
Stainless Steel Flanges: Common Pipe Fittings and Their Applications
2025-07-07
Stainless steel flanges are widely used in piping systems due to their corrosion resistance, high strength, and durability. They connect pipes, valves, pumps, and other equipment, ensuring leak-proof joints in high-pressure and high-temperature environments. Below is a detailed breakdown of the most common pipe fittings used with stainless steel flanges, along with their functions, standards, and applications.
1. Stainless Steel Pipes
Stainless steel flanges are primarily used to connect stainless steel pipes in various industries, including:
Oil & Gas (high-pressure pipelines, offshore platforms)
Chemical Processing (acid, alkali, and solvent transport)
Food & Beverage (hygienic piping, CIP/SIP systems)
Pharmaceuticals (sterile fluid transfer)
Water Treatment (desalination, wastewater systems)
Common Stainless Steel Pipe Grades for Flanged Connections
Grade
Standard
Key Properties
Application
304/304L
A312/A790
Good corrosion resistance, weldability
General-purpose piping, food industry
316/316L
A312/A790
Superior pitting resistance (Mo-added)
Marine, chemical processing
904L
B677
High Ni & Cu for extreme corrosion
Sulfuric & phosphoric acid plants
Duplex 2205
A928
High strength, chloride resistance
Offshore, seawater cooling systems
Flange Connection Types:
Butt-Weld Flanges (WN) – Welded to pipes for high-integrity joints.
Socket-Weld Flanges (SW) – Used for small-diameter, high-pressure pipes.
Slip-On Flanges (SO) – Easier alignment, suitable for low-pressure systems.
Lap Joint Flanges (LJ) – Used with stub ends for easy disassembly.
2. Stainless Steel Valves
Flanges are commonly paired with stainless steel valves to control fluid flow. The most widely used types include:
A. Gate Valves
Function: On/off flow control (not for throttling).
Flange Types: RF (Raised Face), RTJ (Ring-Type Joint) for high pressure.
Standards: API 600, ASME B16.34.
B. Ball Valves
Function: Quick shutoff, low-pressure drop.
Flange Types: RF, FF (Flat Face) for low-pressure systems.
Standards: API 6D, ASME B16.34.
C. Check Valves
Function: Prevent backflow.
Flange Types: SW (Socket Weld) for compact systems, WN for large pipes.
Standards: API 6D, ASME B16.34.
D. Butterfly Valves
Function: Throttling & shutoff in large pipes.
Flange Types: Lug-type or wafer-style (for space-saving designs).
Standards: API 609, AWWA C504.
E. Globe & Control Valves
Function: Precise flow regulation.
Flange Types: RF, RTJ for high-pressure steam/gas.
Standards: ANSI B16.10, ISA 75.
3. Stainless Steel Fittings (Elbows, Tees, Reducers, Caps)
Flanged connections often require stainless steel pipe fittings to change direction, split flows, or adjust pipe sizes.
A. Elbows (90° & 45°)
Function: Change flow direction.
Flange Types: WN (Butt-Weld) for high-pressure systems.
Standards: ASME B16.9, MSS SP-43.
B. Tees (Equal & Reducing)
Function: Split or combine flow.
Flange Types: SO (Slip-On) for easy installation.
Standards: ASME B16.9, MSS SP-75 (for high-yield strength).
C. Reducers (Concentric & Eccentric)
Function: Adjust pipe diameter.
Flange Types: WN for high-pressure, SO for low-pressure.
Standards: ASME B16.9, ANSI B16.11 (for threaded/socket-weld).
D. Caps
Function: Seal pipe ends.
Flange Types: Blind flanges (for maintenance access).
Standards: ASME B16.9, MSS SP-73.
4. Stainless Steel Strainers & Filters
Flanged strainers protect downstream equipment from debris.
A. Y-Strainers
Function: Remove particles from liquids/gases.
Flange Types: RF, RTJ for high-pressure steam.
Standards: ASME B16.34, API 598.
B. Basket Strainers
Function: High-capacity filtration.
Flange Types: RF, FF for low-pressure water systems.
Standards: MSS SP-71, ISO 5208.
5. Stainless Steel Expansion Joints & Flexible Couplings
Used to absorb thermal expansion, vibration, and misalignment.
A. Bellows Expansion Joints
Function: Compensate for pipe movement.
Flange Types: WN for high-pressure steam.
Standards: EJMA (Expansion Joint Manufacturers Association).
B. Flexible Rubber/Pump Couplings
Function: Reduce vibration in pumps/compressors.
Flange Types: DIN or ANSI standard flanges.
6. Specialty Flanged Components
A. Sight Glasses & Flow Meters
Function: Visual inspection/flow measurement.
Flange Types: Hygienic clamp flanges (Tri-Clamp) in food/pharma.
B. Heat Exchangers & Pressure Vessels
Function: Heat transfer/storage.
Flange Types: RTJ for high-pressure ASME vessels.
Stainless steel flanges are essential for connecting pipes, valves, strainers, and fittings in demanding industries. The choice of flange type (WN, SO, SW, LJ) depends on pressure, temperature, and corrosion requirements. Proper material selection (304, 316, duplex, nickel alloys) ensures long-term reliability in aggressive environments.
For critical applications, always follow ASME, API, and ISO standards to ensure safe and leak-free performance.
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Performance Differences of Flanges Made from Different Materials in High-Temperature Environments
2025-07-07
The performance of flanges in high-temperature environments varies significantly depending on the material used, primarily in terms of strength retention, oxidation resistance, creep resistance, thermal stability, and compatibility with media. Below is an analysis of typical material categories:
1. Carbon Steel Flanges (e.g., Q235, 20# Steel) – Basic Choice for Low to Medium TemperaturesStrength Degradation at High TemperaturesCarbon steel flanges are typically limited to temperatures below 425°C. Beyond 350°C, their yield strength drops significantly (e.g., 20# steel’s yield strength decreases from 245 MPa at room temperature to 180 MPa at 400°C). Above 450°C, pearlite spheroidization occurs, leading to grain coarsening and eventual creep rupture.Poor Oxidation ResistanceRapid oxidation begins above 300°C, forming a loose Fe₃O₄ layer. At 500°C, the oxidation rate is five times faster than at 300°C. Exposure to sulfur or water vapor further accelerates corrosion.
2. Austenitic Stainless Steel Flanges (304/316, etc.) – Preferred for High-Temperature Corrosion ResistanceBetter High-Temperature Strength and Oxidation Resistance304 stainless steel can withstand up to 870°C, while 316L (with molybdenum) maintains good strength (yield strength ≥ 120 MPa) below 650°C.The Cr₂O₃ oxide layer (from 18-20% chromium) provides superior oxidation resistance (e.g., 90% lower oxidation rate than carbon steel at 800°C).High-Temperature RisksSensitization (450-850°C): Carbide precipitation may cause intergranular corrosion (mitigated by stabilization treatments, e.g., 321 stainless steel with titanium).Creep Limitations: Above 650°C, creep deformation accelerates, requiring reduced allowable stress (e.g., 316L at 700°C has only 15% of its room-temperature strength).
3. Duplex Steel Flanges (2205, 2507, etc.) – Cost-Effective for High-Temperature CorrosionIntermediate High-Temperature Performance2205 duplex steel is usable up to 300°C, while super duplex 2507 extends to 350°C (yield strength > 400 MPa at 300°C, twice that of 304 stainless steel).Beyond 350°C, ferrite phase degradation accelerates, reducing creep resistance faster than austenitic steels.
4. Chromium-Molybdenum Steel Flanges (15CrMo, P91, etc.) – Ideal for High-Temperature, High-Pressure ConditionsEnhanced Strength and Creep Resistance15CrMo (1-1.5% Cr, 0.5% Mo) operates up to 550°C (yield strength > 200 MPa at 500°C).P91 (9% Cr, 1% Mo) withstands 650°C long-term, with twice the creep rupture strength of 15CrMo (e.g., 100 MPa vs. 40 MPa at 600°C for 100,000 hours).
5. Nickel-Based Alloy Flanges (Inconel 625, Hastelloy C-276, etc.) – Ultimate Solution for Extreme ConditionsUnmatched High-Temperature PerformanceInconel 625 retains > 100 MPa tensile strength at 1093°C.Hastelloy C-276 resists oxidation up to 1200°C, with creep life exceeding 100,000 hours (e.g., 5x stronger than 316L at 800°C).Resistance to Complex CorrosionHigh nickel (≥50%), chromium (20-30%), and molybdenum (10-16%) content enables resistance to:Oxidation, stress corrosion, and intergranular attack in harsh environments (e.g., 650°C coal gasifiers with H₂S/CO₂).Suitable for 20+ years of service in extreme conditions like high-temperature sulfuric acid or sulfur-rich oil/gas.
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Fun Sports Competition on June 15, 2025
2025-06-15
Six Longwan Enterprises Join Hands for a Successful Fun Sports Day—Yuhao Clinches Basketball Championship, Showcasing Team Spirit
To strengthen inter-enterprise collaboration and enhance employee cohesion, the "2023 Longwan Enterprise Joint Sports Day," co-organized by six renowned enterprises in the Longwan district, kicked off with great energy at Longwan on June X. The event, featuring an opening ceremony, fun competitions, a basketball tournament, and a closing ceremony, highlighted the camaraderie and competitive spirit among the participating companies. Among them, the Yuhao team stood out with an outstanding performance, securing the basketball championship and becoming the center of attention.
YUHAO – Excellence Through StrengthAs a leading industry player in Longwan, Yuhao has always prioritized team building and employee development. This sports event was not just a competition but also an opportunity to strengthen partnerships and foster mutual growth. Moving forward, Yuhao will continue upholding its philosophy of "Pursuing Excellence, Achieving Win-Win Cooperation," working hand in hand with partners to create a brighter future!
The success of this sports event has not only deepened inter-company relationships but also injected new vitality into Longwan’s collaborative development. Inspired by this championship, Yuhao will continue striving for excellence in its industry!
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Exciting Basketball Tournament Strengthens Bonds Between Yuhao and Partner Companies
2025-06-12
Wenzhon, June, 2025– A thrilling basketball tournament recently took place at [venue name or description], bringing together teams from Yuhao and several partner companies for a day of spirited competition and camaraderie. The event, held in a bright and energetic indoor court, showcased teamwork, sportsmanship, and friendly rivalry among participants.
The tournament featured intense games between teams donning black and red jerseys, with players displaying impressive skills and determination. Key moments included a clutch jump shot by player No. 20 and tight defensive plays by competitors like No. 19 and No. 24. The scoreboard reflected the competitive spirit, with one match ending at a dynamic 46-23.
The tournament wasn’t just about scores—it was a celebration of relationships. Spectators cheered from the sidelines as players from Intelhansa, Outong Group, and other partners forged connections on the court. The blend of natural light from the gymnasium’s large windows and the polished hardwood floor created an ideal setting for both competition and networking.
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June 2025 Sales Commendation Conference
2025-06-12
June 10, 2025 — The Sales Department celebrated outstanding achievements at its June Monthly Awards Ceremony,
honoring top performers who demonstrated exceptional dedication and results
"Success stems from bold actions and relentless focus on customer needs"."Every team member’s growth fuels our collective success".
The ceremony concluded with a call to action for all employees to embrace the momentum, aiming for even greater milestones in July.
The company remains committed to fostering talent and celebrating achievements that drive shared success.
Congratulations to all awardees! Let’s continue to strive for excellence together.
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