About all kinds of corrosive medium conditions of chemical regulator type selection in sulfuric acid, hydrochloric acid, nitric acid, acetic acid, alkali, Sodium hydroxide) , ammonia, Ammonia hydroxide) , chlorine ( Liquid chlorine) , brine ( The sea) , alcohols, esters, ketones, ethers, corrosive medium, such as working conditions of valve, anti-corrosion chemical equipment is the key place, if can't choose the right chemical valve metal material, a little careless, light damage to the equipment, or caused by accidents and even cause disaster. In this paper some commonly used chemical media talk about the main points of the valve material selection: 1. Sulfuric acid medium of sulfuric acid as one of strong corrosive 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 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 the material of the valve; 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 valve) Manufacturing. Fluorine plastic has good acid resistance, fluorine-butterfly valves ( F46） Is a kind of more economical choice. If too much pressure, temperature, plastic valve with hit points, can only choose ceramic ball valve is more expensive than it. 2. Hydrochloric acid medium most metal materials ( Including all kinds of stainless steel materials) Don't resist the corrosion of hydrochloric acid, 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. But if such medium temperature over 150 ℃, or pressure is greater than PN16 kg, any plastic ( Including polypropylene, fluorine plastic even ptfe) Will not be able to do, but at present, there is no ideal valve on the market, but can have a try now emerging ceramic ball valve, the valve has the advantage of self-lubrication, torque force is small, not aging, service life is much longer than the average valve, its shortcoming is that price is much higher than the plastic valve. 3. General metal nitric acid medium corrosion and damage, mostly in nitric acid was quickly stainless steel is the most widely used of nitric acid resistant 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 ball valve and titanium alloy materials. 4. Acetic acid medium of acetic acid 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 or fluorine plastic pump. 5. Alkali ( Sodium hydroxide) Steel is widely used in under 80 ℃, 30% concentration of sodium hydroxide solution, there are also many petrochemical enterprise under 100 ℃, 75% still USES the ordinary steel, while 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. Gate valves for high temperature and alkali liquor with titanium and titanium alloy or high alloy stainless steel. 6. Ammonia ( Ammonia hydroxide) Most metals and non-metallic liquid ammonia and ammonia ( Ammonia hydroxide) The corrosion is very slight, only copper and copper alloy should not be used. 7. Chlorine ( Liquid chlorine) Most metal Industrial Valves resistance to corrosion of chlorine gas is very limited, especially chlorine water, including all kinds of alloy steel valves, in this case, the lining ptfe Industrial Valves is a very good choice, but in the production of chlor-alkali chemical factory will find: lining ptfe valve with a slightly long, torque force increase, four fluorine aging problem will be highlighted, in this case the leak is fatal. Consider using four fluorine lined ceramic ball core to replace the original common lining ptfe valve, using ceramic self-lubrication and four fluorine corrosion resistance will be a perfect effect. 8. 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, 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. 9. Brine ( The sea) Ordinary steel in sodium chloride solution and sea water, salt water corrosion rate is not too high, the coating should be used in general protection; All kinds of stainless steel has a very low uniform corrosion rate, but may be localized corrosion caused by chloride ion, usually adopts 316 stainless steel is better.
Shenzhen Mech Valve Trading Co., Ltd. promises that we will manufature our products in accordance with the strictest quality standards.
To know more about flanged gate valve resilient gate valve, visit Mech Valve for more reviews, tips and advice. Shenzhen Mech Valve Trading Co., Ltd. won't let you down for your options. visit!
Unlike the os & y valve fire protection, the is more flexibly used in accasions where y gate valve .