Metal Seated Wedge Gate Valve 3" 2500LB Stellite Hardfaced

Product Introduction

This metal seated high pressure wedge gate valve is engineered for the most severe abrasive and erosive service conditions where soft-seated valves would fail within weeks. The ASTM A182 F11 (1.25Cr-0.5Mo) alloy steel body with Class 2500LB pressure seal bonnet is equipped with full Stellite 6 cobalt-based hardfacing on all seating, guiding, and backseat surfaces. This metal-to-metal seating design eliminates the weak point of polymer-based soft seats while providing superior resistance to erosion from entrained catalyst particles, abrasive slurries, high-velocity fluids, and flashing condensate. Proven in fluid catalytic cracking (FCCU) catalyst handling, delayed coker slurry service, coal gasification, and high-temperature erosive steam conditioning applications.

Key Features & Characteristics

• Full Stellite 6 Hardfaced Trim (Trim 5+): Unlike standard Trim 8 (13% Cr) which offers limited hardness, our Trim 5+ specification deposits Stellite 6 cobalt-chromium-tungsten alloy by PTA (Plasma Transferred Arc) welding on all seating, guiding, and backseat surfaces. Stellite 6 maintains hardness (38-45 HRC) up to 500°C where conventional materials soften and gall.
• PTA Welding Process: Plasma Transferred Arc deposition produces a metallurgically bonded overlay with minimal dilution (< 10%) from the base metal, ensuring consistent hardness and corrosion resistance throughout the deposit thickness (minimum 1.5mm after finish machining).
• Guided Wedge with Hardfaced Guides: Both body guide slots and wedge guide surfaces are Stellite 6 hardfaced, preventing galling and seizing during operation, even with abrasive particles embedded in the guiding surfaces.
• Integral Welded Seat Rings: Unlike pressed-in seat rings that can loosen under thermal cycling, our seat rings are PTA welded into the body and then hardfaced, creating a monolithic seat structure with zero leak paths behind the seat.
• F11 Chrome-Moly Body: The 1.25Cr-0.5Mo alloy steel body provides enhanced creep resistance at elevated temperatures (up to 593°C) and resistance to hydrogen attack in refinery hydroprocessing environments.
• Metal Backseat for Packing Protection: A hardfaced backseat on the stem and bonnet allows the valve to be fully backseated in the open position, protecting the packing from line pressure and allowing packing replacement under pressure.

Why Choose Us

• In-House PTA Welding Capability: We operate our own Plasma Transferred Arc welding stations with closed-loop control of all welding parameters, ensuring consistent hardfacing quality from first to last valve in any production batch.
• Hardness Verified on Every Valve: Every hardfaced surface is hardness tested (HRC) at multiple points and documented in the final inspection report. Dye penetrant inspection (PT) of all hardfaced surfaces verifies crack-free deposits.
• Metallurgical Lab Support: Our in-house metallurgical laboratory can perform deposit chemistry verification, microstructure analysis, and dilution rate measurement for critical application qualification.
• Abrasive Service References: Our metal seated valves have demonstrated 3-5x longer service life than standard trim valves in FCCU catalyst handling, delayed coker slurry pumps discharge, and coal slurry pipeline isolation applications.

Technical Parameter Table

FAQ

Q: What is the difference between Stellite 6 and Stellite 21 for valve trim?
A: Stellite 6 (Co-28Cr-4W-1.1C) provides higher hardness (38-45 HRC) and better abrasive wear resistance, ideal for catalyst and slurry services. Stellite 21 (Co-27Cr-5Mo-0.25C) has lower hardness (28-35 HRC) but better corrosion resistance in oxidizing acids and higher thermal shock resistance. We recommend Stellite 6 for abrasive services and Stellite 21 for combined corrosion-erosion in chemical processing.

Q: How do you prevent coating delamination in service?
A: Our PTA welding process creates a true metallurgical bond (not a mechanical coating) between the Stellite overlay and the base metal. The controlled dilution rate (< 10%) ensures the first deposited layer retains full Stellite properties. Pre-heat and post-weld heat treatment per ASME Section IX minimizes residual stresses that could cause cracking. Each deposit is PT inspected for crack-free quality.

Q: Can metal seated valves achieve zero leakage?
A: Metal seated valves typically achieve API 598 leakage Rate B (0.1 mL/min per inch of diameter for liquid, 0.3 ft³/min per inch for gas) rather than Rate A (zero leakage) for soft seated valves. For applications requiring bubble-tight metal-to-metal shutoff, we offer a lapped seat finishing process that can achieve Rate A tightness at an additional cost. Please specify your leakage class requirements when inquiring.