What is SA 204 material?

What is SA 204 Material?

At Gangsteel, a leading manufacturer and exporter of steel products, we supply high-quality SA 204 alloy steel plates compliant with ASME SA 204 standards.

SA 204, formally known as ASME SA-204/SA-204M, is a specification for pressure vessel plates made of carbon-molybdenum alloy steel, designed for welded boilers and other pressure vessels.

Unlike stainless steels like SA 240 GR 304, SA 204 is a ferritic alloy steel with molybdenum (approximately 0.5%) to enhance high-temperature strength and creep resistance. It is available in three grades (A, B, and C), each with varying strength levels and thickness limits. This article details the SA 204 material specification, grades, chemical composition, mechanical properties, and applications. For inquiries, contact us at admin@gangsteel.com or explore our related ASME SA 240 stainless steel plate offerings.

Overview of SA 204 Material

SA 204 covers carbon-molybdenum alloy steel plates intended for moderate- to high-temperature service in pressure vessels. The molybdenum content improves resistance to creep and stress rupture at elevated temperatures, making it suitable for welded constructions. Plates are produced from killed steel and must be normalized for thicknesses over 40 mm (Grade A) or as specified. The specification aligns with ASTM A204/A204M and is used in ASME Boiler and Pressure Vessel Code (BPVC) Section II.

Key grades:

• Grade A: Lowest strength, maximum thickness ~150 mm.
• Grade B: Intermediate strength, maximum thickness ~150 mm.
• Grade C: Highest strength, maximum thickness ~100 mm.

SA 204 is not stainless steel (no chromium >10.5%) but is often compared to it for pressure vessel applications. Gangsteel can supply SA 204 plates alongside stainless grades like sa 240 gr 304.

Chemical Composition of SA 204 Grades

The chemical composition of SA 204, as per ASME SA-204/SA-204M, emphasizes molybdenum for high-temperature performance. Below is a table for the three grades (weight %):

*Source: ASME SA-204/SA-204M standards, as of October 14, 2025. Carbon equivalent (CEQ) is controlled for weldability: CEQ = C + Mn/6 + (Cr + Mo + V)/5 + (Ni + Cu)/15 ≤ 0.45% for all grades.

• Molybdenum: Enhances high-temperature strength and creep resistance.
• Carbon: Limited to ≤0.20% to balance strength and weldability.
• Manganese: Improves hardenability and toughness.

For comparison, SA 204 differs from stainless grades like SA 240 GR 304 (18-20% Cr, 8-10.5% Ni).

Mechanical Properties of SA 204 Grades

The mechanical properties of SA 204 for normalized plates ensure suitability for pressure vessels. Below is a table for the three grades (minimum values):

*Source: ASME SA-204/SA-204M standards, as of October 14, 2025. Properties are for normalized condition; impact testing is optional.

• Tensile Strength: Increases from Grade A to C, suitable for higher-pressure applications.
• Yield Strength: Grade C offers the highest resistance to deformation.
• Elongation: Decreases with higher strength, but all grades are formable.

SA 204 Grade B is the most common for general use.

Physical Properties

• Density: ~7.85 g/cm³ (typical for carbon steels).
• Melting Point: ~1420-1460°C.
• Thermal Conductivity: ~50 W/m·K at room temperature.
• Coefficient of Thermal Expansion: 12.0 × 10⁻⁶/K (up to 500°C).
• Modulus of Elasticity: ~200 GPa.

These properties support high-temperature service up to ~540°C (1000°F) for Grade B.

Applications of SA 204 Material

SA 204 is used in:

• Pressure Vessels: Welded boilers and reactors for moderate temperatures.
• Heat Exchangers: Where creep resistance is needed.
• Power Generation: Steam drums and headers.
• Oil and Gas: Piping and vessels for sour service (with additional testing).

Unlike stainless SA 240 GR 304 (for corrosive environments), SA 204 is for high-temperature, non-corrosive applications. For stainless alternatives, explore sa 240 gr 304.

Pricing and Availability

As of October 14, 2025, SA 204 Grade B plate prices (normalized, 3-6mm thick) range from $0.80-$1.50/kg globally, lower than stainless grades due to simpler alloying. Gangsteel offers competitive pricing starting at $0.90/kg FOB (MOQ 1 ton) for SA 204 Grade B plates, with custom sizes up to 150 mm thick. Contact sales@gangsteel.com for quotes.

Why Choose Gangsteel?

Gangsteel provides certified SA 204 plates with consistent properties and competitive pricing. Our inventory supports applications from pressure vessels to heat exchangers. For quotes or to learn more, visit our ASME SA 240 stainless steel plate page or email admin@gangsteel.com.

Values based on ASME SA-204/SA-204M 2023 edition; verify with the latest standard for your application.