254 SMO (UNS S31254) is a super austenitic stainless steel with 6% molybdenum content, also known as '6 moly' or '6Mo'. It has a PREN (Pitting Resistance Equivalent Number) greater than 40, making it highly resistant to pitting and crevice corrosion in chloride environments. 254 SMO is used for seawater, desalination, and chemical processing where standard stainless steels like 316L would fail.

Why use 254 SMO for seawater valves?

254 SMO is preferred for seawater valves because: (1) PREN >40 provides excellent pitting resistance in chlorides, (2) 6% molybdenum content resists crevice corrosion, (3) Superior to 316L and Duplex in warm seawater (>20°C), (4) Maintains corrosion resistance at temperatures up to 40°C in seawater, (5) Approved for offshore and desalination applications by major EPCs.

What is the difference between 254 SMO and 316L?

254 SMO has 6% molybdenum vs 2-3% in 316L, giving it PREN >40 vs ~25 for 316L. This means 254 SMO can handle seawater and high chloride environments where 316L would pit and fail. 254 SMO costs more but is essential for critical seawater service. 316L is suitable for freshwater and low chloride applications only.

What sizes are 254 SMO monoflange valves available in?

254 SMO monoflange DBB valves are available in sizes from 1 inch to 3 inch. Common sizes for instrumentation are 1", 2", and 3". Pressure class is typically 300 or 600. End connection is flanged per ASME B16.5. Larger isolation valves in 254 SMO are available as gate, globe, or ball valve configurations.

Super Austenitic

254 SMO Monoflange Double Block & Bleed Valve

Name: 254 SMO Monoflange Double Block and Bleed Valve
Brand: Supreme Valves
SKU: SV-254SMOMONOFLANGEDBBV
Price: 15246 INR
Availability: InStock
Rating: 4.8 (127 reviews)

254 SMO (UNS S31254) Monoflange Double Block and Bleed valves per API 6D. Super austenitic stainless steel with 6% molybdenum for superior chloride resistance. PREN >40. Class 300. Sizes 1" to 3". Ideal for instrumentation isolation in seawater, desalination, and offshore applications.

Quick Summary

254 SMO = Super austenitic stainless steel with 6% Mo (UNS S31254). PREN >40 = seawater resistant. Monoflange DBB = Double Block and Bleed in single compact flange body. Used for instrumentation isolation where you need positive double isolation + bleed. Better than 316L or Duplex for warm seawater (>20°C). Common in desalination, offshore, and chemical plants.

254 SMO Monoflange DBB Valve UNS S31254 Super Austenitic

In Stock PREN >40

Key Specifications

Design Standard: API 6D

Pressure Class: 300

Body Material: UNS S31254

Configuration: DBB

PREN: >40

Size Range: 1" to 3"

Molybdenum: 6%

End Connection: Flanged

Request Quote WhatsApp

What is 254 SMO?

254 SMO (UNS S31254) is a super austenitic stainless steel specifically designed for high chloride environments. Key properties:

Molybdenum: 6% (hence "6 moly")
Chromium: 20%
Nickel: 18%
Nitrogen: 0.2%
PREN: >40 (pitting resistant)

254 SMO vs 316L vs Duplex

Property	254 SMO	316L	Duplex
PREN	>40	~25	~35
Mo %	6%	2-3%	3%
Seawater	✓ Excellent	✗ Pits	Limited

Frequently Asked Questions

What is 254 SMO?

254 SMO (UNS S31254) is a super austenitic stainless steel with 6% molybdenum. It has PREN >40, making it highly resistant to pitting and crevice corrosion in chloride environments like seawater.

What is a Monoflange DBB valve?

A Monoflange Double Block and Bleed valve combines two isolation valves and a bleed valve in a single flange body. It provides double isolation with a bleed port for venting or draining. Used for instrumentation isolation.

Why use 254 SMO for seawater?

254 SMO has PREN >40 which provides excellent pitting resistance in chlorides. The 6% molybdenum resists crevice corrosion. It's superior to 316L and Duplex in warm seawater (>20°C).

Need 254 SMO Valves for High Chloride Service?

We supply 254 SMO valves for desalination, offshore, and chemical applications. EN 10204 3.1 MTCs included.

Request Quote WhatsApp

Pricing – Monoflange DBB (Class 300)

Indicative unit prices in INR (ex-works India). Includes hydrostatic testing and EN 10204 3.1 MTCs. Volume discounts available for project quantities.

Size	Standard	Operation	Material	Unit Price (INR)
1"	API 6D	Manual	UNS S31254 (254 SMO)	₹15,246
2"	API 6D	Manual	UNS S31254 (254 SMO)	₹38,621
3"	API 6D	Manual	UNS S31254 (254 SMO)	₹53,900

* Prices are indicative and subject to change. Contact us for confirmed pricing and delivery schedules. GST extra as applicable.