321 Stainless Steel Tube

321 is an 18-10 stainless steel with added titanium. Because titanium binds the carbon, 321 stays resistant to intergranular corrosion after welding and during long service at roughly 425–850 °C. At room temperature its general corrosion resistance is about the same as that of 304; the difference shows in welded parts that run hot.

If chlorides are present (salt water, seawater, chlorinated chemicals), 316L is the better choice: its molybdenum gives clearly higher resistance to pitting. If the deciding factors are heat and welding (exhausts, expansion joints, furnaces, the hot zone of heat exchangers), 321 is the stronger option.

In air it resists scaling up to about 850 °C in continuous service; some producers quote up to about 900 °C. In sulphur-bearing atmospheres the limit falls to about 750 °C. For pressure-bearing tube at high temperature, creep strength governs, and above roughly 500–550 °C 321H is normally specified. At the low end it keeps its toughness down to −196 °C.

For high pressure, heavy walls, or creep and fatigue risk (boilers, superheaters, refinery lines), seamless tube (EN 10216-5, ASTM A312 / A213) is chosen. For thin-wall, cost-sensitive or large-diameter needs (exhausts, expansion joints, ducting, heat exchangers), welded tube (EN 10217-7, ASTM A312) is usually enough. With 321, the weld seam itself also stays resistant to intergranular corrosion.

Normally not: titanium stabilisation keeps the weld zone resistant to intergranular corrosion. Because titanium does not transfer well across the arc, 347-type (niobium-stabilised) filler wire or electrodes are used. Heat tint and scale are removed afterwards by pickling or with a stainless-steel brush.

Annealed 321 is essentially non-magnetic, although slight magnetism can appear after cold forming. Because of its titanium carbonitride particles it does not polish well to a mirror finish; for decorative use, 304 or 316L is the better choice.

We only need the outside diameter and wall thickness (or nominal size and schedule), whether you need seamless or welded tube, the required standard, the number of lengths or total metres, and the delivery location.

1.4541: X6CrNiTi18-10, AISI 321, UNS S32100, JIS SUS321. Any of these designations can be used in your enquiry; we will match the correct material.

The calculator gives the theoretical weight. The actual weight varies with dimensional tolerances and cutting allowance; we invoice on the actual weight as weighed.