A240 304H Stainless Steel Temperature Limits Max Service Ran

A240 304H Stainless Steel Temperature Limits: Maximum Service Range

At Gangsteel, a leading manufacturer and exporter of stainless steel products, we supply premium A240 304H stainless steel plates compliant with ASTM A240 and ASME SA 240 standards. A240 304H stainless steel, also known as AISI 304H, UNS S30409, or EN 1.4948, is a high-carbon austenitic stainless steel optimized for high-temperature service up to 1500°F (815°C). This guide details the temperature limits and maximum service range of A240 304H stainless steel, including continuous and intermittent limits, scaling onset, and sensitization risks, for applications like boilers, heat exchangers, and SA 240 GR 304 pipe. For inquiries, contact us at admin@gangsteel.com or explore our ASME SA240 Stainless sheet offerings.

Overview of A240 304H Stainless Steel Temperature Limits

A240 304H stainless steelis engineered for elevated-temperature performance, with maximum service range determined by ASME BPVC Section II, Part D, and ASTM A240. Its high carbon content (0.04-0.10%) enhances creep and stress rupture strength, making it superior to 304 (≤0.08% C) or 304L (≤0.03% C) for high-heat environments. Key temperature limits include:

• Continuous Service Temperature: Up to 1500°F (815°C) – Recommended for long-term exposure in pressure vessels, boilers, and heat exchangers, where the material maintains structural integrity without excessive creep.
• Intermittent Service Temperature: Up to 1600°F (871°C) – Suitable for short-term or cyclic exposure, such as during startup/shutdown cycles.
• Scaling Onset: Mild oxidation/scaling begins at ~1200°F (649°C), accelerating above 1500°F, limiting prolonged use beyond this threshold.
• Sensitization Range: Avoid prolonged exposure to 797°F-1580°F (425°C-860°C) during service or welding to prevent chromium carbide precipitation, which can compromise corrosion resistance.

These limits, driven by the elevated carbon content, position A240 304H stainless steel as a robust choice for high-temperature structural applications. For low-carbon variants, see sa240 gr 304l.

Chemical Composition Supporting Temperature Performance

The chemical composition of A240 304H stainless steel contributes to its high-temperature capabilities:

• Carbon: High (0.04-0.10%) enhances creep resistance above 800°F (427°C), critical for the 1500°F limit.
• Chromium: 18-20% forms a protective oxide layer, resisting scaling up to 1200°F.
• Nickel: 8-10.5% stabilizes the austenitic structure (SA 240 304 non magnetic), aiding thermal stability.
• Comparison: Unlike sa240 gr 316l with molybdenum for chlorides, 304H prioritizes heat over corrosion in non-chloride settings.

Mechanical Properties

The mechanical properties of A240 304H stainless steel for annealed plates (8-75 mm thick) support its temperature limits:

• High-Temperature Strength: Allowable stress of 25.5 ksi at 1000°F (538°C), superior to 304 (18.6 ksi) and 304L (14.9 ksi), per ASME BPVC Section II, Part D.
• Ductility: 40% elongation supports forming for applications like plat SS 304 3mm or plate 2 mm SUS 304.

Physical Properties

• Density: 8.00 g/cm³, 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 at 100°C.
• Coefficient of Thermal Expansion: 17.2 × 10⁻⁶/K (20-100°C).
• Electrical Resistivity: 0.72 × 10⁻⁶ Ω·m.

These properties support the maximum service range, while ferritic grades like sa240 gr 430 have lower limits.

Corrosion Resistance

A240 304H stainless steeloffers excellent corrosion resistance in mild acids and atmospheric conditions, outperforming SS204 vs SS 304 due to high chromium (18-20%) and nickel (8-10.5%). Higher carbon (0.04-0.10%) increases sensitization risk in the 797°F-1580°F (425°C-860°C) range during welding, requiring annealing. It’s less resistant to chlorides than sa240 gr 316l.

Weldability

Fair with ER308H fillers; low heat input (<2.0 kJ/mm) and post-weld annealing (1870-2050°F) required to mitigate sensitization. For better weldability, see sa240 gr 304l.

Applications Leveraging Temperature Limits

A240 304H stainless steelis used in:

• Boilers and pressure vessels (steam drums, headers).
• Heat exchangers (tubes, shells).
• Power generation (superheaters, reheaters).
• High-temperature chemical processing (vessels, SA 240 GR 304 pipe).
• Elevated-temperature piping and fittings.

For cost-effective alternatives, see sa240 gr 201.

Pricing and Availability

As of October 19, 2025, A240 304H stainless steel plate prices (2B finish, 3-6mm) range from $1.60-$3.50/kg globally. 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 A240 304H Stainless Steel Temperature Limits

What is the maximum continuous temperature for A240 304H stainless steel?

Up to 1500°F (815°C), with excellent creep resistance for long-term high-temperature service.

What is the intermittent temperature limit for A240 304H stainless steel?

Up to 1600°F (871°C) for short-term exposure, suitable for cyclic operations in power plants.

How does A240 304H compare to 304L in temperature limits?

304H supports 1500°F continuous service with higher creep strength, while 304L is limited to ~800°F (427°C).

What is the sensitization range for A240 304H stainless steel?

797°F-1580°F (425°C-860°C); avoid prolonged exposure during welding to prevent carbide precipitation.

Why is A240 304H suitable for high-temperature applications?

High carbon (0.04-0.10%) and fine grain size (ASTM 5-8) ensure creep resistance and structural integrity up to 1500°F.