HB 304H Stainless Steel Overview and Specifications

HB 304H Stainless Steel: Overview and Specifications

At Gangsteel, a leading manufacturer and exporter of stainless steel products, we supply premium HB 304H stainless steel plates compliant with ASME SA 240 and ASTM A240 standards. HB 304H stainless steel, equivalent to SA 240 GR 304H, AISI 304H, UNS S30409, or EN 1.4948, is a high-carbon variant of 304 stainless steel designed for enhanced high-temperature strength and creep resistance.

The “HB” likely refers to Brinell hardness or a specific designation in certain contexts, but it aligns with standard 304H specifications.

This guide provides an overview and detailed specifications of HB 304H stainless steel for applications like boilers, heat exchangers, and high-temperature piping. For inquiries, contact us at admin@gangsteel.com or explore our ASME SA240 Stainless sheet offerings.

Overview of HB 304H Stainless Steel

HB 304H stainless steelis a high-carbon (0.04-0.10%) austenitic stainless steel specified under ASME SA 240 for plates, sheets, and strips used in pressure vessels and high-temperature service. It offers superior creep and stress rupture strength up to 1500°F (815°C) compared to 304 (≤0.08% C) or 304L (≤0.03% C). Non-magnetic in the annealed state, it has a density of 8.00 g/cm³ and is ideal for demanding applications like power generation. The “HB” may denote a focus on hardness (Brinell ≤201 HB) or a supplier-specific term, but properties align with SA 240 GR 304H. For related grades, see our sa240 gr 304 and sa240 gr 304l pages.

Chemical Composition of HB 304H Stainless Steel

The chemical composition of HB 304H stainless steel ensures high-temperature performance and corrosion resistance:

• Carbon: Higher content enhances creep resistance but increases sensitization risk during welding.
• Chromium: Provides corrosion resistance via a passive oxide layer.
• Nickel: Maintains non-magnetic austenitic structure.
• Comparison: Lacks molybdenum (unlike sa240 gr 316l) and titanium (unlike sa240 gr 321).

Mechanical Properties of HB 304H Stainless Steel

The mechanical properties of HB 304H stainless steel for annealed plates (8-75 mm thick) support high-temperature applications:

• High-Temperature Strength: Allowable stress of 25.5 ksi at 1000°F (538°C) outperforms 304 (18.6 ksi) and 304L (14.9 ksi).
• Ductility: 40% elongation supports forming for applications like plat SS 304 3mm.
• Hardness: Brinell ≤201 HB ensures good machinability.

Physical Properties of HB 304H Stainless Steel

• 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 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.
• Service Temperature: Up to 1500°F (815°C) continuous; 1600°F (871°C) intermittent.

These properties support high-heat stability. For alternatives, see sa240 gr 316ln.

Corrosion Resistance of HB 304H Stainless Steel

HB 304H stainless steeloffers excellent corrosion resistance in:

• Atmospheric conditions, freshwater, and mild acids (food-grade).
• General environments, outperforming SS204 vs SS 304 due to higher nickel.

It’s less resistant to chloride-induced pitting compared to sa240 gr 317l. Higher carbon increases sensitization risk in weld zones (797°F-1580°F), requiring annealing.

Weldability of HB 304H Stainless Steel

Weldability is fair using ER308H fillers. Higher carbon (0.04-0.10%) risks sensitization, necessitating low heat input (<2.0 kJ/mm) or post-weld annealing at 1870-2100°F (1020-1149°C). For better weldability, see sa240 gr 201.

Applications of HB 304H Stainless Steel

HB 304H stainless steelis used in:

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

For low-cost options, see sa240 gr 202.

Pricing and Availability at Gangsteel

As of October 19, 2025, HB 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 plates, including custom sizes like plate 2 mm SUS 304. Contact admin@gangsteel.com.

Why Choose Gangsteel for HB 304H Stainless Steel?

Gangsteel provides certified HB 304H stainless steel with competitive pricing and a 600+ ton inventory for global delivery. For quotes or to learn more, visit our astm a 240 stainless plate page or email admin@gangsteel.com.