321 Stainless Steel Flanges
Filters
Quick filters
List of products
1.4541 flanges – titanium-stabilized steel
1.4541 (AISI 321), X6CrNiTi18-10, is an austenitic stainless steel similar in composition to 304, with added titanium. Titanium ties up carbon as stable carbides, so no chromium carbides form at the grain boundaries after welding or during long service at approx. 400–800 °C (750–1,470 °F). The steel therefore keeps its resistance to intergranular corrosion in heavier sections and at elevated temperatures. 321 flanges are used in steam, district heating and condensate systems, on heat exchanger connections, in flue gas systems and in chemical and petrochemical piping.
Chemical composition of 1.4541 / 321
| Grade | C | Cr | Ni | Ti |
|---|---|---|---|---|
| 1.4541 / 321 | ≤ 0.08 | 17.0–19.0 | 9.0–12.0 | 5×C – 0.70 |
| 1.4301 / 304 (for comparison) | ≤ 0.07 | 17.5–19.5 | 8.0–10.5 | – |
Values in wt. % per EN 10088. Equivalents: 1.4541 = X6CrNiTi18-10 = AISI 321 = UNS S32100; forgings per ASTM A182 – F321.
Sizes and pressure ratings
We stock 59 sizes of 321 flanges: slip-on plate and weld neck flanges from DN15 to DN300 and blind flanges from DN15 to DN250, for pipe from 21.3 to 323.9 mm OD. Pressure ratings are PN10, PN16 and PN40 per EN 1092-1. Make sure DN and PN match the mating flange – this pair determines the bolt circle and the number and size of bolt holes. At high temperatures, the allowable working pressure is lower than the nominal rating.
Welding and service
321 is welded by TIG or MIG, most often with niobium-stabilized filler (type 347), because titanium transfers poorly across the arc. A weld neck flange with a full-penetration butt weld handles thermal cycling and vibration better than a plate flange. Note that 321 contains no molybdenum – in chloride-bearing water or acidic media, 316L or 316Ti is the better choice.
Matching pipe and fittings
In the same grade we offer 321 / 1.4541 pipe & tube and 321 / 1.4541 elbows. For chloride-bearing media, choose 316L / 1.4404 flanges or 316Ti / 1.4571 flanges. Other types and grades are in the Flanges category.