1. What is EN 10297 X6CrNiMoTi17-12-2?
Answer:
EN 10297 X6CrNiMoTi17-12-2 is a stabilized austenitic stainless steel seamless tube under the European standard EN 10297. It is a titanium-stabilized variant of 316Ti (AISI 316Ti), designed to prevent sensitization during welding.
Key Composition: 17% Cr, 12% Ni, 2% Mo, and titanium (Ti) ≥5×C content to bind carbon.
Equivalent Grades: UNS S31635, DIN 1.4571.
Key Feature: Superior intergranular corrosion resistance after welding or high-temperature exposure.
2. What are the mechanical properties?
Answer (annealed condition):
Tensile Strength: 520–720 MPa
Yield Strength (0.2% offset): ≥205 MPa
Elongation: ≥40%
Hardness: ≤215 HB
Note: Ti stabilization reduces carbide precipitation, maintaining ductility in welded structures.
3. How does it differ from non-stabilized grades like X5CrNiMo17-12-2 (316L)?
Answer:
Stabilization: Ti in X6CrNiMoTi17-12-2 prevents chromium carbide formation (sensitization) at 450–850°C, unlike 316L.
Applications: Preferred for welded components in high-temperature environments (e.g., exhaust systems, heat exchangers).
Trade-off: Slightly reduced machinability due to Ti carbides.
4. What are critical fabrication guidelines?
Answer:
Welding: Use matching filler metals (e.g., ER316Ti). No post-weld heat treatment needed for most cases.
Machining: Ti increases tool wear; use sharp carbide tools and lower speeds.
Corrosion Protection: Avoid prolonged exposure to temperatures >850°C to prevent σ-phase embrittlement.
5. Where is this grade typically applied?
Answer:
Automotive: Exhaust manifolds, turbocharger parts (resists thermal cycling).
Chemical Processing: Piping for acidic/chloride-rich media.
Energy: Boiler tubes, superheater components.
Medical: Implantable devices (biocompatible, stable after sterilization).
