Reduced Port Butt Weld Ball Valve | Full Welded Zero Leakage

A Reduction Welding Ball Valve (also known as Reduced Diameter Welded Ball Valve, Small-Bore Welding Ball Valve, or Full-Welded Reduced-Port Butt-Weld Ball Valve) is a quarter-turn (90° rotation) on-off shut-off valve with a reduced-diameter (reduced-port) ball and an integrated fully-welded steel body with butt-weld (BW) ends - the valve body ends are directly butt-welded to the pipeline without any flanges, gaskets, or bolts, creating a permanently leak-free, high-integrity connection that is the industry standard for long-distance natural gas transmission, district heating, oil pipelines, and buried pipeline systems. Unlike conventional flanged ball valves which have bolted body joints and flange gasket connections that are potential external leakage points, this valve uses an integrated fully-welded body manufactured from carbon steel seamless steel pipe (A105, ST37.0, A106-B) or forged steel - the body is formed by pressing and welding seamless steel pipe sections, with all circumferential welds performed by automatic submerged-arc or TIG welding and 100% non-destructively tested (RT/UT), eliminating all body joints and external leakage paths. The butt-weld ends are directly welded to the pipeline on site, creating a monolithic valve-pipe connection with zero external leakage - there are no flanges to loosen, no gaskets to degrade, and no bolted joints to corrode underground. This is the most reliable connection type for buried gas and heating pipelines where external leakage is a safety hazard and inline maintenance is impractical. The reduced-diameter (reduced-port) design means the ball bore and valve flow passage are smaller than the nominal pipe diameter (typically ≥80% of pipe bore per standard reduced-port definition), reducing valve weight and material cost while still providing adequate flow capacity - flow resistance is among the lowest of all valve types, approximately 1/7 that of a globe valve of the same nominal size. The valve uses a precision-ground stainless steel ball (304/316/316L) rotating 90° between fully open and fully closed, with a carbon-reinforced PTFE (RPTFE with 20% carbon content) or EPDM/NBR seat ring backed by a butterfly spring - the butterfly spring provides a constant, uniform seating force that adapts to pressure and temperature changes, ensuring bidirectional zero leakage even at low pressure. The valve stem is stainless steel 420 / 2Cr13 with anti-blowout design (stem retained from inside body, cannot be ejected by line pressure), and the valve includes anti-static and fire-safe features per API 607 - steel balls and springs between stem-ball and stem-stuffing box ensure electrical conductivity of all parts, releasing static electricity to prevent fires and corrosion, and the fire-safe design ensures the valve remains sealed even if the soft seat is destroyed by fire (the metal-to-metal backup seal engages). The valve is designed for truly maintenance-free operation - no adjustment, no lubrication, no external leakage - with a service life matching the pipeline system (typically 20–30 years for buried gas/heating pipelines). Because the valve is fully welded and directly butt-welded to the pipe, it can be directly buried underground without building large valve wells - only a small shallow access pit is needed for the handle/operator, greatly reducing construction cost and shortening project schedule.

The valve is available in manual operation with a 90° handle (standard), gear operation (vertical or horizontal gearbox for large sizes DN300+), electric actuation, or pneumatic actuation - supporting remote operation and automatic control for modern pipeline SCADA systems. The valve body length and stem height can be customized according to construction and design requirements (e.g., extended stem for deep buried installation, special body length for pipeline retrofit), and materials and specifications can be customized for specific working conditions. With sizes from DN15 to DN1800 (the largest size range among full-welded ball valves, covering small residential branch lines to very large transmission mains), pressures from PN16 to PN420 (Class 150 to 2500), and temperatures from -29°C to 220°C (special materials can extend to -40°C to 300°C), this valve covers an extremely wide range of applications - including steam service (with appropriate high-temperature seat material), which distinguishes it from the flange-weld version that is not suitable for steam. Applicable media include natural gas, LPG, oil, gasoline, hot water, steam, and chemical media. The valve is designed per ISO, DIN, API 6D, API 607 (fire-safe), PED 2014/68/EU, and GB/T 37827 (Chinese national standard for fully-welded ball valves); tested per API 598 / GB/T 13927 (shell 1.5× rated, seat 1.1× rated) with 100% factory hydrostatic testing and weld NDE. Certified CE, ISO 9001, and Green Building Material Certification. Widely used in natural gas long-distance transmission and city gas distribution (where zero external leakage and buried installation are mandatory), district heating networks (where direct burial and maintenance-free operation reduce cost), petroleum refining and transportation, thermal power plants, steel plants, chemical plants, pharmaceutical factories, papermaking, and municipal water supply - providing zero-leakage, maintenance-free, full-welded reduced-bore butt-weld ball valve solutions for long-distance buried pipelines worldwide, with an 18-month warranty and OEM/ODM customization.

1.Full-Welded Butt-Weld Body - Zero External Leakage

Integrated fully-welded body manufactured from A105/ST37.0/A106-B carbon steel seamless steel pipe (pressed and welded) or forged steel - all circumferential welds by automatic SAW/TIG welding, 100% RT/UT non-destructive tested. Eliminates all body-body bolted joints. Butt-weld (BW) ends directly welded to pipeline on site - no flanges, gaskets, or bolts, creating a monolithic valve-pipe connection with zero external leakage. No flange loosening, no gasket degradation, no bolt corrosion underground - the most reliable connection for buried gas/heating pipelines. High axial-force resistance - withstands geological subsidence, earthquakes, and ground vehicle load without deformation. Body material matches pipeline material for uniform stress and long-term anti-aging. Full-welded design is the industry standard for long-distance gas transmission.

2.Reduced-Port - Lightweight + Low Flow Resistance

Reduced-diameter (reduced-port) design - ball bore and flow passage smaller than nominal pipe diameter (≥80% of pipe bore per standard). Optimizes flow resistance coefficient - among the lowest of all valve types, approximately 1/7 of globe valve same size - reducing pumping/compression energy consumption and improving pipeline efficiency. Lightweight and compact - reduces material cost, transport cost, pipeline load, and support requirements. Suitable for viscous fluids, slurries, and solid particles in addition to general media (smooth reduced-bore passage does not trap particles). Full-port version available on request for applications requiring maximum flow or pigging. When valve bore ≥80% of pipe bore, impact on pipeline flow capacity is minimal - cost-effective for most transmission and distribution lines.

3.Bidirectional Zero-Leakage + Butterfly Spring Seat

Carbon-reinforced PTFE (RPTFE with 20% carbon content) sealing ring - stronger wear resistance and better thermal stability than pure PTFE; optional EPDM, NBR for specific media. Butterfly spring structure behind seat - provides constant, uniform seating force that adapts to pressure and temperature fluctuations, ensuring tight sealing even at low pressure and compensating for seat wear over time. Precision-ground stainless steel ball (304/316/316L) provides smooth surface and low friction. Bidirectional sealing - blocks flow from either direction, no preferred inlet/outlet. Zero internal and external leakage within rated pressure/temperature range - prevents media loss and safety hazards, critical for natural gas, LPG, and toxic chemical service.

4.Anti-Static + Fire-Safe (API 607) + Anti-Blowout Stem

Anti-static design - steel balls and springs installed between stem and ball, and between stem and stuffing box, ensuring electrical conductivity of all metal parts, releasing static electricity in real time to prevent static sparks, fires, and electrochemical corrosion - mandatory for flammable gas and liquid service. Fire-safe design per API 607 - if soft PTFE seat is destroyed by fire, the metal-to-metal backup seal engages, preventing massive media release and containing the fire. Anti-blowout stem - stem retained from inside body (larger diameter shoulder under bonnet), cannot be ejected by line pressure even if packing fails - safety critical for high-pressure gas. Stem 420/2Cr13 stainless, hardened for wear and galling resistance. Multiple safety protections make this valve suitable for hazardous flammable media.

5.Direct Burial + Maintenance-Free

Full-welded butt-weld connection allows direct burial underground - no need to build large valve wells (only small shallow access pit for handle/operator), greatly reducing construction cost, shortening project schedule, and saving land. Valve body can be pre-insulated for heating pipelines before burial. Requires no regular maintenance, adjustment, or lubrication - self-lubricating stem bearing, preloaded butterfly spring seat compensates for wear, no external leakage points - truly maintenance-free for 20–30 years, matching pipeline system life. Greatly reduces total cost of ownership (TCO) vs. gate valves and flanged ball valves requiring periodic maintenance in valve pits. Exterior anti-corrosion coating protects carbon steel body in buried and underground service.

6.Wide Range + Multiple Operation + Global Standards

DN15–DN1800 (largest size range among full-welded ball valves - small branch to very large transmission mains, customizable); PN16–PN420 (Class 150–2500); -29~220°C (special materials -40~300°C, including steam service with high-temp seat). Operation: manual 90° handle (standard), gear (vertical/horizontal, DN300+), electric, pneumatic - remote operation and automatic control for SCADA/DCS. Body length and stem height customizable for construction requirements (extended stem for deep burial, special length for retrofit). Materials: A105/ST37/A106-B carbon steel, 304/316L stainless, alloy steel. Standards: ISO, DIN, API 6D, API 607 (fire-safe), PED 2014/68/EU, GB/T 37827; tested API 598/GB/T 13927 (shell 1.5×, seat 1.1×), 100% weld NDE. Certified CE, ISO 9001, Green Building Material. 18-month warranty. OEM/ODM customization.

A Reduction Welding Ball Valve operates on the principle of a 90° rotating reduced-port ball inside a fully-welded seamless steel body, with butt-weld ends permanently welded to the pipeline, to provide fully open or fully closed (on-off) shut-off - it is not designed for throttling or flow regulation. The valve consists of a fully-welded body (pressed from seamless steel pipe, with circumferential welds), a reduced-diameter spherical ball, two seat rings (upstream and downstream) with butterfly springs, a stem connecting the operator to the ball, self-lubricating stem bearings, stem packing, anti-static steel balls/springs, and a fire-safe metal backup seal. In the fully open position, the ball has been rotated 90° so its reduced-diameter through-hole is aligned with the pipeline flow direction - fluid flows through the ball bore with minimal obstruction. Because the bore is reduced (typically ≥80% of the pipe diameter), there is a slight contraction and expansion at the valve, but the flow resistance is still very low - among the lowest of all valve types, approximately 1/7 that of a globe valve - making it energy-efficient for transmission pipelines. In the fully closed position, the ball has been rotated 90° so the solid (non-perforated) side of the ball faces the pipeline flow - the ball is pressed against both the upstream and downstream seat rings by line pressure and the butterfly spring force, creating a bidirectional bubble-tight seal that blocks flow completely. The key design features that make this valve unique are: (1) Full-welded seamless steel body - the body is pressed from carbon steel seamless steel pipe (A105, ST37.0, A106-B) and the body sections are welded together by automatic submerged-arc or TIG welding, then 100% RT/UT tested. There are no bolted body joints - the body is a single monolithic pressure-containing structure with zero external leakage paths. This is fundamentally different from two-piece/three-piece cast ball valves where the body halves are bolted together with a gasket, which is a potential external leakage point. (2) Butt-weld (BW) ends - the valve body ends are prepared for butt welding (per ANSI B16.25 / GB/T 985) and directly welded to the pipeline on site. This creates a permanent, monolithic valve-pipe connection - there are no flanges, gaskets, or bolts at the valve-pipe interface. This is the most reliable connection for buried pipelines because: (a) zero external leakage at the connection, (b) no flanges to loosen due to vibration or thermal cycling, (c) no gaskets to degrade over time, (d) no bolts to corrode underground, (e) the smooth cylindrical body is easy to insulate and bury. The tradeoff is that the valve cannot be easily removed for maintenance - it must be cut out of the pipeline, which is why the valve is designed to be maintenance-free with a 20–30 year service life. (3) Reduced-port ball - the ball bore is smaller than the pipe bore (≥80% of pipe diameter), reducing weight and cost. The ball is precision-ground stainless steel (304/316/316L) for smooth surface and low friction. (4) Butterfly spring seat - the carbon-reinforced PTFE (RPTFE) seat ring is backed by a butterfly (disc) spring that provides a constant, uniform seating force around the entire circumference. Unlike a conventional coil spring which provides point loading, the butterfly spring distributes force evenly, ensuring uniform seat compression and consistent sealing around the entire ball circumference. The butterfly spring also adapts to pressure and temperature changes - as pressure increases, the spring compresses and the seat force increases; as temperature changes cause thermal expansion/contraction, the spring compensates. (5) Anti-static design - steel balls and springs are installed between the stem and ball, and between the stem and stuffing box, ensuring that all metal parts (body, ball, stem, operator) are electrically continuous. This prevents static electricity buildup on the ball (which can occur when fluid flows past an insulated ball) and discharges it to ground through the body and pipeline - preventing static sparks that could ignite flammable gas or liquid. This is a mandatory safety feature for natural gas, LPG, gasoline, and other flammable media. (6) Fire-safe design (API 607) - in the event of a fire, the soft PTFE seat will melt or burn away. The fire-safe design includes a metal-to-metal backup seat - when the PTFE seat is destroyed, the ball contacts the metal seat backup, providing a secondary metal seal that prevents massive media release and contains the fire. This is tested per API 607 (fire test for quarter-turn valves). (7) Anti-blowout stem - the stem has a larger diameter shoulder under the body bonnet area, so the stem is retained from inside the body. Even if the stem packing fails completely and line pressure acts on the stem, the stem cannot be blown out of the valve - a critical safety feature for high-pressure gas service. The valve is operated by rotating the stem 90° - manual via a 90° handle, via a gearbox (vertical or horizontal) for large sizes, or via electric/pneumatic actuator for remote/automated control. The valve is bidirectional (no preferred flow direction) because both seats are spring-loaded. It can be installed in any orientation (horizontal, vertical, inclined), though horizontal with stem upright is recommended for operator access. For buried installation, the valve body is welded into the pipeline and buried directly, with only the stem and handle/operator extending into a small shallow access pit - or an extended stem can be provided so the operator is at ground level. The valve is for on-off service only - partial opening will cause high-velocity erosion of the seat and ball edge, especially with the reduced-port design. For steam service, a high-temperature seat material (e.g., PEEK or metal) should be specified, and the special material temperature range (-40~300°C) applies.

• Energy & Natural Gas

Natural gas long-distance transmission pipelines, urban gas distribution mains and branch lines, LNG/LPG storage and transfer, oil refining and transportation pipelines, gasoline and fuel oil lines - full-welded butt-weld zero external leakage mandatory for gas safety, anti-static fire-safe API 607 for flammable media, PN16-420 covers gathering to transmission, direct burial no valve well reduces cost, anti-blowout stem for high-pressure gas, DN15-1800 covers small service to large transmission.

• Municipal & District Heating

District heating hot water pipelines, large heating equipment output lines, heat exchanger station pipelines, urban water supply and drainage, thermal power plant heating networks - full-welded body easy to pre-insulate before burial, maintenance-free eliminates underground valve pit maintenance, carbon-reinforced PTFE handles hot water to 220°C, reduced-port cost-effective for large heating mains, direct burial saves construction cost and land, Green Building Material certification for municipal projects.

• Industrial Manufacturing

Steel plants (fluid/gas/heating/fuel supply pipelines), chemical plants (raw material transportation, reactor inlet/outlet), pharmaceutical factories, papermaking factories, industrial process piping - stainless steel 304/316L body option for corrosive chemicals, EPDM/NBR seat options for chemical compatibility, anti-static for flammable solvents, fire-safe API 607 for hazardous areas, gear/electric/pneumatic operation for remote control in plants, customizable body length/stem height for existing pipeline retrofit.

• Power Generation

Thermal power plant pipelines, power station cooling and heating water lines, steam transmission pipelines (with high-temp seat), boiler auxiliary systems, circulating water - full-welded zero leakage for high-pressure water/steam, special materials to 300°C for steam, anti-static for fuel gas lines, wide size DN15-1800 covers small auxiliary to large mains, multiple operation modes adapt to power plant SCADA, maintenance-free reduces downtime in continuous-operation power plants.

• Petrochemical & Oil Refining

Oil refinery offsites and process units, petroleum product pipelines, chemical reactor isolation, hazardous fluid storage tank inlet/outlet, tank farm piping - full-welded body eliminates gasket leakage for toxic/corrosive/flammable media, anti-static fire-safe API 607 mandatory for refinery hazardous areas, bidirectional zero leakage prevents cross-contamination, PED 2014/68/EU certification for European market, electric/pneumatic actuation for remote ESD and DCS integration, 18-month warranty for refinery turnaround planning.

Our Reduction Welding Ball Valves are manufactured under an ISO 9001:2015 certified quality management system, with every valve undergoing rigorous inspection and testing at each production stage - because these valves are fully welded and permanently installed in buried pipelines, often carrying flammable natural gas or high-pressure hot water, where failure and external leakage are not acceptable.

Raw material control: every seamless steel pipe batch (A105, ST37.0, A106-B) comes with a mill test certificate (MTC EN 10204 3.1) verifying chemical composition, mechanical properties (tensile, yield, elongation, impact), wall thickness, ovality, and straightness; stainless steel (304/316/316L) verified by PMI spectrometer; alloy steel verified for grade and hardenability; ball and stem materials verified for grade and heat treatment.

Body manufacturing & welding: seamless steel pipe cut and pressed to form body halves/sections; circumferential body welds and butt-weld end preparations performed by certified welders per qualified WPS/PQR (ASME BPVC Section IX / ISO 9606), using automatic submerged-arc welding (SAW) for circumferential welds and TIG for root passes; all pressure-containing welds 100% visually inspected (VT), 100% penetrant tested (PT) for surface defects, and 100% radiographically tested (RT) or ultrasonically tested (UT) for volumetric defects per ASME BPVC Section V - weld quality is the most critical quality point for full-welded valves. Post-weld heat treatment (PWHT) performed for carbon steel bodies above specified thickness to relieve residual welding stress. Butt-weld end preparation verified per ANSI B16.25 / GB/T 985 (bevel angle, root face, alignment).

Machining & assembly: dimensional inspection per API 6D / GB/T 37827, body wall thickness verified (minimum wall thickness per pressure rating), ball sphericity and surface finish verified (Ra ≤0.2μm for precision-ground ball), reduced bore diameter verified (≥80% of nominal pipe bore), seat ring flatness and surface finish verified, butterfly spring force measured and recorded (spring force must be within specification for uniform seating), ball-to-stem connection verified for 90° rotation accuracy, stem dimensions and anti-blowout shoulder verified, stem bearing clearance verified for smooth rotation.

Anti-static & fire-safe verification: anti-static continuity tested - electrical resistance between ball and body, and between stem and body, must be ≤10Ω per API 607 / ISO 10497; steel balls and springs verified for proper installation and contact. Fire-safe design verified per API 607 (type-tested prototype, not every valve - but every valve is built to the fire-safe design with metal backup seat).

Ball & seat inspection: stainless steel ball inspected for surface defects (no pits, scratches, porosity), polishing quality verified by surface roughness tester; carbon-reinforced PTFE (RPTFE 20% carbon)/EPDM/NBR seats inspected for dimensional accuracy, surface defects, and material certification; butterfly spring inspected for spring force, flatness, and fatigue.

Pressure testing: 100% hydrostatic shell test at 1.5× rated pressure per API 598 / GB/T 13927 - held for specified duration with zero visible leakage (including all weld seams and butt-weld ends); 100% seat leak test at 1.1× rated pressure - must achieve zero leakage (Class A) for both directions (bidirectional test); 100% operation test - valve must fully open and close smoothly with torque within specification, verify 90° rotation, verify handle/gear operation.

Coating inspection: exterior surface preparation verified (Sa 2.5 blast cleaning per ISO 8501-1), coating dry film thickness (DFT) measured, coating adhesion tested (cross-cut test per ISO 2409), spark test for holiday detection on buried-service coating.

Marking & documentation: each valve permanently marked per API 6D / MSS SP-25 with material grade, pressure rating, size, reduced-bore designation, flow direction (bidirectional), welding standard, and standard; shipped with hydrostatic test report, material certificate (MTC 3.1), weld NDE report (RT/UT), welding procedure and welder qualification records, anti-static test report, coating inspection report, and installation/welding instructions including butt-weld procedure, preheat, and PWHT guidance for field welding.

Warranty: 18 months from date of shipment or 12 months from installation, whichever comes first - free repair or replacement for any manufacturing defect; for gas pipeline and district heating EPC projects, extended warranty and third-party inspection (BV, SGS, TUV) available on request.

Q: What is the difference between Reduction Welding Ball Valve and Reduction Diameter Flange Welding Ball Valve?

A: Both are reduced-port (reduced-diameter) full-welded ball valves, but they differ in connection method: (1) Reduction Welding Ball Valve (this valve) has butt-weld (BW) ends - the valve body ends are directly butt-welded to the pipeline on site, with NO flanges, gaskets, or bolts at the valve-pipe connection. This creates a permanent, monolithic, zero-leakage connection. It is used for buried pipelines where the valve will not need to be removed for maintenance, and where zero external leakage is critical (natural gas, district heating). Size range DN15–1800, temperature -29~220°C (special -40~300°C), can be used for steam with high-temp seat, includes anti-static and fire-safe API 607 features. (2) Reduction Diameter Flange Welding Ball Valve has flange-weld ends - flanges are welded onto the valve body, and the valve is bolted to pipeline flanges with gaskets (like a conventional flanged valve). This allows the valve to be removed and replaced if needed, but introduces flange gasket leakage points. Size range DN15–1400, temperature -29~200°C, NOT suitable for steam, standard anti-static not emphasized. In summary: choose butt-weld (this valve) for permanent buried installation with zero leakage requirement (gas, heating); choose flange-weld for applications where the valve may need to be removed for maintenance or where flanged pipeline connection is required. Both have full-welded bodies (no bolted body joints) and reduced-port design.

Q: Why is butt-weld connection preferred for buried natural gas pipelines?

A: Butt-weld (BW) connection is the industry standard for buried natural gas pipelines for several reasons: (1) Zero external leakage - the valve is permanently welded to the pipe, creating a monolithic connection with no flanges, gaskets, or bolts that could leak. For natural gas, external leakage is a serious safety hazard (explosion, fire, asphyxiation), so zero leakage is mandatory. (2) No maintenance - flanged connections require periodic bolt re-torquing and gasket replacement, which is difficult and expensive in buried valve pits. Butt-weld connections are permanent and maintenance-free. (3) No corrosion - buried flanges and bolts are prone to corrosion (galvanic corrosion, soil corrosion), which can cause leakage over time. Butt-weld connections have no exposed bolts or flange faces to corrode. (4) No loosening - flanged connections can loosen due to vibration, thermal cycling, and ground movement, especially in buried pipelines. Butt-weld connections cannot loosen. (5) Cost savings - direct burial without large valve wells saves construction cost, land, and schedule. (6) Structural integrity - welded connections have better axial force resistance than flanged connections, important for buried pipelines subject to soil load, ground settlement, and earthquakes. The tradeoff is that the valve cannot be easily removed - but full-welded ball valves are designed to be maintenance-free with a 20–30 year service life, so removal is rarely needed. When removal is required, the valve is cut out and a new one welded in.

Q: What is the anti-static and fire-safe design, and why is it important?

A: Anti-static design ensures electrical continuity between all metal parts of the valve (body, ball, stem, operator). Steel balls and springs are installed between the stem and ball, and between the stem and stuffing box, so that any static electricity generated by fluid flow (especially when non-conductive fluids like gasoline, LPG, or natural gas flow past the ball) is discharged to ground through the body and pipeline, rather than building up on the ball and creating a static spark. Electrical resistance is tested to ≤10Ω per API 607 / ISO 10497. This is critical for flammable media - a static spark in a natural gas or gasoline pipeline can cause explosion. Fire-safe design (API 607) ensures that if the soft PTFE seat is destroyed by fire, the valve still provides a secondary metal-to-metal seal that prevents massive media release. The design includes a metal backup seat that engages when the PTFE seat burns away. This is tested per API 607 (fire test for quarter-turn valves) - the valve is exposed to a 750–800°C fire for 30 minutes while under pressure, and must not leak more than the allowable rate during and after the fire. Both features are mandatory for valves handling flammable media in refineries, gas pipelines, chemical plants, and tank farms. This valve includes both anti-static and fire-safe (API 607) features as standard - distinguishing it from basic full-welded ball valves that may not include these safety features.

Q: Can this valve be used for steam? What are the limitations?

A: Yes, this Reduction Welding Ball Valve CAN be used for steam service, with appropriate material selection - this is a key difference from the flange-weld version which is NOT suitable for steam. For steam service: (1) Seat material - standard carbon-reinforced PTFE (RPTFE) is limited to approximately 220°C. For saturated steam above ~220°C (e.g., 25 bar = 225°C, 40 bar = 250°C), you must specify a high-temperature seat material such as PEEK (up to ~280°C) or a metal seat (Stellite, for higher temperatures). EPDM and NBR are NOT suitable for steam. (2) Temperature range - standard materials: -29~220°C; special materials (alloy steel body + PEEK/metal seat): -40~300°C. For superheated steam above 300°C, a gate valve or globe valve with metal seat is recommended instead of a ball valve. (3) Thermal cycling - steam systems experience frequent thermal cycling. The full-welded body and butterfly spring seat are designed to accommodate thermal expansion/contraction, but for severe cycling service, please consult our engineering team. (4) Maintenance - full-welded valves cannot be maintained inline. For steam systems where seat wear may be higher due to high velocity and condensate, consider whether a maintainable flanged valve is more appropriate. (5) Water hammer - steam systems are prone to water hammer. The full-welded body has high structural strength and can withstand water hammer, but proper pipeline design (drip legs, steam traps) is still required. In summary: this valve is suitable for saturated steam up to 220°C with standard RPTFE seat, and up to 300°C with special high-temperature seat and alloy body. For superheated steam above 300°C, use a gate/globe valve.

Q: How is the valve installed and welded in the field?

A: Field installation of a butt-weld ball valve requires qualified welding procedures and personnel: (1) Pre-weld preparation - clean the pipe ends and valve butt-weld ends of oil, rust, and debris; verify bevel angle and root face per ANSI B16.25 / GB/T 985 (typically 30–37.5° bevel, 1.5–2mm root face); align valve and pipe with proper gap (root gap typically 1.5–3mm); use alignment clamps to hold position. (2) Preheating - for carbon steel valves (A105, A106-B), preheat may be required depending on wall thickness and ambient temperature (typically 100–150°C for thick wall or low temperature); follow the qualified WPS. (3) Welding - root pass typically TIG (GTAW) for full penetration, fill and cap passes typically SMAW or SAW; use qualified welders and qualified welding consumables matching the valve material (e.g., E7018 for A105 carbon steel); weld both ends sequentially or simultaneously to minimize distortion. (4) Post-weld heat treatment (PWHT) - for carbon steel valves above specified thickness (typically >38mm wall), PWHT may be required to relieve residual stress; follow WPS and project specification. (5) Post-weld inspection - visual inspection (VT) of all field welds; for high-pressure gas service, 100% RT or UT of field welds may be required by project specification; hydrostatic test of the completed pipeline section. (6) Important - do NOT weld the valve with the ball in the fully closed position (weld heat can damage the PTFE seat); keep the ball in the fully OPEN position during welding to protect the seat from weld heat. Use heat sinks or wet rags around the valve body if welding heat could exceed seat temperature limit. (7) Burial - after welding and testing, the valve can be directly buried; for heating pipelines, pre-insulate the valve body before burial; for corrosion protection, apply field-applied coating or heat-shrink sleeve at the weld joints. We provide installation and welding instructions with every valve, and can provide WPS/PQR and on-site welding supervision for large projects.

Q: What sizes, pressures, materials, and operation modes are available?

A: Size range: DN15–DN1800 (NPS 1/2"–72") - the largest size range among full-welded ball valves, from small residential/branch lines to very large transmission mains; custom sizes available. Pressure range: PN16–PN420 (Class 150–Class 2500) - from low-pressure district heating to ultra-high-pressure gas transmission. Temperature range: standard -29~220°C; special materials -40~300°C (for steam and low-temperature service). Body materials: carbon steel A105 / ST37.0 / A106-B seamless steel pipe (standard); stainless steel 304 / 316L (optional, corrosive service); alloy steel (optional, high-temperature/high-pressure). Ball material: stainless steel 304 / 316 / 316L (customizable). Seat material: carbon-reinforced PTFE (RPTFE 20% carbon, standard), EPDM, NBR (optional for specific media); PEEK or metal seat for high-temperature/steam service. Operation modes: manual 90° handle (standard, DN15–DN300), gear operated (vertical or horizontal gearbox, DN300+ large sizes), electric actuated (optional, remote/DCS), pneumatic actuated (optional, remote/ESD). Customization: valve body length and stem height can be adjusted for construction requirements (extended stem for deep burial, special body length for pipeline retrofit); materials and specifications customizable for specific working conditions. Standards: ISO, DIN, API 6D, API 607 (fire-safe), PED 2014/68/EU, GB/T 37827. Certification: CE, ISO 9001, Green Building Material. Warranty: 18 months from shipment or 12 months from installation. MOQ: 1 piece for standard carbon steel manual models; stainless steel, large-bore (DN500+), high-pressure (PN100+), gear/electric/pneumatic orders minimum 1–2 pieces. Lead time: standard models 20–35 days; custom/special 35–60 days. Please provide size, pressure, medium, temperature, and operation mode when requesting a quotation.

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