What is ASME SA 240 304H Material?

What is ASME SA 240 304H Material?

At Gangsteel, a leading manufacturer and exporter of stainless steel products, we supply premium ASME SA 240 304H material (SA 240 GR 304H) stainless steel plates compliant with ASME SA 240 and ASTM A240 standards. SA 240 GR 304H, also known as AISI 304H, UNS S30409, or 1.4948, is a high-carbon variant of the austenitic stainless steel 304, designed for enhanced high-temperature strength and creep resistance.

This article details the meaning, properties, specifications, and applications of ASME SA 240 304H material for uses in high-temperature environments like boilers, heat exchangers, and SA 240 GR 304 pipe. For inquiries, contact us at admin@gangsteel.com or explore our ASME SA 240 stainless steel plate offerings.

What is ASME SA 240 304H Material?

ASME SA 240 304H materialrefers to a high-carbon austenitic stainless steel specified under ASME SA-240/SA-240M, a standard published by the American Society of Mechanical Engineers (ASME) for chromium and chromium-nickel stainless steel plates, sheets, and strips used in pressure vessels, boilers, and general corrosive service. The designation breaks down as follows:

• SA: Indicates an ASME-adopted specification, aligned with ASTM A240/A240M, part of the ASME Boiler and Pressure Vessel Code (BPVC) Section II, Part A (Ferrous Material Specifications).
• 240: Refers to the specific ASME standard number for stainless steel plates, sheets, and strips.
• 304H: Identifies the grade, a high-carbon (0.04-0.10%) version of 304 stainless steel (UNS S30409, EN 1.4948), optimized for high-temperature applications due to improved creep and stress rupture properties compared to SA 240 GR 304 (≤0.08% carbon) or SA 240 GR 304L (≤0.03% carbon).

ASME SA 240 304H material is non-magnetic in the annealed state, with a density of 7.93 g/cm³, and is designed for elevated-temperature service (up to ~815°C/1500°F). It’s ideal for applications requiring strength at high temperatures, such as in boilers and heat exchangers. Gangsteel’s sa 240 gr 304h plates meet these standards.

Chemical Composition of ASME SA 240 304H Material

The chemical composition of ASME SA 240 304H material, as per ASME SA 240, ensures enhanced high-temperature strength and corrosion resistance:

• Carbon: Higher content (0.04-0.10%) compared to 304 (≤0.08%) and 304L (≤0.03%) improves creep resistance and strength at elevated temperatures but may reduce weldability.
• Chromium: Forms a passive oxide layer for corrosion resistance in mild environments.
• Nickel: Ensures austenitic structure and non-magnetic properties.
• Comparison: Unlike SA 240 GR 316L (which includes 2-3% molybdenum), 304H lacks molybdenum, limiting its chloride resistance.

For detailed specifications, refer to our SS 304 data sheet for comparison with SA 240 GR 304.

Mechanical Properties of ASME SA 240 304H Material

The mechanical properties of ASME SA 240 304H material for annealed plates (8-75 mm thick) support its use in high-temperature applications:

• Comparison: Similar to SA 240 GR 304 (515 MPa tensile, 205 MPa yield) but stronger than SA 240 GR 304L (485 MPa tensile, 170 MPa yield) at room temperature. Higher carbon enhances creep strength at elevated temperatures (e.g., allowable stress of 25.5 ksi at 1000°F vs. 18.6 ksi for 304).
• Cold-Working: Can increase tensile strength (up to 900 MPa) but reduces ductility.

Physical Properties

• Density: 8.00 g/cm³, identical to SA 240 GR 304, ideal for lightweight designs (e.g., a 1m x 1m x 3mm plate weighs ~24 kg).
• Melting Point: ~1400-1450°C, suitable for high-temperature processing.
• Thermal Conductivity: 16.2 W/m·K, moderate for heat transfer.
• Coefficient of Thermal Expansion: 17.2 × 10⁻⁶/K, stable across temperatures.
• Electrical Resistivity: 0.72 × 10⁻⁶ Ω·m, good for non-conductive applications.

These properties make ASME SA 240 304H material suitable for high-temperature structural applications.

Corrosion Resistance

ASME SA 240 304H material offers corrosion resistance similar to SA 240 GR 304:

• Excellent in atmospheric conditions, freshwater, and mild acids (food-grade applications).
• Outperforms SS204 vs SS 304 due to higher nickel content.
• Less resistant to chloride-induced pitting compared to SA 240 GR 316L, which contains molybdenum. For chloride-heavy environments, explore sa 240 gr 316l.

The higher carbon content may increase susceptibility to sensitization during welding, potentially reducing corrosion resistance in weld zones unless annealed.

Weldability

• Weldability: Fair, using ER308 or ER308H fillers. The higher carbon content (0.04-0.10%) increases the risk of sensitization (chromium carbide precipitation), requiring controlled heat input (<2.0 kJ/mm) or post-weld annealing to maintain corrosion resistance.
• Comparison: SA 240 GR 304L (≤0.03% carbon) is preferred for critical welds due to lower sensitization risk. For high-temperature welds, explore sa 240 gr 321 for titanium-stabilized performance.

Applications of ASME SA 240 304H Material

ASME SA 240 304H material is used in:

• Boilers and Pressure Vessels: High-temperature strength for steam drums and headers.
• Heat Exchangers: Creep resistance in elevated-temperature environments.
• Chemical Industry: Vessels and SA 240 GR 304 pipe for mild corrosives at high temperatures.
• Power Generation: Components requiring durability up to 815°C (1500°F).
• Piping and Fittings: SA 240 GR 304H pipe and flanges for high-temperature systems.

For milder environments, consider sa 240 gr 304 or sa 240 gr 304l for better weldability.

Pricing and Availability at Gangsteel

As of October 15, 2025, ASME SA 240 304H material plate prices (2B finish, 3-6mm thick) range from $1.60-$3.50/kg globally, slightly higher than SA 240 GR 304 ($1.55-$3.50/kg) due to specialized high-temperature applications. Gangsteel offers competitive pricing starting at $1.60/kg FOB (MOQ 1 ton) for standard sizes (e.g., 4’x8’, 5’x10’) and custom cuts, with finishes like 2B, No.1, and polished. Our SS 304 plate price is 5-10% below market averages, and dual-certified SA 240 TP 304/304L plates are available for flexibility. For pricing details, contact admin@gangsteel.com.

Why Choose Gangsteel?

Gangsteel provides certified ASME SA 240 304H material with consistent properties and competitive SA 240 304 plate price. Our 600+ ton inventory supports global delivery for applications from high-temperature pressure vessels to heavy plates. For quotes or to learn more about ASME SA 240 304H material, visit our sa 240 gr 304h page or email admin@gangsteel.com.