Cast Iron Ball Valves

​I. Basic Structure of Cast Iron Ball Valves​

A cast iron ball valve primarily consists of the following components:

1. ​Body: Made of gray cast iron (HT200/HT250) or ductile iron (QT450-10), providing pressure resistance and corrosion resistance.
2. ​Ball Core: Typically made of stainless steel (SS304/SS316), designed in a spherical shape to enable 90° rapid opening and closing.
3. ​Seat: Sealing materials include PTFE, RPTFE, or metal seals, suitable for different media.
4. ​Stem: Stainless steel material (e.g., 2Cr13), connected to the ball core to drive valve operation.
5. ​Actuation: Supports manual, pneumatic, or electric operation, adapting to industrial automation needs.

​II. Material Properties and Selection​

​Types of Cast Iron:

• ​Gray Cast Iron: Low cost, excellent castability, suitable for low-pressure and ambient temperature environments (e.g., standard water supply systems).
• ​Ductile Iron: High strength and toughness, with a pressure rating up to PN16, ideal for municipal water supply and industrial pipelines.

​Sealing Materials:

• ​Soft Seal (PTFE): Corrosion-resistant and highly sealing, suitable for non-corrosive media (water, steam).
• ​Metal Seal: Withstands high temperature and pressure, applicable in harsh environments such as oil and chemical industries.

​III. Technical Parameters and Performance​

1. ​Nominal Pressure: Commonly PN16 (1.6 MPa), with some models reaching PN25.
2. ​Temperature Range: -20°C to 150°C (soft seal); special designs can withstand higher temperatures.
3. ​Applicable Media: Water, steam, oil, gas, and non-corrosive industrial fluids.
4. ​Size Specifications: DN15 to DN300, with flange connections compliant with GB and DIN standards.

​IV. Application Scenarios​

1. ​Municipal Engineering: Water supply systems, wastewater treatment, due to cost-effectiveness and corrosion resistance.
2. ​Industrial Fields: Oil, chemical, and power industries, requiring high-pressure or high-temperature resistance (select ductile iron + metal seals for such cases).
3. ​Building Equipment: HVAC systems, fire protection, relying on rapid shut-off capabilities.