304H vs 316L Stainless Steel Molybdenum Impact Comparison

304H vs 316L Stainless Steel: Molybdenum Impact Comparison

At Gangsteel, a leading supplier of stainless steel, we provide high-quality SA 240 GR 304H and SA 240 GR 316L plates compliant with ASME SA 240 and ASTM A240 standards.

304H stainless steel(UNS S30409, AISI 304H, EN 1.4948) is a high-carbon austenitic grade optimized for high-temperature strength up to 1500°F (815°C).

316L stainless steel(UNS S31603, AISI 316L, EN 1.4404) is a low-carbon, molybdenum-enhanced grade designed for superior corrosion resistance, especially in chloride environments.

Both are non-magnetic with a density of 8.00 g/cm³. This guide compares 304H vs 316L stainless steel, focusing on molybdenum’s impact on corrosion resistance, strength, and applications like plat stainless 304 and SA 240 GR 304 pipe. Contact us at admin@gangsteel.com or explore our ASME SA240 Stainless sheet.

Chemical Composition Comparison

Molybdenum and carbon content are the primary differentiators affecting corrosion and strength.

Molybdenum Impact: 316L’s 2-3% molybdenum strengthens the oxide layer, improving resistance to chloride-induced pitting and crevice corrosion, making it superior for harsh environments. 304H lacks molybdenum, limiting its chloride resistance but optimizing it for high-temperature, non-corrosive settings. Carbon differences drive 304H’s high-temperature strength and 316L’s weldability. See sa240 gr 304h and sa240 gr 316l.

Corrosion Resistance Comparison

304H: Offers excellent corrosion resistance in mild acids, freshwater, and atmospheric conditions, outperforming SS204 vs SS 304 due to higher nickel (8-10.5%). Without molybdenum, it’s less effective against chloride pitting, making it suitable for non-corrosive high-temperature environments like boilers.

316L: Superior in chloride-heavy environments (e.g., marine, chemical processing) due to molybdenum, which enhances resistance to pitting and crevice corrosion. Its low carbon (≤0.03%) also preserves corrosion resistance in weld zones, unlike 304H’s higher carbon (0.04-0.10%) which risks sensitization.

Molybdenum Impact: 316L’s molybdenum makes it the preferred choice for corrosive environments, particularly in coastal or chemical applications, while 304H is better for high-temperature, non-chloride settings. For enhanced chloride resistance, see sa240 gr 317l.

Strength Comparison

Mechanical properties for annealed plates (8-75 mm thick) highlight strength differences influenced by carbon and molybdenum:

• Tensile Strength: 304H’s 515 MPa outperforms 316L’s 485 MPa, particularly in high-temperature environments, due to higher carbon content enhancing creep resistance.
• Yield Strength: 304H’s 205 MPa exceeds 316L’s 170 MPa, making it better for load-bearing applications at elevated temperatures.
• Elongation: Both offer 40% elongation, ensuring excellent formability for applications like plate 2 mm SUS 304.
• Hardness: 316L’s molybdenum slightly increases hardness (≤217 HB vs. ≤201 HB for 304H), but both are easily machinable.
• Molybdenum Impact: Molybdenum has minimal effect on strength; 304H’s higher carbon drives superior high-temperature performance, while 316L prioritizes corrosion resistance.

For comparison with other grades, see sa240 gr 304.

Weldability Comparison

• 304H: Fair weldability using ER308H fillers. Higher carbon (0.04-0.10%) increases sensitization risk in the 797°F-1580°F (425°C-860°C) range, requiring controlled heat input (<2.0 kJ/mm) or post-weld annealing (1870-2050°F) to restore corrosion resistance. Suitable for high-temperature welded components like boilers.
• 316L: Excellent weldability with ER316L fillers. Low carbon (≤0.03%) minimizes sensitization, preserving corrosion resistance in weld zones without annealing. Molybdenum requires careful heat control to avoid cracking, but overall weldability is superior, ideal for chemical and marine applications.

Molybdenum Impact: 316L’s molybdenum necessitates precise welding to prevent hot cracking, but its low carbon makes it more forgiving than 304H’s higher carbon content. For high-temperature welds with better stabilization, see sa240 gr 321.

Temperature Performance Comparison

• 304H:
  • Continuous service: Up to 1500°F (815°C) with excellent creep resistance (25.5 ksi allowable stress at 1000°F).
  • Intermittent service: Up to 1600°F (871°C).
  • Scaling onset: ~1200°F (649°C).
  • Optimized for high-temperature strength in non-corrosive environments.
• 316L:
  • Continuous service: Up to ~800°F (427°C), less suited for sustained high temperatures.
  • Better for corrosion resistance than high-temperature strength.
  • Scaling onset: Similar to 304H at ~1200°F.

Molybdenum Impact: Molybdenum has minimal effect on temperature limits; 304H’s higher carbon drives its superior creep resistance for high-temperature applications like boilers. For cost-effective alternatives, see sa240 gr 201.

Physical Properties Comparison

Both grades share similar physical properties due to comparable compositions, with slight differences from molybdenum:

• Density: 8.00 g/cm³ for both, ideal for lightweight designs (e.g., a 1m x 1m x 3mm plate weighs ~24 kg).
• Melting Point: 1400-1450°C for 304H; 1370-1400°C for 316L (slightly lower due to Mo).
• Thermal Conductivity: 16.2 W/m·K at 100°C for both.
• Coefficient of Thermal Expansion: 17.2 × 10⁻⁶/K for 304H; 16.5 ×10⁻⁶/K for 316L (lower due to Mo).
• Electrical Resistivity: 0.72 × 10⁻⁶ Ω·m for 304H; 0.74 ×10⁻⁶ Ω·m for 316L.

Molybdenum Impact: Slightly reduces thermal expansion in 316L, aiding stability in corrosive high-temperature environments, but has minimal impact on overall physical properties.

Applications of 304H vs 316L Stainless Steel

• 304H: Ideal for high-temperature, non-corrosive applications:
  • Boilers and pressure vessels (steam drums, headers).
  • Heat exchangers (tubes, shells).
  • Power generation (superheaters, reheaters).
  • High-temperature piping (SA 240 GR 304 pipe).
    See sa240 gr 304h.
• 316L: Suited for corrosive environments, especially with chlorides:
  • Marine equipment (ship components, coastal structures).
  • Chemical processing (vessels, tanks).
  • Pharmaceuticals (hygienic equipment).
  • Welded structures in chloride-heavy settings.
    See sa240 gr 316l.

For enhanced corrosion resistance, explore sa240 gr 317l.

Cost Comparison

As of October 19, 2025:

Gangsteel offers competitive pricing: $1.60/kg FOB for 304H and $2.50/kg FOB for 316L (MOQ 1 ton). Contact admin@gangsteel.com or visit astm a 240 stainless plate.

Which is Better for Specific Applications?

• Choose 304H: For high-temperature applications (e.g., boilers, heat exchangers) in non-corrosive environments, where creep resistance and cost-effectiveness are priorities.
• Choose 316L: For applications in chloride-heavy or corrosive environments (e.g., marine, chemical processing), where molybdenum’s pitting resistance is critical, despite higher cost.

Summary

304H stainless steelexcels in high-temperature strength (515 MPa tensile, 205 MPa yield) for non-corrosive environments like boilers, driven by its high carbon content (0.04-0.10%).

316L stainless steel, with 2-3% molybdenum and low carbon (≤0.03%), offers superior chloride corrosion resistance and weldability, ideal for marine and chemical applications. 304H is better for heat, while 316L’s molybdenum ensures durability in corrosive settings.

Gangsteel offers both grades at competitive prices ($1.60/kg for 304H, $2.50/kg for 316L FOB). Contact admin@gangsteel.com for quotes.