Comparison of 316H and 316Ti Stainless Steel: High-Carbon Strengthened vs Titanium-Stabilized Grade

Design Intent: High-Carbon Strengthening vs Titanium Stabilization

316H and 316Ti are both derived from Type 316, but their alloy design points in opposite directions. 316H deliberately raises carbon to 0.04–0.10% so that the steel gains higher creep strength at elevated temperature, making it suitable for load-bearing components operating between 500°C and 870°C. 316Ti instead keeps carbon low and adds titanium at a level of at least five times the carbon content, so that carbon is locked up as stable titanium carbides and cannot form chromium carbides at grain boundaries. This makes 316Ti the better choice where welding and long-term resistance to intergranular corrosion matter.

Chemical Composition Comparison

Element wt%	316H UNS S31609	316Ti UNS S31635
Carbon	0.04 – 0.10	≤ 0.08
Chromium	16.0 – 18.0	16.0 – 18.0
Nickel	10.0 – 14.0	10.0 – 14.0
Molybdenum	2.0 – 3.0	2.0 – 3.0
Titanium	Not required	5 × C to 0.70
Iron	Balance	Balance

Mechanical Properties and Service Temperature

Property	316H	316Ti
Tensile strength, annealed	≥ 515 MPa	≥ 515 MPa
Yield strength, annealed	≥ 205 MPa	≥ 205 MPa
Elongation	≥ 40%	≥ 40%
Hardness	≤ 217 HB	≤ 217 HB
Continuous service temperature	500 – 870°C	400 – 900°C

High-Temperature Performance Differences

In the 500–870°C range, 316H offers higher creep strength than 316Ti, with a creep rupture life reported at roughly 1.5 to 2 times that of 316Ti under the same stress and temperature. This is why 316H is preferred for components that carry steady stress at high temperature. 316Ti, on the other hand, has better intergranular corrosion resistance because titanium prevents chromium carbide precipitation; it can also be exposed briefly to 900°C, about 30°C higher than the practical limit of 316H. When welding 316H, heat input must be controlled to avoid chromium carbide precipitation and the resulting intergranular corrosion.

How to Choose Between 316H and 316Ti

Choose 316H for high-temperature, stress-bearing components such as boiler superheater tubes, high-temperature reactor internals at 500–700°C and high-temperature fan blades.

Choose 316Ti for long-term hot service where intergranular corrosion resistance is critical, such as petrochemical cracking furnace tubes, heat-exchanger tubes in nuclear plants and welded high-temperature pipelines.

For piping with many field welds in the 400–900°C range, 316Ti is the safer choice; for pressure- and load-dominated lines up to 870°C with limited welding, 316H is more cost-effective.

316Ti typically costs 15–20% more than 316H because of the titanium addition and tighter composition control.

Frequently Asked Questions

Q1: What is the core difference between 316H and 316Ti?
A1: 316H focuses on high-temperature creep strength for dynamic load-bearing parts; 316Ti focuses on intergranular corrosion resistance for static components in long-term hot and corrosive environments.

Q2: Can 316H be used in sulfur-containing high-temperature environments?
A2: Yes. Molybdenum forms a stable protective layer that inhibits sulfur corrosion, and 316Ti has similar behavior; for stress-bearing parts 316H is usually more cost-effective.

Q3: What welding precautions apply to 316Ti?
A3: Titanium can burn off at high welding temperatures, so use TIG with pure argon shielding, keep the arc dwell time short, and use ER316Ti filler to maintain titanium in the weld metal.

Q4: Which grade is more expensive, 316H or 316Ti?
A4: 316Ti is about 15–20% more expensive than 316H, mainly due to the titanium addition and stricter composition control.

Q5: Which grade should I choose for high-temperature pipelines?
A5: Choose 316H if the line bears high pressure and dynamic load with temperature up to 870°C; choose 316Ti if the line has many welds, runs at 400–900°C for long periods, or demands high intergranular corrosion resistance.