1. Cast iron is a cast iron with flake graphite, which is called cast iron because the fracture is dark gray when broken. The casting performance, cutting performance and wear resistance of cast iron are very good. Its disadvantage is that the strength, plasticity, and toughness are lower than other cast irons. The cast iron butterfly valve is suitable for weak acid and weak alkaline media such as water and air, but not suitable for pipelines with hydrochloric acid and nitric acid media.
2. Ductile iron is a kind of high-strength cast iron material, its strength, toughness, wear resistance are very high, comprehensive performance is close to steel, we often say "replace steel with iron" refers to ductile iron. Ductile iron butterfly valves have a certain degree of corrosion resistance, and their performance is much higher than that of cast iron butterfly valves. The media that can pass through include steam, general gases and oils.
3. Cast steel is a cast iron alloy, a general term for iron-based alloys used to produce castings that do not undergo eutectic transformation during solidification. The advantages of cast steel materials are greater design flexibility and variability, improved overall structural strength and wide range of weight changes. The butterfly valve is made of cast steel, which has better performance than cast iron but not as good as stainless steel. The medium that the cast steel butterfly valve can pass through includes steam, non-corrosive gas, petroleum, etc.
4. Stainless steel refers to steel that is resistant to weak corrosive media such as air, steam, and water, and chemically corrosive media such as acid, alkali, and salt. It is also called stainless acid-resistant steel. The stainless steel butterfly valve has good performance and can be used in more severe working conditions. It is used in some ultra-high temperature, ultra-low temperature, acid and alkali corrosive media pipelines. At the same time, the stainless steel butterfly valve has stronger hardness, more wear resistance and long service life long.