304H vs 347H Stainless Steel Stabilization Differences

304H vs 347H Stainless Steel: Stabilization Differences

At Gangsteel, a leading supplier of stainless steel, we provide high-quality SA 240 GR 304H and SA 240 GR 347H 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 for high-temperature strength up to 1500°F (815°C).

347H stainless steel(UNS S34709, AISI 347H, EN 1.4961) is a high-carbon, niobium-stabilized grade for enhanced high-temperature performance and weldability.

Both are non-magnetic with a density of 8.00 g/cm³. This guide compares 304H vs 347H stainless steel, focusing on stabilization differences, 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.

Overview of 304H vs 347H Stainless Steel

304Hrelies on high carbon for creep resistance in high-heat environments like boilers.

347Huses niobium stabilization to prevent sensitization, improving weldability and high-temperature performance.

Both are austenitic, but 347H’s stabilization makes it better for welded high-temperature applications.

Chemical Composition Comparison

Stabilization comes from 347H’s niobium, while carbon content drives strength.

Stabilization: 347H’s niobium binds carbon, preventing chromium carbide formation, unlike 304H. See sa240 gr 304h and sa240 gr 347h.

Stabilization Differences

304H: No stabilization; high carbon (0.04-0.10%) risks sensitization in welds, reducing corrosion resistance.

347H: Niobium (10xC - 1.00%) stabilizes by forming niobium carbides, preventing chromium depletion, improving weldability and corrosion resistance.

Impact: 347H is better for welded high-temperature applications; 304H suits non-welded heat environments.

Corrosion Resistance Comparison

304H: Resists mild acids and atmospheric conditions, outperforming SS204 vs SS 304.

347H: Similar corrosion resistance but better in welded applications due to niobium stabilization.

Stabilization Benefit: 347H maintains corrosion resistance in welds. See sa240 gr 316l for chloride resistance.

Strength Comparison

304H and 347H: Equal strength (25.5 ksi at 1000°F), but 347H’s stabilization enhances weld performance. See sa240 gr 304.

Temperature Performance

304H: Continuous up to 1500°F (815°C); intermittent up to 1600°F (871°C).

347H: Similar range, but better for welded high-temperature applications due to stabilization.

Stabilization Benefit: 347H maintains corrosion resistance in welds at high temperatures.

Weldability Comparison

304H: Fair with ER308H fillers; needs annealing to avoid sensitization.

347H: Excellent with ER347 fillers; niobium prevents sensitization.

For welds, see sa240 gr 321.

Applications

304H: Boilers, heat exchangers, power generation (non-welded).

347H: Welded high-temperature components, aerospace, chemical processing.

For cost-effective options, see sa240 gr 201.

Cost Comparison

As of October 19, 2025:

• 304H: $1.60-$3.50/kg.
• 347H: $2.00-$3.80/kg.

Gangsteel offers $1.60/kg for 304H, $2.00/kg for 347H FOB (MOQ 1 ton). Visit astm a 240 stainless plate.

Summary

304His cost-effective for high-temperature, non-welded applications, while 347H’s niobium stabilization enhances weldability and corrosion resistance for high-temperature welded components. Choose 304H for heat, 347H for welds.