Chemical valve material selection of flying Wolf teach you

For a long time, the corrosion is one of the dangers of chemical equipment is the most headache, a little careless, light damage to the equipment, or caused by accidents and even cause disaster. According to the statistics, about 60% is the destruction of chemical equipment caused by corrosion, therefore in chemical valve selection should first pay attention to the science of material selection. Usually there is a myth that stainless steel is 'a universal material', no matter what medium and environmental conditions are holding out of stainless steel valves, this is very dangerous. Below for some commonly used chemical media talk about selection of sulfuric acid as one of strong corrosive medium, the main points of the 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 is above 80%, the temperature is less than 80 ℃ 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 a pump valve materials; Ordinary stainless steel such as 304 ( 0Cr18Ni9） , 316 ( 0Cr18Ni12Mo2Ti） Also limited use in sulfuric acid medium. So transport of sulfuric acid pump valve usually use high silicon cast iron ( Casting and machining is difficult) , high alloy stainless steel, 20 alloy) Manufacturing. Fluorine plastic has good acid resistance, using fluorine-butterfly valves is a more economical choice. The vast majority don't hydrochloric acid corrosion resistant metal materials ( Including all kinds of stainless steel materials) , also can only be used for high molybdenum ferrosilicon 50 ℃ and below 30% 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 valve ( Such as polypropylene, fluorine plastic, etc. ) Is the best choice of transportation hydrochloride. General metal corrosion and damage, mostly in nitric acid was quickly is the most widely used nitric acid resistant stainless steel material, all to room temperature the concentration of nitric acid have good corrosion resistance, it is worth mentioning the molybdenum stainless steel ( Such as 316, 316 l) For nitric acid corrosion resistance not only no better than ordinary stainless steel ( Such as 304, 321) And sometimes not. For the high-temperature nitric acid, usually with titanium and titanium alloy materials. 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, 316 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 valves or fluorine plastic valves.