SUS316Ti Stainless Steel Knowledge

SUS316Ti is a titanium-stabilized variant of SUS316, containing 0.10-0.30% Ti. Titanium binds with carbon, preventing chromium carbide precipitation, enhancing intergranular corrosion resistance at high temps, suitable for long-term high-heat service.

Chemical Composition (wt%): C ≤0.08, Si ≤1.00, Mn ≤2.00, P ≤0.045, S ≤0.030, Cr=16.00-18.00, Ni=10.00-14.00, Mo=2.00-3.00, Ti=0.10-0.30, Fe=Balance

Mechanical Properties: Tensile Strength ≥515MPa, Yield Strength ≥205MPa, Elongation ≥40%, Hardness (HB) ≤217

Performance Advantages: Excellent high-temp intergranular corrosion resistance; superior creep resistance vs SUS316; good chloride corrosion resistance; stable at 400-900°C.

Equivalent Grades: ASTM A240 316Ti, EN 1.4571, UNS S31635

Applications: High-temperature heat exchanger tubes, chemical furnace tubes, boiler superheaters, nuclear power plant components, exhaust systems of high-performance engines.

FAQ

1. Q: How does titanium stabilize SUS316Ti at high temps? A: Titanium (0.10-0.30%) has higher affinity for carbon than chromium, forming TiC instead of Cr₂₃C₆. At 400-900°C, SUS316 forms chromium carbides at grain boundaries, causing intergranular corrosion. SUS316Ti's TiC prevents this, keeping Cr uniformly distributed. This stabilization ensures corrosion resistance in long-term high-temp service (e.g., furnace tubes operating 24/7 at 600°C).

2. Q: How does SUS316Ti compare to SUS316H and SUS316L? A: vs SUS316H: Both have good high-temp strength, but SUS316Ti has better intergranular corrosion resistance without post-weld annealing. vs SUS316L: SUS316Ti has higher high-temp strength and creep resistance, while SUS316L is better for low temps. SUS316Ti is ideal for high-temp welded structures (heat exchangers), balancing strength and corrosion vs the other two.

3. Q: Can SUS316Ti be used in nuclear power plants? A: Yes, it's used in secondary circuit components. Its Ti stabilization resists corrosion from high-temp water/steam, and Mo enhances chloride resistance. It meets nuclear safety standards for low radioactivity absorption. Its creep resistance at 300-400°C ensures component integrity for 30+ years. Unlike SUS316, it avoids intergranular corrosion in long-term high-temp nuclear service.

4. Q: What welding precautions for SUS316Ti? A: Use ER316Ti filler metal to maintain Ti content. Avoid ER316 (no Ti) or ER316L (low Ti), as they reduce high-temp corrosion resistance. Weld with TIG/MIG, control heat input (100-140A) to prevent Ti burnout. No post-weld heat treatment is needed, simplifying fabrication. Clean weld zones to remove oxide scale, which contains Ti and reduces corrosion resistance.

5. Q: What's the maximum operating temperature of SUS316Ti? A: It works continuously at up to 900°C, higher than SUS316 (870°C) and SUS316L (870°C). At 900°C, its TiC remains stable, and the oxide layer resists oxidation. Short-term use can reach 950°C. Above 950°C, TiC dissolves, and strength drops. For temps over 900°C, choose SUS310S. SUS316Ti is cost-effective for 400-900°C high-temp, corrosive environments.