316Ti Stainless Steel 321 vs 316Ti Comparison

316Ti Stainless Steel 321 vs 316Ti Comparison

Published: November 11, 2025 | Updated: November 11, 2025By Gangsteel Engineering Team – 25+ Years in Stainless Steel Export Excellence

In the competitive landscape of stainless steels compliant with ASTM A240/A240M and ASME SA240/SA240M standards, comparing 316Ti (titanium-stabilized austenitic) and 321 (niobium-stabilized austenitic) reveals key differences in corrosion resistance, high-temperature performance, and suitability for welded structures.

As a premier producer and exporter based in China, Gangsteel has supplied thousands of tons of both 316Ti and 321 stainless steel, meeting ASTM A240/A240M specs for plates and sheets, to industries such as petrochemical, marine, and power generation.

If you're evaluating 316Ti vs 321 under ASME SA240/SA240M for a heat exchanger or exhaust system where pitting, oxidation, or sensitization risk is critical, this guide provides a clear, data-driven comparison. We'll break down their attributes, including corrosion, mechanicals, and more, based on ASTM A240/A240M and ASME SA240/SA240M standards and our mill data.

From our production lines, we've seen the contrast: In a 2024 European power plant retrofit, our 316Ti tubes under ASTM A240 /A240M resisted pitting in chloride-laden flue gas better than 321, with CPT 25-35°C vs 15-25°C, as per client immersion tests. Compliant with ASME SA240/SA240M for pressure apps, 316Ti's PREN 23-28 vs 321's 18-20 supports chloride-heavy use. Let's delve into the comparison, from composition to applications, to guide your choice.

Summary

316Ti and 321 stainless steel under ASTM A240/A240M and ASME SA240/SA240M are both stabilized austenitic grades for high-temp service, but 316Ti's molybdenum (2-3%) provides better pitting and crevice corrosion resistance (PREN 23-28 vs 18-20 for 321), making it ideal for chloride and acid environments. 321's niobium stabilization excels in oxidation and scaling at continuous high temps (up to 925°C intermittent), while 316Ti's Ti is better for welded IGC prevention. Both have tensile 515 MPa min and yield 205 MPa min, but 321 is more formable. Density 8.00 g/cm³ for both. 316Ti costs 5-10% more but offers broader corrosion protection. Choose 316Ti for chlorides/acids, 321 for pure heat. Gangsteel stocks both with certs for custom needs.

Chemical Composition: The Key Differentiator

The compositions of 316Ti and 321, as per ASTM A240/A240M and ASME SA240/SA240M, show why 316Ti edges in pitting while 321 wins in oxidation.

316Ti's Mo gives it better pitting, while 321's Nb excels in scaling.

Mechanical Properties: Comparable with Edges

Both have similar room-temp properties, but 321 shows better creep at elevated temps.

321's Nb strengthens at high temps, making it more durable in continuous heat.

Physical Properties: Minor Variations

Both have similar physicals, but 321's Nb improves high-temp stability.

316Ti's lower expansion enhances durability in thermal cycling.

Corrosion Resistance: 316Ti's Pitting Edge

Both resist general corrosion well, but 316Ti's Mo provides better pitting, while 321's Nb excels in scaling.

• Pitting/Crevice: 316Ti superior with Mo (PREN 23-28 vs 18-20 for 321); CPT ~25°C vs 15°C.
• IGC: Both resistant (316Ti Ti, 321 Nb).
• SCC: Both good; 316Ti better in chlorides.
• Uniform: <0.1 mm/year in dilute acids; similar.
• High-Temp: 321 better for scaling; 316Ti for IGC in welds.

316Ti is more versatile for corrosives; 321 for pure oxidation.

Weldability and Fabrication: Similar Ease

Both weld well with fillers like ER316L; no preheat. 316Ti's Ti prevents IGC at heat, 321's Nb for scaling. Machinability ~60% for both.

Gangsteel's 316Ti SA240 Type 316Ti offers superior weld performance.

Applications: Overlapping but Specialized

• Common: Heat exchangers (both durable).
• 316Ti Specific: Marine, chemical (pitting in chlorides).
• 321 Specific: Aerospace, exhausts (oxidation at heat).

In Gangsteel's supply to U.S. marine, 316Ti lasted longer in salt.

Equivalents: Alternatives for Both

316Ti equivalents: EN 1.4571. 321 equivalents: EN 1.4541. For A240 GR 316Ti, not interchangeable with 321 in chlorides.

Sourcing from Gangsteel: Stock and Pricing

Gangsteel stocks 316Ti and 321 at $3,200-3,800/ton (316Ti) and $3,000-3,500 (321) FOB. 1-200mm thick, certs. Contact for comparisons.

FAQ: 316Ti vs 321 Stainless Steel Questions Answered

Q: How does corrosion resistance compare between 316Ti and 321 stainless steel?

A: 316Ti has superior pitting/crevice resistance (PREN 23-28 vs 18-20) due to Mo, while 321 excels in oxidation/scaling at high temps from Nb; both good IGC with stabilizers.

Q: What are the mechanical property differences between 316Ti and 321?

A: Both have tensile 515 MPa min and yield 205 MPa min, but 321 shows better creep at >600°C due to Nb, while 316Ti has higher pitting strength.

Q: Which is better for high-temperature applications, 316Ti or 321?

A: 321 is better for continuous high-temp oxidation (up to 925°C intermittent), while 316Ti excels in welded IGC resistance and chlorides due to Mo.

Q: How do pitting and crevice corrosion compare for 316Ti and 321?

A: 316Ti is superior with CPT 25-35°C vs 15-25°C for 321, thanks to Mo; 321's Nb doesn't enhance pitting.

Q: Is 316Ti or 321 more cost-effective for high-temperature apps?

A: 316Ti for chlorides/acids (higher initial cost but better pitting); 321 for pure oxidation (lower cost, similar heat stability).

Q: What is the PREN of 316Ti vs 321 stainless steel?

A: 316Ti PREN 23-28 (Mo boost); 321 ~18-20—no Mo, lower pitting.

Q: Can I substitute 321 for 316Ti in corrosion apps?

A: Yes for high-temp oxidation, but not for chlorides where 316Ti's Mo is essential; check specs for equivalence.