KSB Cast Alloy Steel Globe Valve Class 150/300/600 WC6

A217 WC6 (1.25Cr-0.5Mo) body for high-temperature steam and process service up to 593°C. Bolted bonnet, BS 1873 design. Stellite hard-faced seats. NPS 2–10. IBR certified for boiler and power plant applications.

Alloy Steel WC6Class 150, 300, 600NPS 2–10 (DN 50–DN 250)IBR Certified

Specifications

ParameterSpecification
SeriesSICCA 150-600 GLC
Body MaterialA217 WC6 (1.25Cr-0.5Mo Alloy Steel)
Pressure ClassClass 150, 300, 600
Size RangeNPS 2–10 (DN 50–DN 250)
Max Temperature593°C (1100°F)
Max Pressure103 bar (1500 psi)
Design StandardBS 1873
End ConnectionsFlanged RF/RTJ, Butt Weld
Bonnet DesignBolted bonnet, outside screw & yoke
TrimTrim 5 (Stellite/Stellite) for high-temperature service
IBR CertifiedYes
✓ Stellite Hard-Faced Seats✓ IBR Certified✓ BS 1873

Material & Applications

Why Alloy Steel WC6: A217 WC6 contains 1.25% chromium and 0.5% molybdenum, providing significantly better creep and oxidation resistance than carbon steel above 425°C. It is the standard upgrade from WCB for main steam and high-temperature applications. Must be used in normalised and tempered condition.

Typical applications: High-temperature steam systems in power plants, sugar factory boilers, refinery heaters, and process plants where carbon steel WCB reaches its temperature limit. WC6 extends service capability to 593°C with superior creep resistance.

Pressure/Temperature Ratings

Permissible operating pressures per ASME B16.34:

RatingPermissible Operating Pressure at Temperature
Class 150-29 to 38°C: 20 bar316°C: 10 bar427°C: 6 bar593°C: 1 bar
Class 300-29 to 38°C: 52 bar316°C: 42 bar427°C: 35 bar593°C: 7 bar
Class 600-29 to 38°C: 103 bar316°C: 83 bar427°C: 70 bar593°C: 13 bar

Alloy Steel WC6 Globe Valve FAQs

What is WC6 material?
ASTM A217 WC6 is a 1.25% Chromium, 0.5% Molybdenum alloy steel casting grade. The chromium and molybdenum additions provide improved high-temperature strength, creep resistance, and oxidation resistance compared to carbon steel WCB. Temperature limit is 593°C (1100°F). Must be normalised and tempered.
When should I use WC6 instead of WCB?
Use WC6 when operating temperatures exceed 425°C. Carbon steel WCB is not recommended for prolonged service above 425°C due to graphitization risk. WC6 is commonly specified for main steam lines, superheated steam applications, and high-temperature process piping in power plants and refineries.
Is WC6 more expensive than WCB?
Yes, typically 30–50% more than WCB depending on size and class. However, the cost is justified for high-temperature applications where WCB would degrade. Using WCB beyond its temperature limit risks valve failure, which is far more costly than the material premium.
Is this valve IBR certified?
Yes. KSB SICCA 150-600 GLC valves in WC6 meet the requirements of the Indian Boiler Regulations 1950. IBR certification is mandatory for boiler feed, main steam, and reheat steam applications in Indian power plants.

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