Why Ductile Iron Is Widely Used to Make Valves?

As an alternative to steel, man developed ductile iron in 1949. While cast steel contains less than 0.3% carbon, the amount of carbon in cast iron and ductile iron is at least 3%. Ductile iron has many advantages over ordinary cast iron, which makes it widely used in the manufacture of valves. LIWEI introduces you the characteristics of gate valves and why ductile iron is so famous.

Within ductile iron, the graphite flakes are changed into tiny spheres by a special treatment. This improved sphericity allows for superior physical properties of ductile iron compared to cast iron and steel. It is this spherical microstructure of carbon that gives ductile iron better ductility and impact resistance, whereas the flake form inside cast iron results in cast iron without ductility. The spherical structure inside the ductile iron also eliminates the cracking that can occur with the flake graphite inside the cast iron after the pressure-loaded parts of the ductile iron have been subjected to the ferritization annealing cycle.

In microscopic photographs of ductile iron, cracks can be seen to march to the graphite spheres and then terminate. In the ductile iron industry, these graphite spheres are called "crack terminators" because of their ability to prevent fracture.

Compared to cast iron, ductile iron has a definite strength advantage. The tensile strength of ductile iron is 60k, compared to 31k for cast iron, and the yield strength of ductile iron is 40k, while cast iron does not exhibit yield strength and eventually fractures. The strength-to-cost ratio of ductile iron is far superior to cast iron.

The strength of ductile iron is comparable to the strength of cast steel. Ductile iron has a higher yield strength and exceeds the corrosion and oxidation resistance of cast steel in most municipal applications such as: water, salt water, steam, etc. Due to its spheroidal graphite microstructure, ductile iron is superior to cast steel in its ability to damp vibrations and is therefore more conducive to stress reduction. You can find more details and specifications in LIWEI, and we also have check valves for sale.

Gate Valves

The improved gate valve has significant advantages such as light switch, reliable seal, good elastic memory and long service life. It can be widely used in water, sewage, construction, petroleum, chemical, food, medicine, light textile, electric power, ships, metallurgy, energy systems and other body pipelines as a regulating and intercepting device.

1, Light weight: the body is made of high-grade ductile iron, the weight is about 20%~30% lighter than the traditional gate valve, easy to install and maintain.

2, Flat-bottom gate: traditional gate valve is often in the water wash pipe that is due to foreign objects such as stones, wood, cement, iron, debris, etc. silt in the bottom groove of the valve, easy to close the tight and form a leak, resilient seat gate valve bottom with the same flat bottom design of the water pipe machine, not easy to cause debris siltation, so that the fluid flow unimpeded.

3, Overall rubber cover: The gate adopts high quality rubber for overall internal and external rubber cover, the European first-class rubber vulcanization technology makes the gate after vulcanization can guarantee the precise geometry, and the rubber and ductile ink cast gate is firmly attached, not easy to fall off.

4, Precision cast valve body: The valve body is precision cast, and the precise geometry makes the valve sealing without any finishing inside the valve body.

In addition, an important reason for choosing ductile iron is that it is less costly than cast steel. The low cost of ductile iron makes this material more popular, with more efficient casting and less machining cost of ductile iron.LIWEI is a professional valve manufacturer, we sell all kinds of gate valves and butterfly valves, etc. Ductile iron gate valves are also one of the most popular products. If you need, contact us now, LIWEI will provide professional service for you.