SA240 GR 304H UNS Number S30409 and Its Meaning

SA240 GR 304H UNS Number: S30409 and Its Meaning

At Gangsteel, a leading manufacturer and exporter of stainless steel products, we supply premium SA240 GR 304H stainless steel plates compliant with ASME SA 240 and ASTM A240 standards. SA240 GR 304H UNS number S30409, also known as AISI 304H or EN 1.4948, is a high-carbon austenitic stainless steel optimized for high-temperature strength and creep resistance up to 1500°F (815°C).

This guide explains the SA240 GR 304H UNS number S30409 and its meaning, including specifications, properties, and applications for uses like plat stainless 304 and SA 240 GR 304 pipe. For inquiries, contact us at admin@gangsteel.com or explore our ASME SA240 Stainless sheet offerings.

What is the UNS Number S30409 in SA240 GR 304H?

The SA240 GR 304H UNS number S30409 is the Unified Numbering System (UNS) designation for this high-carbon stainless steel grade. UNS S30409 identifies the material's composition universally across standards, ensuring traceability and compatibility. "S" indicates stainless steel, "3" denotes austenitic family, and "0409" specifies the exact alloy. It aligns with AISI 304H, where the "H" denotes high carbon (0.04-0.10%). See sa240 gr 304h.

Meaning of S30409 in SA240 GR 304H

S30409means a high-carbon austenitic stainless steel with enhanced creep resistance for high-temperature service. In SA240 GR 304H, it signifies a grade for pressure vessels, with allowable stress of 25.5 ksi at 1000°F (538°C). The UNS system standardizes it globally, equivalent to EN 1.4948 or JIS SUS 304H. See sa240 gr 304l for low-carbon variant.

Chemical Composition

The chemical composition of SA240 GR 304H UNS number S30409 is:

High carbon (0.04-0.10%) boosts creep resistance. See sa240 gr 304.

Mechanical Properties

High strength at high temperatures (25.5 ksi allowable at 1000°F). See sa240 gr 316l.

Physical Properties

• Density: 8.00 g/cm³.
• Melting Point: 1400-1450°C.
• Thermal Conductivity: 16.2 W/m·K.
• Coefficient of Thermal Expansion: 17.2 × 10⁻⁶/K.
• Max Service Temperature: 1500°F (815°C) continuous.

Corrosion Resistance

SA240 GR 304H UNS number S30409 resists mild acids and atmospheric conditions, outperforming SS204 vs SS 304. Higher carbon risks sensitization in welds; anneal for protection. See sa240 gr 321 for stabilization.

Weldability

Fair with ER308H fillers; low heat input (<2.0 kJ/mm) and annealing required. See sa240 gr 304l.

Applications

SA240 GR 304H UNS number S30409 is used in:

• Boilers and pressure vessels.
• Heat exchangers.
• Power generation piping.
• High-temperature chemical processing.

For cost-effective options, see sa240 gr 201.

Pricing and Availability

As of October 19, 2025, SA240 GR 304H plate prices (2B finish, 3-6mm) range from $1.60-$3.50/kg. Gangsteel offers $1.60/kg FOB (MOQ 1 ton) for sa240 gr 304h. Contact admin@gangsteel.com or visit astm a 240 stainless plate.

FAQ on SA240 GR 304H UNS Number S30409

What does the UNS number S30409 mean for SA240 GR 304H?

S30409 indicates a high-carbon austenitic stainless steel with enhanced creep resistance, where "S" denotes stainless, "3" austenitic, and "0409" the specific alloy.

How does SA240 GR 304H UNS number S30409 compare to 304L?

S30409 (304H) has higher carbon (0.04-0.10%) for high-temperature strength; 304L (S30403) has ≤0.03% C for weldability. See sa240 gr 304l.

What is the EN equivalent of SA240 GR 304H UNS number S30409?

EN 1.4948 (X6CrNi18-10), matching the high-carbon composition for creep resistance.

What is the JIS equivalent of SA240 GR 304H UNS number S30409?

JIS SUS 304H, used in Asia for piping and sheets with similar properties.

What applications benefit from SA240 GR 304H UNS number S30409?

High-temperature pressure vessels, boilers, and heat exchangers, leveraging its creep resistance up to 1500°F.