Pipes & Tubes · Tube specification

Round Tube — Tube specification

Round tube — tube ordered by exact OD and wall thickness. Round tube is used for heat exchangers, boilers and instruments, with tighter tolerances than pipe.

Tube specification
22 grades
EN 10204 3.1 / 3.2

Reviewed by the Kanak Steel & Engineering Co. technical team · Updated October 2026

Round Tube: What to Know Before Ordering

OD × wall ordering
Seamless or welded
Straight or U-bent

TYPE · ROUND TUBEDIM · Tube specification22 GRADESKANAK STEEL

Round Tube Materials & Grades

Grade	Material standard	Best for
Inconel 825 round tube	ASTM B163 · B423	Sulphuric and phosphoric acid service, chloride stress-corrosion cracking and sour gas
SS 904L round tube	ASTM B677 · B674	Dilute sulphuric acid, phosphoric acid and chloride-bearing cooling water
SS 304 round tube	ASTM A213 · A269 · A249	General corrosion resistance, food, water and architectural work
SS 304L round tube	ASTM A213 · A269 · A249	Welded tanks, piping and vessels in general corrosive service
SS 310 / 310S round tube	ASTM A213	Furnaces, burners and heat treatment at high temperature
SS 316 / 316L round tube	ASTM A213 · A269 · A249	Chloride-bearing process fluids, marine air and pharmaceutical service
SS 321 round tube	ASTM A213	High-temperature service between 425 and 815 °C
SS 347 round tube	ASTM A213	Welded high-temperature piping in refineries and power plants
Duplex 2205 round tube	ASTM A789	Strength with chloride resistance at a stainless-steel budget
Super Duplex 2507 round tube	ASTM A789	Seawater and high-chloride service where strength also matters
Inconel 600 round tube	ASTM B163 · B167	High-temperature oxidation, caustic and nuclear service
Inconel 625 round tube	ASTM B444 · B704	Seawater, high strength and high temperature in one alloy
Inconel 718 round tube	AMS 5589	Very high strength at temperatures up to about 650 °C
Incoloy 800 / 800H / 800HT round tube	ASTM B163 · B407	Furnaces, petrochemical heaters and high-temperature piping
Hastelloy C276 round tube	ASTM B622 · B626	The most aggressive mixed acids, wet chlorine and hypochlorite
Hastelloy C22 round tube	ASTM B622 · B626	Mixed oxidising and reducing acids, and weld overlays
Monel 400 round tube	ASTM B163 · B165	Seawater, hydrofluoric acid and marine service
Super Duplex S32760 round tube	ASTM A789	Seawater firewater, injection and offshore piping
ASTM A335 P11 round tube	ASTM A335 P11	Steam and hot-oil piping up to about 550 °C
ASTM A335 P22 round tube	ASTM A335 P22	High-pressure steam and hydrogen service up to about 580 °C
S275JR round tube	EN 10219 square & rectangular sections	General structures, frames and fabrication
S355J2+N round tube	EN 10219 square & rectangular sections	Heavy structures, cranes and offshore frames

Other pipes & tubes

Seamless pipePipe made without a weld seam, by piercing and drawing.Welded pipePipe formed from plate or strip and welded along its length.Square tubeSquare hollow section.Rectangular tubeRectangular hollow section.Capillary tubeSmall-bore tube for instruments and medical use.

Round tube — questions buyers ask

What is the difference between tube and pipe?

Tube is specified by exact OD and wall; pipe by nominal size and schedule.

Which grades are round tubes available in?

Inconel 825, SS 904L, SS 304, SS 304L, SS 310 / 310S, SS 316 / 316L, SS 321, SS 347, Duplex 2205, Super Duplex 2507, Inconel 600, Inconel 625, Inconel 718, Incoloy 800 / 800H / 800HT, Hastelloy C276, Hastelloy C22, Monel 400, Super Duplex S32760, ASTM A335 P11, ASTM A335 P22, S275JR, S355J2+N.

Which standard covers round tube dimensions?

Tube specification. The material standard depends on the grade.

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