904L National Standard Flange Butterfly Valve

Description

904L (00Cr20Ni25Mo4.5Cu) is a high-alloy stainless steel engineered for severe service:

• Superior Sulfuric Acid Protection: The specific addition of Copper grants this valve outstanding resistance to sulfuric acid across a wide range of concentrations.
• Pitting & Crevice Defense: High molybdenum and nickel content ensure the valve remains intact in high-chloride environments where standard 316L would fail.
• Stress Corrosion Cracking (SCC) Immunity: The high nickel concentration provides a robust defense against SCC, ensuring long-term structural integrity in volatile chemical processing.

Features

• Multi-Level Metal Seal: The seal features interleaved layers of stainless steel and flexible graphite. This “hard-soft” layering provides the durability of a metal-to-metal seal with the zero-leakage performance of a flexible seal.
• Hardened Sealing Surface: The valve seat is reinforced with cobalt-based alloy (Stellite) welding, offering extreme resistance to wear and high-velocity fluid erosion.
• Torque-Tightened Integrity: The “more closed, more tight” design allows the seal to be adjusted by torque, ensuring a reliable “never-pass” seal even under high-pressure shocks.
• Nimble Operation: The unique structure reduces effort during manual or automated operation, remaining unaffected by high medium pressures.

Specifications

Applications

• Chemical Industry: Sulfuric and phosphoric acid production and transport.
• Petrochemical: Refining processes involving aggressive acidic catalysts.
• Pollution Control: Flue gas desulfurization (FGD) systems in power plants.
• Metallurgy: High-temperature corrosive gas handling and acid pickling lines.