GB/API Standard Cast Steel /Stainless Steel Flanged Slab Gate Valve

Specification

TIANYU GB/API Standard Cast Steel/Stainless Steel Flanged Slab Gate Valves: Multi-Standard Solutions for Industrial Fluid Control

I. Product Overview

TIANYU GB/API standard flanged slab gate valves are engineered for industrial fluid systems, constructed from cast steel (WCB/WCA) or stainless steel (304/316), compatible with GB/T 12234, API 6D, and other international/domestic standards. The valves achieve fluid shut-off via a slab gate lifting mechanism, with a straight-through flow path minimizing pressure loss, suitable for high-pressure applications involving oil, natural gas, water, and other media. Ranging from DN32 to DN800 (1-1/4″ to 32″) in nominal diameter and PN1.6 to 16.0MPa (Class150 to 400LB) in pressure rating, they meet rigorous demands in chemical, energy, municipal, and other sectors.

II. Core Technical Parameters

Specifications & Pressure Ratings
- Nominal diameter: DN32-DN800 (1-1/4″-32″), supporting NPS 1″-32″ inch conversion
- Pressure classes: PN1.6/2.5/4.0/6.4/10.0/16.0MPa (Class150/300/400)
- Temperature range: -29°C to 425°C (low-temperature type down to -196°C, high-temperature up to 550°C)
Materials & Sealing System
- Body/gate: Cast steel (WCB/WCC), stainless steel (CF8/CF8M), tensile strength ≥485MPa
- Sealing pair: Metal hard seal (STL overlay) or soft seal (NBR/PTFE), leakage rate compliant with API 598
- Stem: 2Cr13 stainless steel, chrome-plated surface (hardness ≥HRC35), corrosion-wear resistant
Connections & Actuation
- Flange standards: ASME B16.5, GB/T 9113, HG/T 20592, etc., supporting multi-standard adaptation
- Actuators: Manual (handwheel/gear), pneumatic, hydraulic, electric, with ISO 5211 mounting interface

Product Overview

III. Structural Design & Technical Features

Slab Gate Flow Optimization
- Straight-through full-bore design, flow coefficient Cv 20% higher than conventional gate valves, ideal for pigging operations
- Double-eccentric gate-seat structure, automatically compensating for wear during opening/closing, sealing specific pressure ≥15MPa
Multi-Standard Compatibility
- Compliant with GB/T 12234 (China), API 6D (US), GOST 594 (Russia) design standards simultaneously
- Flange dimensions compatible with ASME B16.5 and GB/T 9112 for easy international project replacement

IV. Manufacturing Processes & Quality Control

Precision Casting & Heat Treatment
- Lost foam casting process, body blank dimension tolerance ≤±0.8mm, surface roughness Ra≤12.5μm
- Cast steel parts normalized at 920°C + tempered at 650°C to eliminate internal stress, impact energy ≥34J (-20°C)
3D Quality Inspection
- Ultrasonic testing (UT): 100% body inspection, conforming to GB/T 2970, defect evaluation grade ≥III
- Pressure testing: Shell test at 1.5x working pressure (30min hold), sealing test at 1.1x pressure (zero leakage)
- Spectral analysis: C, Cr, Ni element deviation ≤0.05% per heat to ensure material consistency
Surface Treatment Technology
- Cast steel parts with zinc-rich epoxy primer (dry film thickness ≥80μm) + topcoat (RAL7035 industrial gray)
- Stainless steel parts pickled and passivated, salt spray test ≥500 hours without corrosion

Valve Details

V. Core Product Advantages

Multi-Medium Adaptability
- Oil & gas: H2S corrosion resistance (optional NACE MR0175 certified materials)
- Chemical processes: Stainless steel compatible with acid/alkali media, seals resistant to strong corrosion (e.g., 316+VITON)
- Municipal engineering: Wear-resistant coatings suitable for sewage, seawater, and other particulate-laden media
Long-Life Maintenance-Free Design
- Stem packing with V-type composite seal (PTFE+graphite), service life ≥8 years
- Replaceable seat design allows on-site maintenance without pipeline disassembly, reducing maintenance costs by 40%
Global Service Support
- Certification system: ISO 9001, API 6D, CE-PED certified, registered for Russian GOST R
- Delivery capability: 7-day delivery for standard products, 35 days for customized items, 100% on-time delivery rate
- After-sales guarantee: 18-month warranty with online installation guidance and fault diagnosis

Application

VI. Application Scenarios & Cases

Petroleum Refining: A refinery’s atmospheric-vacuum unit adopted DN300 PN10.0MPa cast steel slab gate valves, reducing pressure drop from 0.3MPa to 0.1MPa, saving 120,000 kWh annually.
Natural Gas Pipeline: A West-East Gas Pipeline branch used DN600 Class300 stainless steel gate valves with NACE-certified materials, operating leak-free for 5 years in 150ppm H2S conditions.
Municipal Heating: DN800 PN1.6MPa gate valves in northern central heating networks, with graphite seals maintaining integrity at 180°C steam, annual leakage ≤0.5m³.
Seawater Desalination: DN200 Class150 stainless steel gate valves, 316L material + Teflon coating, resisting seawater chloride corrosion (Cl- content ≥20,000ppm).

VII. Customization Solutions

Material Customization
- Low-temperature conditions: LCB/LCC cast steel (-46°C), 304L (-196°C)
- High-temperature/high-pressure: A105N+STL overlay (425°C, PN16.0MPa)
Functional Enhancements
- Fire-safe design: Compliant with API 6FA, ensuring 30-minute leakage-free performance during fires
- Anti-static structure: Conductive spring between gate and body, static grounding resistance ≤10Ω
Special Interfaces
- Butt-welded (BW) connection: Conforms to ASME B16.25, suitable for high-pressure pipelines
- Threaded (NPT) connection: API 5B standard, for instrument pipelines DN≤50mm

VIII. Installation & Maintenance Guide

Installation requirements: Flange parallelism deviation ≤0.1mm/m, bolt pre-tightening torque per ASME PCC-1
Maintenance cycle: Inspect packing seal every 12 months, replace sealing grease every 36 months
Troubleshooting: Common leakage points at seats and packing, replaceable seal components online