National Standard Flange Shut-Off Valve | DN15–300 | PN10–40

National Standard Flange Shut-Off Valve - flow control for on-off fluid, flange install/maintain. Complies GB/T 12224/12229/12234/12235 - quality, GB pipeline compatibility. Secure flange - strong, good sealing, easy disassembly, large-diameter/HP. Reliable shut-off - core/seat precision grinding, metal or soft seal (PTFE/EPDM/NBR), zero leakage. Durable - cast steel (WCB/WC6/WC9), stainless (CF8/CF8M/CF3/CF3M), ductile iron (QT450-10). Easy operation - cast iron/SS handwheel, light, smooth stem, short stroke. Wide range - water/steam/oil/gas/chemical, industrial/civil. DN15–300 (1/2"–12"), PN10–40 (CL150/300), -20~425℃ (HT opt 550℃). Operation manual/pneumatic/electric. Stem 1Cr13/2Cr13/304/316. Test GB/T13927/API598. Exported SE Asia/Middle East/Africa/South America. OEM/ODM direct.

1. Strictly GB-Compliant - GB/T 12224/12229/12234/12235, Precise Dimensions, Standardized Flange (GB/T 9112-9124), Consistent Performance, Matches GB Pipelines/Equipment, No Compatibility Issues: Fully meets Chinese National Standards (GB/T 12224, GB/T 12229, GB/T 12234, GB/T 12235), with precise dimensions, standardized flange connections, and consistent performance. It can be perfectly matched with GB-standard pipelines and equipment, avoiding compatibility problems in installation and replacement. GB/T 12224 specifies steel valve dimensions, face-to-face, and end connections - ensuring interchangeability with any GB-compliant valve of the same size/pressure. GB/T 12229 covers general-purpose cast steel valves - material, design, and performance requirements. GB/T 12234 specifies steel valves with flanged and butt-welding ends. GB/T 12235 covers steel globe valves specifically. The flange dimensions comply with GB/T 9112-9124 (steel pipe flanges - types, dimensions, tolerances) - including GB/T 9113 (integral flanges), GB/T 9115 (weld neck), GB/T 9116 (slip-on), GB/T 9117 (socket weld), GB/T 9119 (plate flat), etc. This strict GB compliance means the valve drops directly into any GB-standard piping system - no adapters, no modifications, no dimensional surprises. It is especially valuable for projects in Southeast Asia, the Middle East, Africa, and South America - regions where GB-standard piping and equipment are widely used (often supplied by Chinese EPC contractors). The consistent quality and interchangeability simplify spare parts management and reduce long-term maintenance costs. Each valve is dimensionally inspected against GB standards before shipment - ensuring every unit meets the specified tolerances.

2. Secure Flange Connection - Strong Connection Stability, Good Sealing, Easy Disassembly, Large-Diameter/HP Systems, Quick Maintenance No Pipeline Removal, Reduces Downtime: Adopts standard flange connection (GB/T 9112-9124), with strong connection stability, good sealing performance, and easy disassembly. It is suitable for large-diameter, high-pressure pipeline systems, and can be quickly maintained without removing the entire pipeline - reducing downtime. The flanged connection is the most versatile and widely used end connection for industrial valves: (a) Strong and rigid - the flange joint distributes bolt load evenly, providing a secure, vibration-resistant connection suitable for high pressure and large diameters; (b) Good sealing - the flange face (RF raised face standard, FF flat face optional) with appropriate gasket (spiral-wound graphite/stainless, PTFE, rubber) provides reliable sealing; (c) Easy disassembly - simply unbolt the flange bolts to remove the valve for maintenance or replacement - no cutting or welding required; (d) Suitable for large-diameter/HP - flanged connections are standard for DN≥15 and all pressure classes in this range (PN10–40); (e) Quick maintenance - the valve can be removed and replaced in minutes, minimizing pipeline downtime - critical for continuous-process industries. The flange connection also allows the valve to be installed between any two standard GB flanges - no special tools or skills required. For high-pressure service, the number and grade of flange bolts are specified per GB/T 9112 - ensuring the joint can withstand the rated pressure. The gasket selection should match the media and temperature: spiral-wound graphite for high-temp steam/oil, PTFE for chemical/corrosive, rubber for water/low-temp. The flanged design combined with the bolted bonnet means the entire valve (body + bonnet + trim) can be serviced without removing the body from the line - further reducing maintenance time.

3. Reliable Shut-Off & Throttling - Optimized Core/Seat, Precision Grinding, Tight Fit, Metal-to-Metal or Soft Seal (PTFE/EPDM/NBR), Zero Leakage Rated P/T, On-Off + Simple Flow Regulation: The valve core and seat adopt a precision grinding process, with tight fit and excellent sealing performance. The metal-to-metal or soft-seal structure (PTFE, EPDM, NBR) can effectively prevent fluid leakage, ensuring zero leakage under rated pressure and temperature, and improving the safety of the pipeline system. Different from ordinary shut-off valves, this national standard flange shut-off valve adopts an optimized valve core and seat structure - not only ensures reliable shut-off performance to prevent fluid leakage, but also has good throttling performance, making it suitable for both on-off control and simple flow regulation scenarios. The precision grinding (lapping) of the disc and seat sealing surfaces achieves a mirror-like finish (Ra ≤0.8μm) - ensuring intimate contact and zero visible leakage. Two sealing options: (a) Metal-to-metal seal - disc and seat both metal (1Cr13/2Cr13 stainless, or Stellite hardfaced for severe service), suitable for high temperature (>200℃), high pressure, steam, oil, and general service; durable, long-lasting; (b) Soft seal - PTFE (chemical, ≤200℃, bubble-tight), EPDM (water/steam/oil, ≤150℃, good elasticity), NBR (oil/water, ≤120℃, oil-resistant) - provides bubble-tight (zero bubble) sealing for gases and low-temperature service. The optimized core/seat geometry (tapered or plug profile) enables flow proportional to disc lift - allowing simple flow regulation (throttling) in addition to positive shut-off. This dual capability (on-off + throttling) makes the valve more versatile than a gate valve (on-off only). Every valve is 100% seat-tested at 1.1× rated pressure per GB/T 13927 / API 598 - zero leakage for soft seats, zero visible leakage for metal seats.

4. Durable Material Selection - Cast Steel (WCB/WC6/WC9), Stainless (CF8/CF8M/CF3/CF3M), Ductile Iron (QT450-10), Corrosion/HT/HP Resistant, Harsh Environments, Long Service Life: The valve body is made of high-quality cast steel (WCB, WC6, WC9), stainless steel (CF8, CF8M, CF3, CF3M), and other materials, which have excellent corrosion resistance, high temperature resistance, and pressure resistance, adapting to various harsh working environments and extending the service life of the valve. Material options: (a) Cast steel WCB (ASTM A216 WCB) - carbon steel, general water/steam/oil service, -29~425℃, most common and economical; (b) WC6 (ASTM A217 WC6) - 1.25Cr-0.5Mo alloy cast steel, high-temperature service to 550℃+, power plant steam, hydrogen; (c) WC9 (ASTM A217 WC9) - 2.25Cr-1Mo alloy cast steel, higher temperature than WC6, high-pressure high-temperature steam, refinery; (d) CF8 (ASTM A351 CF8) - 304 stainless cast, general corrosive, nitric acid, oxidizing; (e) CF8M (ASTM A351 CF8M) - 316 stainless cast with molybdenum, improved pitting/crevice resistance, chloride/seawater/chemical/acetic acid/urea/pharma; (f) CF3/CF3M - low-carbon 304L/316L cast, improved weldability and intergranular corrosion resistance, critical corrosive/sanitary; (g) Ductile iron QT450-10 - nodular cast iron, high strength/toughness, economical, water/general service, -20~350℃. The valve stem is stainless steel (1Cr13, 2Cr13 - hardenable, wear-resistant; 304, 316 - corrosion-resistant). All materials undergo strict quality inspection - chemical composition, mechanical properties (tensile, hardness), UT for castings - ensuring structural integrity. The cast body is shot-blasted and coated (epoxy paint for carbon/ductile iron, pickled/passivated for stainless) for external corrosion protection. This wide material range allows optimal selection per medium, temperature, and pressure - ensuring long service life in any application.

5. Easy Operation - High-Strength Cast Iron/SS Handwheel, Light Labor-Saving, Smooth Lifting Stem, Small Opening/Closing Stroke, Quick Response, Clear On-Off Indication: Equipped with a high-strength cast iron or stainless steel handwheel, the operation is light and labor-saving. The valve stem adopts a smooth lifting structure, with small opening and closing stroke, quick response, and clear on-off indication, which is convenient for on-site operation and management. The handwheel is designed with proper diameter and rim thickness per GB standards - providing sufficient mechanical advantage for manual operation without excessive force. The cast iron handwheel is epoxy-coated for corrosion resistance; stainless steel handwheel available for corrosive/sanitary environments. The rising stem (OS&Y optional) provides clear visual position indication - stem rises when opening, lowers when closing - operators can see valve position at a glance without gauges. The stem threads are ACME or trapezoidal profile - smooth, self-locking, resistant to galling. The stem is guided by a bushing in the yoke - preventing side loading and ensuring smooth vertical movement. The small opening/closing stroke (typically 1/4 of valve bore for globe valves) means faster operation than gate valves (which require multiple turns) - reducing actuation time and water hammer risk. The packing (graphite or PTFE) provides reliable stem sealing with low friction - allowing smooth stem movement without leakage. The yoke and handwheel are designed for easy operation even with gloves or in confined spaces. For automated operation, pneumatic or electric actuators can be mounted (ISO 5210/5211 standard) - replacing the handwheel. The electric actuator provides remote on/off or 4-20mA modulating control; the pneumatic actuator provides fast on/off (1–5 seconds) with failsafe option. This combination of easy manual operation and automation capability makes the valve suitable for both manual and automated systems.

6. Wide Application & Cost-Effective - Water/Steam/Oil/Gas/Chemical/Urban Water, Industrial/Civil, Direct Factory Batch Production, Optimized Processes, Competitive Prices, GB Compliant, Reduces Procurement Costs: Suitable for a variety of media such as water, steam, oil, gas, chemical reagents, and urban water supply and drainage. It is widely used in industrial and civil fields, with strong adaptability to different working conditions. As a direct factory, we adopt batch production and optimized production processes to reduce production costs. While ensuring GB compliance and product quality, we provide competitive prices, helping customers reduce procurement costs. The wide application range covers: (a) Water supply & drainage - urban water supply pipelines, sewage treatment plants, water conservancy projects, building water supply/drainage; (b) Thermal power & heating - thermal power plants, central heating systems, boiler pipelines, steam/hot water; (c) Petrochemical & oil - refineries, oil storage tanks, oil transmission pipelines, crude/diesel/oil products; (d) Chemical - chemical plants, pharmaceutical factories, chemical reagent pipelines, corrosive media (stainless optional); (e) Civil & commercial buildings - hotels, hospitals, shopping malls, residential buildings, water supply/heating/AC; (f) Other - food & beverage, metallurgical, environmental protection. The cost-effectiveness comes from: (a) Direct factory - no middleman markup; (b) Batch production - economies of scale reduce per-unit cost; (c) Optimized processes - lean manufacturing, efficient supply chain, reduced waste; (d) GB compliance - standardized design reduces engineering and customization costs; (e) Long service life - durable materials and quality construction reduce total cost of ownership. This makes the valve an excellent value for projects in cost-sensitive markets (Southeast Asia, Middle East, Africa, South America) where GB-standard equipment is prevalent. Despite the competitive price, quality is not compromised - every valve undergoes full inspection and testing per GB/T 13927 / API 598 before shipment. OEM/ODM services available - custom sizes, materials, logos, packaging per customer requirements.

National Standard Flange Shut-Off Valve: cast/stainless/ductile iron S-body, GB flanged ends, bolted bonnet, rising stem, optimized plug disc, precision-ground seat, handwheel. Handwheel rotates stem - rises/lowers, disc moves vertically along valve axis. Opening: disc lifts, flow follows S-passage - area increases. Closing: disc lowers onto precision-ground seat, blocks flow - metal/soft seal, zero leakage. Optimized core/seat enables reliable shut-off + good throttling. GB dimensions ensure interchangeability. Flange connection easy install/maintenance. On/off + simple flow regulation. DN15–300 (1/2"–12"), PN10–40 (CL150/300), -20~425℃. GB/T 12224/12229/12234/12235, test GB/T13927/API598.

Water Supply & Drainage - Urban Water Supply Pipelines, Sewage Treatment Plants, Water Conservancy Projects, Building Water Supply/Drainage, On-Off Water Flow: Used in urban water supply pipelines, sewage treatment plants, water conservancy projects, and building water supply and drainage systems - for on-off control of water flow. The ductile iron (QT450-10) or cast steel (WCB) body is economical and durable for water service; the soft seal (EPDM/NBR) provides bubble-tight sealing for water/gas; the GB-standard flange matches municipal water piping (GB/T 9112 flanges are standard in Chinese water systems); the easy operation and maintenance make it suitable for widespread use in municipal networks. Sizes DN15–300 cover small building connections to large water mains. PN10/16 is standard for municipal water; PN25/40 for high-rise building water supply and water conservancy. The valve is widely used in projects across Southeast Asia, Africa, and other regions where GB-standard water infrastructure is common.

Thermal Power & Heating - Thermal Power Plants, Central Heating Systems, Boiler Pipelines, Steam/Hot Water Control, HP/HT Resistance: Used in thermal power plants, central heating systems, and boiler pipelines - for controlling the flow of steam and hot water, with high temperature and pressure resistance. The cast steel (WCB) body handles general steam/hot water to 425℃; the alloy steel (WC6/WC9) body handles high-temperature steam to 550℃+ (optional high-temperature type); the metal-to-metal seal (1Cr13/2Cr13) resists steam erosion; the GB-standard flange matches power plant and heating piping. The optimized core/seat allows both shut-off and simple throttling of steam/hot water - useful for balancing heating circuits. The bolted bonnet allows in-line maintenance during planned outages. PN16/25 is standard for district heating; PN40 for boiler feedwater and high-pressure steam. The valve is suitable for both industrial power plants and district heating networks - common in China and GB-standard markets worldwide.

Petrochemical & Chemical - Oil Refineries, Storage Tanks, Transmission Pipelines, Crude/Diesel/Oil Products; Chemical Plants, Pharmaceutical, Chemical Reagent Pipelines, Corrosive Media (Stainless Optional): Used in oil refineries, oil storage tanks, and oil transmission pipelines - for on-off control of crude oil, diesel, and other oil products. Also used in chemical processing plants, pharmaceutical factories, and chemical reagent pipelines - suitable for controlling corrosive media (optional stainless steel material). The cast steel (WCB) body for general oil/hydrocarbon service; the stainless (CF8/CF8M/CF3/CF3M) body for corrosive chemicals, acids, alkalis, solvents; the metal-to-metal seal for high-temperature oil/chemical; the PTFE soft seal for chemical/corrosive bubble-tight service. The GB-standard flange matches petrochemical and chemical plant piping in GB-standard projects. The reliable shut-off prevents hazardous media leakage - critical for oil and chemical safety. PN16–40 covers general process to medium-high pressure. The valve is widely used in refineries and chemical plants in the Middle East, Southeast Asia, and Africa - regions with significant oil/chemical infrastructure and GB-standard equipment.

Civil & Commercial Buildings - Hotels, Hospitals, Shopping Malls, Residential Buildings, Water Supply/Heating/AC Pipelines, Easy Install/Maintenance: Used in hotels, hospitals, shopping malls, and residential buildings - for water supply, heating, and air conditioning pipeline systems, with easy installation and maintenance. The ductile iron (QT450-10) or cast steel (WCB) body is economical for building services; the soft seal (EPDM/NBR) provides quiet, bubble-tight operation for water/heating; the GB-standard flange matches building HVAC/plumbing piping; the compact design and easy operation make it suitable for mechanical rooms and confined spaces in buildings. The handwheel operation is simple for building maintenance staff. PN10/16 is standard for building water supply/heating; PN25 for high-rise building systems. The valve is widely used in commercial and residential construction projects - especially in markets where GB-standard building services are common (China, Southeast Asia, Africa).

General Industrial & Other - Food & Beverage, Metallurgical, Environmental Protection Projects, Adapts to Different Media/Working Conditions: Used in food and beverage industry, metallurgical industry, and environmental protection projects - adapting to different medium and working condition requirements. The stainless (CF8/CF8M) body with pickled/passivated finish is suitable for food & beverage (sanitary, rust-free, easy to clean); the cast steel (WCB) body for metallurgical (cooling water, process water, gas); the ductile iron or cast steel for environmental protection (wastewater treatment, flue gas desulfurization, water recycling). The wide material and sealing options allow configuration per specific medium. The GB-standard flange ensures compatibility with industrial piping. The cost-effective pricing makes it suitable for large-scale projects with many valves. This general industrial versatility makes the valve a standard choice across diverse industries - wherever GB-standard piping is used and reliable, cost-effective flow control is needed.

Every National Standard Flange Shut-Off Valve: Casting - cast steel/stainless/ductile iron body, UT, blasting. Material - certified, MTR 3.1, heat traceable, chemical. Trim - optimized plug disc, precision-ground seat, stem, machined, lapped. Machining - GB flange, face-to-face, dimensions. Assembly - bolted bonnet, rising stem, disc, stroke, no binding. Pressure - 100% shell 1.5×PN, seat 1.1×PN, zero leak GB/T13927/API598. Functional - open/close cycle, smooth, throttling. Surface - carbon epoxy paint, stainless pickled. Marking - standard, material/size/pressure/serial/flow. Standards GB/T 12224/12229/12234/12235. Docs - MTR, cert. Lead: 20–40 days. Warranty: 18 months.

Q1: What GB standards does this valve comply with, and how does it differ from ASME/API standard valves?

A: This valve complies with Chinese National Standards (GB/T): (1) GB/T 12224 - "Steel Valves - Dimensions, Faces and Ends" - specifies overall dimensions, face-to-face length, end connections, ensuring interchangeability; (2) GB/T 12229 - "Cast Steel Valves for General Purpose" - covers material, design, performance requirements for general cast steel valves; (3) GB/T 12234 - "Steel Valves - Flanged and Butt Welding Ends" - specifies flanged and butt-welded end dimensions; (4) GB/T 12235 - "Steel Globe Valves" - specific requirements for steel globe valves; (5) GB/T 9112-9124 - "Steel Pipe Flanges" - flange dimensions (types, dimensions, tolerances); (6) GB/T 13927 - "Industrial Valves - Pressure Testing" - inspection and testing (strength test 1.5× rated, leakage test 1.1× rated). Differences from ASME/API: (a) Flange dimensions - GB/T 9112 flanges differ from ASME B16.5 in bolt circle diameter, bolt size/number, and flange thickness - they are NOT directly interchangeable (a GB flange will not bolt to an ASME flange without an adapter); (b) Face-to-face - GB/T 12224 dimensions may differ from ASME B16.10 for the same size/pressure; (c) Pressure-temperature ratings - GB PN ratings vs ASME Class ratings have different temperature derating curves; (d) Material grades - GB material designations (WCB equivalent, CF8, etc.) may have slightly different chemical/mechanical requirements than ASTM/AISI equivalents (though often cross-compatible); (e) Testing - GB/T 13927 vs API 598 have similar but not identical test procedures and acceptance criteria. Which to choose: If your project/piping uses GB-standard flanges and dimensions (common in China, Southeast Asia, Middle East, Africa, South America - especially Chinese EPC projects), choose this GB-standard valve for direct compatibility. If your project uses ASME/API standard (common in Americas, Europe, international oil majors), choose our ASME/API-compliant valves (e.g., American Standard Stainless Steel Globe Valve). We can also supply GB valve body with ASME B16.5 flanges as an optional hybrid - consult factory. Note: the valve is also tested to API 598 (in addition to GB/T 13927) - providing an internationally recognized test standard for global customers.

Q2: What materials are available (cast steel WCB/WC6/WC9, stainless CF8/CF8M/CF3/CF3M, ductile iron QT450-10), and how do I select?

A: Available body materials: (1) Cast steel WCB (ASTM A216 WCB / GB ZG230-450) - carbon steel, general water/steam/oil/air service, -29~425℃, most common and economical; (2) WC6 (ASTM A217 WC6 / GB ZG15CrMo) - 1.25Cr-0.5Mo alloy cast steel, high-temperature service to 550℃+, power plant steam, hydrogen service; (3) WC9 (ASTM A217 WC9 / GB ZG12Cr2Mo) - 2.25Cr-1Mo alloy cast steel, higher temperature than WC6 (to 590℃), high-pressure high-temperature steam, refinery hydrogen; (4) CF8 (ASTM A351 CF8 / GB ZG06Cr19Ni10) - 304 stainless cast, general corrosive, nitric acid, oxidizing environments, -196~425℃; (5) CF8M (ASTM A351 CF8M / GB ZG06Cr17Ni12Mo2) - 316 stainless cast with molybdenum, improved pitting/crevice resistance in chloride (seawater, chemicals), acetic acid, urea, pharmaceutical; (6) CF3/CF3M - low-carbon 304L/316L cast, improved weldability and intergranular corrosion resistance, for critical corrosive and sanitary service; (7) Ductile iron QT450-10 (GB QT450-10) - nodular cast iron, high strength/toughness, economical, water/general service, -20~350℃. Valve stem: 1Cr13 (hardenable, wear-resistant, general), 2Cr13 (higher hardness, wear), 304/316 (corrosion-resistant). Selection guide: general water/steam/oil → WCB (most economical); high-temp steam >425℃ (power/refinery) → WC6/WC9; corrosive/chemical/nitric → CF8; chloride/seawater/acetic/urea/pharma → CF8M; welded critical corrosive/sanitary → CF3/CF3M; water/general/low-cost → QT450-10. Note: austenitic stainless (CF8/CF8M) retains toughness at cryogenic temperatures (to -196℃) - suitable for LNG and cryogenic service with extended bonnet option. All materials come with MTR and heat traceability. For special materials (CF8C, CN7M, 254SMO, etc.) - consult factory.

Q3: What sealing options are available (metal-to-metal vs soft seal PTFE/EPDM/NBR), and which should I choose?

A: Two sealing options available: (1) Metal-to-metal seal - disc and seat both metal (typically 1Cr13/2Cr13 stainless, or Stellite hardfaced for severe service). Advantages: high temperature capability (to 425℃+ WCB, 550℃+ WC6/WC9), high pressure, durable, resistant to abrasion and thermal cycling, suitable for steam, hot oil, and general process. Limitations: allows a small amount of visible leakage per API 598 (zero visible liquid, but may allow a few bubbles for gas) - not "bubble-tight." (2) Soft seal - soft material insert in seat or disc: (a) PTFE (Teflon) - excellent chemical resistance (inert to most chemicals), bubble-tight zero leakage, low friction, ≤200℃; (b) EPDM (ethylene propylene diene monomer) - good for water, steam (≤150℃), hot water, ozone, weathering; excellent elasticity; not for oil/petroleum; (c) NBR (nitrile butadiene rubber) - excellent oil resistance (crude, diesel, gasoline), water, ≤120℃; not for steam/ozone. Advantages of soft seal: bubble-tight (zero bubble) sealing - ideal for gases, toxic/volatile chemicals, vacuum, and applications requiring zero leakage; lower operating torque (soft material conforms to seat). Limitations: temperature limited (PTFE ≤200℃, EPDM ≤150℃, NBR ≤120℃); not for abrasive media (soft material can be damaged by particles); PTFE can cold-flow under high load/temperature. Selection guide: high temperature (>200℃), steam, hot oil, abrasive, general process → metal-to-metal seal; gas, chemical, toxic/volatile, vacuum, zero-leakage requirement, ≤200℃ → PTFE soft seal; water, hot water, heating, ozone, ≤150℃ → EPDM; oil, diesel, gasoline, ≤120℃ → NBR. The sealing surfaces are precision-ground and lapped for both types - ensuring consistent performance. The seat is typically removable/replaceable - you can change from metal to soft seal (or vice versa) if service conditions change, provided temperature/pressure limits are respected. Every valve is 100% seat-tested per GB/T 13927 / API 598.

Q4: What flange standard is used (GB/T 9112-9124), and is it compatible with ASME B16.5 or other international flanges?

A: The valve uses GB/T 9112-9124 steel pipe flanges - the Chinese national standard for flanges. This series includes: GB/T 9113 (integral flanges), GB/T 9114 (threaded), GB/T 9115 (weld neck), GB/T 9116 (slip-on), GB/T 9117 (socket weld), GB/T 9118 (lap joint), GB/T 9119 (plate flat), GB/T 9120 (blind), GB/T 9121 (boss), GB/T 9122 (ring joint), GB/T 9123 (large diameter), GB/T 9124 (technical conditions). The most common for this valve is weld neck (GB/T 9115) or plate flat (GB/T 9119) with RF (raised face). Compatibility with ASME B16.5: GB/T 9112 flanges are NOT directly interchangeable with ASME B16.5 flanges - they differ in: (a) Bolt circle diameter - GB PN flanges have different bolt circle than ASME Class flanges; (b) Bolt size/number - e.g., DN50 PN16 GB uses 4×M16 bolts, while ASME 1" Class 150 uses 4×5/8" bolts (similar but not identical); (c) Flange thickness and OD - differ; (d) Pressure-temperature ratings - GB PN vs ASME Class have different ratings. For small sizes (DN≤50) and low pressure (PN10/16), some GB and ASME flanges may be close - but it is NOT recommended to bolt them together without verification (risk of leakage or bolt mismatch). Options for international compatibility: (1) GB flange (standard) - for GB-standard piping systems (China, SE Asia, Middle East, Africa, South America, Chinese EPC projects); (2) ASME B16.5 flange (optional) - we can supply the valve with ASME B16.5 flanges (Class 150/300) for direct compatibility with ASME piping - this is listed as "compatible with ASME B16.5 (optional)" in the parameters; (3) Adapter flanges - GB-to-ASME adapter flanges can be used if you need to connect a GB valve to ASME piping (or vice versa). Other flange standards: JIS B2220 (10K/20K), DIN EN 1092 (PN), BS 4504 - available as custom options. Recommendation: always match the valve flange standard to your existing piping flange standard. If your project uses GB piping, the standard GB flange is the correct and most economical choice. If you need ASME/API compatibility, specify ASME B16.5 flanges when ordering. Provide your piping standard and pressure rating for a precise recommendation.

Q5: What are the installation, maintenance, and testing requirements (GB/T 13927 / API 598)?

A: Installation: (1) Flanged: install between GB/T 9112 standard flanges with appropriate gasket (spiral-wound graphite/stainless for high-temp, PTFE for chemical, rubber/EPDM for water) and bolts; tighten bolts cross-pattern to specified torque (per GB/T 9124). (2) Flow direction: install with flow direction arrow - globe valves typically have flow under the disc (bottom inlet, top outlet) for optimal sealing and reduced disc wear; verify arrow on body. (3) Support valve near both ends to prevent pipe weight stress. (4) Ensure adequate space above handwheel/actuator for operation and bonnet removal. (5) For stainless valves, avoid carbon steel contamination; for carbon/ductile iron, ensure epoxy coating is intact. Maintenance: Bolted bonnet allows in-line disassembly for seat/disc inspection/replacement; inspect packing/seal for leakage; replace seat if worn/eroded; lubricate stem threads periodically; for soft seal (PTFE/EPDM/NBR), inspect for deformation/cold flow and replace if damaged. Testing: Factory - (a) Shell strength test - hydrostatic at 1.5× nominal pressure per GB/T 13927 / API 598 - no leakage, no deformation, no sweating; (b) Seat leakage test - hydrostatic at 1.1× nominal pressure - zero leakage for soft seats, zero visible leakage for metal seats; (c) Functional test - full open/close stroke, smooth operation, no binding; (d) Dimensional inspection - flange dimensions (GB/T 9112), face-to-face (GB/T 12224), bore; (e) Material verification - MTR, heat number. After installation, line hydrotest and valve stroke test. Operation: Manual handwheel (standard), pneumatic (fast on/off, ESD), electric (on/off or 4-20mA modulating). Commercial: Lead time 20–40 days standard (batch production, faster than custom valves); MOQ 1 pc; T/T 30% deposit + 70% before shipment, L/C at sight for large orders; warranty 18 months from shipment. OEM/ODM available (custom size/material/logo/packaging). Marking: per GB standard - material, size (DN), pressure (PN), design standard, serial number, heat number, flow direction arrow, manufacturer. The valve is widely exported to Southeast Asia, Middle East, Africa, South America - trusted by industrial customers for stable performance and easy installation.

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