Ss321 Stainless Steel Flange Pn16 25 40 Wn Flange GOST 33259 12820 Standard Steel Flange

SS321 Stainless Steel Weld Neck Flanges – PN16/25/40 – GOST 33259/12820 Standard – SSM

SSM offers high-quality SS321 stainless steel weld neck (WN) flanges, manufactured according to GOST 33259 and GOST 12820 standards. Available in pressure ratings PN16, PN25, and PN40, these flanges are designed for corrosion resistance, durability, and leak-proof pipeline connections.

Material Composition of SS321 Stainless Steel

SS321 is a austenitic stainless steel with the following typical chemical composition:

C: ≤0.08%

Cr: 17–19% (Chromium provides corrosion resistance)

Ni: 9–12% (Nickel improves ductility and toughness)

Mn: ≤2%

Si: ≤1%

Ti: ≥5×C to ≤0.70% (Titanium stabilizes against intergranular corrosion)

P, S: ≤0.045%

Mechanical Properties

Tensile Strength: 520–750 MPa

Yield Strength: ≥205 MPa

Elongation: 40% minimum

Hardness: ≤200 HB

Operating Temperature: -196°C to +900°C (depending on pressure and application)

What is a SS321 Weld Neck Flange?

A weld neck flange features a tapered hub welded directly to the pipe, providing:

Even stress distribution along the hub and pipe joint

Enhanced mechanical strength for high-pressure systems

Reliable sealing for industrial pipelines

Advantages of SS321 Stainless Steel Flanges

Excellent corrosion resistance – suitable for chemical, marine, and high-temperature environments

High mechanical strength – withstands high pressure and mechanical stress

Good weldability – can be welded without losing corrosion resistance

Dimensional stability – titanium stabilization prevents intergranular corrosion

Limitations / Considerations

Cost – higher than carbon steel flanges due to alloying elements

Lower strength at very high temperatures compared to some nickel-based alloys

Not suitable for highly reducing acids without special treatment

Material and Specifications

Material: SS321 Stainless Steel

Standards: GOST 33259, GOST 12820

Pressure Ratings: PN16, PN25, PN40

Size Range: DN15 – DN600 (½" – 24")

Face Types: RF (Raised Face), FF (Flat Face), RTJ (Ring Type Joint)

Type: Weld Neck (WN), Standard Steel Flange

Applications

SSM's SS321 stainless steel WN flanges are widely used in:

Chemical and petrochemical pipelines

Oil & gas and refinery pipelines

Offshore and marine piping systems

Power plants and high-temperature industrial pipelines

Water treatment and desalination plants

Why Choose SSM?

Over 30 years of experience in stainless steel flange manufacturing

Advanced forging and CNC machining for precision and durability

ISO, PED, and TS certified for quality assurance

Wide range of pressure ratings, sizes, and finishes available

Reliable global delivery and competitive pricing

Conclusion

For SS321 stainless steel weld neck flanges PN16/25/40 (GOST 33259/12820), SSM provides high-quality, corrosion-resistant, and durable flange solutions suitable for demanding industrial piping systems.

📩 Contact SSM today for quotations, technical drawings, or custom flange solutions.

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