The way to choose material of chemical pumps
The corrosion is one of the most dangerous harm to chemical equipment all the time, a little carelessness will damage the equipment or cause accidents and disasters. According to statistics, 60% of damages are caused by corrosion, so it’s first to choose the material of pumps.
It’s a misconception that a lot of people think stainless steel is almighty. Now let’s talk about the point of choosing materials for chemical medium.
1, Sulfuric acid(H2SO4)is one of the most strong corrosive medium, and it’s widely used as industrial raw materials. Different temperature and concentrations have different corrosive, if the concentration is higher than 80%,temperature is lower than 80℃ cast iron is best, but it’s not appropriate to high speed flow Sulfuric acid and not suitable to make pump valve.
General stainless steel like SS304 (0Cr18Ni9) and SS316 (0Cr18Ni12Mo2Ti) are limited use to Sulfuric acid. So we often use high silicon cast iron (different processing) and high alloy stainless steel.
Fluorine plastic has good ability of corrosion resistance and fluorine pump is economical.
The pumps’ type is IHF fluorine plastic pump, PF (FS) centrifugal pump, CQB-F fluorine plastic magnetic pump.
2, Hydrochloric acid Most of metallic materials are not resistant to hydrochloric acid corrosion (include a lot of stainless steel materials).Molybdenum containing high silicon iron only use for the hydrochloric acid that temperature below 50centigrade concentration below 30%.On contrary, a lot of non-metallic materials have good ability of corrosion resistance, so lining rubber pumps and plastic pumps (polypropylene, fluorine plastic) are the best choose.
The pumps’ type are: IHF fluorine plastic pump, PF (FS) centrifugal pump, CQ fluorine plastic magnetic pump.
3, Nitrate acid General metals are damaged in nitrate acid quickly, tainless steel is widely used, it has good ability of corrosion resistance in normal temperature and all kinds of concentration. The ability of corrosion resistance of stainless steel containing molybdenum like SS316,SS316L are not better than SS304,SS321.We often use titanium and titanium alloy materials for high temperature nitrate acid.
Our pumps’ type are: DFL(W)H chemical pump, DFL(W)PH shielding chemical pump, DFCZ process pump, DFLZP self-priming chemical pump, IH chemical pump, CQB magnetic pump, the material is SS304.