce the cost structure, the polystyrene unsaturated polyester resin was selected, and the thickness was calculated according to the specific structure design.Mixed acid and waste acid storage tank due to corrosion medium is more complex, generally choose PVDF/FRP composite cans, but between PVDF composite cans and glass fiber reinforced plastic binder is a problem to be solved, and the price is higher due to cost increase, appropriate chooses hite acid resin (791 h) as lining anticorrosion material, can satisfy the requirement of the above medium of anti-corrosion.
1. Suitable for pickling method of wire and semi-finished products Wire is now taken as an example to describe several commonly used pickling processes. As for semi-finished products that have undergone heat treatment, they are generally not subjected to shelling and rust removal, that is, directly to pickling. The other operating sequence is the same as the wire.
(1) The process of the pickling process, which mainly includes peeling and lime paste, is as follows. Wire rods - → peeling rust - → pickling - → washing - → high-pressure water rinse - → fat and lime paste - → dry This process has been widely used in the past, and is suitable for the drawing of raw carbon steel wire, structural steel wire, steel-cored-aluminum-stranded steel wire, general spring steel wire blanks and semi-finished products. The disadvantage is that it has a lot of dust and has been replaced by other pickling processes.
(2) PPPL process mainly based on peeling and rusting - its process flow is. Wire rods - → peeling rust - → pickling - → washing - → high-pressure water rinse - → rust - → thin lime water - → dry This kind of drawing dust is less and it is currently used more often. It is suitable for the drawing of blanks and semi-finished products such as plain carbon steel wire, structural steel wire, rope-making steel wire, steel-cored-aluminum-strand wire, general spring wire, and the like. Some units also eliminate the need for rusting and direct ashing after rinsing.
(3) Pickling (PPPL)and phosphatizing pickling process.
Process flow Wire rods - → peeling rust - → pickling - → washing - → high-pressure water rinse - → phosphating - → rinse - → saponification - → dry Some units use this process for the drawing and semi-finishing of general spring steel wire. However, in the heat treatment, it is only suitable for electric contact furnace, but not for the fuel heat treatment furnace, because it will cause blockage of the Mavr brick furnace hole (electrical exposure furnace does not have this defect). This kind of process is not suitable for the pickling of rough blanks. For thick gauge wire rods, the thicker phosphatizing layer remaining after drawing will also cause lead to hang, which is especially unfavorable for high-grade steel wires and has a high cost. (4) The process of pickling process based on normalizing and rusting is: Wire-→Normalizing→→Pickling→→Washing→→High-pressure water rinsing→→Rusting→→Dip-lime→-Dry This process is different from the above, it does not shell rust and need to go through normalizing, suitable for the drawing of high strength spring steel wire blanks and other wire semi-finished products.