Manufacturer, Supplier & Exporter of UNS S32304 Spool

The UNS S32304 grade, also known as Duplex 2304, is a lean duplex stainless steel alloy that combines a two-phase microstructure—roughly balanced between ferrite and austenite—to provide an excellent mix of strength, corrosion resistance, and cost-effectiveness. A spool made from this alloy is a prefabricated piping assembly (pipes + fittings + welds) used in industrial systems. Because of its high strength and moderate corrosion resistance, UNS S32304 spools are widely used in pressure vessel lines, piping systems for chemical plants, water treatment, and other applications where conventional stainless steels might be over-specified..

UNS S32304, commonly known as Duplex 2304, is a lean duplex stainless steel grade combining a roughly equal proportion of austenite and ferrite phases. This dual-phase structure gives it a unique combination of high strength, good toughness, and moderate corrosion resistance, making it ideal for industrial spool fabrication. A spool of UNS S32304 is a prefabricated piping assembly that includes pipes, fittings, and welds, designed for seamless installation in complex piping systems. Riddhi Siddhi Impex, a leading manufacturer and supplier in India, specializes in producing high-quality S32304 spools tailored to industrial needs..

The chemical composition of UNS S32304 (Duplex 2304) ensures both mechanical strength and corrosion resistance. Key elements include 21.5–24.5% chromium, 3–5.5% nickel, 2–2.5% manganese, and nitrogen content of 0.05–0.20%. Carbon is kept below 0.03% to minimize sensitization during welding. This composition provides resistance against chloride stress corrosion cracking, pitting, and crevice corrosion, while maintaining cost-efficiency compared to higher alloyed duplex grades. The alloy’s lean composition also enhances weldability and formability...

UNS S32304 spools offer superior mechanical performance. The typical yield strength is around 485 MPa, with ultimate tensile strength approximately 690 MPa. Elongation is generally around 36%, indicating good ductility, while hardness remains moderate, allowing ease of fabrication. Its strength allows for reduced wall thickness in piping systems, leading to lighter and more cost-effective installations without compromising safety or durability. These mechanical properties make UNS S32304 suitable for high-pressure and temperature applications..

Riddhi Siddhi Impex manufactures UNS S32304 spools in multiple configurations, including welded spools, buttweld spools, and custom assemblies. The company employs advanced fabrication techniques and strict adherence to duplex welding procedures (like GTAW and SMAW) to maintain phase balance and structural integrity. Their spools are manufactured as per project-specific isometric drawings, P&IDs, and client requirements, ensuring precision and quality in each assembly..

UNS S32304 Spool (Duplex 2304)

Specification

Property	Details
Product Name	UNS S32304 Spool
Manufacturer	Riddhi Siddhi Impex
Material Type	Duplex Stainless Steel
Standard	ASTM A789 / ASTM A182 / ASME B16.9
Form	Pipe Spools, Welded Spools
Application	Chemical, Petrochemical, Water Treatment, Marine, Industrial Piping

Chemical Composition

Element	Composition (%)
Carbon (C)	≤0.03
Chromium (Cr)	21.5–24.5
Nickel (Ni)	3–5.5
Manganese (Mn)	2–2.5
Molybdenum (Mo)	2–3
Nitrogen (N)	0.05–0.20
Phosphorus (P)	≤0.03
Sulfur (S)	≤0.02

Mechanical Properties

Property	Value
Tensile Strength	≈ 690 MPa
Yield Strength (0.2% offset)	≈ 485 MPa
Elongation	≈ 36%
Hardness	≤ 250 HB

Dimension Chart (Nominal)

Pipe Size (NB)	Outside Diameter (mm)	Wall Thickness (mm)	Length
1/2"	21.3	2.77	Up to 12 m
1"	33.4	3.38	Up to 12 m
2"	60.3	3.91	Up to 12 m
4"	114.3	6.02	Up to 12 m
6"	168.3	7.11	Up to 12 m
8"	219.1	8.18	Up to 12 m

Equivalent Grades

Standard	Equivalent Grade
AISI / ASTM	2304 / UNS S32304
EN	1.4362
DIN	X2CrNi22-3

Equivalent Standards

Standard	Description
ASTM A789	Seamless and Welded Austenitic and Duplex Stainless Steel Tubes
ASTM A182	Forged or Rolled Alloy and Stainless Steel Pipe Flanges, Forgings, and Fittings
ASME B16.9	Factory-Made Wrought Buttwelding Fittings

Other Types

Type	Description
Duplex 2205 Spool	Higher alloyed duplex stainless steel with better corrosion resistance
Duplex 2507 Spool	Super duplex stainless steel for extreme chloride environments
Lean Duplex 2101 Spool	Cost-effective duplex stainless steel for mild corrosive applications

S32304 provides moderate resistance to general corrosion and excellent resistance to stress corrosion cracking, especially in chloride-rich environments. It is commonly used in chemical processing plants, water treatment facilities, marine applications, and pulp & paper industries. Compared to conventional austenitic stainless steels like 304L or 316L, it offers higher strength and comparable corrosion resistance, allowing for longer service life and lower maintenance costs in demanding applications..

Frequently Asked Questions (FAQs)

Q1: What are the typical applications of UNS S32304 Spool?

A1: Commonly used in chemical processing, water treatment, desalination plants, marine piping, and industrial process pipelines.

Q2: Can Riddhi Siddhi Impex supply custom-length spools?

A2: Yes, custom-length and diameter spools are manufactured based on project requirements.

Q3: Is UNS S32304 suitable for chloride-rich environments?

A3: Yes, it offers moderate resistance to pitting and stress corrosion cracking in chloride-containing media.

Q4: What certifications are provided with the spools?

A4: Material Test Certificates (MTC), NDT reports, and third-party inspection certificates can be provided.