How to select the corrosion resistance of pneumatic valve

　 . As one of the strong corrosive medium, sulfuric acid medium: sulfuric acid is an important industrial raw material is very versatile. Corrosion of different concentration and temperature of sulfuric acid on the material difference is bigger, the concentration in the % above, temperature less than ℃ concentrated sulfuric acid, carbon steel and cast iron has good corrosion resistance, but it is not suitable for high-speed flow of sulfuric acid, is not used as pump pneumatic valve materials; Ordinary stainless steel such as ( CrNi、( CrNiMoTi also limited use for sulphuric acid medium. So transport of sulfuric acid pump pneumatic valve usually use high silicon cast iron ( Casting and machining is difficult, high alloy stainless steel, Alloy manufacture. Fluorine plastic has good acid resistance, the use of pneumatic valve fluorine-butterfly pump ( F is a more economical choice.
　　. Hydrochloric acid medium: most don't hydrochloric acid corrosion resistant metal materials ( Including all kinds of stainless steel material, high molybdenum silicon also can only be used for ℃, % the following hydrochloric acid. And metal materials contrary, the vast majority of non-metallic materials of hydrochloric acid have good corrosion resistance, so the lining rubber and plastic pump ( Such as polypropylene, fluorine plastic is the best choice of transportation hydrochloride.
　　. Nitric acid medium: general metal corrosion and damage, mostly in nitric acid was quickly is the most widely used nitric acid resistant stainless steel material, all on room temperature the concentration of nitric acid have good corrosion resistance, it is worth mentioning the molybdenum stainless steel ( Such as, L of nitric acid corrosion resistance not only no better than ordinary stainless steel ( Such as, and sometimes even better. For the high-temperature nitric acid, usually with titanium and titanium alloy materials.
　　. Acetic acid medium, it is one of the strongest material corrosion in organic acids, ordinary steel in all concentration and temperature of severe corrosion of acetic acid, acetic acid proof material is stainless steel, stainless steel containing molybdenum can also apply to high temperature and dilute acetic acid steam. For high temperature and high concentration of acetic acid or contain other corrosive medium such as strict requirements, can choose high alloy stainless steel or fluorine plastic pump.
　　. Alkali ( Sodium hydroxide: steel is widely used in ℃ below, % concentration of sodium hydroxide solution, there are also many petrochemical plant in ℃, while % the following USES the ordinary steel, although the corrosion increases, but the economy better. Ordinary stainless steel for corrosion resistance of lye no significant advantages compared to cast iron, as long as the medium for allowing a small amount of iron added, stainless steel is not recommended. For high temperature and alkali liquor with titanium and titanium alloy or high alloy stainless steel.
　　. Ammonia ( Hydroxide ammonia: most metal and non-metallic liquid ammonia and ammonia ( Hydroxide in the ammonia corrosion is very slight, only copper and copper alloy should not be used.
　　. Brine ( Water: the ordinary steel in sodium chloride solution and sea water, salt water corrosion rate is not high, the coating protection should be used in general; All kinds of stainless steel has a very low uniform corrosion rate, but may be localized corrosion caused by chloride ion, usually adopt stainless steel is better.
　　. Alcohols, esters, ketones, ethers, common alcohol medium such as methanol, ethanol, ethylene glycol, propylene glycol, ketone medium such as acetone, butanone, there are all kinds of methyl esters medium, ethyl ester, ethers media such as methyl ether, ethyl ether, butyl ether, their basic no corrosive, commonly used materials are applicable, the specific selection should also according to the requirements of the dielectric properties and related make reasonable choice. In addition it is worth noting that the ketone, ester, ether has solubility to a variety of rubber, when choosing sealing material to avoid mistakes.
there are many other media can not cover here, anyhow when select material should not be arbitrary and blind, or use for reference the experience of mature should refer to more related information.