316Ti (1.4571) and 316L (1.4404) are both molybdenum-bearing austenitic grades; the difference is stabilisation and high-temperature behaviour.

Key points:

• Chemistry: 316Ti adds Ti (typically ≥5×C), which ties up carbon as titanium carbides and reduces chromium depletion at grain boundaries; 316L uses extra-low carbon (≤0.03%) to reduce sensitisation risk. • High temperature: 316Ti resists sensitisation and knife-line attack better during long service at 500–800°C, and is common in high-temperature piping and furnace parts. • Ambient and welding: 316L is sufficient for normal welded structures and ambient corrosion, and is more widely available. • Processing: titanium-stabilised grades can slightly affect polishing and forming; evaluate when surface quality is critical.

Guidance:

1) Long-term high temperature (>500°C) or repeated thermal cycles: prefer stabilised grades such as 316Ti/321. 2) Ambient corrosion and general welding: 316L is the common and cost-effective choice. 3) Do not expect 316L to match 316Ti after long high-temperature service.

State the maximum service temperature and thermal cycling conditions on the purchase order to support correct grade selection.