Hofmann (Beijing) Engineering Technology Co.,Ltd
Add:6F, East International Building, No.2 DongZhiMen Outside Street, DongCheng District, Beijing
Material 1: 904L, SUS890L Stainless Steel
Austenitic Stainless Steel, which is of fair price, corrosion-resistant and cost-effective, is particularly suitable for general acid (such as sulphate, phosphate) and halide (including Cl-, F-). Due to the high content of Cr, Ni, Mo, it has good resistance to stress corrosion, pitting and crevice corrosion, meeting the requirements of the Cl-containing medium.
Material 2: 254SMO high-quality Stainless Steel
Advanced ultra-low carbon stainless steel which is improved by increasing the content of Mo in 316 Stainless Steel has an excellent resistance to chloride pitting and crevice corrosion. It is suitable for the medium containing salt and inorganic acid which cannot use 316 Stainless Steel.
Material 3: Titanium
Unalloyed titanium with light weight and the density of 4.51 can naturally generate passivation protection film (Ti2O3). Once destroyed, it possesses ‘self-healing’ property, thus its corrosion resistance is better than that of the stainless steel, making it suitable for typical materials containing Cl-(with concentration > 200mg/ L, temperature ≤130°C). In fact, it is incorruptible in the seawater with temperature of no more than 120°C and other chloride solution (such as CaCl2). Generally it can be used in the seawater below 135°C and various kinds of saline (NaCl) below 165°C.
Titanium has good corrosion resistance in the organic acid (such as concentrated nitric acid, concentrated carbonate, etc.) and dilute alkali solution below the boiling point while it is inferior in H2SO4, HCl, HF and aqua regia. Crevice corrosion or stress corrosion may also occur in high temperature (above 120°C) or certain concentrated chloride solution (such as the waste with PH>7 and chloride concentration> 200mg/L). In this case, you should adopt Titanium-Palladium alloy.
Material 4: Titanium-Palladium alloy
The non-alloyed titanium added with palladium (0.12% to 0.25%). Its corrosion resistance in acid medium (especially less harsh conditions) is significantly improved, such as 70% nitric acid, hydrochloric acid containing oxidizing ions (Fe+, Cu+) and electroplating solution. In addition, it can be used for dilute sulphuric acid with the concentration ≤10% and temperature ≤70°C.
Material 5: Ni20 / Ni202
Pure nickel plate with purity of over 99%, mainly used for high-concentration (50%~70%) and high-temperature (up to boiling point) caustic solution (NaOH, KOH, etc.). However, it is susceptible to crevice corrosion caused by chlorides such as brackish water.
Material 6: Hastelloy C-276
Good corrosion resistance, hardly affected by the Cl-, excellent performance in sulfuric acid at various concentrations, one of few materials that can be used in hot concentrated sulfuric acid. It is widely used in organic acid (such as formic acid, acetic acid), high-temperature HF acid and hydrochloride with a certain concentration(<40%), phosphoric acid (≦50%), chloride, fluoride and organic solvent (such as methanol, ethanol).
Material 7: Monel400
Ni (about 70%) - Cu (about 30%) Ni-based alloy. It has good corrosion resistance in non-aerated sulfuric acid with concentration of 80% and temperature of no higher than 50°C~100°C, medium such as HF acid，acetic acid and caustic alkahi with concentration of 50% or less and temperature below 100°C, especially suitable for acidic chloride solution, brine and brackish water and in certain conditions. It has good high-temperature resistance properties. However, it is not suitable for concentrated sulfuric acid, hydrochloric acid and nitric acid, and is sensitive to the corrosion of mercury (sometimes as an impurity).
Material 7: Incoloy 825
It is suitable for sulfuric acid of various concentrations at low temperature and caustic alkali solution at a concentration of 50%~70% (such as NaOH). It has good corrosion resistance and do not generate stress corrosion cracking while it is very sensitive to the crevice corrosion caused by chloride. Further, it doesn’t have good stamping property, thus not a commonly used plate material.