Plate heat exchanger plate is a plate specifically used in plate heat exchangers to isolate the medium and perform heat exchange. It is an important part of plate heat exchangers. Its main materials are stainless steel (SUS304.316), titanium and titanium palladium (Ti, Ti-Pd), 20Cr, 18Ni, 6Mo (254SMO), alloy (C276), copper (H68).
1.904L, 890L stainless steel. This is a cost-effective austenitic stainless steel that combines both price and corrosion resistance. It has good corrosion resistance and is especially suitable for general acids such as sulfuric acid and phosphoric acid and halides (including Cl-, F-). Due to the high content of Cr, Ni and Mo, it has good resistance to stress corrosion, pitting and crevice corrosion.
2.254 SMO advanced stainless steel. The ultra-low-carbon high-grade stainless steel modified by increasing the Mo content has excellent resistance to chloride pitting and crevice corrosion. It is suitable for mediums such as 316 salt water and inorganic acids.
3. Titanium. Unalloyed titanium, light weight, density 4.51, it can naturally generate a passivation protective film (Ti2O3). Once damaged, it has "self-healing", so it has better corrosion resistance than stainless steel. It is a typical material suitable for chlorine-containing media (Cl-concentration> 200mg / L, temperature ≤130 ℃).In seawater and other chloride (such as CaCl2) solutions up to 120 ° C, it is virtually uncorroded.Generally, it can be used in seawater below 135 ° C and brine (NaCl) with various concentrations below 165 ° C.Titanium has good corrosion resistance in organic acids (such as concentrated nitric acid and concentrated carbonic acid) and dilute lye below the boiling point.Titanium has poor corrosion resistance in H2SO4, HCl, HF and aqua regia. In some concentrated chloride solutions at high temperature (above 120 ° C) (such as wastewater with pH> 7 and chloride concentration> 200mg / L), crevice corrosion or stress corrosion may also be caused. At this time, titanium-palladium alloy should be selected.
4.Hastelloy C-276 has good corrosion resistance. C-276 has excellent corrosion resistance to various concentrations of sulfuric acid. It is widely used in organic acids (such as formic acid, acetic acid), high-temperature HF acid and certain concentrations of hydrochloric acid (<40%), phosphoric acid (≤50%), chloride , Fluoride and organic solvents (such as methanol, ethanol).
5. Nickel 200. This is a pure nickel plate containing more than 99% nickel. It is mainly used for caustic solution (NaOH, KOH) with high concentration (50% ~ 70%) and high temperature (up to boiling point). However, it is sensitive to crevice corrosion caused by chlorides such as brackish water.